Inflammatory Myopathy (Myositis)

Difficulty rising from a chair or a low toilet, climbing stairs, lifting the arms overhead or washing hair. The weakness is proximal — shoulders and hips — and progresses over weeks to months. Pain may be mild or absent.

A rash on the eyelids, knuckles or chest points to dermatomyositis. Difficulty swallowing occurs in a proportion of patients and is a safety issue that needs assessment rather than dietary adjustment at home.

Progressive proximal weakness is not a physiotherapy problem in the first instance. It needs blood tests, and usually EMG, MRI or muscle biopsy, and treatment is immunosuppressive.

Some inflammatory myopathies are associated with underlying malignancy, particularly dermatomyositis in adults, so investigation is broader than the muscle itself.

For decades patients were told to avoid exercise for fear of worsening muscle inflammation. Studies have since found supervised exercise safe at all stages of disease studied, with moderate gains in strength and aerobic capacity and no rise in the muscle enzyme creatine kinase, although the certainty of this evidence is limited 1.

Programmes start at low intensity with monitoring and progress as tolerated. Deconditioning from prolonged rest accounts for a substantial part of the disability seen in these conditions.

Progressive resistance training for proximal muscle groups, aerobic conditioning, functional task training for the specific activities that have been lost, and swallowing assessment where indicated.

Corticosteroid treatment causes its own muscle weakness and bone loss, so resistance training and bone protection run alongside the medical treatment rather than after it.

Exercise was avoided in inflammatory myopathy for years on the assumption that it worsened muscle damage. Studies since have shown supervised exercise to be safe and beneficial, including during active disease.

Much of the weakness these patients carry is disuse layered on top of the disease, and it is the part that is recoverable.

Harder than was once thought. In a randomised trial of 23 people with recently diagnosed myositis, 12 weeks of high-intensity interval training raised aerobic capacity by 16%, against 1.8% with standard home exercise, and muscle enzymes stayed stable in both groups 2. Pooled studies show moderate gains in strength and aerobic capacity, but most were small and the certainty of the evidence is limited 1.

Exercise works alongside immunosuppressive treatment, not instead of it, and it does not treat swallowing problems or lung involvement. Inclusion body myositis, a form that mainly weakens the thigh muscles, is different: no drug has shown convincing functional benefit, and exercise appears safe in small studies 3. There is moderate evidence that resistance training improves strength and function in it, but not yet that it reduces falls 4.