11th August 2024

Inclusion-body myositis (IBM)

IBM causes a specific pattern of muscle wasting, with weakness of the quadriceps and forearm muscles. Swallow function may also be affected. Onset is generally in the 4th to 6th decade. There is no current treatment.

Muscle enzymes and CK are often mildly elevated. Diagnosis is on the basis of typical examination findings, lab tests and muscle biopsy which may show the characteristic rimmed-vacuoles, along with mononuclear cell inflammatory infiltrates and non-necrotic fibres.