We report the case of a 19-year-old woman who had been suffering from general
fatigue and exercise intolerance since 15 years old. At 18 years old, she experienced
muscle weakness and
myalgia of the calves. Six months later, she was admitted to our hospital. She showed
muscle weakness of the neck and proximal limbs, and
myalgia of the calves was prominent. Serum levels of
creatine kinase (CK) and
lactic acid were elevated, as was the level of
lactic acid in cerebrospinal fluid. T2-weighted and short-inversion-time inversion recovery (STIR) imaging of the lower limbs showed hyperintensity on bilateral gastrocnemius muscles, and the region revealed Gd enhancement. Based on histopathological findings from muscle and identification of a m.3271T>C point mutation,
mitochondrial myopathy was diagnosed. Rest and administration of
vitamins B1 and B2,
coenzyme Q10, and
L-carnitine improved serum CK levels; however, exercise intolerance,
myalgia, and lactic acidemia remained.
Sodium pyruvate was then administered, and
lactic acid levels, exercise intolerance, and findings on magnetic resonance imaging improved.
Sodium pyruvate could prove effective in addressing both elevated serum
lactic acid levels and exercise intolerance in
mitochondrial disease.