Muscle biopsy in patients with myalgia

Muscle pain is among the most common complaints encountered by primary care physicians, and may be the commonest presenting symptom in neuromuscular clinics. Population-based studies have suggested that the incidence of diffuse, persistent muscle pain is approximately 10%, with the prevalence of fibromyalgia as high as 3%.1 Despite the prevalence of myalgia, the evaluation of patients with isolated persistent muscle pain in the absence of weakness can prove frustrating for both patients and health care providers. The reasons for this are many. Muscle pain is a nonspecific descriptor that can describe a wide range of abnormal muscle sensations such as cramping, stiffness, and tenderness. Patients often complain of myalgia when the source of pain lies in the joints, skin, bone, or viscera. Myalgia as a symptom often resists the classic neurologic localization paradigm, since muscle pain can result from disparate pathophysiologic phenomena (e.g., cramp, contracture) and from disorders involving any part …