SN6 SHORT NOTE 5M ★ High-yield

Describe scorpion sting and the other animal poisons.

Forensic Medicine · 2nd Professional — Para-Clinical

Scorpion Sting

Scorpion sting is a major paediatric emergency in western and southern India, particularly in Maharashtra, Gujarat, Karnataka and Tamil Nadu. The dangerous species is the Indian red scorpion, Mesobuthus tamulus; the black scorpion Heterometrus causes only local pain
Mechanism — the venom acts on voltage-gated sodium channels, prolonging their opening and causing a massive release of catecholamines — an "autonomic storm". The picture is therefore of sympathetic overactivity, sometimes preceded by a brief parasympathetic phase
Features — excruciating local pain with little swelling, and marked tenderness on tapping the site (the "tap test"); then, in severe cases and especially in children, vomiting, profuse sweating, priapism, hypertension followed by hypotension, tachycardia, cool extremities, and the two features that kill — myocarditis with cardiogenic shock, and acute pulmonary oedema
Treatment — the key advance is prazosin, an alpha-1 blocker, which is the pharmacological antidote to the autonomic storm and has markedly reduced mortality in Indian practice; it is given early and repeated. Also: scorpion antivenom where available; local anaesthetic infiltration and analgesia (avoiding opioids, which may worsen the picture); dobutamine for myocardial failure; and management of pulmonary oedema. Do not apply a tourniquet or incise

CLINICAL PEARL

Prazosin transformed the outcome of scorpion sting, and it is the single fact worth carrying from this topic. The venom kills by a catecholamine storm producing myocarditis and pulmonary oedema, and an alpha blocker directly opposes it. Given early in a child from an endemic district, it has taken mortality from double figures to close to zero — an antidote in the pharmacological rather than the immunological sense.

Other Animal Poisons

Source	Features and management
BEES, WASPS and hornets	Local pain and swelling. The danger is anaphylaxis in a sensitised person after a single sting, treated with adrenaline; and, after multiple stings (hundreds), a direct toxic syndrome with rhabdomyolysis, haemolysis, renal failure and hepatic injury. A bee sting leaves the barbed sting and venom sac in the skin, which should be scraped off rather than squeezed; a wasp does not
Spiders	The black widow (Latrodectus) causes severe muscle cramps and abdominal rigidity mimicking an acute abdomen; the brown recluse (Loxosceles) causes local necrosis. Both are uncommon in India
Cantharides (Spanish fly)	Dried beetle Lytta vesicatoria, containing cantharidin. A powerful vesicant and renal irritant, historically used as an aphrodisiac and an abortifacient — the reputation resting on the urethral and genital irritation it causes, and it has killed for that reason. Produces haemorrhagic nephritis, cystitis, priapism and gastrointestinal burns
Marine — pufferfish	Tetrodotoxin, a sodium channel blocker; perioral paraesthesia, ascending paralysis and respiratory failure with consciousness retained; supportive treatment and ventilation only
Marine — other	Stingray (a mechanical wound with venom; treated with hot water immersion, which denatures the venom); jellyfish and box jellyfish (vinegar to inactivate undischarged nematocysts); and ciguatera from reef fish, with the characteristic reversal of hot and cold sensation
Centipedes and ants	Local pain and inflammation; rarely serious

Applied Aspects

Give prazosin early in Indian red scorpion sting, particularly in a child; it opposes the autonomic storm directly and has transformed mortality
Watch for pulmonary oedema and myocarditis for at least 24 hours after a significant sting; the local pain settles long before the cardiac risk does
Scrape a bee sting out rather than squeezing it; squeezing injects the remaining venom from the attached sac
Anaphylaxis needs adrenaline, not antihistamine, and a single sting can kill a sensitised person while hundreds are needed for direct toxicity
Immerse a stingray wound in hot water, as hot as can be tolerated; the venom is heat-labile and this is both analgesic and specific
Consider cantharides in unexplained haemorrhagic cystitis with genital irritation; its use as an aphrodisiac persists and it has caused deaths
Manage tetrodotoxin by ventilation alone; there is no antidote, consciousness is preserved throughout, and recovery is complete with support
The Indian red scorpion is the dangerous species; the black scorpion causes only local pain and needs analgesia alone
The venom acts on sodium channels and releases catecholamines, so the syndrome is an autonomic storm rather than a local toxin effect
Vinegar inactivates jellyfish nematocysts that have not yet fired, and fresh water makes them discharge
Ciguatera reverses hot and cold sensation, which is a distinctive and diagnostic symptom after eating reef fish

All questions in Toxicology II — Specific Poisons

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