IM21.8 | Scorpion Envenomation — Summary & Reflection

KEY TAKEAWAYS

Scorpion envenomation in India is caused primarily by Mesobuthus tamulus (Indian red scorpion) — predominantly rural, Maharashtra/AP/TN/Rajasthan/Gujarat, paediatric peak.

Pathophysiology: Venom toxins prolong voltage-gated Na+ channel opening → massive catecholamine release → alpha-1 vasoconstriction + direct catecholamine myotoxicity → increased afterload → LV failure → pulmonary oedema + shock.

Grading: Grade I (local pain only), Grade II (autonomic storm: HTN + tachycardia + sweating + vomiting), Grade III (cardiovascular failure: pulmonary oedema + cardiogenic shock).

Treatment — specific: Prazosin (alpha-1 blocker) — 30 micrograms/kg orally (max 1 mg child), repeated every 3 h up to 4 doses if needed. Reduces afterload, corrects the pathophysiology. Beta-blockers are CONTRAINDICATED — block beta-1 cardiac response while alpha-1 vasoconstriction continues → collapse.

Grade II supportive: IV access, O2, antiemetics, ECG monitoring, admission.
Grade III: ICU, O2/ventilation, dobutamine 5–10 mcg/kg/min IV for cardiogenic shock, IV furosemide for pulmonary oedema, antivenom if available.

Investigations: ECG (mandatory), CXR, echo if available, troponin, blood glucose.

Key exam trap: Do NOT give antihypertensives without addressing the mechanism; do NOT give beta-blockers.

REFLECT

Reflect on the case in the hook: the junior doctor gave paracetamol and a sedative — entirely missing the autonomic storm. He may have seen the hypertension but, lacking a framework for scorpion envenomation grading, did not know what it meant or that prazosin was the answer. Think about how the lack of a mental schema (grade → treatment) created a dangerous clinical gap. Now that you have the schema, how would you teach it to a junior colleague in 60 seconds at the bedside — what single sentence captures the essence of scorpion envenomation management? Consider also: if you are posted to a primary health centre in rural Maharashtra, what would you want to have in your emergency tray before the monsoon season starts — when scorpion encounters peak?