Survival from severe methemoglobinemia after intentional ingestion of sodium nitrite. is this an emerging method recommended for suicide?.

Abstract

Background: Deliberate self-poisoning with sodium nitrite is uncommon. There is limited literature reporting survival after potentially fatal concentrations of methemoglobinemia. Method(s): A 25-year-old man researched suicide methods on the internet and found a recommendation for sodium nitrite as a painless and potentially reversible formof suicide. The patient purchased 100 g and ingested 15 g. He immediately had second thoughts about the attempt and called an ambulance within 10 minutes of ingestion. On paramedic arrival, he was alert, deeply cyanotic and admitted to sodium nitrite ingestion. In the emergency department, 40 minutes post-ingestion, GCS = 4, he had ashen gray skin, pulse-oximetry saturation 60% on mask high-flow oxygen, pulse 180 bpm, and BP 91/45 mmHg. He was emergently intubated to facilitate oxygen delivery. Peri-intubation hypotension was treated with intravenous crystalloids, metaraminol, and norepinephrine. Result(s): Initial VBG revealed a methemoglobin fraction of 88%, lactate 19mmol/L, and bicarbonate 14mmol/L. Three 70mg doses ofmethylene blue (1 mg/kg) were administered in the first hour post-presentation. Activated charcoal (50 g) was administered naso-gastrically. Methemoglobin fraction fell to 22%in the first hour and was 16%2 hours after methylene blue treatment. Hemodynamics also improved: pulse 120 bpm, BP 126/73 mmHg with successful cessation of norepinephrine infusion. Methemoglobin fraction fell to 0.9% over 30 hours. No further methylene blue was administered. He was extubated the next day without complication and discharged home after psychiatric treatment on day 4. Conclusion(s): Intentional ingestion of sodium nitrite is currently an uncommon method of deliberate self-poisoning. However, it is an easily accessible and unregulated salt, used in the food industry. Rapid development of methemoglobinemia can result in death without prompt medical care. In this case, early notification of the poisoning by the patient and timely methylene blue administration rapidly reversed severe methemoglobinemia and prevented irreversible end-organ dysfunction and death.