According to the “National Snakebite Management Protocol” issued by Directorate General of Health Services Ministry of Health and Family Welfare Government of India in 2009 the treatment protocol is defined.
India is estimated to have the highest snakebite mortality in the world. Almost 52 species of snakes found in India are venomous. According to estimates of World Health Organization (WHO), the number of bites is around 83,000 per annum in India with 11,000 deaths.
Research has shown that primary health care doctors do not treat snakebite mainly due to lack of confidence.At the secondary and tertiary care level, multiple protocols are followed mainly from western textbooks, which are not appropriate for Indian settings. Anti-snake venom (ASV) is administered when it is not required and/or in doses well in excess of the required amount. The “National Snakebite Management Protocol” issued by Directorate General of Health Services Ministry of Health and Family Welfare Government of India in 2009 the treatment protocol attempts to target such issues.
Basics of snakes in India and their venom
A substantial number of snakebites in India are due to non-poisonous snakes.Even, many bites by poisonous snakes are dry bites implying that the snakes fail to inject the venom. However, the non-poisonous bites and the dry bites may cause a panic reaction and local injury. There 15 varieties that are highly venomous and four among them' namely cobra (Naja naja), the Russell's viper (baioia russelii), the saw- scaled viper (Echis carinatus) and the krait (bangarus caerulus) commonly cause evenomation.
Snake venom contains proteins that are predominantly neuro toxic or haemotoxic. Cobras and Kraits have neuro toxins and present with neurological manifestations. Haemostatic abnormalities are prima facie evidence of a Viper bite. Russell's viper can also manifest neurotoxic symptoms in a wide area of India. Saw Scaled Vipers do not cause renal failure whereas Russell's viper and Hump-nosed pit viper do. In bites by poisonous and non-poisonous snakes, anxiety is a predominant manifestation. Non-poisonous snakebites may also leave puncture marks and swelling at the site.
A substantial number of snakebites in India are due to non-poisonous snakes.Even, many bites by poisonous snakes are dry bites implying that the snakes fail to inject the venom. However, the non-poisonous bites and the dry bites may cause a panic reaction and local injury. There 15 varieties that are highly venomous and four among them' namely cobra (Naja naja), the Russell's viper (baioia russelii), the saw- scaled viper (Echis carinatus) and the krait (bangarus caerulus) commonly cause evenomation.
Snake venom contains proteins that are predominantly neuro toxic or haemotoxic. Cobras and Kraits have neuro toxins and present with neurological manifestations. Haemostatic abnormalities are prima facie evidence of a Viper bite. Russell's viper can also manifest neurotoxic symptoms in a wide area of India. Saw Scaled Vipers do not cause renal failure whereas Russell's viper and Hump-nosed pit viper do. In bites by poisonous and non-poisonous snakes, anxiety is a predominant manifestation. Non-poisonous snakebites may also leave puncture marks and swelling at the site.
First aid management of snakebite
- Make the victim lie flat with bitten limb below the heart level
- Remove all the tight things like rings, watch etc. and loosen the clothes from the bitten area as they can act as a tourniquet when swelling occurs
- Immobilize the bitten limb using a splint and lightly put a bandage
- Provide cardiopulmonary resuscitation (CPR)
- A “Pressure Pad” at the site of the bite may be applied.
- Do not apply tourniquet or cut the bitten area or use electrical shock.Do not attempt to suck out venom with mouth .
- Do not freeze or apply extreme cold to the area of the bite.
- Do not apply any kind herbal or folk remedy or do not wash the site with soap or any other solution.
Treatment protocol for snakebite
According to the “National Snakebite Management Protocol” issued by Directorate General of Health Services Ministry of Health and Family Welfare Government of India in 2009 the treatment protocol should comprise of the following:
The initial management of snake bite should include dealing with airway, breathing and treatment of shock. The victim should be given tetanus toxoid if the skin is breached and antibiotics if there is cellulitis or local necrosis. Oral paracetamol or tramadol can be given for pain. But aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) should NOT be administered. Tourniquet, if applied should be removed after confirming the presence of distal pulse. If it is absent, a doctor should be present to handle complications such as sudden respiratory distress or hypotension. Finally, Anti-snake venom (ASV) should be administered as the mainstay of treatment.
Critical care for Vasculotoxic patients
On arrival of a vasculotoxic patient presenting with symptoms like bleeding from multiple orifices with hypotension, reduced urine output, obtunted mentation (drowsy, confused), cold extremities, urgent attention and ICU care is required. Volume replacement, forced alkaline diuresis (FAD), pressor support, dialysis and infusion of blood and blood products should be done.
Critical care for Neuroparalytic patients
On arrival of neuroparalytic patient presenting with symptoms like respiratory paralysis, tachypnoea or bradypnoea or paradoxical respiration (only moving abdomen), obtunded mentation, and peripheral skeletal muscle paralysis need urgent ventilator management with endotracheal intubation, ventilation bag or ventilator assistance should be done and ‘Atropine Neostigmine (AN)’ administered.
Patient assessment: Non critical arrival and Critical patients after stabilization
- History of the bite
- Physical examination of bite site
- Check vitals
- Perform 20 minutes Whole Blood clotting test (20 WBCT) every hour for first 3 hours and every 4 hours for remaining 24 hours.
- Check distal pulses and monitor if there is presence of gross swelling
- Keep check on Compartment Syndrome
Administration of Anti snake venom (ASV) therapy
The range of venom injected is 5 mg-147 mg. The total required dose range between 10 and 30 vials as each vial neutralizes 6 mg of Russell’s viper venom. Depending on the patient condition, additional vials can be considered.
Pregnant women, as well as children, are treated in exactly the same way as other victims and given the ame dosage of ASV.
SKIN/CONJUNCTIVAL HYPERSENSITIVITY TESTING does not reliably predict early or late ASV reactions and is not recommended.
Repeat dose of ASV
In Vasculotoxic or hemotoxic envenomation, repeat clotting test every 6 hours until coagulation is restored. Administer ASV every 6 h until coagulation is restored.
In neuroparalytic or neurotoxic envenomation, repeat ASV when there is worsening neurotoxic or cardiovascular signs even after 1–2 h. Maximum dose 20 vials of ASV for neurotoxically envenomed patients. If large doses have been administered and the coagulation abnormality persists, give fresh frozen plasma (FFP) or cryoprecipitate (fibrinogen, factor VIII), fresh whole blood, if FFP not available or platelet concentrate.
ASV reaction- Do NOT inject the ASV locally at the bite site.NO ASV test dose must be administered.ASV should be given only by the IV route, slowly and immediately stopped at the first sign of any reaction.Epinephrine (adrenaline) should always be drawn up in readiness before ASV is administered.
- Administer full dose of ASV in indicated patients with signs and symptoms of envenomation with or without evidence of laboratory tests.
- Though there are no absolute contraindications to ASV, do not routinely administer ASV to any patient claiming to have bitten by a snake. Do not delay or withhold ASV on the grounds of anaphylactic reaction to a deserving case. Do NO give an incomplete dose.
- Swelling that is old need not to be because of snakebite. However, rapid development of swelling indicates snakebite with envenoming requiring ASV.
- Give 10 vials of ASV to the patient who comes days after snakebite on arrival and if no improvement within one hour repeat 10 vials of ASV (No more than 20 vials of ASV).
- Dose of ASV for neuroparalytic snakebite is 10 vials stat as an infusion over 30 minutes followed by a 2nd dose of 10 vials after 1 hour if no improvement within 1st hour.
i. Low dose infusion therapy: 10 vials for
Russel’s viper or 6 vials for Saw-scaled viper as a stat as an infusion
over 30 minutes followed by 2 vials every 6 hours as an infusion in 100
ml of normal saline till clotting time normalizes or for 3 days
whichever is earlier.
ii. High dose intermittent bolus therapy: 10
vials of polyvalent ASV stat over 30 minutes as an infusion, followed
by 6 vials 6 hourly as bolus therapy till clotting time normalizes
and/or local swelling subsides.
No ASV for Sea snakebite or pit viper bite as available ASV does not contain antibodies against themThe range of venom injected is 5 mg-147 mg. The total required dose range between 10 and 30 vials as each vial neutralizes 6 mg of Russell’s viper venom. Depending on the patient condition, additional vials can be considered.
Pregnant women, as well as children, are treated in exactly the same way as other victims and given the ame dosage of ASV.
SKIN/CONJUNCTIVAL HYPERSENSITIVITY TESTING does not reliably predict early or late ASV reactions and is not recommended.
Repeat dose of ASV
In Vasculotoxic or hemotoxic envenomation, repeat clotting test every 6 hours until coagulation is restored. Administer ASV every 6 h until coagulation is restored.
In neuroparalytic or neurotoxic envenomation, repeat ASV when there is worsening neurotoxic or cardiovascular signs even after 1–2 h. Maximum dose 20 vials of ASV for neurotoxically envenomed patients. If large doses have been administered and the coagulation abnormality persists, give fresh frozen plasma (FFP) or cryoprecipitate (fibrinogen, factor VIII), fresh whole blood, if FFP not available or platelet concentrate.
Any new sign or symptom after starting the ASV in drip should be suspected as a reaction to ASV.Early anaphylactic reactions to ASV occurs within 10–180 min of the start of therapy and is characterized by itching, urticaria, dry cough, nausea and vomiting, abdominal colic, diarrhoea, tachycardia, and fever. Pyrogenic reactions usually develop 1–2 h after treatment with symptoms like chills and rigors, fever, and hypotension. –
Late (serum sickness–type) reactions develop 1–12 (mean 7) days after treatment with clinical features like fever, nausea, vomiting, diarrhoea, itching, recurrent urticaria, arthralgia, myalgia, lymphadenopathy, immune complex nephritis and, rarely, encephalopathy. Rarely patients may develop severe life-threatening anaphylaxis characterized by hypotension, bronchospasm, and angioedema.
Treatment of Early ASV reaction
- Stop ASV temporarily.
- Start fresh IV normal saline infusion with a new IV set
- Administer Epinephrine (adrenaline) (1 in 1,000 solution, 0.5 mg (i e 0.5 ml) in adults intramuscular over deltoid or over thigh; In children 0.01 mg/kg body weight) for early anaphylactic and pyrogenic ASV reactions.
- Administer Chlorpheniramine maleate (adult dose 10 mg, in children 0.2 mg/kg) intravenously.
- Once the patient has recovered, re-start ASV slowly for 10-15 minutes keeping the patient under close observation.
- Treatment of Late (serum sickness–type) reactions
- Inj. Chlorpheniramine 2 mg in adults (In children 0.25 mg/kg/day) 6 hourly for 5 days.
- In patients who fail to respond within 24–48 h give a 5-day course of Prednisolone (5 mg 6 hourly in adults and 0.7 mg/kg/day in divided doses in children.
- Desensitization only in case of severe anaphylaxis reaction to ASV
- Pre-medication: Administer Inj. Hydrocortisone 100 mg I.V. and Inj. Adrenaline 0.5 ml subcutaneously/ intramuscularly (+/-Promethazine)
Management of Shock, myocardial damage
- Correct hypovolaemia with colloid/crystalloids, controlled by observation of the central venous pressure.
- Infusion of isotonic crystalloids or albumin, with boluses of up to 20 ml/kg for crystalloids (or albumin equivalent) over 5 to 10 mins titrated to reversing hypotension, increasing urine output, and attaining normal capillary refill, peripheral pulses and level of consciousness without inducing lung crepitations or hepatomegaly.
- If hepatomegaly or rales develop, initiate inotropic support with dopamine or dobutamine. If a patient doesn’t respond to fluid resuscitation, inotropic support must be given.
- In sepsis, noradrenaline is the inotropic agent of choice. Treat patients with hypotension associated with bradycardia with atropine.
- For coagulopathy – in case of prolonged CT, PT, aPTT administer fresh frozen plasma (FFP) infusion. Low fibrinogen and high FDP will require fibrinogen/FFP supplementation. Bleeding leads to anaemia, PCV of 30% must be maintained, therefore, measure serial PCV every 4 –6 h depending upon bleeding severity of patients. If PCV is lower than 30 needs blood transfusion/PCV transfusion. Avoid intramuscular injections. FFP administration after ASV administration results in more rapid restoration of clotting function in most patients, but no decrease in discharge time. Early FFP administration (<6-8h 10-15="" 30="" 4="" activity="" administer="" administration.="" and="" asv="" be="" because="" can="" effective.="" either="" ffp="" fv="" fviii="" has="" hours="" is="" kg="" less="" likely="" low="" min="" ml="" non="" occur="" of="" or="" over="" poor="" post-bite="" premature="" response="" storage="" that="" thawing="" to="" use="" with="" within=""> 24 hours) prior to administration.
- Heparin is ineffective against venom-induced thrombosis and may cause bleeding on its own account. It should never be used in cases of snakebite. Antifibrinolytic agents are not effective and should not be used in victims of snakebite.
Management of severe local envenoming
Local necrosis, intracompartmental syndromes and even thrombosis of major vessels is more likely in patients who cannot be treated with ASV.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.
Give prophylactic broad-spectrum antimicrobial treatment for cellulitis after completion of first 10 vials of ASV) as following.
- Inj. Amoxiciilin + clavulanic acid 1.2 g IV thrice daily for first 7 days then switch to oral therapy Tab. Amoxiciilin + clavulanic acid 625 mg three times a day for further 3-7 days; In children, the dose is 100 mg/Kg/day in three divided doses intravenously; for oral therapy, the dose is 50 mg/kg/day in three divided doses.
- Inj. Metronidazole 400 mg IV infusion thrice daily for 7 days; in children-30 mg/kg/day in 3-4 divided doses.
- Alternatively, Inj Ceftriaxone 1 g IV twice daily (in children the dose is 100 mg/kg/day in two divided doses) for 7 days if Amoxicillin + clavulanic acid is not available. Both Amoxiciilin+ clavulanic acid and Ceftriaxone are mainly excreted through Kidney. Therefore, in case of acute kidney injury in Viper bites dose of both these antibiotics should be reduced and adjusted according to renal function.
Surgical procedures like debridement of necrotic tissue may be required in order to specify the line of demarcation between viable and non-viable tissue. Skin grafting and amputation of a necrotic digit may be required in some cases of snakebite. Fasciotomy may be required in cases with clinical evidence of an intra-compartmental syndrome.
Discharge and follow up
If no symptoms and signs develop after 24 hours the patient can be discharged. Keep the patient under observation for 48 hours if ASV was infused. A snakebite victim discharged from the hospital should continue to be followed up.
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