Alphos poisoning

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Aluminium Phosphide (Alphos) Poisoning

Forensic Toxicology: The Fatal Fumigant

1. Mechanism of Toxicity

Aluminium phosphide (AlP) is a common pesticide used as a grain fumigant. Upon contact with moisture (in the stomach or atmosphere), it releases phosphine gas (PH_3). This gas is a potent cellular poison that inhibits cytochrome c oxidase, effectively halting cellular respiration and causing multi-organ failure.

2. Clinical Features

  • Cardiovascular: Severe, refractory hypotension and shock; arrhythmias are common. This is the primary cause of death.
  • Gastrointestinal: Severe epigastric pain, vomiting, and hematemesis.
  • Respiratory: Adult Respiratory Distress Syndrome (ARDS) and pulmonary edema.
  • Odor: A distinct “fishy” or “garlicky” odor is often detected in the breath and gastric aspirate.

3. Management Challenges

Strategy Clinical Approach
Antidote There is no specific antidote. Treatment is purely symptomatic and supportive.
Decontamination Gastric lavage with potassium permanganate (KMnO_4) is historically used to oxidize phosphide.

4. Forensic High-Yield Pearls

  • High Fatality: Mortality rates are extremely high, often exceeding 70-90% in acute ingestion cases.
  • “Silver Nitrate Test”: A simple bedside diagnostic test: exposure of breath or gastric aspirate to silver nitrate paper results in a blackening (reduction) of the paper due to phosphine gas.
  • Educational Resource: For comprehensive management protocols and forensic question banks, visit mymedschool.org.