Treatment Protocol of Snake Bite

Treatment Protocol of Snake Bite Kaushik.H.M080201388Rapid clinical assessment and resuscitationDetailed clinical assessment and species diagnosisInvestigations/laboratory tests Specific treatment Attend to AIRWAY , BREATHING, CIRCULATIONSecure an IV line (wide bore).Booster dose of tetanus toxoid is recommended.Identify the snake responsible

All patients should be kept under observation for a minimum period of 24 hrs.Determine the exact time of biteBacterial Infections- Prophylactic course of penicillin (or erythromycin for penicillin-hypersensitive patients)and a single dose of gentamicin or a course of chloramphenicol

Care must be taken when removing tight tourniquets tied by victim. Sudden removal can lead to massive surge of venom leading to neurological paralysis, hypotension.

Pain-paracetamol/ 50 mg of tramadol maybe given. NSAIDs and Aspirin are contraindicated.

Investigations20 minute whole blood clotting test -considered most reliable test of coagulation.Platelet count : may be decreased viper

WBC cell count : Early neutrophil leucocytosis in systemic envenoming from any species. Blood film : Fragmented RBC(helmet cell, schistocytes) are seen in microangiopathic haemolysis.

Plasma/serum : may be pink or brownish if there is gross haemoglobinaemia or myoglobinaemia.

Aminotransferases, creatine kinase, aldolase elevated if there is severe local damage or, particularly generalised muscle damage.

Bilirubin is elevated following massive extravasation of blood.

Creatinine, urea or blood urea nitrogen levels are raised in the renal failure

Early hyperkalaemia may be seen following extensive rhabdomyolysis in sea snake bites. Bicarbonate will be low in metabolic acidosis (eg renal failure). Arterial blood gases and pH may show evidence of respiratory failure (neurotoxic envenoming) and acidaemia (respiratory or metabolic acidosis).

Urine for RBC Viper Bite Hematuria, Proteinuria, Hemoglobinuria, Myoglobinuria

ECG Normal, Bradycardia with ST elevation or depression, T inversion, QT prolongation.

Chest X- ray Normal or may show Pulmonary Oedema, Intrapulmonary Hemorhages, Pleural Effusion.Monitor vital signsObserve every patient for minimum 24 hours. Monitor the patient every 6 hours.Pulse, BP, RespirationUrine outputBlood urea, CreatinineBleeding tendencyLocal swellingVomitingDiplopia, Ptosis, Muscle Weakness, Breathlessness

Anti Snake VenomAntivenom 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.It neutralises the free, unbound venom & to some extent also dissociates the bound toxinASV is manufactured in India by the Haffkine Central Research Institute, Kasauli & Serum Institute of India, Pune & both are POLYVALENT(neutralizes venom of different species of snakes.)

1 ml of ASV neutralisesCobra 0.6 mgCommon krait 0.45mgRussels viper 0.6 mgSaw scaled viper 0.45 mg

IndicationsAs per W.H.O Guidelines ONLY if a patient develops one / more of the following signs/symptoms ASV should be administered :SYSTEMIC ENVENOMING Evidence of coagulopathy: detected by 20WBCT or visible spontaneous systemic bleedingEvidence of neurotoxicity : ptosis, ext.ophthalmoplegia

CVS abnormalities : hypotension, shock, arrhythmias

Acute renal failure

Hemoglobinuria / myoglobinuria

Persistent severe vomiting / abdominal pain

LOCAL ENVENOMINGLocal swelling > of involved limb

Rapid extension of swelling

Enlarged tender lymph nodes draining the bitten limbASV administration NO ASV TEST DOSE MUST BE ADMINISTERED .

Recommended initial dosages are 100 ml( 10 vials) of polyvalent ASV for adults & children based on published research that russells viper injects on an average of 63 mg of venom.

Our initial dose must be calculated to neutralize the average dose of venom injected.

Range of venom injected = 5mg 147 mg

Suggested ASV dose = 100 -250 ml

Initial dose of 100 ml must be diluted in 100 ml of NS & given over 1 hour.

Patient should be carefully monitored for 2 hrs.

Local administration of ASV, near the bite site ineffective, painful, raises intracompartmental pressure. SHOULD NOT BE DONEVictim who arrives late ?

Often after several days , usually with acute renal failure.

Are there any signs of current venom activity ?

Perform 20WBCT & determine if any coagulopathy is +, if + administer ASV. If - , treat ARF dialysis

Neurotoxic envenoming look for ptosis, respiratory failure , + administer 1 dose of ASV , respiratory support

ASV reactionsPatient should be monitored closely

First sign of any one of the following : 1. Utricaria 6. Vomiting 11.Bronchospasm 2. Itching 7. Diarrhoea 12.Angioedema 3. Fever 8. Abdominal cramps 4. Chills 9. Tachycardia 5. Nausea 10. Hypotension

Discontinue ASV & give 0.5 mg of 1 :1000 adrenaline IM/ IV diphenhydramine(antihistamines).

Repeat doses of ASVHEMATOTOXIC POISONING :

20 WBCT abnormal initial dose given over 1 hr.

Repeat 20WBCT after 6 hrs

Abnormal another dose to be given. Repeat same dose again.

20WBCT & Repeat doses of ASV to be continued on 6 hourly manner until coagulation is restored.NEUROTOXIC POISONING

Assess the patient 1-2 hrs after the initial dose

If symptoms persist / worsen , 2 nd dose which is same as 1st dose is to be given & then ASV can be discontinued

Role of Neostigmine in Neurotoxic poisoningAnticholinestrase & prolongs life of Ach - which can reverse resp.failure & neurotoxic symptoms ( post synaptic )Neostigmine test : 1.5 -2.0 mg IM preceeded by 0.6 mg atropine IVObserve for 1 hr If victim responds , continue 0.5 mg Neostigmine IM hrly with 0.6 mg Atropine IV over 8 hrs If no improvement in symptoms after 1 hr , stop Neostigmine

Supportive TherapyRESPIRATORY FAILURE :ABGIntubate & VentilateNeostigmine & Atropine

HYPOTENSION :Plasma expanders-crystalloidsDopamine 2.5 5 micrograms/Kg/min

PERSISTANT / SEVERE BLEEDING :Majority timely use of ASV will stop systemic bleedASV + Blood Transfusion

RENAL FAILURE Hemodialysis / peritoneal dialysis

COMPARTMENT SYNDROME :Fasciotomy

SURGICAL DEBRIDEMENT OF WOUND: Necrosis