Mitochondrial myopathy: A case report on differential diagnosis in uncommon neuropathies

Abstract

Mitochondrial myopathy are a group of rare muscle diseases characterized by mutations in genes enconding mitochondrial respiratory chain proteins. Due to their nonespecific presentation, including muscle weakness, exercice intolerance, muscle pain and fatigue, this condition can be overlooked among various possible differential diagnoses. The definitive diagnosis is established through histopathological evaluation via muscle biopsy.

This study reports the case of a 22-year-old woman with long-standing weakness in the upper and lower limbs, who experienced a more significant sudden weakness in the upper limbs over the past two weeks, initially suspected to have a possible myopathy. After extensive testing, the histopathological analysis of the muscle biopsy revealed "ragged red fibers," confirming the final diagnosis of mitochondrial myopathy. This case report discusses key concepts related to the condition and the diagnostic process. It highlights the crucial role of complementary tests, particularly muscle biopsy, in differential diagnosis to prevent misdiagnosis and reduce the morbidity and mortality associated with this condition.