Two Cases of Intentional Sodium Nitrite Poisoning With Contrasting Outcomes: The Critical Role of Early Recognition and Treatment

Intentional sodium nitrite poisoning may result in severe methemoglobinemia and life-threatening tissue hypoxia. We present two cases of intentional sodium nitrite ingestion with markedly different clinical outcomes, both managed at the same center and treated with methylene blue at different stages of clinical deterioration, thereby illustrating the potential importance of early recognition and treatment timing. The first patient was a 31-year-old man without a significant medical history who was found unconscious in his apartment after an unknown interval following ingestion; therefore, the time to emergency medical intervention could not be determined. He remained in cardiac arrest upon admission, with ongoing advanced life support, mechanical ventilation, and mechanical chest compressions. Methylene blue was administered intravenously immediately upon admission to the Toxicology Unit in two doses of 2 mg/kg (170 mg each) given 15 minutes apart, corresponding to a total cumulative dose of 4 mg/kg (340 mg). Initial laboratory investigations revealed an extremely high methemoglobin level of 97% (typical reference value: <2%), profound acidosis (pH 6.684), severe hyperlactatemia (29 mmol/L), and critically impaired oxygenation. Return of spontaneous circulation was not achieved, and the patient was pronounced dead 40 minutes after admission to the Toxicology Unit. The second patient was a 22-year-old woman with a history of personality disorder who ingested 7.5 g of sodium nitrite and promptly informed her family, enabling rapid activation of Emergency Medical Services (EMS). Methylene blue was administered intravenously approximately 50 minutes after ingestion in two doses of 2 mg/kg (160 mg each) given 15 minutes apart, corresponding to a total cumulative dose of 4 mg/kg (320 mg). Her initial methemoglobin concentration was 66.1%, and antidotal treatment resulted in rapid clinical and laboratory improvement. Despite requiring prolonged intensive care and treatment for pneumonia, she was discharged after 22 days without neurological sequelae. These cases highlight the critical importance of early recognition and prompt initiation of antidotal therapy in sodium nitrite poisoning. The markedly different outcomes observed in two patients exposed to the same toxic agent suggest that prolonged untreated tissue hypoxia may have a greater influence on prognosis than the absolute methemoglobin concentration alone. Although no firm conclusions can be drawn from two cases, the findings suggest that early methylene blue administration combined with intensive supportive care may be associated with favorable outcomes even in severe poisoning.