Snakebite Dr.Pratheeba Durairaj, M.D.,D.A,. Snake bite: an occupational disease Farmers (rice) Farmers (rice) Plantation workers (rubber, coffee) Plantation.

Snakebite Dr.Pratheeba Durairaj, M.D.,D.A,

Snake bite: an occupational disease Farmers (rice) Farmers (rice) Plantation workers (rubber, coffee) Plantation workers (rubber, coffee) Herdsmen Herdsmen Hunters Hunters Snake handlers (snake charmers and in snake restaurants and traditional Chinese pharmacies) Snake handlers (snake charmers and in snake restaurants and traditional Chinese pharmacies) Fishermen and fish farmers Fishermen and fish farmers Sea snake catchers (for sea snake skins, leather) Sea snake catchers (for sea snake skins, leather)

How common are snake bites? How common are snake bites? Many snake bites and even deaths from snakebite are not recorded. Many snake bites and even deaths from snakebite are not recorded. One reason is that many snake bite victims are treated not in hospitals but by traditional healers. One reason is that many snake bite victims are treated not in hospitals but by traditional healers. India - No reliable national statistics are available. India - No reliable national statistics are available. In 1981, a thousand deaths were reported in Maharashtra State. In the Burdwan district of West Bengal 29,489 people were bitten in one year with 1,301 deaths. In 1981, a thousand deaths were reported in Maharashtra State. In the Burdwan district of West Bengal 29,489 people were bitten in one year with 1,301 deaths. It is estimated that between 35,000 and 50,000 people die of snake bite each year among India’s population of 980 million. It is estimated that between 35,000 and 50,000 people die of snake bite each year among India’s population of 980 million.

In the US: Snakebites frequently go unreported. The national average is approximately 4 bites per 100,000 persons. In the US: Snakebites frequently go unreported. The national average is approximately 4 bites per 100,000 persons. Internationally: No accurate international data exist. Most snakebites and deaths due to snakebites are not reported. Internationally: No accurate international data exist. Most snakebites and deaths due to snakebites are not reported.

Worldwide, only about 15% of the more than 3000 species of snakes are considered dangerous to humans. Worldwide, only about 15% of the more than 3000 species of snakes are considered dangerous to humans. The family Viperidae is the largest family of venomous snakes, and members of this family can be found in Africa, Europe, Asia, and the Americas. The family Viperidae is the largest family of venomous snakes, and members of this family can be found in Africa, Europe, Asia, and the Americas. The family Elapidae is the next largest family of venomous snakes. The family Elapidae is the next largest family of venomous snakes. Classification

Classification There are two important groups (families) of venomous snakes in South East Asia There are two important groups (families) of venomous snakes in South East Asia Elapidae have short permanently erect fangs This family includes the cobras, king cobra, kraits, coral snakes and the sea snakes. Elapidae have short permanently erect fangs This family includes the cobras, king cobra, kraits, coral snakes and the sea snakes. The most important species, from a medical point of view include the following: The most important species, from a medical point of view include the following: Cobras: genus Naja Cobras: genus Naja N naja(spectaled cobra –all over in India ) N naja(spectaled cobra –all over in India ) N kaouthia (monocled – West Bengal,MP,U.P, Orissa) N kaouthia (monocled – West Bengal,MP,U.P, Orissa) N oxiana [Black cobra – northern states - patternless] N oxiana [Black cobra – northern states - patternless] N philippinensis N philippinensis N atra N atra King cobra: Ophiophagus hannah King cobra: Ophiophagus hannah

Spectacled Cobra Post synaptic Neurotoxin Good Response to Neostigmine

Short, permanently erect, fangs of a typical elapid

KRAITS (genus Bungarus) KRAITS (genus Bungarus) B caeruleus common krait [all over India ] B caeruleus common krait [all over India ] - paired white bands & large hexagonal scales in top of the snakes - paired white bands & large hexagonal scales in top of the snakes B fasciatus banded krait [black & yellow band –W.B,M.P,A.P,BIHAR,ORRISSA] B fasciatus banded krait [black & yellow band –W.B,M.P,A.P,BIHAR,ORRISSA] B candidus Malayan krait B candidus Malayan krait B multicinctus Chinese krait B multicinctus Chinese krait Sea snakes (important genera include Enhydrina, Lapemis and Hydrophis) Sea snakes (important genera include Enhydrina, Lapemis and Hydrophis) Blue spotted sea snake (Hydrophis cyanocinctus) Blue spotted sea snake (Hydrophis cyanocinctus)

Common Krait Key identification feature are PAIRED white bands. Often enters human habitation Pre Synaptic Neurotoxin. Limited response to Neostigmine

Viperidae Have long fangs which are normally folded up against the upper jaw but, when the snake strikes, are erected. Have long fangs which are normally folded up against the upper jaw but, when the snake strikes, are erected. There are two subgroups, the typical vipers (Viperinae) and the pit vipers (Crotalinae). There are two subgroups, the typical vipers (Viperinae) and the pit vipers (Crotalinae). The Crotalinae have a special sense organ, the pit organ, to detect their warm-blooded prey. This is situated between the nostril and the eye The Crotalinae have a special sense organ, the pit organ, to detect their warm-blooded prey. This is situated between the nostril and the eye

Russell’s vipers details of fangs

Russell's Viper Haemotoxic venom BUT can also present neurotoxic symptoms Although nocturnal, encountered during the day, sleeping under bushes, trees and leaf particularly coconut leaf litter Key identification feature is the black edged almond or chain shaped marks on the back

Medically important species in South East Asia Medically important species in South East Asia Russell’s vipers -Daboia russelii - [Black edged chain like marking on body &white triangular marking on the head – throughout India] Russell’s vipers -Daboia russelii - [Black edged chain like marking on body &white triangular marking on the head – throughout India] Saw-scaled or carpet vipers - Echis carinatus and E sochureki Saw-scaled or carpet vipers - Echis carinatus and E sochureki [most parts of India except Kerala – Arrow shaped mark in head & hoop like markings in flanks ] [most parts of India except Kerala – Arrow shaped mark in head & hoop like markings in flanks ] Pit vipers Pit vipers calloselasma rhodostoma malayan pit viper calloselasma rhodostoma malayan pit viper Hypnale hypnale hump-nosed viper Hypnale hypnale hump-nosed viper Green pit vipers or bamboo vipers (genus trimeresurus) Green pit vipers or bamboo vipers (genus trimeresurus) T albolabris white-lipped green pit viper T albolabris white-lipped green pit viper T gramineus indian bamboo viper T gramineus indian bamboo viper T mucrosquamatus chinese habu T mucrosquamatus chinese habu T purpureomaculatus mangrove pit viper T purpureomaculatus mangrove pit viper T stejnegeri chinese bamboo viper T stejnegeri chinese bamboo viper

Key Identification Feature- large plate scales on the head. Encountered under bushes and leaf litter or in bushes. Haemotoxic venom. Causes Renal failure Late onset envenoming No effective anti venom PIT VIPER

How to identify venomous snakes Some harmless snakes have evolved to look almost identical to venomous ones. Some harmless snakes have evolved to look almost identical to venomous ones. Some of the most notorious venomous snakes can be recognized by their size, shape, colour, pattern of markings, their behaviour and the sound they make when they feel threatened. Some of the most notorious venomous snakes can be recognized by their size, shape, colour, pattern of markings, their behaviour and the sound they make when they feel threatened. The defensive behaviour of the cobras is well known they rear up, spread a hood, hiss and make repeated strikes towards the aggressor. The defensive behaviour of the cobras is well known they rear up, spread a hood, hiss and make repeated strikes towards the aggressor.

CONTD… Colouring can vary a lot. Some patterns, like the large white, dark rimmed spots of the Russell's viper,or the alternating black and yellow bands of the banded krait are distinctive. Colouring can vary a lot. Some patterns, like the large white, dark rimmed spots of the Russell's viper,or the alternating black and yellow bands of the banded krait are distinctive. The blowing hiss of the Russell's viper and the grating rasp of the saw-scaled viper are warning and identifying sounds. The blowing hiss of the Russell's viper and the grating rasp of the saw-scaled viper are warning and identifying sounds. KRAIT bites : nocturnal, indoor, unprovoked & painless KRAIT bites : nocturnal, indoor, unprovoked & painless COBRA & VIPER bites : painful COBRA & VIPER bites : painful & accompanied by neuroparalysis,coagulopathy & accompanied by neuroparalysis,coagulopathy

The venom apparatus Venomous snakes of medical importance have a pair of enlarged teeth, the fangs, at the front of their upper jaw. Venomous snakes of medical importance have a pair of enlarged teeth, the fangs, at the front of their upper jaw. Venom is produced and stored in paired glands below the eye. It is discharged from hollow fangs located in the upper jaw. Fangs can grow to 20 mm in large rattlesnakes Venom is produced and stored in paired glands below the eye. It is discharged from hollow fangs located in the upper jaw. Fangs can grow to 20 mm in large rattlesnakes These fangs contain a venom channel (like a hypodermic needle) or groove, along which venom can be introduced deep into the tissues of their natural prey. These fangs contain a venom channel (like a hypodermic needle) or groove, along which venom can be introduced deep into the tissues of their natural prey. If a human is bitten, venom is usually injected subcutaneously or intramuscularly. If a human is bitten, venom is usually injected subcutaneously or intramuscularly. Spitting cobras can squeeze the venom out of the tips of their fangs producing a fine spray directed towards the eyes of an aggressor. Spitting cobras can squeeze the venom out of the tips of their fangs producing a fine spray directed towards the eyes of an aggressor.

Venom Venom is mostly water. Venom is mostly water. Enzymatic proteins in venom impart its destructive properties. Enzymatic proteins in venom impart its destructive properties. Proteases, collagenase, and arginine ester hydrolase have been identified in pit viper venom. Proteases, collagenase, and arginine ester hydrolase have been identified in pit viper venom. Neurotoxins comprise the majority of coral snake venom. Neurotoxins comprise the majority of coral snake venom. Hyaluronidase allows rapid spread of venom through subcutaneous tissues by disrupting mucopolysaccharides; Hyaluronidase allows rapid spread of venom through subcutaneous tissues by disrupting mucopolysaccharides; Phospholipase A2 plays a major role in hemolysis secondary to the esterolytic effect on red cell membranes and promotes muscle necrosis Phospholipase A2 plays a major role in hemolysis secondary to the esterolytic effect on red cell membranes and promotes muscle necrosis

Contd… Thrombogenic enzymes promote the formation of a weak fibrin clot, which, in turn, activates plasmin and results in a consumptive coagulopathy and its hemorrhagic consequences. Thrombogenic enzymes promote the formation of a weak fibrin clot, which, in turn, activates plasmin and results in a consumptive coagulopathy and its hemorrhagic consequences. Enzyme concentrations vary among species, thereby causing dissimilar envenomations. Enzyme concentrations vary among species, thereby causing dissimilar envenomations. Copperhead bites generally are limited to local tissue destruction. Copperhead bites generally are limited to local tissue destruction. Rattlesnakes can leave impressive wounds and cause systemic toxicity. Rattlesnakes can leave impressive wounds and cause systemic toxicity. Coral snakes may leave small wounds that later result in respiratory failure from the typical systemic neuromuscular blockade Coral snakes may leave small wounds that later result in respiratory failure from the typical systemic neuromuscular blockade

CONTD… ELAPID neurotoxins act at peripheral neuromuscular junction pre /post synaptically – prevent release of acetylcholine – prevents impulse transmission ELAPID neurotoxins act at peripheral neuromuscular junction pre /post synaptically – prevent release of acetylcholine – prevents impulse transmission VIPER –affect coagulation pathway at several points – Russels viper –activates V,IX,X,XIII factors,platelets, protein C fibrinolysis VIPER –affect coagulation pathway at several points – Russels viper –activates V,IX,X,XIII factors,platelets, protein C fibrinolysis

Quantity of venom injected at a bite Quantity of venom injected at a bite This Venom dosage per bite - is very variable - depends on This Venom dosage per bite - is very variable - depends on the elapsed time since the last bite the elapsed time since the last bite the degree of threat the snake feels the degree of threat the snake feels the size of the prey. the size of the prey. the species and size of the snake the species and size of the snake the mechanical efficiency of the bite the mechanical efficiency of the bite whether one or two fangs penetrated the skin whether one or two fangs penetrated the skin whether there were repeated strikes whether there were repeated strikes The nostril pits respond to the heat emission of the prey, which may enable the snake to vary the amount of venom delivered. The nostril pits respond to the heat emission of the prey, which may enable the snake to vary the amount of venom delivered.

Contd… A proportion of bites by venomous snakes do not result in the injection of sufficient venom to cause clinical effects. A proportion of bites by venomous snakes do not result in the injection of sufficient venom to cause clinical effects. About 50% of bites by malayan pit vipers and russell’s vipers, 30% of bites by cobras and 5-10% of bites by saw-scaled vipers do not result in any symptoms or signs of envenoming. About 50% of bites by malayan pit vipers and russell’s vipers, 30% of bites by cobras and 5-10% of bites by saw-scaled vipers do not result in any symptoms or signs of envenoming. Snakes do not exhaust their store of venom, even after several strikes, and they are no less venomous after eating their prey. Snakes do not exhaust their store of venom, even after several strikes, and they are no less venomous after eating their prey. Although large snakes tend to inject more venom than smaller specimens of the same species, the venom of smaller, younger vipers may be richer in some dangerous components, such as those affecting haemostasis. Although large snakes tend to inject more venom than smaller specimens of the same species, the venom of smaller, younger vipers may be richer in some dangerous components, such as those affecting haemostasis.

Pathophysiology The local effects of venom serve as a reminder of the potential systemic disruption of organ system function. The local effects of venom serve as a reminder of the potential systemic disruption of organ system function. Local bleeding - coagulopathies are not uncommon with severe envenomations. Local bleeding - coagulopathies are not uncommon with severe envenomations. Local edema - increases capillary leak and interstitial fluid in the lungs. Pulmonary mechanics may be altered Local edema - increases capillary leak and interstitial fluid in the lungs. Pulmonary mechanics may be altered Local cell death - increases lactic acid concentration secondary to changes in volume status and requires increased minute ventilation. Local cell death - increases lactic acid concentration secondary to changes in volume status and requires increased minute ventilation. The effects of neuromuscular blockade result in poor diaphragmatic excursion. The effects of neuromuscular blockade result in poor diaphragmatic excursion. Cardiac failure can result from hypotension and acidosis. Cardiac failure can result from hypotension and acidosis. Myonecrosis raises concerns about myoglobinuria and renal damage. Myonecrosis raises concerns about myoglobinuria and renal damage.

Symptoms and signs When venom has not been injected Some people who are bitten by snakes or suspect or imagine that they have been bitten, may develop quite striking symptoms and signs, even when no venom has been injected. This results from an understandable fear of the consequences of a real venomous bite. Some people who are bitten by snakes or suspect or imagine that they have been bitten, may develop quite striking symptoms and signs, even when no venom has been injected. This results from an understandable fear of the consequences of a real venomous bite. Anxious people may overbreathe so that they develop pins and needles of the extremities, stiffness tetany of their hands and feet and dizziness. Anxious people may overbreathe so that they develop pins and needles of the extremities, stiffness tetany of their hands and feet and dizziness. Others may develop vasovagal shock after the bite or suspected bite - faintness and collapse with profound slowing of the heart. Others may develop vasovagal shock after the bite or suspected bite - faintness and collapse with profound slowing of the heart. Others may become highly agitated and irrational and may develop a wide range of misleading symptoms. Others may become highly agitated and irrational and may develop a wide range of misleading symptoms.

Contd… Another source of symptoms and signs not caused by snake venom is first aid and traditional treatments. Another source of symptoms and signs not caused by snake venom is first aid and traditional treatments. Constricting bands or tourniquets may cause pain, swelling and congestion. Constricting bands or tourniquets may cause pain, swelling and congestion. Ingested herbal remedies may cause vomiting. Ingested herbal remedies may cause vomiting. Instillation of irritant plant juices into the eyes may cause conjunctivitis. Instillation of irritant plant juices into the eyes may cause conjunctivitis. Forcible insufflations of oils into the respiratory tract may lead to aspiration pneumonia, bronchospasm, ruptured ear drums and pneumothorax. Forcible insufflations of oils into the respiratory tract may lead to aspiration pneumonia, bronchospasm, ruptured ear drums and pneumothorax. Incisions, cauterization, immersion in scalding liquid and heating over a fire can result in devastating injuries. Incisions, cauterization, immersion in scalding liquid and heating over a fire can result in devastating injuries.

When venom has been injected! Early symptoms and signs Early symptoms and signs Following the immediate pain of mechanical penetration of the skin by the snake’s fangs, there may be increasing local pain (burning, bursting, throbbing) at the site of the bite Following the immediate pain of mechanical penetration of the skin by the snake’s fangs, there may be increasing local pain (burning, bursting, throbbing) at the site of the bite Local swelling that gradually extends proximally up the bitten limb Local swelling that gradually extends proximally up the bitten limb Tender, painful enlargement of the regional lymph nodes draining the site of the bite Tender, painful enlargement of the regional lymph nodes draining the site of the bite Bites by kraits, sea snakes and Philippine cobras may be virtually painless and may cause negligible local swelling. Bites by kraits, sea snakes and Philippine cobras may be virtually painless and may cause negligible local swelling. Symptoms and signs vary according to the species of snake responsible for the bite and the amount of venom injected Symptoms and signs vary according to the species of snake responsible for the bite and the amount of venom injected

Signs/Symptoms and Potential Treatments Cobra Krait Russell Viper Saw Scaled Viper Other Vipers Local Tissue Damage/pain YESNOYESYESYES Ptosis/NeurotoxicityYESYESYESNONO CoagulationNONOYESYESYES Renal Problems NONOYESNOYES Neostigmine & Atropine YESNO?NO?NONO

Local symptoms and signs Fang marks Fang marks Local pain Local pain Local bleeding Local bleeding Bruising Bruising Lymphangitis Lymphangitis Lymph node enlargement Lymph node enlargement Inflammation (swelling, redness, heat) Inflammation (swelling, redness, heat) Blistering Blistering Local infection, abscess formation Local infection, abscess formation Necrosis Necrosis

Generalised Symptoms and Signs General General Nausea, vomiting, malaise, abdominal pain, weakness, drowsiness, prostration Nausea, vomiting, malaise, abdominal pain, weakness, drowsiness, prostration Cardiovascular (Viperidae) Cardiovascular (Viperidae) Visual disturbances, dizziness, faintness, collapse, shock, hypotension, cardiac arrhythmias, Visual disturbances, dizziness, faintness, collapse, shock, hypotension, cardiac arrhythmias, pulmonary oedema, conjunctiva oedema pulmonary oedema, conjunctiva oedema

Snake bite: causes of hypotension and shock Anaphylaxis - Vasodilatation Anaphylaxis - Vasodilatation Cardiotoxicity Cardiotoxicity Hypovolaemia Hypovolaemia Antivenom reaction Antivenom reaction Respiratory failure Respiratory failure Acute pituitary adrenal insufficiency[In victims of Russell’s viper bites- haemorrhagic infarction of the anterior pituitary ] Acute pituitary adrenal insufficiency[In victims of Russell’s viper bites- haemorrhagic infarction of the anterior pituitary ] Septicaemia Septicaemia

Bleeding and clotting disorders (Viperidae) Bleeding from recent wounds (including fang marks,venepunctures etc) and old partly-healed wounds Bleeding from recent wounds (including fang marks,venepunctures etc) and old partly-healed wounds Spontaneous systemic bleeding – from gums, epistaxis Spontaneous systemic bleeding – from gums, epistaxis Bleeding into the tears Bleeding into the tears Haemoptysis, haematemesis, rectal bleeding or melaena, Haematuria, vaginal bleeding Haemoptysis, haematemesis, rectal bleeding or melaena, Haematuria, vaginal bleeding Bleeding into the skin and mucosae (petechiae,purpura,ecchymoses) Bleeding into the skin and mucosae (petechiae,purpura,ecchymoses) Intracranial haemorrhage Intracranial haemorrhage CONTD…

Renal (Viperidae, sea snakes) Renal (Viperidae, sea snakes) Loin pain, haematuria, haemoglobinuria myoglobinuria, oliguria/anuria Loin pain, haematuria, haemoglobinuria myoglobinuria, oliguria/anuria Symptoms and signs of uraemia Symptoms and signs of uraemia Endocrine (acute pituitary/adrenal insufficiency) (Russell’s viper) Endocrine (acute pituitary/adrenal insufficiency) (Russell’s viper) Acute phase: shock, hypoglycaemia Acute phase: shock, hypoglycaemia Chronic phase (months to years after the bite) Chronic phase (months to years after the bite) loss of secondary sexual hair, amenorrhoea, testicular atrophy, hypothyroidism etc loss of secondary sexual hair, amenorrhoea, testicular atrophy, hypothyroidism etc CONTD…

CONTD… Neurological (elapidae, russell’s viper) Drowsiness Drowsiness Paraesthesiae Paraesthesiae Abnormalities of taste and smell Abnormalities of taste and smell “Heavy” eyelids, ptosis “Heavy” eyelids, ptosis External ophthalmoplegia External ophthalmoplegia Paralysis of facial muscles and other muscles innervated by the cranial nerves Paralysis of facial muscles and other muscles innervated by the cranial nerves Aphonia Aphonia Difficulty in swallowing secretions Difficulty in swallowing secretions Respiratory and generalised flaccid paralysis Respiratory and generalised flaccid paralysis Skeletal muscle breakdown (sea snakes, russell’s viper) Skeletal muscle breakdown (sea snakes, russell’s viper) Generalised pain Generalised pain Stiffness and Tenderness of Muscles, Trismus Stiffness and Tenderness of Muscles, Trismus Myoglobinuria Myoglobinuria Hyperkalaemia Hyperkalaemia Cardiac arrest Cardiac arrest Acute renal failure Acute renal failure

Complications Compartment syndrome is the most frequent complication of pit viper snakebites. Compartment syndrome is the most frequent complication of pit viper snakebites. Local wound complications may include infection and skin loss. Local wound complications may include infection and skin loss. Cardiovascular complications, hematologic complications, and pulmonary collapse may occur. Cardiovascular complications, hematologic complications, and pulmonary collapse may occur. Prolonged neuromuscular blockade may occur from coral snake envenomations. Prolonged neuromuscular blockade may occur from coral snake envenomations.

Antivenin-associated complications Immediate (anaphylaxis, type I) Immediate (anaphylaxis, type I) Result in laryngospasm, vasodilatation, and leaky capillaries - death Result in laryngospasm, vasodilatation, and leaky capillaries - death Delayed (serum sickness, type iii hypersensitivity reactions) Delayed (serum sickness, type iii hypersensitivity reactions) Serum sickness occurs 1-2 weeks after administering antivenin - arthralgias, urticaria, and glomerulonephritis Serum sickness occurs 1-2 weeks after administering antivenin - arthralgias, urticaria, and glomerulonephritis Usually more than 8 vials of antivenin must be given to produce this syndrome.Usually more than 8 vials of antivenin must be given to produce this syndrome. Supportive care consists of antihistamines and steroids.Supportive care consists of antihistamines and steroids.

Long term complications (sequelae) of snake bite At the site of the bite, loss of tissue may result from sloughing or surgical debridement of necrotic areas or amputation At the site of the bite, loss of tissue may result from sloughing or surgical debridement of necrotic areas or amputation Chronic ulceration, infection, Chronic ulceration, infection, Osteomyelitis or arthritis may persist causing severe physical disability Osteomyelitis or arthritis may persist causing severe physical disability Malignant transformation may occur in skin ulcers after a number of years Malignant transformation may occur in skin ulcers after a number of years

Syndromic Approach It is realised that the range of activities of a particular venom is very wide. For example, some elapid venoms, such as those of Asian cobras, can cause severe local envenoming, formerly thought to be an effect only of viper venoms. It is realised that the range of activities of a particular venom is very wide. For example, some elapid venoms, such as those of Asian cobras, can cause severe local envenoming, formerly thought to be an effect only of viper venoms. In Sri Lanka and South India, Russell’s viper venom causes paralytic signs (ptosis etc) suggesting elapid neurotoxicity, and muscle pains and dark brown urine suggesting sea snake rhabdomyolysis. In Sri Lanka and South India, Russell’s viper venom causes paralytic signs (ptosis etc) suggesting elapid neurotoxicity, and muscle pains and dark brown urine suggesting sea snake rhabdomyolysis. There may be considerable overlap of clinical features caused by venoms of different species There may be considerable overlap of clinical features caused by venoms of different species “Syndromic approach” may still be useful, especially when the snake has not been identified and only monospecific antivenoms are available “Syndromic approach” may still be useful, especially when the snake has not been identified and only monospecific antivenoms are available

SYNDROME 1 SYNDROME 1 Local envenoming (swelling etc) with bleeding/clotting disturbances = Viperidae (all species) Local envenoming (swelling etc) with bleeding/clotting disturbances = Viperidae (all species) SYNDROME 2 SYNDROME 2 Local envenoming (swelling etc) with bleeding/clotting disturbances, Local envenoming (swelling etc) with bleeding/clotting disturbances, shock or renal failure shock or renal failure = Russell’s viper and possibly saw-scaled viper - Echis species - in some areas) = Russell’s viper and possibly saw-scaled viper - Echis species - in some areas) with conjunctival oedema (chemosis) and acute pituitary insufficiency = Russell’s viper, Burma with conjunctival oedema (chemosis) and acute pituitary insufficiency = Russell’s viper, Burma with ptosis, external ophthalmoplegia, facial paralysis etc and dark & brown urine with ptosis, external ophthalmoplegia, facial paralysis etc and dark & brown urine = Russell’s viper, Sri Lanka and South India = Russell’s viper, Sri Lanka and South India SYNDROME 3 SYNDROME 3 Local envenoming (swelling etc) with paralysis Local envenoming (swelling etc) with paralysis = cobra or king cobra = cobra or king cobra

SYNDROME 4 SYNDROME 4 Paralysis with minimal or no local envenoming Paralysis with minimal or no local envenoming Bite on land while sleeping, outside the Philippines = krait Bite on land while sleeping, outside the Philippines = krait in the Philippines = cobra(Naja philippinensis) in the Philippines = cobra(Naja philippinensis) Bite in the sea = sea snake Bite in the sea = sea snake SYNDROME 5 SYNDROME 5 Paralysis with dark brown urine and renal failure Paralysis with dark brown urine and renal failure Bite on land (with bleeding/clotting disturbance) = Russell’s viper, SriLanka/South India Bite on land (with bleeding/clotting disturbance) = Russell’s viper, SriLanka/South India Bite in the sea (no bleeding/clotting disturbances) = sea snake Bite in the sea (no bleeding/clotting disturbances) = sea snake Chronic renal failure occurs after bilateral cortical necrosis (Russell’s viper bites) and chronic panhypopituitarism or diabetes insipidus after Russell’s viper bites in Myanmar and South India Chronic renal failure occurs after bilateral cortical necrosis (Russell’s viper bites) and chronic panhypopituitarism or diabetes insipidus after Russell’s viper bites in Myanmar and South India

Management of snake bite First aid treatment First aid treatment Transport to hospital Transport to hospital Rapid clinical assessment and resuscitation Rapid clinical assessment and resuscitation Detailed clinical assessment and species diagnosis Detailed clinical assessment and species diagnosis Investigations/laboratory tests Investigations/laboratory tests Antivenom treatment Antivenom treatment Observation of the response to antivenom:decision about the need for further dose(s) of antivenom Observation of the response to antivenom:decision about the need for further dose(s) of antivenom Supportive/ancillary treatment Supportive/ancillary treatment Treatment of the bitten part Treatment of the bitten part Rehabilitation Rehabilitation Treatment of chronic complications Treatment of chronic complications

Aims of first aid Attempt to retard systemic absorption of venom Attempt to retard systemic absorption of venom Preserve life and prevent complications before the patient can receive medical care(at a dispensary or hospital) Preserve life and prevent complications before the patient can receive medical care(at a dispensary or hospital) Control distressing or dangerous early symptoms of envenoming Control distressing or dangerous early symptoms of envenoming Arrange the transport of the patient to a place where they can receive medical care Arrange the transport of the patient to a place where they can receive medical care ABOVE ALL, DO NO HARM ! ABOVE ALL, DO NO HARM !

FIRST AID –CONTD … Unfortunately, most of the traditional, popular, available and affordable first aid methods have proved to be useless or even frankly dangerous. Unfortunately, most of the traditional, popular, available and affordable first aid methods have proved to be useless or even frankly dangerous. Making local incisions or pricks/punctures (“tattooing”) at the site of the bite or in the bitten limb Making local incisions or pricks/punctures (“tattooing”) at the site of the bite or in the bitten limb Attempts to suck the venom out of the wound Attempts to suck the venom out of the wound Use of (black) snake stones Use of (black) snake stones Tying tight bands [tourniquets) around the limb Tying tight bands [tourniquets) around the limb Electric shock Electric shock Topical application of chemicals,herbs or ice packs. Topical application of chemicals,herbs or ice packs.

Tight (arterial) tourniquets are not recommended! To be effective, these had to be applied around the upper part of the limb, so tightly that the peripheral pulse was occluded. To be effective, these had to be applied around the upper part of the limb, so tightly that the peripheral pulse was occluded. This method was extremely painful and very dangerous if the tourniquet was left on for too long (more than about 40 minutes), as the limb might be damaged by ischaemia- gangrenous limbs This method was extremely painful and very dangerous if the tourniquet was left on for too long (more than about 40 minutes), as the limb might be damaged by ischaemia- gangrenous limbs Pressure immobilisation is recommended for bites by neurotoxic elapid snakes, including sea snakes but should not be used for viper bites because of the danger of increasing the local effects of the necrotic venom. Pressure immobilisation is recommended for bites by neurotoxic elapid snakes, including sea snakes but should not be used for viper bites because of the danger of increasing the local effects of the necrotic venom.

Tight (arterial) tourniquets are not recommended- WHY? Confining this toxin in a smaller area, by use of compression techniques creates a greater risk of serious local damage. Confining this toxin in a smaller area, by use of compression techniques creates a greater risk of serious local damage. When the tourniquet is removed there is the problem of the venom rapidly entering the system and causing respiratory failure in the case of neurotoxic bites When the tourniquet is removed there is the problem of the venom rapidly entering the system and causing respiratory failure in the case of neurotoxic bites The Viper’s venom contains pro-coagulant enzymes which cause the blood to clot. In the small space below the tourniquet the venom has a greater chance of causing a clot. When the tourniquet is released the clot will rapidly enter the body and can cause embolism and death. The Viper’s venom contains pro-coagulant enzymes which cause the blood to clot. In the small space below the tourniquet the venom has a greater chance of causing a clot. When the tourniquet is released the clot will rapidly enter the body and can cause embolism and death. Lastly, there has been a great deal of research showing that tourniquets DO NOT stop venom from entering the body Lastly, there has been a great deal of research showing that tourniquets DO NOT stop venom from entering the body

Recommended first aid methods Reassure the victim who may be very anxious Reassure the victim who may be very anxious Immobilise the bitten limb with a splint or sling (any movement or muscular contraction increases absorption of venom into the bloodstream and lymphatics) Immobilise the bitten limb with a splint or sling (any movement or muscular contraction increases absorption of venom into the bloodstream and lymphatics) Consider pressure-immobilisation for some elapid bites Consider pressure-immobilisation for some elapid bites Avoid any interference with the bite wound as this may introduce infection,increase absorption of the venom and increase local bleeding Avoid any interference with the bite wound as this may introduce infection,increase absorption of the venom and increase local bleeding

Pressure immobilisation method An elasticated, stretchy, crepe Bandage,approximately 10 cm wide and at least 4.5 metres long should be used. An elasticated, stretchy, crepe Bandage,approximately 10 cm wide and at least 4.5 metres long should be used. If that it not available, any long strips of material can be used. If that it not available, any long strips of material can be used. The bandage is bound firmly around the entire bitten limb, starting distally around the fingers or toes and moving proximally, to include a rigid splint. The bandage is bound firmly around the entire bitten limb, starting distally around the fingers or toes and moving proximally, to include a rigid splint. The bandage is bound as tightly as for a sprained ankle, but not so tightly that the peripheral pulse (radial, posterior tibial, dorsalis pedis) is occluded or that a finger cannot easily be slipped between its layers The bandage is bound as tightly as for a sprained ankle, but not so tightly that the peripheral pulse (radial, posterior tibial, dorsalis pedis) is occluded or that a finger cannot easily be slipped between its layers

Rapid clinical assessment and resuscitation Airway, respiratory movements (Breathing) and arterial pulse (Circulation) must be checked immediately. Airway, respiratory movements (Breathing) and arterial pulse (Circulation) must be checked immediately. The level of consciousness must be assessed. The level of consciousness must be assessed. Urgent Resuscitation is needed in Urgent Resuscitation is needed in a) Profound hypotension and shock resulting from direct cardiovascular effects of the venom or secondary effects such as hypovolaemia or hemorrhagic shock. a) Profound hypotension and shock resulting from direct cardiovascular effects of the venom or secondary effects such as hypovolaemia or hemorrhagic shock. b) Terminal respiratory failure from progressive neurotoxic envenoming that has led to paralysis of the respiratory muscles. b) Terminal respiratory failure from progressive neurotoxic envenoming that has led to paralysis of the respiratory muscles. c) Sudden deterioration or rapid development of severe systemic envenoming following the release of a tight tourniquet or compression bandage c) Sudden deterioration or rapid development of severe systemic envenoming following the release of a tight tourniquet or compression bandage d) Cardiac arrest precipitated by hyperkalaemia resulting from skeletal muscle breakdown (rhabdomyolysis) after sea snake bite. d) Cardiac arrest precipitated by hyperkalaemia resulting from skeletal muscle breakdown (rhabdomyolysis) after sea snake bite.

History Obtain a description of the snake or capture it, if possible, to determine its color, pattern, or the existence of a rattle. Obtain a description of the snake or capture it, if possible, to determine its color, pattern, or the existence of a rattle. Most snakes remain within 20 feet after biting. Most snakes remain within 20 feet after biting. Assess the timing of events and onset of symptoms. Inquire about the time the bite occurred and details about the onset of pain. Early and intense pain implies significant envenomation. Assess the timing of events and onset of symptoms. Inquire about the time the bite occurred and details about the onset of pain. Early and intense pain implies significant envenomation. Local swelling, pain, and paresthesias may be present. Local swelling, pain, and paresthesias may be present. Systemic symptoms include nausea, syncope, and difficulty swallowing or breathing. Systemic symptoms include nausea, syncope, and difficulty swallowing or breathing. Determine history of prior exposure to antivenin or snakebite. Determine history of prior exposure to antivenin or snakebite. history of allergies to medicines history of allergies to medicines history of co morbid conditions or medications (eg, aspirin, anticoagulants such as warfarin or GPIIb/IIIa inhibitors, beta-blockers). history of co morbid conditions or medications (eg, aspirin, anticoagulants such as warfarin or GPIIb/IIIa inhibitors, beta-blockers).

Physical Examination Vital signs, airway, breathing, circulation Vital signs, airway, breathing, circulation Fang marks or scratches (determine coral snake bite pattern by expressing blood from the suspected wound) Fang marks or scratches (determine coral snake bite pattern by expressing blood from the suspected wound) Local tissue destruction Local tissue destruction Soft pitting edema that generally develops over 6-12 hours but may start within 5 minutesSoft pitting edema that generally develops over 6-12 hours but may start within 5 minutes BullaeBullae StreakingStreaking Erythema or discolorationErythema or discoloration ContusionsContusions Systemic toxicity Systemic toxicity HypotensionHypotension Petechiae, epistaxis, hemoptysisPetechiae, epistaxis, hemoptysis Paresthesias and dysthesias - Forewarn neuromuscular blockade and respiratory distress (more common with coral snakes)Paresthesias and dysthesias - Forewarn neuromuscular blockade and respiratory distress (more common with coral snakes)

Early clues that a patient has severe envenoming Snake identified as a very dangerous one Snake identified as a very dangerous one Rapid early extension of local swelling from the site of the bite Rapid early extension of local swelling from the site of the bite Tender enlargement of local lymph nodes, indicating spread of venom in the lymphatic system Tender enlargement of local lymph nodes, indicating spread of venom in the lymphatic system Systemic symptoms: collapse (hypotension, shock) Systemic symptoms: collapse (hypotension, shock) nausea, vomiting,diarrhoea nausea, vomiting,diarrhoea severe headache severe headache “heaviness” of the eyelids “heaviness” of the eyelids inappropriate drowsiness inappropriate drowsiness early ptosis/ophthalmoplegia early ptosis/ophthalmoplegia Early spontaneous systemic bleeding Early spontaneous systemic bleeding Passage of dark brown urine Passage of dark brown urine

Lab Studies CBC with manual differential and peripheral blood smear CBC with manual differential and peripheral blood smear Prothrombin time and activated partial thromboplastin time, international normalized ratio (INR). Prothrombin time and activated partial thromboplastin time, international normalized ratio (INR). Fibrinogen and split products Fibrinogen and split products Type and cross Type and cross Blood chemistries - electrolytes, BUN, creatinine Blood chemistries - electrolytes, BUN, creatinine Urinalysis for myoglobinuria Urinalysis for myoglobinuria Arterial blood gas determinations for patients with systemic symptoms Arterial blood gas determinations for patients with systemic symptoms

CONTD… Imaging Studies: Imaging Studies: Baseline chest radiograph in patients with pulmonary edema Baseline chest radiograph in patients with pulmonary edema Plain radiograph to rule out retained fang Plain radiograph to rule out retained fang Other Tests: Compartmental pressures may need to be measured. Other Tests: Compartmental pressures may need to be measured. Measurement of compartmental pressures is indicated when significant swelling is present, pain is out of proportion to exam, and if paresthesias are present in the affected limb. Measurement of compartmental pressures is indicated when significant swelling is present, pain is out of proportion to exam, and if paresthesias are present in the affected limb.

20 minute whole blood clotting test (20WBCT) This very useful and informative bedside test requires very little skill and only one piece of apparatus - a new, clean, dry, glass vessel (tube or bottle). This very useful and informative bedside test requires very little skill and only one piece of apparatus - a new, clean, dry, glass vessel (tube or bottle). Place a few ml of freshly sampled venous blood in a small glass vessel Place a few ml of freshly sampled venous blood in a small glass vessel Leave undisturbed for 20 minutes at ambient temperature Leave undisturbed for 20 minutes at ambient temperature Tip the vessel once Tip the vessel once If the blood is still liquid (unclotted) and runs out, the patient has hypofibrinogenaemia (“incoagulable blood”) as a result of venom-induced consumption coagulopathy If the blood is still liquid (unclotted) and runs out, the patient has hypofibrinogenaemia (“incoagulable blood”) as a result of venom-induced consumption coagulopathy In the South East Asian region, incoagulable blood is diagnostic of a viper bite and rules out an elapid bite In the South East Asian region, incoagulable blood is diagnostic of a viper bite and rules out an elapid bite Warning! If the vessel used for the test is not made of ordinary glass, or if it has been used before and cleaned with detergent, its wall may not stimulate Warning! If the vessel used for the test is not made of ordinary glass, or if it has been used before and cleaned with detergent, its wall may not stimulate clotting of the blood sample in the usual way and test will be invalid Every 30 minutes for the first 4hours *hourly after that Every 30 minutes for the first 4hours *hourly after that

Haemoglobin concentration/haematocrit: Haemoglobin concentration/haematocrit: a transient increase indicates haemoconcentration resulting from a generalised increase in capillary permeability - in Russell’s viper bite a transient increase indicates haemoconcentration resulting from a generalised increase in capillary permeability - in Russell’s viper bite a decrease reflecting blood loss or intravascular haemolysis - Indian and Sri Lankan Russell’s viper bite a decrease reflecting blood loss or intravascular haemolysis - Indian and Sri Lankan Russell’s viper bite Platelet count: decreased in victims of viper bites. Platelet count: decreased in victims of viper bites. White blood cell count: an early neutrophil leucocytosis is evidence of systemic envenoming from any species. White blood cell count: an early neutrophil leucocytosis is evidence of systemic envenoming from any species. Blood film: fragmented red cells (“helmet cell”, schistocytes) are seen when there is microangiopathic haemolysis. Blood film: fragmented red cells (“helmet cell”, schistocytes) are seen when there is microangiopathic haemolysis. Plasma/serum may be pinkish or brownish if there is gross haemoglobinaemia or myoglobinaemia. Plasma/serum may be pinkish or brownish if there is gross haemoglobinaemia or myoglobinaemia.

Biochemical abnormalities Elevated Aminotransferases and muscle enzymes (creatine kinase, aldolase etc) in severe local damage or generalized muscle damage (Srilankan and South Indian Russell's viper bites, sea snakebites). Elevated Aminotransferases and muscle enzymes (creatine kinase, aldolase etc) in severe local damage or generalized muscle damage (Srilankan and South Indian Russell's viper bites, sea snakebites). Slight increases in other serum enzymes - Mild hepatic dysfunction Slight increases in other serum enzymes - Mild hepatic dysfunction Elevated Bilirubin - in massive extravasation of blood. Elevated Bilirubin - in massive extravasation of blood. Creatinine, urea or blood urea nitrogen levels - raised in the renal failure of russell’s viper and saw-scaled viper bites and sea snake bites. Creatinine, urea or blood urea nitrogen levels - raised in the renal failure of russell’s viper and saw-scaled viper bites and sea snake bites. Early hyperkalaemia - in extensive rhabdomyolysis in sea snake bites. Early hyperkalaemia - in extensive rhabdomyolysis in sea snake bites. Bicarbonate will be low in renalfailure Bicarbonate will be low in renalfailure

Arterial blood gases and pH may show evidence of respiratory failure (neurotoxic envenoming) and acidaemia Arterial blood gases and pH may show evidence of respiratory failure (neurotoxic envenoming) and acidaemia Desaturation: patients with respiratory failure or shock using a finger oximeter. Desaturation: patients with respiratory failure or shock using a finger oximeter. Urine examination: the urine should be tested by dipsticks for blood/haemoglobin/myoglobin. Haemoglobin and myoglobin can be separated by immunoassays but there is no easy or reliable test. Microscopy will confirm whether there are erythrocytes in the urine. Urine examination: the urine should be tested by dipsticks for blood/haemoglobin/myoglobin. Haemoglobin and myoglobin can be separated by immunoassays but there is no easy or reliable test. Microscopy will confirm whether there are erythrocytes in the urine. Red cell casts indicate glomerular bleeding. Massive proteinuria is an early sign of the generalised increase in capillary permeability Red cell casts indicate glomerular bleeding. Massive proteinuria is an early sign of the generalised increase in capillary permeability

GRADES- MILD, MODERATE, OR SEVERE Mild envenomation - local pain, edema, no signs of systemic toxicity and normal lab values. Moderate envenomation - severe local pain edema larger than 12 inches surrounding the wound edema larger than 12 inches surrounding the wound systemic toxicity including nausea, vomiting systemic toxicity including nausea, vomiting alterations in lab values (fallen hematocrit or platelet values). alterations in lab values (fallen hematocrit or platelet values). Severe envenomation generalized petechiae, ecchymosisgeneralized petechiae, ecchymosis blood-tinged sputumblood-tinged sputum hypotension, hypoperfusion hypotension, hypoperfusion renal dysfunction renal dysfunction changes in prothrombin time and activated partial thromboplastin time, and other abnormal tests defining consumptive coagulopathy.changes in prothrombin time and activated partial thromboplastin time, and other abnormal tests defining consumptive coagulopathy. Grading envenomations is a dynamic process. Over several hours, an initially mild syndrome may progress to a moderate or even severe reaction. Grading envenomations is a dynamic process. Over several hours, an initially mild syndrome may progress to a moderate or even severe reaction.

Medical Care Treatment is based on the severity of envenomation; it is divided into field care and hospital management. Treatment is based on the severity of envenomation; it is divided into field care and hospital management. Field care Field care Reassure the patient to preclude hysteria during the implementation of ABCs.Reassure the patient to preclude hysteria during the implementation of ABCs. Monitor vital signs and establish at least 1 large bore intravenous and crystalloid infusion.Monitor vital signs and establish at least 1 large bore intravenous and crystalloid infusion. Administer oxygen therapy.Administer oxygen therapy. Restrict activity and immobilize the affected area (commonly an extremity); keep walking to a minimum.Restrict activity and immobilize the affected area (commonly an extremity); keep walking to a minimum. Negative-pressure suctioning devices offer some benefit if used within several minutes of envenomation. Do not make an incision in the field.Negative-pressure suctioning devices offer some benefit if used within several minutes of envenomation. Do not make an incision in the field. Immediately transfer to definitive care.Immediately transfer to definitive care. Do not give antivenin in the field.Do not give antivenin in the field.

CONTD… Hospital care Hospital care Physicians who have little experience treating snakebites frequently see patients.Physicians who have little experience treating snakebites frequently see patients. Regional centers often have more experience in the care of snakebite victims. Surgical evaluation for envenomation is paramount.Regional centers often have more experience in the care of snakebite victims. Surgical evaluation for envenomation is paramount. Definitive treatment includes reviewing the ABCs and evaluating the patient for signs of shock (eg, tachypnea, tachycardia, dry pale skin, mental status changes, hypotension).Definitive treatment includes reviewing the ABCs and evaluating the patient for signs of shock (eg, tachypnea, tachycardia, dry pale skin, mental status changes, hypotension).

Surgical Care Surgical assessment follows the injury site and assess for the development of compartment syndrome. Surgical assessment follows the injury site and assess for the development of compartment syndrome. Fasciotomy is not indicated in every bite, only for those patients with objective evidence of elevated compartment pressures.Fasciotomy is not indicated in every bite, only for those patients with objective evidence of elevated compartment pressures. Liberal use of the Stryker pressure monitor is warranted. Tissue injury after compartment syndrome is not reversible but is preventableLiberal use of the Stryker pressure monitor is warranted. Tissue injury after compartment syndrome is not reversible but is preventable Make serial evaluations for further grading and to rule out compartment syndrome. Depending on clinical scenarios, measure compartment pressures every 30-120 minutes. Fasciotomy is indicated for pressures greater than 30-40 mm Hg. Make serial evaluations for further grading and to rule out compartment syndrome. Depending on clinical scenarios, measure compartment pressures every 30-120 minutes. Fasciotomy is indicated for pressures greater than 30-40 mm Hg.

Compartmental syndromes and fasciotomy Compartmental syndromes and fasciotomy Clinical features Disproportionately severe pain Disproportionately severe pain Weakness of intracompartmental muscles Weakness of intracompartmental muscles Pain on passive stretching of intracompartmental muscles Pain on passive stretching of intracompartmental muscles Hypoaesthesia of areas of skin supplied by nerves running through the compartment Hypoaesthesia of areas of skin supplied by nerves running through the compartment Obvious tenseness of the compartment on palpation Obvious tenseness of the compartment on palpation

CONTD… The most reliable test is to measure intracompartmental pressure directly through a cannula introduced into the compartment and connected to a pressure transducer or manometer The most reliable test is to measure intracompartmental pressure directly through a cannula introduced into the compartment and connected to a pressure transducer or manometer Intracompartmental pressures exceeding 40 mmHg (less in children) may carry a risk of ischaemic necrosis Intracompartmental pressures exceeding 40 mmHg (less in children) may carry a risk of ischaemic necrosis Early treatment with antivenom remains the best way of preventing irreversible muscle damage Early treatment with antivenom remains the best way of preventing irreversible muscle damage Criteria for fasciotomy in snake-bitten limbs Criteria for fasciotomy in snake-bitten limbs Haemostatic abnormalities have been corrected Haemostatic abnormalities have been corrected Clinical evidence of an intracompartmental syndrome Clinical evidence of an intracompartmental syndrome Intracompartmental pressure >40 mmHg (in adults) Intracompartmental pressure >40 mmHg (in adults)

Pharmacotherapy The goals of pharmacotherapy are to neutralize the toxin, to reduce morbidity and to prevent complications The goals of pharmacotherapy are to neutralize the toxin, to reduce morbidity and to prevent complications Antibiotics Antibiotics Immunizations -- Snakes do not harbor Clostridium tetani in their mouths, but bites may carry other bacteria, especially gram-negative species. Immunizations -- Snakes do not harbor Clostridium tetani in their mouths, but bites may carry other bacteria, especially gram-negative species. Tetanus prophylaxis recommended if patient not immunized. Tetanus prophylaxis recommended if patient not immunized. Antivenin Antivenin

What is antivenom? Antivenom is immunoglobulin (usually the enzyme refined F(ab)2 fragment of IgG] purified from the serum or plasma of a horse or sheep that has been immunised with the venoms of one or more species of snake. Antivenom is immunoglobulin (usually the enzyme refined F(ab)2 fragment of IgG] purified from the serum or plasma of a horse or sheep that has been immunised with the venoms of one or more species of snake. “Specific” antivenom, implies that the antivenom has been raised against the venom of the snake that has bitten the patient and that it can therefore be expected to contain specific antibody that will neutralise that particular venom. “Specific” antivenom, implies that the antivenom has been raised against the venom of the snake that has bitten the patient and that it can therefore be expected to contain specific antibody that will neutralise that particular venom. Monovalent or monospecific antivenom neutralises the venom of only one species of snake. Monovalent or monospecific antivenom neutralises the venom of only one species of snake. Polyvalent or polyspecific antivenom neutralises the venoms of several different species of snakes. Polyvalent or polyspecific antivenom neutralises the venoms of several different species of snakes.

CONTD… CONTD… For example, Haffkine, Kasauli, Serum Institute of India and Bengal “polyvalent anti-snake venom serum” is raised in horses using the venoms of the four most important venomous snakes in India (Indian cobra, Naja naja; Indian krait, Bungarus caeruleus; Russell’s viper,Daboia russelii; saw-scaled viper, Echis carinatus). For example, Haffkine, Kasauli, Serum Institute of India and Bengal “polyvalent anti-snake venom serum” is raised in horses using the venoms of the four most important venomous snakes in India (Indian cobra, Naja naja; Indian krait, Bungarus caeruleus; Russell’s viper,Daboia russelii; saw-scaled viper, Echis carinatus). Antibodies raised against the venom of one species may have cross-neutralising activity against other venoms, usually from closely related species. This is known as paraspecific activity. Antibodies raised against the venom of one species may have cross-neutralising activity against other venoms, usually from closely related species. This is known as paraspecific activity.

CONTD… Antivenom treatment carries a risk of severe adverse reactions and in most countries it is costly and may be in limited supply. It should therefore be used only in patients in whom the benefits of antivenom treatment are considered to exceed the risks. Antivenom treatment carries a risk of severe adverse reactions and in most countries it is costly and may be in limited supply. It should therefore be used only in patients in whom the benefits of antivenom treatment are considered to exceed the risks. How long after the bite can antivenom be expected to be effective? How long after the bite can antivenom be expected to be effective? Antivenom treatment should be given as soon as it is indicated. It may reverse systemic envenoming even when this has persisted for several days or, in the case of haemostatic abnormalities, for two or more weeks. Antivenom treatment should be given as soon as it is indicated. It may reverse systemic envenoming even when this has persisted for several days or, in the case of haemostatic abnormalities, for two or more weeks. However, when there are signs of local envenoming, without systemic envenoming, antivenom will be effective only if it can be given within the first few hours after the bite. However, when there are signs of local envenoming, without systemic envenoming, antivenom will be effective only if it can be given within the first few hours after the bite.

Indications for Antivenom Antivenom treatment is recommended if and when a patient with proven or suspected snake develops one or more of the following signs Systemic envenoming Haemostatic abnormalities: Haemostatic abnormalities: spontaneous systemic bleeding (clinical) spontaneous systemic bleeding (clinical) coagulopathy (20WBCT or other laboratory) coagulopathy (20WBCT or other laboratory) thrombocytopenia (<100 x 109/litre) (laboratory) thrombocytopenia (<100 x 109/litre) (laboratory) Neurotoxic signs: ptosis, external ophthalmoplegia, paralysis etc (clinical) Neurotoxic signs: ptosis, external ophthalmoplegia, paralysis etc (clinical) Cardiovascular abnormalities: hypotension, shock, cardiac arrhythmia (clinical),abnormal ECG Cardiovascular abnormalities: hypotension, shock, cardiac arrhythmia (clinical),abnormal ECG Acute renal failure: oliguria/anuria, rising blood creatinine/ urea, (Haemoglobin-/myoglobin-uria:) dark brown urine, other evidence of intravascular haemolysis or generalised rhabdomyolysis (muscle aches and pains, hyperkalaemia) Acute renal failure: oliguria/anuria, rising blood creatinine/ urea, (Haemoglobin-/myoglobin-uria:) dark brown urine, other evidence of intravascular haemolysis or generalised rhabdomyolysis (muscle aches and pains, hyperkalaemia)

CONTD… Local envenoming  Local swelling involving more than half of the bitten limb (in the absence of a tourniquet) tourniquet)  Swelling after bites on the digits (toes and especially fingers)  Rapid extension of swelling (for example beyond the wrist or ankle within a few hours of bites on the hands or feet) hours of bites on the hands or feet)  Development of an enlarged tender lymph node draining the bitten limb

Contraindications to antivenom There is no absolute contraindication to antivenom treatment There is no absolute contraindication to antivenom treatment Patients who have reacted to horse (equine) or sheep (ovine) serum in the past (for example after treatment with equine Anti-tetanus serum, equine anti-rabies serum or equine or ovine antivenom) Patients who have reacted to horse (equine) or sheep (ovine) serum in the past (for example after treatment with equine Anti-tetanus serum, equine anti-rabies serum or equine or ovine antivenom) Those with a strong history of atopic diseases (especially severe asthma) should be given antivenom only if they have signs of systemic envenoming. Those with a strong history of atopic diseases (especially severe asthma) should be given antivenom only if they have signs of systemic envenoming.

Prophylaxis in high risk patients High risk patients may be pre-treated empirically with High risk patients may be pre-treated empirically with Subcutaneous epinephrine Subcutaneous epinephrine Intravenous antihistamines (both anti-H1, such as promethazine, anti- H2, such as cimetidine or ranitidine) Intravenous antihistamines (both anti-H1, such as promethazine, anti- H2, such as cimetidine or ranitidine) Corticosteroid. Corticosteroid. In asthmatic patients, prophylactic use of an inhaled adrenergic ß2 agonist such as salbutamol may prevent bronchospasm In asthmatic patients, prophylactic use of an inhaled adrenergic ß2 agonist such as salbutamol may prevent bronchospasm

Selection of antivenom Antivenom should be given only if its stated range of specificity includes the species known or thought to have been responsible for the bite. Antivenom should be given only if its stated range of specificity includes the species known or thought to have been responsible for the bite. Liquid antivenoms that have become opaque should not be used as precipitation of protein indicates loss of activity and an increased risk Liquid antivenoms that have become opaque should not be used as precipitation of protein indicates loss of activity and an increased risk of reactions. of reactions. If the biting species is known, the ideal treatment is with a monospecific/monovalent antivenom, as this involves administration of a lower dose of antivenom protein than with a polyspecific/ polyvalent antivenoms. If the biting species is known, the ideal treatment is with a monospecific/monovalent antivenom, as this involves administration of a lower dose of antivenom protein than with a polyspecific/ polyvalent antivenoms. Polyspecific/polyvalent antivenoms are preferred in many countries because of the difficulty in identifying species responsible for bites. Polyspecific/polyvalent antivenoms are preferred in many countries because of the difficulty in identifying species responsible for bites.

Administration of antivenom Freeze-dried (lyophilised) antivenoms are reconstituted, usually with 10 ml of sterile water. The freeze-dried protein may be difficult to dissolve Freeze-dried (lyophilised) antivenoms are reconstituted, usually with 10 ml of sterile water. The freeze-dried protein may be difficult to dissolve Skin and conjunctival “hypersensitivity” tests may reveal IgE mediated Type I hypersensitivity to horse or sheep proteins but do not Predict the large majority of early (anaphylactic) or late (serum sickness type) antivenom reactions. Since they may delay treatment and can in themselves be sensitizing, these tests should not be used. Skin and conjunctival “hypersensitivity” tests may reveal IgE mediated Type I hypersensitivity to horse or sheep proteins but do not Predict the large majority of early (anaphylactic) or late (serum sickness type) antivenom reactions. Since they may delay treatment and can in themselves be sensitizing, these tests should not be used. Epinephrine should always be drawn up in readiness before antivenom is administered. Epinephrine should always be drawn up in readiness before antivenom is administered. Antivenom should be given by the intravenous route whenever possible. Antivenom should be given by the intravenous route whenever possible.

Intravenous injection Intravenous “push” injection: reconstituted freeze- dried antivenom or neat liquid antivenom is given by slow intravenous injection (not more than 2 ml/minute). This method has the advantage that the doctor/nurse/dispenser giving the antivenom must remain with the patient during the time when some early reactions may develop. It is also economical, saving the use of intravenous fluids, giving sets, cannulae etc. Intravenous “push” injection: reconstituted freeze- dried antivenom or neat liquid antivenom is given by slow intravenous injection (not more than 2 ml/minute). This method has the advantage that the doctor/nurse/dispenser giving the antivenom must remain with the patient during the time when some early reactions may develop. It is also economical, saving the use of intravenous fluids, giving sets, cannulae etc. Intravenous infusion: reconstituted freeze-dried or neat liquid antivenom is diluted in approximately 5- 10 ml of isotonic fluid per kg body weight (ie 250- 500 ml of isotonic Intravenous infusion: reconstituted freeze-dried or neat liquid antivenom is diluted in approximately 5- 10 ml of isotonic fluid per kg body weight (ie 250- 500 ml of isotonic saline or 5% dextrose in the case of an adult patient) and is infused at a constant rate over a period of about one hour saline or 5% dextrose in the case of an adult patient) and is infused at a constant rate over a period of about one hour

Local administration of antivenom at the site of the bite is not recommended Extremely painful Extremely painful Increase intracompartmental pressure Increase intracompartmental pressure Not effective. Not effective. Intramuscular injection of antivenom Antivenoms are large molecules are absorbed slowly via lymphatics. Antivenoms are large molecules are absorbed slowly via lymphatics. Bioavailability is poor, especially after intragluteal injection and blood levels of antivenom never reach those achieved rapidly by intravenous administration. Bioavailability is poor, especially after intragluteal injection and blood levels of antivenom never reach those achieved rapidly by intravenous administration. Pain of injection of large volumes of antivenom Pain of injection of large volumes of antivenom Risk of haematoma formation in patients with haemostatic abnormalities. Risk of haematoma formation in patients with haemostatic abnormalities. OTHER ROUTES

CONTD… Situations in which intramuscular administration might be considered 1) At a peripheral first aid station, before a patient with obvious envenoming is put in an ambulance for a journey to hospital that may last several hours 2) On an expedition exploring a remote area very far from medical care 3) When intravenous access has proved impossible. Although the risk of antivenom reactions is less with intramuscular than intravenous administration, epinephrine (adrenaline) must be readily available. Although the risk of antivenom reactions is less with intramuscular than intravenous administration, epinephrine (adrenaline) must be readily available. The dose of antivenom should be divided between a number of sites in the upper anterolateral region of both thighs. The dose of antivenom should be divided between a number of sites in the upper anterolateral region of both thighs. A maximum of 5-10 ml should be given at each site by deep intramuscular injection followed by massage to aid absorption. A maximum of 5-10 ml should be given at each site by deep intramuscular injection followed by massage to aid absorption. Finding enough muscle mass to contain such large volumes of antivenom is particularly difficult in children Finding enough muscle mass to contain such large volumes of antivenom is particularly difficult in children

Dose of antivenom The recommended dose is often the amount of antivenom required to neutralise the average venom yield when captive snakes are milked of their venom. The recommended dose is often the amount of antivenom required to neutralise the average venom yield when captive snakes are milked of their venom. In practice, the choice of an initial dose of antivenom is usually empirical. In practice, the choice of an initial dose of antivenom is usually empirical. Since the neutralising power of antivenoms varies from batch to batch, the results of a particular clinical trial may soon become obsolete if the manufacturers change the strength of the antivenom. Since the neutralising power of antivenoms varies from batch to batch, the results of a particular clinical trial may soon become obsolete if the manufacturers change the strength of the antivenom. Snakes inject the same dose of venom into children and adults. Snakes inject the same dose of venom into children and adults. Children must therefore be given exactly the same dose of antivenom as adults. Children must therefore be given exactly the same dose of antivenom as adults.

How much ? Intial dose to neutralise likely average dose venom of the snake Intial dose to neutralise likely average dose venom of the snake Russell viper – 63 mg +/-7mg Russell viper – 63 mg +/-7mg Indian ASV 1 vial neutralises 7mg of venom – so 10 vials ![starting dose ] Indian ASV 1 vial neutralises 7mg of venom – so 10 vials ![starting dose ] COBRA -100-150 ml +neostigmine +ventilatory support COBRA -100-150 ml +neostigmine +ventilatory support VIPER -150 ml –retest 6 hrs-no clot –ASV 50- 100ml- retest /observe VIPER -150 ml –retest 6 hrs-no clot –ASV 50- 100ml- retest /observe If in renal failure - dialysis If in renal failure - dialysis

ADVERSE REACTIONS OF ASV NO test dose – [poor predictors & may sensitise the patient to ASV] NO test dose – [poor predictors & may sensitise the patient to ASV] A proportion of patients, usually more than 20%, develop a reaction either early (within a few hours) or late (5 days or more) after being given antivenom. A proportion of patients, usually more than 20%, develop a reaction either early (within a few hours) or late (5 days or more) after being given antivenom. Early anaphylactic reactions: usually within 10- 180 minutes of starting antivenom, the patient begins to itch (often over the scalp) and develops urticaria, dry cough, fever, nausea, Early anaphylactic reactions: usually within 10- 180 minutes of starting antivenom, the patient begins to itch (often over the scalp) and develops urticaria, dry cough, fever, nausea, vomiting, abdominal colic, diarrhoea and tachycardia. vomiting, abdominal colic, diarrhoea and tachycardia. A minority of these patients may develop severe life-threatening anaphylaxis: hypotension, bronchospasm and angio-oedema. A minority of these patients may develop severe life-threatening anaphylaxis: hypotension, bronchospasm and angio-oedema.

CONTD… Pyrogenic (endotoxin) reactions usually develop 1-2 hours after treatment. Symptoms include shaking chills (rigors), fever, vasodilatation and a fall in blood pressure. Febrile convulsions may be precipitated in children. These reactions are caused by pyrogen contamination during the manufacturing process. They are commonly reported. Pyrogenic (endotoxin) reactions usually develop 1-2 hours after treatment. Symptoms include shaking chills (rigors), fever, vasodilatation and a fall in blood pressure. Febrile convulsions may be precipitated in children. These reactions are caused by pyrogen contamination during the manufacturing process. They are commonly reported. Late (serum sickness type) reactions develop 1-12 (mean 7) days after treatment. Clinical features include fever, nausea, vomiting, diarrhoea, itching, recurrent urticaria, arthralgia, myalgia, lymphadenopathy, periarticular swellings, mononeuritis multiplex, proteinuria with Late (serum sickness type) reactions develop 1-12 (mean 7) days after treatment. Clinical features include fever, nausea, vomiting, diarrhoea, itching, recurrent urticaria, arthralgia, myalgia, lymphadenopathy, periarticular swellings, mononeuritis multiplex, proteinuria with immune complex nephritis and rarely encephalopathy. immune complex nephritis and rarely encephalopathy. Patients who suffer early reactions and are treated with antihistamines and corticosteroid are less likely to develop late reactions. Patients who suffer early reactions and are treated with antihistamines and corticosteroid are less likely to develop late reactions.

Treatment of early Anaphylactic and Pyrogenic Antivenom reactions At the earliest sign of a reaction: Antivenom administration must be temporarily suspended Antivenom administration must be temporarily suspended Epinephrine (adrenaline) (0.1% solution, 1 in 1,000, 1 mg/ml) is the effective treatment for early anaphylactic and pyrogenic antivenom reactions Epinephrine (adrenaline) (0.1% solution, 1 in 1,000, 1 mg/ml) is the effective treatment for early anaphylactic and pyrogenic antivenom reactions Epinephrine (adrenaline) is given intramuscularly (into the deltoid muscle or the upper lateral thigh) in an initial dose of 0.5 mg for adults, 0.01 mg/kg body weight for children. Epinephrine (adrenaline) is given intramuscularly (into the deltoid muscle or the upper lateral thigh) in an initial dose of 0.5 mg for adults, 0.01 mg/kg body weight for children. Severe,life-threatening anaphylaxis can evolve very rapidly and so epinephrine (adrenaline) should be given at the very first sign of a reaction, even when only a few spots of urticaria have appeared or at the start of itching, tachycardia or restlessness. Severe,life-threatening anaphylaxis can evolve very rapidly and so epinephrine (adrenaline) should be given at the very first sign of a reaction, even when only a few spots of urticaria have appeared or at the start of itching, tachycardia or restlessness. The dose can be repeated every 5-10 minutes if the patient’s condition is deteriorating The dose can be repeated every 5-10 minutes if the patient’s condition is deteriorating

Anti H1 antihistamine such as chlorpheniramine maleate (adults 10 mg, children 0.2 mg/kg by intravenous injection over a few minutes) Anti H1 antihistamine such as chlorpheniramine maleate (adults 10 mg, children 0.2 mg/kg by intravenous injection over a few minutes) Intravenous hydrocortisone (adults 100 mg, children 2 mg/kg bodyweight) - prevent recurrent anaphylaxis. Intravenous hydrocortisone (adults 100 mg, children 2 mg/kg bodyweight) - prevent recurrent anaphylaxis. Anti H2 antihistamines such as cimetidine or ranitidine have a role in the treatment of severe anaphylaxis. Anti H2 antihistamines such as cimetidine or ranitidine have a role in the treatment of severe anaphylaxis. Both drugs are given, diluted in 20 ml isotonic saline, by slow intravenous injection (over 2 minutes). Doses: cimetidine - adults 200 mg, children 4 mg/kg;ranitidine - adults 50 mg, children 1 mg/kg. Both drugs are given, diluted in 20 ml isotonic saline, by slow intravenous injection (over 2 minutes). Doses: cimetidine - adults 200 mg, children 4 mg/kg;ranitidine - adults 50 mg, children 1 mg/kg. Late (serum sickness) reactions usually respond to a 5-day course of oral antihistamine. Patients who fail to respond in 24-48 hours should be given a 5-day course of prednisolone. Late (serum sickness) reactions usually respond to a 5-day course of oral antihistamine. Patients who fail to respond in 24-48 hours should be given a 5-day course of prednisolone. Doses: Chlorpheniramine: adults 2 mg six hourly, children 0.25 mg/kg /day in divided doses Doses: Chlorpheniramine: adults 2 mg six hourly, children 0.25 mg/kg /day in divided doses Prednisolone: adults 5 mg six hourly, children 0.7 mg/kg/day in divided doses for 5-7days Prednisolone: adults 5 mg six hourly, children 0.7 mg/kg/day in divided doses for 5-7days

Recurrence of systemic envenoming In patients envenomed by vipers, after an initial response to antivenom (cessation of bleeding, restoration of blood coagulability), signs of systemic envenoming may recur within 24-48 hours. In patients envenomed by vipers, after an initial response to antivenom (cessation of bleeding, restoration of blood coagulability), signs of systemic envenoming may recur within 24-48 hours. This is attributable to: This is attributable to: Continuing absorption of venom from the “depot” at the site of the bite, perhaps assisted by improved blood supply following correction of shock, hypovolaemia etc. Continuing absorption of venom from the “depot” at the site of the bite, perhaps assisted by improved blood supply following correction of shock, hypovolaemia etc. A redistribution of venom from the tissues into the vascular space, as the result of antivenom treatment. A redistribution of venom from the tissues into the vascular space, as the result of antivenom treatment.

Conservative treatment when no antivenom is available Neurotoxic envenoming with respiratory paralysis: assisted ventilation. Anticholinesterases should always be tried Neurotoxic envenoming with respiratory paralysis: assisted ventilation. Anticholinesterases should always be tried Haemostatic abnormalities - strict bed rest to avoid even minor trauma Haemostatic abnormalities - strict bed rest to avoid even minor trauma transfusion of clotting factors and platelets; transfusion of clotting factors and platelets; fresh frozen plasma and cryoprecipitate with platelet fresh frozen plasma and cryoprecipitate with platelet concentrates concentrates fresh whole blood. fresh whole blood. Intramuscular injections should be avoided. Intramuscular injections should be avoided. Shock, myocardial damage: Shock, myocardial damage: Hypovolaemia corrected with colloid/crystalloid, Hypovolaemia corrected with colloid/crystalloid, Ancillary pressor drugs (dopamine or adrenaline) Ancillary pressor drugs (dopamine or adrenaline) Renal failure: conservative treatment or dialysis Renal failure: conservative treatment or dialysis Dark brown urine (myoglobinuria or haemoglobinuria) correct hypovolaemia and acidosis and consider a single infusion of mannitol Dark brown urine (myoglobinuria or haemoglobinuria) correct hypovolaemia and acidosis and consider a single infusion of mannitol Severe local envenoming Severe local envenoming Surgical intervention may be needed but the risks of surgery in a patient with consumption coagulopathy, thrombocytopenia and enhanced fibrinolysis must be balanced against the life threatening complications of local envenoming. Surgical intervention may be needed but the risks of surgery in a patient with consumption coagulopathy, thrombocytopenia and enhanced fibrinolysis must be balanced against the life threatening complications of local envenoming. Prophylactic broad spectrum antimicrobial treatment is justified Prophylactic broad spectrum antimicrobial treatment is justified

Anticholinesterase (eg “Tensilon”/edrophonium) test Anticholinesterase (eg “Tensilon”/edrophonium) test Baseline observations Baseline observations Give atropine intravenously Give atropine intravenously Give anticholinesterase drug Give anticholinesterase drug Observe effect Observe effect If positive, institute regular atropine and (long acting) anticholinesterase If positive, institute regular atropine and (long acting) anticholinesterase

Criteria for giving more antivenom Persistence or recurrence of blood incoagulability after 6 hr of bleeding after 1-2 hr Persistence or recurrence of blood incoagulability after 6 hr of bleeding after 1-2 hr Deteriorating neurotoxic or cardiovascular signs after 1-2 hr Deteriorating neurotoxic or cardiovascular signs after 1-2 hr If the blood remains incoagulable (as measured by 20WBCT) six hours after the initial dose of antivenom, the same dose should be repeated. If the blood remains incoagulable (as measured by 20WBCT) six hours after the initial dose of antivenom, the same dose should be repeated. In patients who continue to bleed briskly, the dose of antivenom should be repeated within 1-2 hours. In patients who continue to bleed briskly, the dose of antivenom should be repeated within 1-2 hours. In case of deteriorating neurotoxicity or cardiovascular signs, the initial dose of antivenom should be repeated after 1-2 hours, and full supportive treatment must be considered. In case of deteriorating neurotoxicity or cardiovascular signs, the initial dose of antivenom should be repeated after 1-2 hours, and full supportive treatment must be considered.

How can snake bites be avoided ?  Education ! Know your local snakes, know the sort of places where they like to live and hide, know at what times of year, at what times of day/night or in what kinds of weather they are most likely to be active.  Be vigilant after rains, during flooding, at harvest time and at night.  Wear proper shoes or boots and long trousers, especially when walking in the dark or in undergrowth.  Use a light (torch) when walking at night.

CONTD…  Avoid snakes as far as possible, including snakes performing for snake charmers. Never handle, threaten or attack a snake and never intentionally trap or corner a snake in an enclosed space.  Avoid sleeping on the ground.  Keep young children away from areas known to be snake-infested.  Avoid or take great care handling dead snakes, or snakes that appear to be dead.  Avoid having rubble, rubbish, termite mounds or domestic animals close to human dwellings, as all of these attract snakes.

CONTD… Frequently check houses for snakes and, avoid types of house construction that will provide snakes with hiding places (eg thatched roof with open eaves, mud and straw walls with large cracks and cavities, large unsealed spaces beneath floorboards). Frequently check houses for snakes and, avoid types of house construction that will provide snakes with hiding places (eg thatched roof with open eaves, mud and straw walls with large cracks and cavities, large unsealed spaces beneath floorboards). To prevent sea snake bites, fishermen should avoid touching sea snakes caught in nets and on lines. The head and tail are not easily distinguishable. There is a risk of bites to bathers and those washing clothes in muddy water of estuaries, river mouths and some coastlines To prevent sea snake bites, fishermen should avoid touching sea snakes caught in nets and on lines. The head and tail are not easily distinguishable. There is a risk of bites to bathers and those washing clothes in muddy water of estuaries, river mouths and some coastlines

CASE REPORT Year : 2007 | Volume : 11 | Issue : 3 | Page : 161-164 Neurotoxic snake bite with respiratory failure Department of Anesthesiology, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221 005, India Thirteen patients with severe neuroparalytic snake envenomation admitted in intensive care unit with respiratory failure over a four months period. Initially ptosis and ophthalmoplegia, followed by bulbar palsy and respiratory muscle weakness was the common sequele. Thirteen patients with severe neuroparalytic snake envenomation admitted in intensive care unit with respiratory failure over a four months period. Initially ptosis and ophthalmoplegia, followed by bulbar palsy and respiratory muscle weakness was the common sequele. All of them received cardio-respiratory support with mechanical ventilation, anti-snake venom (median dose of 20 vials) and anticholinesterase therapy. All of them received cardio-respiratory support with mechanical ventilation, anti-snake venom (median dose of 20 vials) and anticholinesterase therapy. Except one suffering from hypoxic brain injury due to delayed presentation, rest survived with complete neurological recovery. Except one suffering from hypoxic brain injury due to delayed presentation, rest survived with complete neurological recovery. So good outcome in such cases is related with early cardio respiratory support and anti venom therapy So good outcome in such cases is related with early cardio respiratory support and anti venom therapy Polyvalent anti-snake venom (ASV) started as loading dose (50 ml over two hours) and maintenance infusion (50 ml six hourly). Polyvalent anti-snake venom (ASV) started as loading dose (50 ml over two hours) and maintenance infusion (50 ml six hourly). We have also used anticholinesterase (i.e. neostigmine started at a rate of 25 mcg/kg/hour) and anticholinergic (glycopyrolate) combination as infusion to reverse the neuromuscular blockade till ptosis improved in every case We have also used anticholinesterase (i.e. neostigmine started at a rate of 25 mcg/kg/hour) and anticholinergic (glycopyrolate) combination as infusion to reverse the neuromuscular blockade till ptosis improved in every case

Low dose of snake antivenom is as effective as high dose in patients with severe neurotoxic snake envenoming Department of Pulmonary Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India In the study, 55 snake bite victims requiring ventilatory support for severe neurotoxic envenoming received either 150 ml of polyvalent snake antivenom (SAV) (low dose SAV group, n = 28) or 100 ml of SAV at presentation followed by 100 ml every 6 hours until recovery of neurological manifestations (high dose group, n = 27). In the study, 55 snake bite victims requiring ventilatory support for severe neurotoxic envenoming received either 150 ml of polyvalent snake antivenom (SAV) (low dose SAV group, n = 28) or 100 ml of SAV at presentation followed by 100 ml every 6 hours until recovery of neurological manifestations (high dose group, n = 27). The median dose of SAV in the high dose group was 600 ml (range 300 to 1600). The median dose of SAV in the high dose group was 600 ml (range 300 to 1600). The duration of mechanical ventilation in the low dose group (median 47.5 hours; range 14 to 248) was similar to that in the high dose group (median 44 hours; range 6 to 400). The duration of mechanical ventilation in the low dose group (median 47.5 hours; range 14 to 248) was similar to that in the high dose group (median 44 hours; range 6 to 400). The mean (SD) duration of intensive care unit stay was similar in the two groups. The mean (SD) duration of intensive care unit stay was similar in the two groups. There were three deaths in the high dose group; two patients in the low dose group had neurological sequelae. All other patients improved, had no residual neurological deficit, and were discharged. There were three deaths in the high dose group; two patients in the low dose group had neurological sequelae. All other patients improved, had no residual neurological deficit, and were discharged. We conclude that there is no difference between a protocol using lower doses of SAV and one with higher doses in the management of patients with severe neurotoxic snake envenoming We conclude that there is no difference between a protocol using lower doses of SAV and one with higher doses in the management of patients with severe neurotoxic snake envenoming

REFERENCES REFERENCES WHO/SEARO GUIDELINES FOR THE CLINICAL MANAGEMENT OF SNAKE BITE IN THE SOUTH EAST ASIAN REGION by David A Warrell- Supplement to The Southeast Asian Journal of Tropical Medicine & Public Health WHO/SEARO GUIDELINES FOR THE CLINICAL MANAGEMENT OF SNAKE BITE IN THE SOUTH EAST ASIAN REGION by David A Warrell- Supplement to The Southeast Asian Journal of Tropical Medicine & Public Health

Snakebite Dr.Pratheeba Durairaj, M.D.,D.A,. Snake bite: an occupational disease Farmers (rice) Farmers (rice) Plantation workers (rubber, coffee) Plantation.

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Snakebite Dr.Pratheeba Durairaj, M.D.,D.A,. Snake bite: an occupational disease Farmers (rice) Farmers (rice) Plantation workers (rubber, coffee) Plantation.

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