Case study of an inborn error manifested in the elderly: A woman with adult‐onset mitochondrial disease mimicking systemic vasculitis.

Mitochondrial diseases are a group of disorders presenting mainly during infancy due to pathological dysfunction of the mitochondrial respiratory chain. We report a case of mitochondrial disease in an elderly woman complaining of generalized myalgia. A 69‐year‐old woman was admitted due to fatigue, general weakness, and a drowsy mental status. A brain magnetic resonance imaging (MRI) demonstrated multifocal lesions of increased T2 signal intensity, and laboratory findings were consistent with Fanconi syndrome. During her hospital course, she developed seizures, stress‐induced cardiomyopathy, and respiratory failure. A muscle biopsy demonstrated ragged‐red fibers in the muscle tissues seen in mitochondrial myopathy. We confirmed an 8 kb deletion in her mitochondrial DNA. Following treatment with l‐carnitine, coenzyme Q10, and supportive measures, brain lesions on MRI scans disappeared, and the general symptoms gradually improved. [ABSTRACT FROM AUTHOR]