Myopathic Carnitine Palmitoyltransferase II (CPT II) Deficiency: A Rare Cause of Acute Kidney Injury and Cardiomyopathy.

Abstract

Carnitine palmitoyltransferase II (CPT II) deficiency is a long-chain fatty acid (LCFA) oxidation disorder. There are three main types classified by symptoms and age of onset: the neonatal form, the infantile hepatocardiomuscular form, and the adult or myopathic form. The first two are early-onset severe disorders presenting with marked hypoketotic hypoglycemia, cardiomyopathy, and liver dysfunction. The latter is characterized by muscle pain and weakness and stiffness, typically triggered by exercise or febrile illnessesand occasionally associated with myoglobinuria. One of the most common complications is acute kidney injury (AKI) following massive rhabdomyolysis, which is managed with aggressive fluid therapy; crystalloid solutions are preferred. We report an otherwise healthy 38-year-old patient who presented with severe myalgia, cramps, fatigue, low-grade fever, and transient myoglobinuria, after intense physical training. Significant recurrent muscle pain was reported. Family history was unremarkable. Imaging studies showed no abnormalities. Echocardiogram showed a left ventricle ejection fraction (LVEF) of 40%. Acetylcarnitine analysis with tandem mass spectrometry and molecular tests confirmed the diagnosis. Fluid resuscitation was started. Acute kidney injury was diagnosed and managed with plasmapheresis and five sessions of hemodialysis. The patient was discharged upon the improvement of renal function with lifestyle modification recommendations. In otherwise healthyyoung adults presenting with myalgia and rhabdomyolysis triggered by physical activity or infection, CPT II deficiency should be considered, and genetic testing should be initiated to provide an opportunity for patients to modify their daily lifestyle, preventing future attacks and the development of complications.