Presentation on theme: "Management of Snake Bites"— Presentation transcript:
1Management of Snake Bites Dr. Cheetanand MahadeoRegistrar General SurgeryGPHC
2Relevance of topicThe people most affected by rabid dog bites, snake bites and scorpion stings usually live in poor rural communities where medical resources are often sparse. Because they lack a strong political voice, their problems tend to be overlooked by politicians and health authorities who are based in capital cities and are poorly informed about major public health issues affecting rural areas. Consequently, the impact of these health issues, although dramatic and economically significant, does not appear as a priority in the design of national public health programmes. These are therefore the most neglected among today’s neglected global health problems…Rabies and Envenomings, a neglected public health issue, World Health Organization,
3Disclaimers Independent Study and analysis No funding provided If any medication is recommended or condemned it was based on pharmacological evidence and not commercial influenceOnly GPHC data was studied
4International Epidemiology Only 15% of approximately 3000 species of snakes worldwide are dangerous to humansAge range yrsPredominantly MalesMost common site being Lower LimbsSummary: “5.4 million bites, about 2.5 million envenomings and over 125,000 deaths annually” ,A Kasturiratne et al The Global Burden of Snakebite: A Literature Analysis and Modelling Based on Regional Estimates of Envenoming and Deaths, PLOS Medicine.
5Classification of snakes Colubridae: most non-venomous snakes e.g grass snakeElapidae: Venemous: e.g. Cobras, Kriats, Mambas, Coral snakes (present in Guyana)Viperidae: Venomous: e.g. Rattlesnakes, Adders, Vipers (in Guyana, the notorious Labaria)Hydrophidae: sea snakesModified classification from: W. Rushin, Taxonomy of snakes, 2700 species, 2004; pg 3B S Gold et al, Bites of venomous snakes, N Engl J Med, Vol. 347, No. 5, August 1st 2002.
6Bothropos atox (labaria) Photographs Of Labaria Snake from Iwokrama, Guyana
7Guyana Blackback Coral Snake (Leptomicrurus collaris) Photograph taken in Region 1 Guyana
9Understanding Antivenom(or antivenin or antivenene) A biologic product used in treatment of venomous bites/stingsThe principle of antivenom is based on that of vaccines; antibodies against proteinsMonovalent (when they are effective against a given species' venom) orPolyvalent (when they are effective against a range of species, or several different species at the same time).
10Production of Antivennin Made according to WHO Biological Guidelines and Good Manufacturing PracticesVenom injected into Horses or SheepAntibodies are harvested from these animalsFreeze dried for reconstitutionSome contain whole IgG others fragments of IgG (Fab or Fab2)Binds to circulating venom components blocking their attachment to receptorscomplexes are removed by Reticuloendothelial systemC D Richard, (3rd Ed.) Medical Toxicology, Lippencot-Williams-Wilkins, 2009, pg
11Symptomatology/Signs of Envenomation* Hematoxic (Labaria)Neurotoxic (Coral Snake)Intense painEdemaWeaknessNumbness/paraesthesiaTachycardiaEcchymosisFasciulationsMetallic tasteConfusionHypotension/shockRenal failureBleeding diathesisDICLocal necrosisBlebsMinimal painsPtosisDiplopiaDisphagiaHypersalivationDiaphoresisHyporeflexiaRespiratory depressionParalysisGREGORY JUCKETT, M.D., M.P.H., and JOHN G. HANCOX, M.D Am Fam Physician Apr 1;65(7):
12Grading of a Snake bite (Haemotoxic) GradePresentationPunctures or abrasions; some pain or tenderness at the bite1- MildPain, tenderness, edema at the bite; perioral paresthesias may be present2 ModeratePain, tenderness, erythema, edema beyond the area adjacent to the bite; often, systemic manifestations and mild coagulopathy3 SevereIntense pain and swelling of entire extremity, often with severe systemic signs and symptoms; Coagulopathy4 Life ThreateningMarked abnormal signs and symptoms; severe coagulopathyDICGREGORY JUCKETT, M.D., M.P.H., and JOHN G. HANCOX, M.D, Am Fam Physician Apr 1;65(7):
13Pathophysiology of snake bites Enzymatic proteins in venom causes manifestations.Neurotoxins e.g coral snake venom, ultimately causes respiratory arrest.Specific details(1) hyaluronidase allows rapid spread of venom through subcutaneous tissues by disrupting mucopolysaccharides;(2) phospholipase A2 plays a major role in hemolysis secondary to the esterolytic effect on red cell membranes and promotes muscle necrosis; and(3) thrombogenic enzymes promote the formation of a weak fibrin clot, which, in turn, activates plasmin and results in a consumptive coagulopathy.
14J White, Snake venoms and coagulopathy, J Toxicon 24(2005); 951-957
16Management begins in the field Prevention of snake bitesProper boots and leather leggings in snake infested areasSnakes generally bite only when threatened/provoked
17First aid guidelines First Aid: summary of guidelines* Remove patient from areaDo not attempt to capture snake for identificationCalm the patient and Call for helpDo not give alcohol or anti-inflammatory medicationsRemove constrictive clothingSplint limbs to minimize movementNO ICE PACKSNO TORNIQUETSDO NOT INCISE BITE SITEDO NOT SUCK WOUND TO REMOVE POISON*American Medical Association, American Red Cross, National Health and Research Council Australia, Indian Ministry of Health Snake bite Protocol 2007
18What do we need to understand about snake bites? Envenomation is a medical emergencyAll principles of initial emergency care appliesRapid Triage as IMMEDIATEABC’s to Stabilize PatientSpecific treatment if availableEarly referral to MEDICAL staff.Early identification of the type of toxicity and managementManagement will be symptom guided if the type of snake is unknown
19ABCDE of Trauma care Examine and manage the Airway Examine quality of Breathing and Maintain functionMonitor for signs of Circulatory compromiseAssess for Neurologic DysfunctionExamine the patient thoroughly for multiple sites of Exposure (>1 bite)OXYGEN, MONITORS, IV FLUIDS FOR ALL UNTIL SEVERITY OF ENVENOMATION IS QUANTIFIEDEnquire about Tetanus Immunization in HPI
20These patients are in pain!! Oral analgesia and IV narcotics should be consideredDO NOT ADMINISTER ASPIRIN OR NSAIDSDO NOT GIVE DICLOFENAC OR OTHER INTRAMUSCULAR MEDICATIONSSplint the bite area if possible and remove all constricting bandages/tourniquets
21Role of neostigmineAnticholinestrase & prolongs life of Ach - which can reverse resp.failure & neurotoxic symptoms ( post synaptic )Neostigmine test : mg IM preceeded by 0.6 mg atropine IVObserve for 1 hrIf victim responds , continue 0.5 mg Neostigmine IM ½ hrly with 0.6 mg Atropine IV over 8 hrsIf no improvement in symptoms after 1 hr , stop Neostigmine
23Additional Investigations If severity requires or clinical examination suggests the need:ECG- severe bradycardia, ischemia etcArterial blood Gas: severe acidosis can be presentChest X-ray: pulmonary edema, effusion or hemorrhageCT scans, esp. head: Intracranial bleeds can occur
24After stabilization, what do we do? Admit for serial clinical/laboratory assessmentWhich ward? Usually general medical ward. The ward is determined by the severity of the envenomation and the patient’s specific requirements eg. Ventilator support, Holter monitoring, continuous oximetry etc.Seek consultation early! This includes:ToxicologistHematologistOrthopedicsIntensivist etc.
25Antivenoms: to give or not to give? Antivenoms are life saving; give earlyCAVEAT! Give the correct antivenom for the bite. Polyvalent multiple genus/species generally do not work well and the patient can have life threatening reactions.e.g. the Rattlesnakes of USA antivenom may have no use in the South American Vipers.
26No Specific Antivenom in Guyana SUERO ANTIBOTROPICO POLIVALENTE (Equine); Peruvian AntivenomBothrops atrox Common Lancehead, Fer de lanceBothrops brazili Brazil’s Lancehead Bothrops pictus Desert Lancehead, Bothrops barnetti Barnett’s Lancehead, Bothrocophias hyoprora Amazonian Toadheaded Pit-viperB.atrox-Lachsis equine (Fab')2 antivenom, Fundacao Ezequiel Dias, Minas Gerais State, Brazil
27How to use antivenom Pre-Med Step Proced. Comment Sensitivity test no Apart from the rare cases of a pre-existing sensitivity, e.g. to horse serum, sensitivity tests (intradermal, intraconjunctival) have no predictive value for an antivenom reaction (Malasit et al. 1986)Pre-MedAdren. Steroids, Antihist.Patients with atopy and previous reactions to products from Equine sources are at riskSpeed of Adm.IV, 5ml/minMost effective as an IV administered medicationDoseThis is guided by degree of envenomation and the manufacturers usually recommend doses depending on the concentrations of Fab within antivenom.CautionsAnaphylaxis can occur
28drugs of controversial/unproven value Non-specific antivenomsCorticosteroids: hydrocortisone, prednisone,(steroids have a role in management of type III hypersensitivity reactions that may occur 7-21 days after a snake bite)Antihistamines andVitamin K
29Reassuring FactsNot all venomous snake bites will have venom injected (“Dry Bite”);Amount of venom depends on several factors:How hungry ?How angry?How threatened?How long since the last bite?1No consensus, but approximately 20% of venomous snake bites will have no venom injected.21.http://reference.medscape.com/features/slideshow/snake-envenomation2. Longo et al, Harrison’s Principles of internal Medicine, 18th Edition, MvGraw-Hill Co. 2012: Sect. 18, ch.396:
30The Local Arena N= 240 cases from Jan 2010 to Dec 2012 Approximately 80 cases/year seen at GPHCMales =153, Females = 87Average age of victim = 33.5 with range of 5/12 to 76Average Hb = 12.3 with range from 2.2g/dL to 18.1g/dLWBC mean 9954; rangePlatelet mean ; range of 8000 –Average duration of hospitalization 4.75 days
31BT, CT ordered for almost all patients PTT, PT, INR ordered for 4 patients (all values elevated)Total Packed cells transfused = 28 unitsTotal platelets transfused 4 UnitsTotal Plasma 460 Units; average 2 u per patientAntivenom administered to 1 patient18 patients received corticosteroids (16 hydrocortisone and 2 prednisone)34 patients received Vitamin K5 patients received Desmopressin6 patients had surgical intervention (drainage of Hematoma, Compartment syndrome, Debridement and skin grafting)
325 patients had HDU monitoring 1 patient had ICU management100% patients received antibiotics with the most common combination being Cloxacillin/Flagyl or Augmentin/Clindamycin; few patients received 3rd generation cephalosporins14 patients received NSAIDS orally and 1 patient received Novalgin IV; all others had IV morphine or pethidine or oral Tramadol in combination with Paracetamol.
33Deaths 5 patients died (N=240) All were over 60 years old 2 = Suspected Cerebral hemorrhage3 = Pulmonary Hemorrhage with their bleeding diathesis and DICAll were over 60 years oldAll came 24 hrs after the biteAll had signs of multiple organ failure (elevated transaminases and creatinine average of 3.5[range ])
42Debridement /skin graft Photographs by Dr. Shilendra Rajkumar, Registrar, Plastic Surgery, GPHC
43Summary Management begins in the field Emergency triage as immediate ABCDE takes priorityTetanus prophylaxisEarly administration of Antivenom IF specificClose monitoring of coagulation profileResponse guided supportive careClotting factors to replace that consumed Plasma or Cryoprecipitate (not a substitute for antivenom but useful)Avoid dubious medications: Steroids, Antihistamines and Vitamin KEarly/appropriate consultation with specialty