Muscle diseases

Question 1

What is the main feature of polymyositis and dermatomyositis?

Answer 1

Insidious onset of progressive, proximal, symmetrical muscle weakness

Question 2

In which group of patients is polymyositis/dermatomyositis increased? What investigation is important to carry out in patients you suspect of having one of these illnesses?

Answer 2

Cancer patients- paraneoplastic syndrome. Need to screen patients for malignancy

Question 3

How might poly/dermatomyositis manifest other than muscle weakness?

Answer 3

Dysphagia
Interstitial lung disease
Weight loss
Raynaud’s

Question 4

What skin signs are seen in dermatomyositis?

Answer 4

Heliotrope rash
“Shawl” sign
Gottron’s papules (pathognemonic is CK is elevated and myositis)

Question 5

What is the gold standard for investigation in polymyositis/dermatomyositis?

Answer 5

Muscle biopsy showing perivascular inflammation and muscle necrosis

Question 6

What is seen in the following tests?

a) muscle enzymes
b) autoantibody screen

Answer 6

a) ALT, AST, LDH and CK all elevated

b) dermatomyositis usually ANA+ve. Mi-2 is specific for dermatomyositis. Jo-1 is more often seen in polymyositis

Question 7

How are dermatomyositis and polymyositis treated?

Answer 7

High dose prednisolone
AZT, MTX, ciclosporin
Topical steroids for skin manifestation

Question 8

How does inclusion body myositis differ in presentation?

Answer 8

More insidious onset, more distal joints, more often in men

Question 9

What is fibromyalgia? How is it diagnosed?

Answer 9

Idiopathic disease causing widespread chronic muscle pain in the absence of inflammation. Diagnosis of exclusion

Question 10

How is fibromyalgia treated?

Answer 10

Education and counselling
CBT
Graded exercise programmes
Low dose tricyclics may be useful