Management of scorpion bite
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I now have comprehensive, authoritative content from Harrison's 22E (2025), Tintinalli's Emergency Medicine, Rosen's Emergency Medicine, Andrews' Dermatology, and forensic medicine texts. Here is the full management guide:
Management of Scorpion Sting (Scorpion Envenomation)
Background
Scorpions are nocturnal arachnids that inject venom via a tail stinger. Of ~1,000 known species, only about 30 are potentially lethal. Medically important species include:
| Species | Region | Primary Toxicity |
|---|---|---|
| Centruroides sculpturatus/exilicauda | USA (Arizona, NM, TX) | Neuromuscular |
| Leiurus quinquestriatus | Middle East, North Africa | Neurotoxic (50% mortality in children) |
| Mesobuthus tamulus | India, Nepal, Pakistan | Cardiovascular (catecholamine excess) |
| Androctonus spp. | North Africa, Middle East | Cardiovascular |
| Tityus serrulatus | Brazil | Cardiovascular + neuromuscular |
| Tityus trinitatis | Trinidad | Acute pancreatitis |
| Hemiscorpius lepturus | Iran | Cytotoxic - hemolysis, tissue necrosis |
| Parabuthus/Buthotus | South Africa | CNS toxicity |
Mechanism: Venom contains neurotoxins that keep sodium channels open, causing prolonged depolarization of both somatic and autonomic nervous systems. Catecholamine excess with some species causes cardiovascular complications.
Clinical Features
Local (Grade 1 - most cases)
- Sharp pain immediately at sting site
- Paresthesia, hyperesthesia - "tap test" positive (tapping over sting site accentuates pain)
- Edema, erythema, burning sensation
- Minimal swelling with dangerous species (neurotoxic)
Systemic (Grade 2-4 - <10% of stings)
Neuromuscular/Cranial nerve dysfunction (Centruroides):
- Restlessness, agitation, profuse salivation, lacrimation, rhinorrhea
- Blurred vision, abnormal eye movements, slurred speech
- Muscle twitching/jerking (may mimic seizures), opisthotonos
- Dysphagia, difficulty handling secretions - airway risk
Autonomic/Cardiovascular (Mesobuthus, Androctonus, Tityus):
- Hypertensive crisis, tachycardia, arrhythmias
- Pulmonary edema, myocardial damage, cardiogenic shock
Cholinergic (Tityus species):
- Bradycardia, hypotension, sweating, salivation, abdominal pain, pancreatitis
Other complications: Rhabdomyolysis, acidosis, hyperthermia, acute kidney injury (Hemiscorpius)
Grading System (Centruroides - North American)
(Rosen's Emergency Medicine / JTS Clinical Practice Guideline)
| Grade | Clinical Features | Antivenom Indicated? |
|---|---|---|
| 1 | Local effects only: pain and paresthesias at sting site | No |
| 2 | Local AND remote (distant) pain/paresthesias | No |
| 3 | Cranial nerve dysfunction OR skeletal neuromuscular dysfunction (+ autonomic signs) | Yes |
| 4 | Cranial nerve dysfunction AND skeletal neuromuscular dysfunction | Yes |
Management
Initial / Prehospital
- Move patient away from scorpion; identify species if safe to do so
- Rest and immobilize the sting site (slows venom absorption)
- Apply cold pack/ice pack to sting site (decreases absorption)
- Pressure dressing over sting site
- Keep patient calm
- Do NOT: suck out venom, apply tourniquet (older forensic texts recommended this but it is not current practice), incise, cauterize, or apply heat
Grade 1-2 (Local/Mild) - Can be managed at home or in ED
- Analgesia: Acetaminophen or NSAIDs first-line; local lidocaine (without epinephrine) infiltration at sting site is highly effective and recommended
- Oral antihistamines for allergic symptoms
- Tetanus prophylaxis if not up to date
- Observe 4-6 hours for onset of systemic symptoms
- Discharge with return precautions (return if cranial nerve or neuromuscular symptoms develop)
- No prophylactic antibiotics needed
Grade 3-4 (Severe / Systemic)
Supportive Care:
| Problem | Treatment |
|---|---|
| Agitation, anxiety, muscle hyperactivity | IV midazolam (continuous infusion) or diazepam |
| Neuromuscular symptoms + respiratory risk | Opioids/sedatives with close respiratory monitoring; consider intubation |
| Hypertension, pulmonary edema | Nifedipine, nitroprusside, hydralazine, prazosin, or nitroglycerin |
| Cardiogenic shock | Dobutamine 5-15 mcg/kg/min + sodium nitroprusside 0.3-5 mcg/kg/min |
| Bradyarrhythmia | Atropine (especially for cholinergic species - Tityus, Parabuthus) |
| Catecholamine excess (Mesobuthus) | Prazosin (alpha-blocker) ± antivenom |
| Airway compromise (hypersalivation + cranial nerve dysfunction) | Intubation; suction secretions |
| Rhabdomyolysis | IV isotonic fluids (target urine output 200-300 mL/hr) |
| Hyperthermia | Active cooling |
Antivenom:
- Indicated for Grade 3 and 4 envenomations
- In the USA: Anascorp (Centruroides immune F[ab']2 equine IgG) - FDA approved
- Initial dose: 3 vials IV as soon as possible
- Additional 1 vial every 30-60 min as needed
- Rapidly reverses cranial nerve and neuromuscular symptoms
- Effective and safe in pediatric and young adult populations
- Role becomes unclear once severe systemic symptoms are established
- Internationally: antivenoms available for Leiurus, Androctonus, Mesobuthus, Tityus species in respective countries
- Premedicate before antivenom: IV diphenhydramine (antihistamine), corticosteroid, and have epinephrine at bedside - risk of immediate hypersensitivity and delayed serum sickness
Special Considerations
- Children: Higher risk for severe systemic symptoms; more likely to require antivenom; fatal respiratory arrest most common in young children and elderly
- Hemiscorpius lepturus (Iran): Cytotoxic venom - watch for hemolysis, hemoglobinuria, renal failure (AKI); supportive care +/- dialysis
- Pancreatitis (Tityus trinitatis): Standard pancreatitis management
- Pulmonary edema: Morphine is contraindicated (unlike standard pulmonary edema management); use nitrates + dobutamine
What to Avoid
- Morphine in pulmonary edema secondary to scorpion envenomation
- Steroids, antihistamines, calcium channel blockers, diuretics - can worsen cardiac complications
- Lytic cocktail (pethidine + promethazine + chlorpromazine) - historically used, not effective
- Beta-blockers, digoxin, nifedipine as primary treatments - limited or harmful evidence
- Tourniquet, cauterization, incision and drainage
- Sucking out venom
Disposition
- Grade 1-2: Observe 4-6 hours; discharge if no systemic symptoms
- Grade 3-4: Admit; ICU for severe cardiovascular or respiratory compromise
- Transfer if antivenom or ICU care unavailable
- Patients who received antivenom: counsel about serum sickness (fever, arthralgias, rash) developing 1-3 weeks later
Sources:
- Harrison's Principles of Internal Medicine 22E (2025), Scorpion Stings chapter
- Tintinalli's Emergency Medicine, Table 211-2: Scorpion Sting Effects and Treatment
- Rosen's Emergency Medicine, Table 53.4: North American Centruroides Scorpion Envenomation Grading
- Andrews' Diseases of the Skin, Scorpion Sting
- Dikshit Textbook of Forensic Medicine and Toxicology, Scorpion Venom
- JTS Global Spider and Scorpion Envenomation Management CPG ID:84
- UN DHMOSH Guidance for Prevention & Management of Scorpion Stings (January 2024)
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