SNAKE BITES A PRACTICAL APPROACH Epidemiology q q

SNAKE BITES : A PRACTICAL APPROACH

Epidemiology q q 2, 000 snake bites and 15 -20, 000 deaths per year Males : Females : : 2: 1 Majority of bites occur on the lower extremities 50% of bites by venomous snakes are dry bites –negligible envenomation

CLASSIFICATION q POISONOUS / NON POISONOUS q LAND / WATER (FRESH / SALT WATER)

Poisonous Snakes In India > 200 species of snakes only 52 are poisonous Elapidae Cobra ; kraits Neuro toxc, cardiotoxic Viperidae (Vipers) Russell’s viper, Saw scaled vipers, Pit vipers Hemotoxic Hydrophidae Sea snakes Myotoxic Krait and Russells’ viper more toxic than cobra

Severity of Snakebite q q q The location of the bite (fatty tissue absorbs the venom more slowly than muscle tissue) Whether disease-causing organisms are in the venom The size and weight of the victim The general health and condition of the victim How much physical activity the victim engaged in immediately following the bite (physical activity helps spread venom)

Diagnosis of poisonous snake bite FANG MARKS : classically , two puncture marks separated by a distance varying from 8 mm to 4 cm, depending upon the species involved. However a side swipe may produce only a single puncture, while multiple bites could result in numerous fang marks

Signs and Symptoms of Snakebite q q q � Two distinct fang marks about half an inch apart at the bite site, which may or may not bleed (in some cases there may be only one fang mark) Immediate and severe burning pain and swelling around the fang marks, usually within 5 minutes but sometimes taking as long as 4 hours to develop (swelling may affect the entire arm or leg) Purplish discolouration and blood-filled blisters around the bite, usually within 2 to 10 hours Numbness around the bite

Effects of envemomation q q Local effects Systemic effects: - Neurotoxic - Haemotoxic - Cardiotoxic

Clinical features Venomous snake bites • Elapid Bites ( Krait ; Cobra) q Local features -indistinct fang marks -burning pain -swelling and discoloration -serosanguinous discharge q Pre paralytic stage : emesis -headache

Elapid Bites ( Krait ; Cobra) q Paralytic stage: -Ptosis -Opthalmoplegia -Drowsiness -Dysarthria -Dysphagia -Convulsions -Bulbar paralysis -Respiratory failure q

COBRA ENVENOMATION q. Cardiotoxicity q. Cardiac depression q. Cardiogenic / vasogenic shock q. Systolic cardiac arrest

VIPERID BITE (VIPER) • Local features: q. Rapid swelling q. Discolouration q. Blister formation q. Bleeding from bite site q. Severe pain

Systemic features (hemotoxic) Ø bleeding from nose Ø Hemoptysis Ø Bleeding gums Ø Hematuria Ø purpuric spots Ø Renal failure •

HYDROPHID BITE (sea snake) Myotoxic q. Local features : minimal swelling and pain q. Systemic features : Muscle pain and stiffness q. Myoglobinuria , renal tubular necrosis

Snake-bite management Snakes don’t bite out of whim q Usually forced to bite q Venom has evolved as a mechanism to subdue prey and snakes need to conserve their venom for that purpose q

FIRST AID Things you should do: q q Make sure the victim and others are a safe distance away from the snake and try to memorize its appearance STAY CALM and in control. Take charge of the situation and reassure the victim Remove Watches, rings, bangles and anything else that will become constrictive if the limb was to swell up. Try to immobilise the victim. Never let him/ her run and only allow them to walk if unavoidable.

q q q In case of neurotoxic bites (All elapids and hydrophiids: Cobras, King cobras, kraits, coral snakes and sea snakes), pressure immobilization (Sutherland method) with long crepe or other elastic bandage(5=10 cm wide, several rolls) and splint to be applied immediately to the bitten limb, starting at the digits and working up to the groin or arm pit. Don’t waste time with trying to get any elaborate first aid done. Get to hospital as soon as is safely possible. Note the time of the bite and the progression of any visible symptoms. Give the doctor a brief and detailed description of the bite and symptoms. Antisnake venom serum is the only proven cure for venomous snakebite

First Aid Things'Not'to'Do: q q q q Never try to suck out the venom Never make an incision Never go to traditional healers or try home remedies Tie tourniquets or use ice Never clean out or tamper with the site of the bite Never try and catch the snake or kill it All the above actions do not work and often cause more damage than good.

ASVS (ANTI SNAKE VENOM SERUM) Made from equine serum q Polyvalent against cobra, viper (russell and saw scaled), krait q 1 ml neutralises : q 0. 6 mg Cobra ; 0. 45 mg Krait q 0. 6 mg Russells; 0. 45 mg Saw scaled Lethal dose : Cobra -0. 12 gm, Krait 0. 06 gm, Russels 0. 15 gm q

Snakebite Prevention q q q q As always, prevention is better than cure. Take care when clearing vegetation, raking dry leaves in your garden. Supervise kids in the outdoors, especially in a green neighborhood. Use torch/flashlight at night and keep wearing shoes. Check shoes before wearing them. Watch your step and see before you sit! Keep your backyard free of junk and make sure your solid waste is managed properly. If you see a snake, do nothing. Let it go. Do not try to pick it up or kill it. If a snake has entered Your premises, call professional snake rescuers.