Snake Bite in Children
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Direct answer
Snake bite in children is envenoming that is either neurotoxic or haemotoxic, depending on the snake. Indian cobra and common krait bites are neurotoxic, causing ptosis and descending paralysis, while Russell's viper and saw-scaled viper bites are haemotoxic, causing incoagulable blood. The 20 minute whole blood clotting test is the bedside screen, and polyvalent anti-snake venom is the specific treatment.
What you must remember
- Big Four snakes: Indian cobra, common krait, Russell's viper and saw-scaled viper account for most clinically significant bites in India.
- Neurotoxicity: Ptosis, ophthalmoplegia, dysphagia and respiratory muscle weakness, typical of cobra and krait envenoming.
- Haemotoxicity: Coagulopathy, spontaneous bleeding and acute kidney injury, typical of Russell's viper and saw-scaled viper.
- 20 minute whole blood clotting test (20WBCT): About 2 mL of blood is left undisturbed in a clean glass tube; no clot after 20 minutes, or a clot that breaks down on tilting, indicates coagulopathy.
- Painless krait bite: Local signs are often minimal, so the absence of pain does not exclude envenoming.
- First aid: Immobilise the limb and transport promptly; tourniquets, incision, suction and ice are avoided.
- Antivenom dosing: Children receive the same dose as adults, because it neutralises venom load rather than body size; repeat doses follow clinical progress and clotting status.
Comparing the two venom patterns
Neurotoxic and haemotoxic envenoming need different monitoring, so the likely snake matters at the bedside. The table summarises the features that separate the two patterns in a child.
| Feature | Neurotoxic (cobra, krait) | Haemotoxic (Russell's viper, saw-scaled viper) |
|---|---|---|
| Local signs | Swelling and pain in cobra bites; often minimal in krait | Marked swelling, pain, blistering and bleeding |
| Early systemic sign | Ptosis, drowsiness, dysphagia | Gum bleeding, haematuria, blood oozing from the bite |
| Clotting on 20WBCT | Usually normal | Incoagulable blood |
| Main complication | Respiratory failure | Acute kidney injury and bleeding |
Neurotoxic bites can look benign early, so repeated neurological checks matter, and feeding is held while swallowing is impaired because of aspiration risk. Haemotoxic bites need repeat clotting tests, because coagulopathy can persist after the first dose of antivenom.
Bystanders should not try to catch or kill the snake. A photograph is more useful than the dead animal for identification, and the clinical pattern guides treatment more than the snake's appearance.
Where the exam tries to catch you
Questions on snake bite usually test the first aid error or the wrong conclusion from a test.
- Trap: Assuming a painless bite is harmless. Correct: Krait bites are often painless, yet envenoming can still be severe and needs observation.
- Trap: Applying a tourniquet or cutting over the bite. Correct: Both damage tissue; immobilise the limb and transfer the child to a centre with antivenom.
- Trap: Treating a normal 20WBCT as proof of no envenoming. Correct: Neurotoxicity is independent of clotting, so ptosis and breathing must still be watched.
- Trap: Calculating antivenom by body weight. Correct: A child gets the same dose as an adult under the national protocol, since the dose neutralises venom load, not body size.
Frequently asked questions
What is the 20 minute whole blood clotting test in snake bite?
The 20 minute whole blood clotting test is a bedside screen for venom-induced coagulopathy. About 2 mL of the child's blood is placed in a clean glass tube and left undisturbed for 20 minutes. If it does not clot, or the clot breaks down when the tube is gently tilted, the snake bite is likely to have caused coagulopathy.
Which snakes in India cause neurotoxic envenoming in children?
The Indian cobra and the common krait are the main neurotoxic snakes in India. Their bites cause ptosis, ophthalmoplegia, dysphagia and, in severe cases, descending paralysis with respiratory failure. A child with these features needs airway monitoring and specialist care.
Why are tourniquets and incision avoided in snake bite?
Tourniquets and incision are avoided in snake bite in children because they damage tissue and can worsen local injury. Suction and ice are not recommended either. Immobilising the limb and transporting the child promptly to a centre with antivenom is the correct first aid.
How is antivenom used in children with snake bite?
Polyvalent anti-snake venom is the specific treatment for envenoming in children. The initial dose is the same as in adults, not scaled to weight, because it neutralises venom rather than body size. Repeat doses depend on repeat clotting tests and clinical response.