Proximal myopathy

The clinical diagnosis of proximal myopathy is usually straightforward. Proximal muscle wasting and weakness is easily demonstratable.

Tips:
**The weakness is bilateral and usually symmetrical.
**The sensory is always INTACT!

The causes that you need to consider are:
1. Muscular dystrophy
**Duchenne/ Becker muscular dystrophy (look for pseudohypertrophy of calf muscle
** Fascioscapulohumeral dystrophy (look for facial muscle weakness)
**Limb girdle muscular dystrophy

2. Inflammatory muscle disease
** Polymyositis (muscle may be tender)
** Dermatomyositis (Facial heliotrope rash and Gottron's sign)

3. Endocrinopathy
** Cushing's syndrome
** Thyrotoxicosis
** Acromegaly
**ALL will have obvious external features

4. Metabolic myopathies
** Hypo/hyperkalemia, Hypo/hypercalcemia

Wasting of deltoid muscle
Difficulty in standing up from squatting

This patient was referred to neurology clinic for an investigation. He was then planned for an elective procedure.

What is the respective investigation and procedure?