Metabolic myopathies: clinical features and diagnostic approach.

The rheumatologist is frequently called on to evaluate patients with complaints of myalgia, muscle cramps, and fatigue. The evaluation of these patients presents a diagnostic challenge given the nonspecific and intermittent nature of their complaints, often leading to inappropriate diagnostic testing. When these symptoms are associated with physical exertion, a metabolic myopathy should be suspected Although inflammatory myopathies may present with similar features, such a pattern should prompt a thorough evaluation for an underlying metabolic myopathy. This review discusses the most common causes of metabolic myopathies and reviews the current diagnostic options available to the clinician.