What is the role of sarcoid myopathy in the etiology of focal muscular atrophy (FMA)?

Updated: Feb 20, 2018
  • Author: Sridharan Ramaratnam, MD, MBBS; Chief Editor: Helmi L Lutsep, MD  more...
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Sarcoid myopathy

  • Consider muscular involvement by sarcoid in the differential diagnosis of focal muscle disease, especially in a patient with a known history of sarcoid.

  • Muscular sarcoid may be nodular, atrophic myopathic or acute myositic. Muscle involvement can be focal, multifocal, or generalized. Patients may present with focal muscle pain, tenderness, and weakness. Atrophy of the involved muscles occurs with chronic disease. Asymptomatic granulomas may be palpated within the muscle. Rarely, a superimposed neuropathy is also evident.

  • Most patients have coexisting pulmonary symptoms and lymphadenopathy.

  • The presence of typical bilateral hilar adenopathy on a chest radiograph and abdominal findings (eg, hepatosplenomegaly and retroperitoneal adenopathy) may help establish the diagnosis. Ultrasonically guided biopsy may be necessary for definitive diagnosis.

  • Many patients with sarcoidosis have granulomas in the muscle, although signs and symptoms of muscle involvement may be absent. Serum angiotensin-converting enzyme (ACE) levels often are elevated, and these patients are frequently anergic to tuberculin skin testing. Chest films usually demonstrate hilar lymphadenopathy and parenchymal involvement of the lungs. Serum CPK is usually normal or only mildly elevated. EMG may appear normal or show myopathic or mixed myopathic and neurogenic features. Treatment usually is focused on other systemic manifestations, as the myositis is typically asymptomatic. Corticosteroids are effective in treating the myositis.

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