Muscle Diseases

Question 1

How do muscle diseases present?

Answer 1

Muscle pain (myalgia), muscle weakness/tiredness, stiffness, abnormal blood tests, other organ features

Question 2

What is a myopathy?

Answer 2

Disease of the muscle in which the muscle fibres don’t function properly, causing muscular weakness

Question 3

What are polymyositis and dermatomyositis?

Answer 3

Idiopathic inflammatory myopathies

Question 4

What are some features of inflammatory myopathies?

Answer 4

Autoimmune, twice as common in females, common in ages 40-50 years, increased incidence of malignancy

Question 5

What are some clinical features of inflammatory myopathies?

Answer 5

Muscle weakness = insidious onset, worsening over months
Usually symmetrical, proximal muscles
Often specific problems (e.g climbing stairs)
Myalgia in 25-50% (usually mild)

Question 6

What does dermatomyositis affect as well as muscles?

Answer 6

The skin = Gottron’s sign, heliotrope rash, shawl sign, purple/red rash

Question 7

What are some common manifestations of inflammatory myopathies?

Answer 7

Interstitial lung disease, respiratory muscle weakness, dysphagia, myocarditis, fever, weight loss, Reynaud’s, inflammatory arthritis

Question 8

What is the link between inflammatory myopathies and malignancy?

Answer 8

9% incidence in polymyositis, 15% incidence in dermatomyositis, greatest risk in men >45, ovarian, breast, stomach, lung, bladder and colon cancer

Question 9

What are two methods of testing muscle strength?

Answer 9

Confrontational testing = direct testing of power

Isotonic testing = 30 second sit to stand test

Question 10

What blood tests can be done to investigate inflammatory myopathies?

Answer 10

Muscle enzymes (CK), inflammatory markers, electrolytes, calcium, PTH, TSH (to exclude other causes)

Question 11

What auto-antibodies may be present in inflammatory myopathies?

Answer 11

ANA, anti-Jo-1, myositis specific antibodies

Question 12

What would an electromyography of inflammatory myopathies show?

Answer 12

Increased fibrillation, abnormal motor potentials, complex repetitive discharges

Question 13

What would a muscle biopsy show for inflammatory myopathies?

Answer 13

Periarticular inflammation and muscle necrosis (definitive test for diagnosis)

Question 14

What would be some MRI findings for a patient with an inflammatory myopathy?

Answer 14

Muscle inflammation, oedema, fibrosis, calcification

Question 15

How should inflammatory myopathies be treated?

Answer 15

Corticosteroids

Immunosuppression = azathioprine, methotrexate, ciclosporin, rituximab, IV immunoglobulin

Question 16

What is the epidemiology of polymyalgia rheumatica?

Answer 16

Occurs almost exclusively in those >50 years old, incidence higher in northern regions

Question 17

What is polymyalgia rheumatica associated with?

Answer 17

Temporal/giant cell arteries

Question 18

How does polymyalgia rheumatic manifest clinically?

Answer 18

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

Question 19

How does granulomatous arteritis of large vessels present?

Answer 19

Headache, scalp tenderness, jaw claudication, visual loss (amaurosis fugax), tender enlarged non-pulsatile temporal arteries

Question 20

What can be used to diagnose polymyalgia rheumatica?

Answer 20

ESR (raised), PV, CRP, temporal artery biopsy (best option), temporal artery USS

Question 21

How should polymyalgia rheumatica be treated?

Answer 21

Rapid and dramatic response to low dose steroids, gradually reduce dose over 18months to 2 years, start at prednisolone 15mg daily

Question 22

How should granulomatous arteritis be treated?

Answer 22

Start at 40-60mg of prednisolone daily

Question 23

What is fibromyalgia the most common cause of?

Answer 23

Chronic MSK pain, especially in women aged 22-50

Question 24

What are some associations of fibromyalgia?

Answer 24

Not associated with inflammation, may begin after emotional or physical trauma, linked to IBS, more common in women (6:1)

Question 25

What are some neurological symptoms of fibromyalgia?

Answer 25

Headaches, sleep disorders, dizziness, cognitive and memory impairment, anxiety, depression

Question 26

What are some muscular symptoms of fibromyalgia?

Answer 26

Myofascial pain, fatigue, twitches

Question 27

What are some general symptoms of fibromyalgia?

Answer 27

Morning stiffness, problems urinating, dysmenorrhoea, nausea, chest pain, vision problems, jaw dysfunction, weight gain, cold symptoms, multiple chemical sensitivity

Question 28

What are the hallmark symptoms of fibromyalgia?

Answer 28

Skin/muscle hypersensitivity to touch

Question 29

What makes up the ACR Proposed Diagnostic Criteria (2010) for fibromyalgia?

Answer 29

Patient experiences widespread pain and associated symptoms = unrefreshed sleep, cognitive symptoms, fatigue etc
Symptoms have been present at same level for >= 3 months
No other condition explains pain

Question 30

What are some non-pharmacological treatments for fibromyalgia?

Answer 30

Patient education, multi-disciplinary response, graded exercise program, cognitive behavioural therapy, complementary medicine (e.g acupuncture)

Question 31

What are some pharmacological treatments of fibromyalgia?

Answer 31

Anti-depressants = tricyclics, SSRIs
Analgesia
Gabapentin and pregabalin