Which physical findings are characteristic of sporadic inclusion body myositis (s-IBM)?

Updated: Jun 08, 2018
  • Author: Michael P Collins, MD; Chief Editor: Nicholas Lorenzo, MD, MHA, CPE  more...
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Clinical suspicion for s-IBM should be very high when the pattern of weakness affects (1) the finger/wrist flexors out of proportion to the finger/wrist extensors and shoulder abductors or (2) knee extensors disproportionate to the hip flexors.

Patients have variable degrees of limb weakness and atrophy, which is usually both proximal and distal, and often, but not always, asymmetric.

Facial muscle weakness may occur, but extraocular muscles are not affected and ptosis is not seen.

Tendon reflexes may be normal or decreased.

Decreased sensation in the distal lower extremities and reduced ankle jerks are not uncommon, as some patients have a concurrent polyneuropathy, which may be disease-related.

Other neurological subsystem involvement (eg, cognitive function, coordination, upper motor neuron dysfunction) is not seen in s-IBM. The presence of such findings should raise suspicion for other processes.

Examination for skin lesions, joint swelling/tenderness, and other systemic signs suggesting a concomitant autoimmune disorder should be routinely performed.

Cardiovascular examination should evaluate for hypertension, cardiac dysrhythmia/conduction abnormalities, and cardiac failure.

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