Proximal myopathy (brief)

Question 1

What causes it?

Answer 1

Proximal myopathy represents a symmetrical weakness of proximal upper and/or lower limbs. Broad range of underlying causes, so I’m just going to list them here and not go into any detail about them.
Drugs, alcohol, thyroid disease, osteomalacia, idiopathic inflammatory myopathies, hereditary myopathies, malignancy, infections and sarcoidosis. Clinical assessment should aim to distinguish proximal myopathy from other conditions that can present similarly, identify patients who need prompt attention, like those with cardiac, respiratory or pharyngeal muscle involvement, and determine underlying cause of myopathy.

Question 2

Investigations

Answer 2

Initial evaluation should include simple tests, like creatine kinase, thyroid function and (25) OH vitamin D levels, but further evaluation including neurophysiological studies, muscle imaging and muscle biopsy should be considered for patients in whom no toxic, metabolic or endocrine cause is found, and in those with clinical features suggestive of inflammatory or hereditary myopathy.

Question 3

Treatment

Answer 3

Management depends on underlying cause, and includes measures, such as removal of offending agent, correction of endocrine or metabolic problem, corticosteroids and immunosuppressive therapy for IIM, and physical therapy, rehabilitation and genetic counselling for muscular dystrophies.