Methemglobinemia from Antifreeze Containing Sodium Nitrite

ABSTRACT

Sodium nitrite is commercially used as a coloring agent, food preservative, and corrosion inhibitor. Accidental poisoning with sodium nitrite from contaminated food and water causes gastrointestinal irritation, vasodilatation, and methemoglobinemia with subsequent tissue hypoxia. We describe an outbreak case of sodium nitrite-induced methemoglobinemia following the ingestion of noodles contaminated with industrial antifreeze. The eEight patients involved initially complained that their noodles tasted 'unpleasant' and soon afterwards experienced nausea, vomiting, dizziness, and fatigue. Some of them noted cyanosis on their lips and fingers. Subsequent investigations demonstrated a high methemoglobin concentration which was corrected by the intravenous administration of methylene blue three hours after the onset of symptoms. The patients made a prompt, uncomplicated recovery and were discharged home 4 four days later. Industrial antifreeze contains sodium nitrite and calcium nitrite. Because an accidental poisoning of industrial antifreeze causes fatal methemoglobinemia, emergency physicians should promptly identify its symptoms and institute treatment with methylene blue promptly. In addition, industrial agencies must caution construction businesses against such contamination events.