What is the management for a patient with a neurotoxic snake bite in India?

Management of Neurotoxic Snake Bite in India

The mainstay of treatment for neurotoxic snake bites in India is prompt administration of antivenom in a hospital setting with close monitoring for adverse reactions and respiratory support as needed. 1

Immediate Care

• Apply pressure immobilization bandage (40-70 mmHg for upper extremity, 55-70 mmHg for lower extremity) to reduce venom spread 1
• Rest and immobilize the bitten extremity to minimize venom circulation 1
• Remove rings and constricting jewelry from the affected limb to prevent complications from swelling 1
• Call emergency services immediately for rapid transport to a healthcare facility 1

Do NOT:

• Apply suction to the bite area (no clinical benefit, may worsen injury) 1
• Use ice, electric shock, or tourniquets (unproven and potentially harmful) 1
• Delay seeking medical attention for traditional remedies (common but ineffective practices include local application of lime, chillies, herbal medicine) 2

Hospital Management

Diagnosis and Assessment

• Identify snake if possible (in India, cobra and krait are the most common neurotoxic snakes) 2
• Look for clinical manifestations of neurotoxicity:
  • Early signs: Drowsiness, ptosis, frothy saliva, slurred speech 3
  • Progressive signs: Respiratory failure, skeletal muscle paralysis 3
  • Note: Symptoms typically appear within 8 hours in 94% of cases 3
• Laboratory tests: Complete blood count, coagulation studies, renal function tests, electrolytes 1
• Monitor oxygen saturation continuously 1

Treatment Protocol

1. Antivenom Administration:

   • Polyvalent snake antivenom (SAV) is the definitive treatment 1, 4
   • Low-dose protocol (150 ml of polyvalent SAV) is as effective as high-dose protocols for severe neurotoxic envenomation 4
   • Monitor closely for allergic reactions to antivenom (occurs in approximately 2.2% of cases) 2

2. Respiratory Support:

   • Provide supplemental oxygen if hypoxic 1
   • Initiate mechanical ventilation for respiratory failure 3
   • Consider anticholinesterase (edrophonium chloride) as supportive therapy against neuromuscular effects 3

3. Supportive Care:

   • Pain management as needed 1
   • Tetanus prophylaxis 1
   • Prophylactic antibiotics if indicated for wound infection 1

Monitoring and Complications

• Monitor for delayed reactions to antivenom, such as serum sickness 1
• Watch for local necrosis (develops in approximately 40% of cases by the end of the first week) 3
• Neurological complications may include:
  • Presynaptic neurotoxicity (β-neurotoxins): inhibition of acetylcholine release
  • Postsynaptic neurotoxicity (α-neurotoxins): reversible blockage of acetylcholine receptors 5

Prognosis

• Mortality is low in well-equipped hospitals with early antivenom administration 2
• Most patients recover without residual neurological deficits when treated promptly 4
• The duration of mechanical ventilation in severe cases averages 44-47.5 hours 4

Important Considerations for Indian Context

• In Gujarat and other regions of India, neuroparalytic manifestations are more prevalent (52% of cases) 2
• Time to treatment is critical - only 14% of patients receive treatment within 1 hour of bite, with 64.84% receiving treatment within 1-6 hours 2
• Rural populations, particularly farmers and laborers, are at highest risk (71% of victims live in rural areas) 2
• Most incidents (61.2%) occur at night or early morning (before 6 a.m.) 2