Mesobuthus tamulus stings cause an autonomic storm with hypertension, myocardial dysfunction and pulmonary oedema, especially in children. Prazosin is the cornerstone; scorpion antivenom added to prazosin speeds recovery.
At the bedside
Timed steps- 1
Grade
RecogniseLocal pain only (grade 1); autonomic storm: sweating, salivation, priapism, vomiting, cold extremities, tachycardia/bradycardia, hypertension (grade 2); pulmonary oedema or shock (grade 3-4).
- 2
Prazosin
Treat30 mcg/kg orally every 3 h until peripheries warm and features settle.
- 3
Add if available
AntivenomScorpion antivenom with prazosin achieved faster resolution (about 8 h vs 17.7 h) and fewer prazosin doses.
- 4
Cardiogenic
Pulmonary oedemaOxygen/NIV, cautious nitrates or dobutamine for myocardial dysfunction; avoid fluid overload.
- 5
Harmful
AvoidRoutine atropine (worsens tachycardia and hypertension), nifedipine (reflex tachycardia), steroids/antihistamines (no benefit).
Scorpion autonomic storm
Prazosin
- Dose
- 30 mcg/kg every 3 h
- Worked example
- 20 kg child: 30 × 20 = 600 mcg = 0.6 mg (crushed immediate-release tablet)
Scorpion sting
Step 1 of ~3
Decision: Autonomic features?
Based on Bawaskar HS, Bawaskar PH. Educational use; follow local protocol.
Evidence
- Bawaskar 2011 (BMJ): 70 patients with grade 2 envenomation; complete resolution at 10 h in 91.4% with antivenom plus prazosin vs 22.9% with prazosin alone; mean recovery 8 h vs 17.7 h; fewer prazosin doses (2 vs 4).
🇮🇳 India notes
- Common in Maharashtra (Konkan), Karnataka, Andhra Pradesh, Tamil Nadu and Gujarat; Dr Bawaskar's prazosin work transformed outcomes.
References
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Educational reference for trained clinicians. Check doses against your hospital protocol and the patient in front of you.