Treatment of Zinc Phosphide Poisoning
There is no antidote for zinc phosphide poisoning; treatment is entirely supportive with aggressive airway management, circulatory support, decontamination, and meticulous attention to preventing secondary phosphine gas exposure to healthcare workers. 1, 2, 3
Immediate Healthcare Worker Protection
- Ensure adequate ventilation of the treatment area immediately to prevent phosphine gas accumulation and secondary exposure to staff 1
- Use appropriate personal protective equipment including organic vapor filters for air-purifying respirators when managing these patients 1
- Avoid direct contact with emesis and gastric contents without proper protection, as phosphine gas is released when zinc phosphide reacts with gastric acid 1
Decontamination Strategy
- Do not induce vomiting, as this worsens the clinical condition and increases phosphine gas exposure 1
- Consider polyethylene glycol for whole bowel irrigation if radiopaque material is visible on abdominal X-ray and the patient presents early 1
- Remove contaminated clothing and perform copious irrigation with soap and water for any dermal exposure 4
Airway and Respiratory Management
- Secure airway, breathing, and circulation as the first priority 4, 3
- Aggressive airway management is critical to successful outcomes, particularly given the risk of pulmonary edema and respiratory insufficiency 3, 5
- Early endotracheal intubation should be performed for life-threatening presentations with respiratory compromise 3, 5
- Monitor closely for acute pulmonary edema, which can cause immediate death 3
Circulatory Support
- Provide aggressive circulatory support for hypotension and shock symptoms 3, 6
- Monitor for cardiovascular complications including myocarditis, pericarditis, and congestive heart failure 3, 6
- Delayed deaths are related to direct cardiotoxicity, requiring continuous cardiac monitoring 3
Metabolic Management
- Correct hypoglycemia, which is a characteristic feature of zinc phosphide toxicity 7
- Address metabolic acidosis with appropriate supportive measures 7
- Monitor and correct electrolyte abnormalities, particularly hypokalemia and hypocalcemia 5
Organ-Specific Monitoring and Support
- Monitor liver function closely, as delayed effects primarily affect the liver, heart, and kidneys 3, 5
- Consider hepatoprotective agents such as N-acetylcysteine for hepatic damage 5
- Alpha-lipoic acid may be considered as an antioxidant and metal chelation agent for prevention and treatment of hepatic damage, though evidence is limited to case reports 5
- Monitor renal function and provide supportive care for kidney damage 3
- Watch for bacterial pneumonia secondary to phosphine-induced atelectasis 5
Critical Pitfalls to Avoid
- Never confuse zinc phosphide poisoning with organophosphate poisoning—atropine and pralidoxime have no role in zinc phosphide toxicity 1
- Do not use neuromuscular blockers metabolized by cholinesterase (succinylcholine and mivacurium), though this caveat applies to organophosphate poisoning, not zinc phosphide specifically 1
- Do not delay supportive care while searching for a non-existent antidote 2
Clinical Course and Monitoring Duration
- Immediate toxicity manifests through phosphine gas production causing nausea, vomiting, dyspnea, and altered mental status 3
- Delayed effects occur secondary to phosphide absorption, requiring prolonged monitoring for at least 48-72 hours 3, 5
- Multiple organ dysfunction can develop, including hepatic damage, renal impairment, and cardiovascular collapse 2, 5