Ank Killer Chalk Poisoning - Clinical Management

What is Ank Killer Chalk?

Mechanism of Toxicity

Pyrethroids (Deltamethrin / Cypermethrin)

• Act by keeping voltage-gated sodium channels open - causing prolonged nerve depolarization
• Also modulate chloride channels and GABA receptors
• Cause repetitive neuronal firing leading to paralysis

Imidacloprid (if present)

• Acts on nicotinic acetylcholine receptors (nAChRs) - initially stimulates, then inhibits
• Selective toxicity for insects > mammals (different receptor subunit composition)
• Can involve GI, CNS, cardiac, and autonomic systems

Clinical Presentation

Gastrointestinal (usually first, within 30-60 min)

• Nausea, vomiting, abdominal pain, diarrhea
• Excessive salivation/hypersalivation

Neurological

• Dizziness, headache, disorientation
• Paresthesias (especially perioral and tongue - characteristic of pyrethroids)
• Tremors, seizures (in severe cases)
• Progressive CNS depression - drowsiness, stupor, coma

Autonomic

• Tachycardia, hypertension (initial stimulation)
• Dilated pupils (mydriasis)
• Sweating
• In severe cases: bradycardia, hypotension

Respiratory

• Respiratory depression or arrest in severe poisoning
• Bronchospasm possible (especially in those with pre-existing airway disease)

Cardiac (mainly with imidacloprid)

• Arrhythmias - paroxysmal atrial fibrillation reported
• Raised cardiac enzymes (myocardial injury)
• Coronary spasm risk

Other

• Rhabdomyolysis (with imidacloprid)
• Hypokalemia

Key Point - Can Mimic Organophosphate Poisoning

• Serum cholinesterase is NORMAL in pyrethroid/neonicotinoid poisoning
• No miosis (pyrethroids typically cause mydriasis)
• No excessive SLUDGE features (Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis) as seen in OP poisoning
• This distinction prevents inappropriate use of atropine and pralidoxime

Investigations

Management

1. Stabilization (ABC)

• Secure airway - intubate if GCS deteriorates or respiratory arrest
• IV access, cardiac monitoring, pulse oximetry
• Call Poison Control helpline: 1800-116-117 (India) or +91-11-26589391

2. Decontamination

• Gastric lavage with warm water or 0.9% saline - within 1-2 hours of ingestion, only if airway protected
• Activated charcoal 1 g/kg orally (50-100 g in adults) - within 1-2 hours if alert and airway intact
• Do NOT induce vomiting (seizure risk)

3. Specific / Supportive Treatment

4. No Specific Antidote

• No antidote exists for pyrethroid or neonicotinoid poisoning
• Atropine is NOT indicated (cholinesterase is normal)
• Pralidoxime (2-PAM) is NOT indicated

5. Observation / Disposition

• Most mild-moderate cases resolve with supportive care in 24-72 hours
• ICU admission for: altered GCS, respiratory compromise, arrhythmias, seizures, rhabdomyolysis
• Discharge when symptom-free for 12-24 hours and GCS 15

Prognosis

• Majority of cases are mild and self-limiting - nausea, vomiting, dizziness resolve spontaneously
• Fatal outcomes are rare but reported with large ingestions or delayed presentation
• Key risk factors for severity: large dose, delayed treatment, co-ingestions, comorbidities

Note: If the Ank Killer chalk available locally contains a different active ingredient (some variants may contain imidacloprid alone), the core management remains supportive with no specific antidote. The pyrethroid vs. neonicotinoid distinction affects subtle clinical features but not the fundamental treatment approach.