Treatment Protocol of Snake Bite

Kaushik.H.M080201388

Rapid clinical assessment and resuscitation

Detailed clinical assessment and species

diagnosis

Investigations/laboratory tests Specific treatment

Attend to AIRWAY , BREATHING, CIRCULATION

Secure 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, Respiration

Urine output

Blood urea, Creatinine

Bleeding tendency

Local swelling

Vomiting

Diplopia, 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 toxin

ASV 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 bleeding

• Evidence of neurotoxicity : ptosis, ext.ophthalmoplegia

• CVS abnormalities : hypotension, shock, arrhythmias

• Acute renal failure

• Hemoglobinuria / myoglobinuria

• Persistent severe vomiting / abdominal pain

LOCAL ENVENOMING• Local swelling > ½ of involved limb

• Rapid extension of swelling

• Enlarged tender lymph nodes draining the bitten limb

ASV 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 DONE

Victim 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 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

Supportive TherapyRESPIRATORY FAILURE :• ABG• Intubate & Ventilate• Neostigmine & Atropine

HYPOTENSION :• Plasma expanders-crystalloids• Dopamine 2.5 – 5 micrograms/Kg/min

PERSISTANT / SEVERE BLEEDING :• Majority – timely use of ASV will stop

systemic bleed• ASV + Blood Transfusion

RENAL FAILURE • Hemodialysis / peritoneal dialysis

COMPARTMENT SYNDROME :• Fasciotomy

SURGICAL DEBRIDEMENT OF WOUND: Necrosis