Muscle Diseases

Question 1

What are polymyositis and dermatomyositis?

Answer 1

Idiopathic inflammatory myopathies.

Question 2

Who would likely present with poly/dermatomyositis?

Answer 2

F:M 2:1, 40-50yo.

Question 3

What clinical features may be seen in poly/dermatomyositis?

Answer 3

Muscle weakness, insidious onset, worsening over months. Usually symmetrical, proximal. Often specific problems-hair brushing etc. Myalgia in 25-50%

Question 4

What are common cutaneous features in dermatomyositis?

Answer 4

Gottrons sign, heliotrope rash, shawl sign

Question 5

What organ involvement bar skin occurs in dermatomyositis?

Answer 5

ILD, resp muscle weakness, dysphagia, myocarditis, fever, wt loss, Raynauds, non-erosive polyarthritis

Question 6

What is the likelihood of malignancy in dermatomyositis and polymyositis, and what associations occur?

Answer 6

15 % d, 9% p. Ovarian, breast, stomach, lung, bladder and colon cancer-risk greatest in men >45yo

Question 7

What is the likely history of someone with poly/dermatomyositis?

Answer 7

Tired muscles, functional difficulty, pain, DM, thyroid disease, on steroids/statins, use of alcohol/illicit drugs, wt loss, cough, SOB, Raynauds

Question 8

What examinations are required in the diagnosis of poly/dermatomyositis?

Answer 8

GALS, confrontational testing, isotonic testing

Question 9

What blood tests are required in diagnosis of poly/dermatomyositis?

Answer 9

Muscle enzymes eg. Creatine kinase (CK) (10x normal)
Inflammatory markers
Electrolytes, calcium, PTH, TSH (to exclude other causes)
Autoantibodies: ANA, Anti-Jo-1, anti-SRP

Question 10

What electrical activity test is used in the diagnosis of poly/dermatomyositis?

Answer 10

Electromyography (EMG):

increased fibrillations, abnormal motor potentials, complex repetitive discharges

Question 11

What biopsy may be used in diagnosis of poly/dermatomyositis?

Answer 11

Muscle biopsy: Definitive test. Perivascular inflammation and muscle necrosis

Question 12

What imaging may be used in diagnosis of poly/dermatomyositis?

Answer 12

MRI: muscle inflammation, oedema, fibrosis and calcification

Question 13

What is the treatment of poly/dermatomyositis?

Answer 13

Glucocorticoids
Azathioprine
Methotrexate
Ciclosporin
IV immunoglobulin

Question 14

What is inclusion body myositis?

Answer 14

Patients >50yo, M:F 3:1. Distal muscle weakness, weakness wrist/finger flexors, quads and anterior tibial muscles. Often asymmetrical

Question 15

What will CK levels in inclusion body myositis be compared to PM?

Answer 15

Lower

Question 16

What will muscle biopsy in inclusion body myositis show?

Answer 16

Shows inclusion bodies

Question 17

What patient would likely present with Polymyalgia Rheumatica?

Answer 17

> 50yo, higher in northern regions. May have temporal arteritis/giant cell arteritis

Question 18

What are the clinical manifestations of PR?

Answer 18

Ache in shoulder and hip girdle
Morning stiffness
Usually symmetrical
Fatigue, anorexia, weight loss and fever may occur
Reduced movement of shoulders, neck and hips
Muscle strength is normal

Question 19

What is temporal/giant cell arteritis?

Answer 19

Granulomatous arteritis of large vessels. Inflammation of intima, media, adventitia of affected arteries.

Question 20

What symptoms/signs are present in temporal/giant cell arteritis?

Answer 20

Headache
Scalp tenderness
Jaw claudication (almost pathognomonic)
Visual loss (amaurosis fugax)
Tender, enlarged, non-pulsatile temporal arteries

Question 21

How is temporal/giant cell arteritis diagnosed?

Answer 21

Exclude other diagnoses, raised ESR, plasma viscosity, CRP. Temporal artery biopsy definitive test.

Question 22

What is the treatment of temporal/giant cell arteritis?

Answer 22

Rapid and dramatic response to low dose steroids
If temporal arteritis higher steroid doses required
Gradual reduction in steroid dose over around 18 months to 2 years

Question 23

What is Fibromyalgia?

Answer 23

Common cause of chronic MSK pain- no inflammation. Commonly women 22-50yo. May occur after emotional/physical trauma

Question 24

What are the clinical manifestations of Fibromyalgia?

Answer 24

Pain neck, shoulders, lower back, chest wall
Diffuse and chronic
Varies in intensity
Symptoms worse with exertion, fatigue and stress
Sensation of swelling
Fatigue and poor, unrefreshing sleep
Pins and needles/tingling, headaches, depression, abdominal pain (IBS), poor concentration and memory

Question 25

What clinical findings are present in Fibromyalgia?

Answer 25

Tenderness on palpitation of soft tissues. 11/18 tender points. No other abnormality of MSK system

Question 26

How is fibromyalgia diagnosed?

Answer 26

Clinical diagnosis partly- no diagnostic tests. Inflamm markers normal, absence of other explanation of symptoms

Question 27

What is the treatment of fibromylagia ?

Answer 27

MDT- exercise programme, cognitive behavioural therapy, complementary medicine, anti-depressants, analgesia, gabapentin and pregabalin

Question 28

What is the treatment for polymyalgia rheumatica?

Answer 28

Low dose steroids (prednisolone 15mg/day)- sometimes used as diagnostic tool. After 18 months should resolve

Question 29

What infiltration can occur in GCA?

Answer 29

Patchy infiltration by lymphocytes, macrophages and multinucleated giant cells

Question 30

What can vessel wall thickening in GCA result in?

Answer 30

Arterial luminal narrowing, leading to subsequent distal ischaemia