Proximal myopathy 2

Common exam question.
Attached is a video of my patient with proximal myopathy. Without the bed, he would show a classical Gower sign.
What is important is to determine the cause for the proximal myopathy.
In the exam, think of the major groups !

1) Muscular Dystrophy - normally Beckers cause Duchenne would be dead by then unless you are sitting for a paeds exam.
2) Polymyositis/Dermatomyositis
3) Endocrinopathies - Acromegaly, Cushing's, Thyrotoxicosis... look for features of those
4) Metabolic causes- Hypokalaemic periodic paralysis...
5) Myasthenia gravis

Those are the common ones.

Remember also to look for the muscle biopsy scar which is normally at the biceps or quadriceps.
There is no sensory involvement as the pathology is the muscle or neuromuscular junction.

Remember the investigations -
CK
Muscle biopsy
EMG

Treatment would depend on the underlying cause.

Refer to previous post on proximal myopathy