Scorpion bite management

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I now have comprehensive information from Harrison's 22E (2025), Andrews' Dermatology, and Medical Microbiology to compose a thorough answer.

Scorpion Bite (Sting) Management

Common Centruroides scorpion (Andrews' Diseases of the Skin)

Overview

Scorpions are nocturnal arachnids with ~1,000 known species, of which only ~30 pose lethal risk to humans. They hide in crevices, shoes, clothing, and bedding. Stings occur only in self-defense. Medically important species include:

Species	Region	Venom Mechanism
Centruroides sculpturatus/exilicauda	USA (Southwest)	Neurotoxin (Na⁺ channel persistent activation)
Leiurus quinquestriatus	Middle East / North Africa	Catecholamine storm
Androctonus spp.	Mediterranean / North Africa	Catecholamine storm
Mesobuthus tamulus	India	Catecholamine storm
Tityus serrulatus	Brazil	Catecholamine storm + pancreatitis
Hemiscorpius lepturus	Iran	Cytotoxic (hemolysis, necrosis)

Venom Mechanisms

Neurotoxic (Centruroides): Keeps voltage-gated Na⁺ channels persistently open → uncontrolled neuronal firing → sympathetic/parasympathetic discharge
Catecholamine storm (Leiurus, Androctonus, Mesobuthus, Tityus): Massive endogenous catecholamine release → hypertensive crisis, arrhythmias, pulmonary edema, myocardial injury
Cytotoxic (Hemiscorpius): Direct tissue damage → hemolysis, tissue necrosis, hemoglobinuria, AKI

Clinical Features

Local (most stings)

Immediate sharp pain, paresthesia, hyperesthesia
Variable edema, ecchymosis, burning sensation
Positive tap test (Centruroides): pain/paresthesia accentuated by tapping the site
Typically resolves within a few hours; skin does not slough (except cytotoxic species)

Local inflammatory progression post-scorpion sting — A: immediate erythema, B: 1-hour hematoma, C: 24-hour peak edema, D: 3-day resolution

Systemic (dangerous species / severe envenomation)

Neuromotor (Centruroides):

Restlessness, profuse salivation, lacrimation, rhinorrhea
Blurred vision, abnormal eye movements, slurred speech
Muscle twitching/jerking (can mimic seizures)
Cranial nerve dysfunction, hypersalivation
Tachycardia, arrhythmias, hypertension, hyperthermia, rhabdomyolysis, acidosis
Peak severity ~5 hours; symptoms subside in 1–2 days (pain/paresthesia may last weeks)
Fatal respiratory arrest — highest risk in young children and elderly

Cardiovascular (Leiurus, Androctonus, Mesobuthus, Tityus):

Hypertensive crises, arrhythmias, pulmonary edema, myocardial damage
Tityus trinitatis → acute pancreatitis
Parabuthus/Buthotus (South Africa) → CNS toxicity

Cytotoxic (Hemiscorpius):

Relatively asymptomatic at first
24h+: pain, hemolysis, tissue necrosis, hemoglobinuria → AKI

Severe scorpion envenomation cardiac complications: (a) Ventricular tachycardia ~300 bpm; (b) Sinus tachycardia with QTc prolongation (550ms) after rhythm reversal; (c) Bilateral non-cardiogenic pulmonary edema on CXR

Management

1. First Aid / Pre-hospital

Move patient away from the scorpion (do not handle it)
Cold packs to the sting site — reduce venom absorption and swelling (hot packs are contraindicated — cause vasodilation and accelerate systemic spread)
Pressure dressing over the site
Keep the patient calm
Assess airway and vital signs
Do not attempt to suck out venom or apply tourniquets

2. Risk Stratification

Grade	Features	Management
Mild (local only)	Pain, paresthesia, positive tap test, no systemic signs	Home management; return precautions
Moderate	Mild systemic: tachycardia, HTN, sweating	ED observation, IV access, monitoring
Severe	Cranial nerve/neuromuscular dysfunction, cardiovascular collapse, respiratory failure	ICU, antivenom

3. Symptomatic/Supportive Treatment

Problem	Treatment
Mild local pain	Ice packs, oral analgesics, oral antihistamines
Agitation / involuntary movements	IV midazolam (continuous infusion)
Hypertension / pulmonary edema	Nifedipine, nitroprusside, hydralazine, or prazosin
Bradydysrhythmia	Atropine
Secretion management	Supportive, consider glycopyrrolate
Sedation with opiates/benzodiazepines	Monitor closely for respiratory compromise
Pain relief	Analgesics; avoid opiates where possible (may increase toxicity)

⚠️ Contraindicated: Steroids, antihistamines, calcium channel blockers, and diuretics should be avoided for cardiac complications — they can worsen outcomes through negative cardiac effects.

4. Antivenom

Indicated for: severe envenomation with cranial nerve/neuromuscular dysfunction, cardiovascular compromise, respiratory failure
FDA-approved (USA): Equine-derived Centruroides sculpturatus IgG F(ab')₂ antivenom (Anascorp®)
- IV administration rapidly reverses cranial nerve dysfunction and muscular symptoms
Other regions: Species-specific antivenoms exist for Leiurus, Androctonus, Tityus, Mesobuthus — follow local availability and national guidelines
More effective when administered early after envenomation
Watch for serum sickness (~1–2 weeks post-administration): treat with antihistamines, analgesics ± oral steroids

5. Pediatric Considerations

Children are at highest risk for severe/fatal envenomation
Even moderate symptoms in children should be treated as medical emergencies
Antivenom threshold is lower in children

6. Tetanus Prophylaxis

Ensure tetanus immunization status is current for all sting patients

What NOT to Do

❌ Hot packs (increase absorption)
❌ Opioid analgesics unless carefully monitored (increase toxicity)
❌ Calcium channel blockers, steroids, antihistamines, or diuretics for cardiac management
❌ Excision or suction of sting site

Disposition

Finding	Disposition
Local pain only, nonlethal species confirmed	Discharge with return precautions
Systemic symptoms, uncertain species	Emergency department for observation
Neuromuscular dysfunction, cardiovascular compromise	ICU admission, antivenom, monitoring

Prevention

Shake out shoes, clothing, and bedding in endemic areas
Use a flashlight at night
Clear debris around dwellings
Wear protective footwear outdoors at night

Sources: Harrison's Principles of Internal Medicine 22E (2025), p. 3778–3779; Andrews' Diseases of the Skin; Medical Microbiology 9e

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