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 bite Bacterial 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 tourniquetstied by victim. Sudden removal can lead to massivesurge of venom leading to neurological paralysis,hypotension.•Pain-paracetamol/ 50 mg of tramadol maybe given.NSAIDs and Aspirin are contraindicated.
Investigations 20 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 signs Observe every patient for minimum 24 hours. Monitor thepatient every 6 hours. Pulse, BP, Respiration Urine output Blood urea, Creatinine Bleeding tendency Local swelling Vomiting Diplopia, Ptosis, Muscle Weakness, Breathlessness
Anti Snake Venom Antivenom 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 neutralises Cobra – 0.6 mg Common krait – 0.45mg Russels viper – 0.6 mg Saw scaled viper – 0.45 mg
Indications As 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
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 reactions Patient 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 ASV HEMATOTOXIC 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 inNeurotoxic poisoning Anticholinestrase & 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