1. Management of Snake Bites
Dr. Cheetanand Mahadeo
Registrar General Surgery
GPHC

2. Relevance of topic
The 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,

3. Disclaimers Independent Study and analysis No funding provided
If any medication is recommended or condemned it was based on pharmacological evidence and not commercial influence
Only GPHC data was studied

4. International Epidemiology
Only 15% of approximately 3000 species of snakes worldwide are dangerous to humans
Age range yrs
Predominantly Males
Most common site being Lower Limbs
Summary: “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.

5. Classification of snakes
Colubridae: most non-venomous snakes e.g grass snake
Elapidae: 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 snakes
Modified classification from: W. Rushin, Taxonomy of snakes, 2700 species, 2004; pg 3
B S Gold et al, Bites of venomous snakes, N Engl J Med, Vol. 347, No. 5, August 1st 2002.

6. Bothropos atox (labaria)
Photographs Of Labaria Snake from Iwokrama, Guyana

7. Guyana Blackback Coral Snake (Leptomicrurus collaris)
Photograph taken in Region 1 Guyana

8. Venom Toxicology
An extremely complex mixture of enzymes, peptides, glycoproteins and metal ions.Proteolytic enzymes,Arginine ester hydrolase,Thrombin-like enzyme,Collagenase,Hyaluronidase,Phospholipase A2(A), Phospholipase B, Phosphomonoesterase Phosphodiesterase, Acetylcholinesterase, RNaseDNase, 5'-Nucleotidase, NAD-ucleotidase, L- Amino acid oxidase,Lactate dehydrogenase…
Component
Action
Serine Proteases
Haemolysis
Other Proteases
Phospholipase A2
Myotoxic, Cardiotoxic, Neurotoxic, increases vascular permeability
Hyaluronidase
Tissue necrosis
Neurotoxins
Synaptic inhibition and paralysis

9. Understanding Antivenom(or antivenin or antivenene)
A biologic product used in treatment of venomous bites/stings
The principle of antivenom is based on that of vaccines; antibodies against proteins
Monovalent (when they are effective against a given species' venom) or
Polyvalent (when they are effective against a range of species, or several different species at the same time).

10. Production of Antivennin
Made according to WHO Biological Guidelines and Good Manufacturing Practices
Venom injected into Horses or Sheep
Antibodies are harvested from these animals
Freeze dried for reconstitution
Some contain whole IgG others fragments of IgG (Fab or Fab2)
Binds to circulating venom components blocking their attachment to receptors
complexes are removed by Reticuloendothelial system
C D Richard, (3rd Ed.) Medical Toxicology, Lippencot-Williams-Wilkins, 2009, pg

11. Symptomatology/Signs of Envenomation*
Hematoxic (Labaria)
Neurotoxic (Coral Snake)
Intense pain
Edema
Weakness
Numbness/paraesthesia
Tachycardia
Ecchymosis
Fasciulations
Metallic taste
Confusion
Hypotension/shock
Renal failure
Bleeding diathesis
DIC
Local necrosis
Blebs
Minimal pains
Ptosis
Diplopia
Disphagia
Hypersalivation
Diaphoresis
Hyporeflexia
Respiratory depression
Paralysis
GREGORY JUCKETT, M.D., M.P.H., and JOHN G. HANCOX, M.D Am Fam Physician Apr 1;65(7):

12. Grading of a Snake bite (Haemotoxic)
Grade
Presentation
Punctures or abrasions; some pain or tenderness at the bite
1- Mild
Pain, tenderness, edema at the bite; perioral paresthesias may be present
2 Moderate
Pain, tenderness, erythema, edema beyond the area adjacent to the bite; often, systemic manifestations and mild coagulopathy
3 Severe
Intense pain and swelling of entire extremity, often with severe systemic signs and symptoms; Coagulopathy
4 Life Threatening
Marked abnormal signs and symptoms; severe coagulopathy
DIC
GREGORY JUCKETT, M.D., M.P.H., and JOHN G. HANCOX, M.D, Am Fam Physician Apr 1;65(7):

13. Pathophysiology 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.

14. J White, Snake venoms and coagulopathy, J Toxicon 24(2005); 951-957

15. Management of the Snake bitten patient

16. Management begins in the field
Prevention of snake bites
Proper boots and leather leggings in snake infested areas
Snakes generally bite only when threatened/provoked

17. First aid guidelines First Aid: summary of guidelines*
Remove patient from area
Do not attempt to capture snake for identification
Calm the patient and Call for help
Do not give alcohol or anti-inflammatory medications
Remove constrictive clothing
Splint limbs to minimize movement
NO ICE PACKS
NO TORNIQUETS
DO NOT INCISE BITE SITE
DO 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

18. What do we need to understand about snake bites?
Envenomation is a medical emergency
All principles of initial emergency care applies
Rapid Triage as IMMEDIATE
ABC’s to Stabilize Patient
Specific treatment if available
Early referral to MEDICAL staff.
Early identification of the type of toxicity and management
Management will be symptom guided if the type of snake is unknown

19. ABCDE of Trauma care Examine and manage the Airway
Examine quality of Breathing and Maintain function
Monitor for signs of Circulatory compromise
Assess for Neurologic Dysfunction
Examine the patient thoroughly for multiple sites of Exposure (>1 bite)
OXYGEN, MONITORS, IV FLUIDS FOR ALL UNTIL SEVERITY OF ENVENOMATION IS QUANTIFIED
Enquire about Tetanus Immunization in HPI

20. These patients are in pain!!
Oral analgesia and IV narcotics should be considered
DO NOT ADMINISTER ASPIRIN OR NSAIDS
DO NOT GIVE DICLOFENAC OR OTHER INTRAMUSCULAR MEDICATIONS
Splint the bite area if possible and remove all constricting bandages/tourniquets

21. Role of neostigmine
Anticholinestrase & prolongs life of Ach - which can reverse resp.failure & neurotoxic symptoms ( post synaptic )
Neostigmine test : mg IM preceeded by 0.6 mg atropine IV
Observe for 1 hr
If victim responds , continue 0.5 mg Neostigmine IM ½ hrly with 0.6 mg Atropine IV over 8 hrs
If no improvement in symptoms after 1 hr , stop Neostigmine

22. What baseline Laboratory tests?
Haemoglobin: anaemia
White cell count/differential: infective process
Blood film: identify fragmented RBC’s
Platelet count: thrombocytopenia
Bleeding time/clotting time: bleeding diathesis
Prothrombin time: bleeding diathesis
Renal function: elevated creatinine, hyperkalemia
Urinalysis: hematuria

23. Additional Investigations
If severity requires or clinical examination suggests the need:
ECG- severe bradycardia, ischemia etc
Arterial blood Gas: severe acidosis can be present
Chest X-ray: pulmonary edema, effusion or hemorrhage
CT scans, esp. head: Intracranial bleeds can occur

24. After stabilization, what do we do?
Admit for serial clinical/laboratory assessment
Which 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:
Toxicologist
Hematologist
Orthopedics
Intensivist etc.

25. Antivenoms: to give or not to give?
Antivenoms are life saving; give early
CAVEAT! 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.

26. No Specific Antivenom in Guyana
SUERO ANTIBOTROPICO POLIVALENTE (Equine); Peruvian Antivenom
Bothrops atrox Common Lancehead, Fer de lance
Bothrops brazili Brazil’s Lancehead Bothrops pictus Desert Lancehead, Bothrops barnetti Barnett’s Lancehead, Bothrocophias hyoprora Amazonian Toadheaded Pit-viper
B.atrox-Lachsis equine (Fab')2 antivenom, Fundacao Ezequiel Dias, Minas Gerais State, Brazil

27. How 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-Med
Adren. Steroids, Antihist.
Patients with atopy and previous reactions to products from Equine sources are at risk
Speed of Adm.
IV, 5ml/min
Most effective as an IV administered medication
Dose
This is guided by degree of envenomation and the manufacturers usually recommend doses depending on the concentrations of Fab within antivenom.
Cautions
Anaphylaxis can occur

28. drugs of controversial/unproven value
Non-specific antivenoms
Corticosteroids: hydrocortisone, prednisone,(steroids have a role in management of type III hypersensitivity reactions that may occur 7-21 days after a snake bite)
Antihistamines and
Vitamin K

29. Reassuring Facts
Not 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?1
No consensus, but approximately 20% of venomous snake bites will have no venom injected.2 1.
2. Longo et al, Harrison’s Principles of internal Medicine, 18th Edition, MvGraw-Hill Co. 2012: Sect. 18, ch.396:

30. The Local Arena N= 240 cases from Jan 2010 to Dec 2012
Approximately 80 cases/year seen at GPHC
Males =153, Females = 87
Average age of victim = 33.5 with range of 5/12 to 76
Average Hb = 12.3 with range from 2.2g/dL to 18.1g/dL
WBC mean 9954; range
Platelet mean ; range of 8000 –
Average duration of hospitalization 4.75 days

31. BT, CT ordered for almost all patients
PTT, PT, INR ordered for 4 patients (all values elevated)
Total Packed cells transfused = 28 units
Total platelets transfused 4 Units
Total Plasma 460 Units; average 2 u per patient
Antivenom administered to 1 patient
18 patients received corticosteroids (16 hydrocortisone and 2 prednisone)
34 patients received Vitamin K
5 patients received Desmopressin
6 patients had surgical intervention (drainage of Hematoma, Compartment syndrome, Debridement and skin grafting)

32. 5 patients had HDU monitoring
1 patient had ICU management
100% patients received antibiotics with the most common combination being Cloxacillin/Flagyl or Augmentin/Clindamycin; few patients received 3rd generation cephalosporins
14 patients received NSAIDS orally and 1 patient received Novalgin IV; all others had IV morphine or pethidine or oral Tramadol in combination with Paracetamol.

33. Deaths 5 patients died (N=240) All were over 60 years old
2 = Suspected Cerebral hemorrhage
3 = Pulmonary Hemorrhage with their bleeding diathesis and DIC
All were over 60 years old
All came 24 hrs after the bite
All had signs of multiple organ failure (elevated transaminases and creatinine average of 3.5[range ])

34. Are there any high risk areas in Guyana?

35. What Ages were affected?

36. Simple cases

38. Extreme Cases

39. Elapidae (Coral Snake bite): full ventilatory support

40. Amputated Arm in Labaria bite
Severe life threatening problems and untreated compartment syndrome can lead to this situation

41. Severe Tissue Necrosis; Labaria bite

42. Debridement /skin graft
Photographs by Dr. Shilendra Rajkumar, Registrar, Plastic Surgery, GPHC

43. Summary Management begins in the field Emergency triage as immediate
ABCDE takes priority
Tetanus prophylaxis
Early administration of Antivenom IF specific
Close monitoring of coagulation profile
Response guided supportive care
Clotting factors to replace that consumed Plasma or Cryoprecipitate (not a substitute for antivenom but useful)
Avoid dubious medications: Steroids, Antihistamines and Vitamin K
Early/appropriate consultation with specialty

44. Thank you. Questions?