Congenital methemoglobinemia in old age

Abstract

Chest infections and ischemic heart disease are the most common causes of shortness of breath and cyanosis in old age. However, the hemoglobinopathies should be considered if the cardiac cause is ruled out, cyanosis that is not responding to oxygen therapy and antibiotic treatment. A 75-year-old retired soldier was admitted to the inpatient department of a tertiary care hospital with symptoms of cyanosis, shortness of breath and fever. Cyanosis was acrocyanosis in nature and not relieved on oxygen therapy.

An initial diagnosis of Lower respiratory tract infection was initiated. However, the cyanosis showed no signs of improvement. Alternate diagnosis was considered, and the patient was started on treatment of ischemic heart disease that included nitrates which further led to worsening of his condition. Blood methemoglobin levels were raised which established the diagnosis of methemoglobinemia. The fast-moving dark brown color band of Hb M on gel electrophoresis confirmed the diagnosis of Hb M. The patient was started on IV ascorbic acid with the patient showing clinical improvement within 36 hours.

The patients presenting with unexplained acrocyanosis should not be treated with oxidizing agents like nitrates, irrespective of age and management of another disease, unless the cause of cyanosis has been established.