There was a sad story about a woman who died from insecticide poisoning inside her home after family member sprayed agricultural insecticide inside the house earlier in the day. While the story was sad, the back story was quite interesting to me.
The poisoning was from aluminum phosphide. When exposed to atmospheric moisture or stomach acid, aluminum phosphate converts to aluminum hydroxide (which is used to treat excess stomach acid) and phosphine gas – which is highly toxic. Phosphine gas typically smells like rotting fish or garlic. Phosphine is explosive and is heavier than air, so it tends to collect in low-lying poorly ventilated areas such as basements. Toxicity usually develops a few hours after exposure and affects the cardiac and vascular tissues, causing hypotension, congestive heart failure and electrocardiographic abnormalities.
Diagnosis of aluminum phosphate poisoning is difficult to make and usually depends on history of exposure due to the nonspecific symptoms. Confirmatory testing involves putting silver nitrate paper over the patient’s mouth or over a heated beaker of the patient’s stomach contents. If positive for exposure, the paper turns black. There’s no antidote for the poisoning, so treatment is supportive, although oils reportedly inhibit phosphine release and there have been case reports of using coconut oil in treatment of aluminum phosphide poisoning. Potassium permanganate (1:10,000) via gastric lavage will also oxidize phosphine to nontoxic phosphate.
Phosphine can be absorbed through the skin, so removing the patient to fresh air and decontamination with water is important.
Although management will probably be in combination with a poison control center, you may just look like a rockstar if you diagnose aluminum phosphide poisoning in a patient in cardiovascular collapse … who smells like rotten fish … and who just happens to have an ant infestation at home.
Also remember that if you smell phosphine on a patient, you could be poisoned, too.
Again, think decontamination and negative pressure ventilation.