Acute Renal Failure Secondary to an Unusual Familial Metabolic Myopathy

Rhabdomyolysis is a major cause of acute kidney failure. The etiology is diverse, from full-blown crush syndrome to less frequent causes, such as metabolic myopathy. We describe the case of a 35-year-old male with a history of intermittent myalgias who was admitted to hospital with acute renal failure secondary to rhabdomyolysis. Moderate to intense diffuse uptake of technetium-99m was seen in soft tissues at scintigraphy. The diagnosis of metabolic myopathy was confirmed after careful workup and genetic testing.

Dal fegato al muscolo: una rara malattia a esordio tardivo

We describe the case of a seven-year-old child who, following the incidental finding of hypertransaminasemia in the blood tests performed for a lymphadenopathy, is subjected to other blood tests that show a persistent moderate increase in CPK values, supporting the hypothesis of a muscle disease even in the absence of specific symptoms. The diagnostic path seems to point towards a late-onset metabolic myopathy. The occasional finding of hypertransaminases , associated with the finding of high CPK levels in an asymptomatic or paucisymptomatic child, orients the diagnostic path. Excluding hepatic storage disease or viral infectious disease, the differential diagnosis leads to a complex late-onset myopathy such as Pompe disease, a rare but important diagnosis whose prognosis could be dramatically improved by the enzyme replacement therapy.

Mitochondrial Structure and Function in the Metabolic Myopathy Accompanying Patients with Critical Limb Ischemia

Mitochondrial dysfunction has been implicated as a central mechanism in the metabolic myopathy accompanying critical limb ischemia (CLI). However, whether mitochondrial dysfunction is directly related to lower extremity ischemia and the structural and molecular mechanisms underpinning mitochondrial dysfunction in CLI patients is not understood. Here, we aimed to study whether mitochondrial dysfunction is a distinctive characteristic of CLI myopathy by assessing mitochondrial respiration in gastrocnemius muscle from 14 CLI patients (65.3 ± 7.8 y) and 15 matched control patients (CON) with a similar comorbidity risk profile and medication regimen but without peripheral ischemia (67.4 ± 7.4 y). Furthermore, we studied potential structural and molecular mechanisms of mitochondrial dysfunction by measuring total, sub-population, and fiber-type-specific mitochondrial volumetric content and cristae density with transmission electron microscopy and by assessing mitophagy and fission/fusion-related protein expression. Finally, we asked whether commonly used biomarkers of mitochondrial content are valid in patients with cardiovascular disease. CLI patients exhibited inferior mitochondrial respiration compared to CON. This respiratory deficit was not related to lower whole-muscle mitochondrial content or cristae density. However, stratification for fiber types revealed ultrastructural mitochondrial alterations in CLI patients compared to CON. CLI patients exhibited an altered expression of mitophagy-related proteins but not fission/fusion-related proteins compared to CON. Citrate synthase, cytochrome c oxidase subunit IV (COXIV), and 3-hydroxyacyl-CoA dehydrogenase (β-HAD) could not predict mitochondrial content. Mitochondrial dysfunction is a distinctive characteristic of CLI myopathy and is not related to altered organelle content or cristae density. Our results link this intrinsic mitochondrial deficit to dysregulation of the mitochondrial quality control system, which has implications for the development of therapeutic strategies.

Carnitine Palmitoyltransferase II deficiency, a Rare Cause of Rhabdomyolysis: A Case Report

Introduction: Muscle weakness and rhabdomyolysis have a wide range of differential diagnosis. In many situations, they are induced by seizure, trauma, drugs, and toxins. They could also be due to inflammatory or metabolic myopathies. Identifying the exact cause is crucial and sometimes challenging. Case Presentation: A 23-year-old man was admitted to our hospital with muscle weakness, fatigue, dyspnea, and dark urine, all preceded by flu-like symptoms, myalgia, and fever. Due to reduced muscle strength, dark urine, elevated serum creatine kinase, and serum creatinine, he was diagnosed with rhabdomyolysis and acute kidney injury. Muscle biopsy was performed three years before for the patient, due to a history of similar episodes and exercise intolerance. Because of recurrent episodes of muscle weakness and rhabdomyolysis along with the negative muscle biopsy for inflammatory myopathies, we suspected metabolic myopathy as a cause. Therefore, metabolic screening was performed for the patient, and he was diagnosed with metabolic myopathy known as Carnitine Palmitoyltransferase II (CPT II) deficiency. Conclusion: In patients with recurrent rhabdomyolysis, we should consider inherited myopathies, especially carnitine palmitoyltransferase II deficiency and glycogen storage disease type V (McArdle disease) as likely causes. CPT II deficiency is regarded as a preventable cause of recurrent rhabdomyolysis. Therefore, by early diagnosis of this disorder we could prevent recurrent episodes of rhabdomyolysis and ultimately avoid life-threatening complications like acute kidney injury