Methemoglobinemia after a Mediastinal Stab Wound

BackgroundMethemoglobinemia is a relatively common, potentially fatal syndrome resulting from oxidative stress. Of the numerous causes identified, toxins are the most common precipitating event.ObjectivesDescribe methemoglobinemia after a stab wound in a man with previously undiagnosed cytochrome b5 reductase deficiency.Case ReportIn this case report, we describe a 27-year-old man with no past medical history who developed clinically significant methemoglobinemia after a mediastinal stab wound. After an extensive toxicologic work-up failed to reveal the etiology of the symptoms, genetic testing was performed, which revealed the individual to have a previously undiagnosed cytochrome b5 reductase deficiency. It is hypothesized that the physiologic stress from the expanding mediastinal stab wound resulted in enough oxidative stress to cause methemoglobinemia in this predisposed individual. A discussion of methemoglobinemia ensues.ConclusionThis case describes an uncommon presentation of a common toxicologic condition and presents a discussion regarding the evaluation, management, and pathophysiology of methemoglobinemia.