An Unusual Case of Methemoglobinemia

Methemoglobinemia is a condition in which an abnormal proportion of the iron in heme moiety of the hemoglobin is oxidized to the ferric state leading to impaired oxygen transport and anemic hypoxia and can cause tissue ischemia and death. A 21 year old male, known case of Hansen’s disease was posted for surgicalneurolysis of ulnar nerve. His surgery was already postponed once as SpO2 waslow on the operation table. He then underwent complete systemic evaluation for the cause of low saturation but was found normal. On pulse oximetry it was seen that SpO2 was 91-93% on room air without any signs and symptoms of hypoxemia. This suggestedmethemoglobinemia due to treatment with dapsone which was being taken by the patient for treatment of Hansen’s disease. The surgery was conducted uneventfully under general anesthesia. The diagnosis was confirmed by laboratory testing.