Muscle Diseases

Question 1

What is polymyalgia rheumatica?

Answer 1

A relatively common chronic inflammatory condition causing myalgia at the hip and shoulder girdles

Question 2

How is polymyalgia rheumatic characterised?

Answer 2

• Proximal myalgia of the hip and shoulder girdles
• Mornign stiffness lasting > 1 hour

Question 3

Polymyalgia rheumatica is strongly related to which other condition?

Answer 3

Giant cell arteritis

Question 4

In what age is polymyalgia rheumatica most common?

Answer 4

> 50

Question 5

Which blood tests can be done for polymyalgia rheumatica?

Answer 5

There are no specific tests

• CRP (will be raised)
• PV/ESR (will be raised)

Question 6

Symptoms of polymyalgia rheumatic respond very well to which treatment?

Answer 6

Low dose steroids

(prenisolone 15mg)

The response is so dramatic that this can be used as a diagnostic tool

Question 7

What is the treatment oplan for polymyalgia rheumatica involving low dosease steroids?

Answer 7

The steroid dose is gradually reduced over around 18 months

By this time the condition will have resolved in most patients

Question 8

What is the most common form of systemic vasculitis?

Answer 8

Giant cell arteritis

Question 9

Giant cell arteritis commony affects older/younger patients?

Answer 9

Older

Question 10

How is giant cell arteritis characterised histologically?

Answer 10

1. Transmural inflammation of the intima, media and adventitia
2. Patchy infiltration by lymphocytes, macrophages and multinucleated giant cells (granulomas)

Question 11

Vessel wall thickening in giant cell arteritis can result in what?

Answer 11

Subsequent distal ischaemia

Question 12

What are the common signs and symptoms of giant cell arteritis?

Answer 12

• Visual disturbaces
• Headaches
• Jaw claudication
• Scalp tenderness
• Fatigue, malaise and fever may be present

Question 13

Which condition should always be considered in the differential diagnosis of new-onset headaches in patients >50 with raised inflammatory markers?

Answer 13

Giant cell arteritis

Question 14

Describe the headache patients may experience in giant cell arteritis

Answer 14

Continuous

Located in the temporal or occipital areas

Question 15

Why does jaw cladication occur in giant cell arteritis?

Answer 15

There is temporal arteritis which causes subsequent ischaemia of the maxillary artery

Question 16

Diplopia may be experienced in patients with giant cell arteritis, what is this?

Answer 16

Double vision

Question 17

What is the most definitive test for giant cell arteritis?

Answer 17

Temporal artery biopsy

Question 18

When should a temporal artery biopsy be done for a patient?

Answer 18

As soon as giant cell arteritis is suspected

Question 19

Why is a positive temporal artery biopsy 100% specific, but only 15-40% sensitive for giant cell arteritis?

Answer 19

Giant cell arteritis is a diffuse condition and has patchy involvement

This means some segments of the artery will be normal

Question 20

What are the typical biopsy findings in an artery with giant cell arteritis?

Answer 20

1. Mononuclear infiltration
2. Granulomatous inflammation (multinucleated giant cells)

Question 21

What is the treatment for giant cell arteritis?

Answer 21

Corticosteroids

• Prednisolone 40mg (no visual impairment)
• Prednisolone 60mg (visual impairment)

Question 22

When should treatment be started for giant cell arteritis?

Answer 22

As soon as the condition is clincially suspected

Question 23

Describe the treatment program involving corticosteroids for giant cell arteritis

Answer 23

The prednisolone dose is gradually tapered over 2 years

After this time, the condition will have resolved for most patients

Question 24

What is polymyositis?

Answer 24

An idiopathic inflammatory myopathy that caused symmetrical proximal muscle weakness

Question 25

How is dermatomyositis different from polymyositis?

Answer 25

It has typical cutaneous manifestations as well as the other symptoms

Question 26

Both polymyositis and dermatomyositis are more common in which sex, and which age group?

Answer 26

Females Adults \> 20, especially 45-60

Question 27

What is the basic pathogenesis of polymyositis?

Answer 27

It is thought that CD8 T cells and macrophages surround healthy muscle tissue and initiate a cytotoxic response (an autoimmune response to both nuclear and cytoplasmic antibodies in seen in most patients)

Question 28

Which antibodies are associated with polymyositis and which of these are specific for polymositis/dermatomyositis?

Answer 28

1. ANA 2. Anti-RNP 3. ANti-Jo-1 (specific) 4. Anti-SRP (specific)

Question 29

How do patients with polymyositis present and what is the onset of the condition?

Answer 29

Symmetrical, proximal muscle weakness in the upper and lower extremities Some patients also have myalgia (insidious in onset)

Question 30

Why may dysphagia occur in polymyositis?

Answer 30

Secondary to oropharyngeal and oesphageal involvement (a poor prognostic sign)

Question 31

Which lung condition is commonly found in those with polymyositis that are postive for anti-Jo-1 antibody?

Answer 31

Interstitial lung disease

Question 32

Which investigations are suitable for polymyositis/dermatomyositis?

Answer 32

* Inflammatory markers * Serum creatinine kinase * Autoantibodies * MRI * Electromyography * **Muscle biopsy**

Question 33

Why is muscle biopsy crucial in polymyositis/dermatomyositis?

Answer 33

It can exclude other rare muscle diseases

Question 34

What does a muscle biopsy classically show in polymyositis/dermatomyositis?

Answer 34

Muscle fibres in varying stages of inflammation, necrosis and regeneration

Question 35

What is the management of polymyositis/dermatomyositis?

Answer 35

Prednisolone (40mg) Immunosuppressive drugs e.g. azathioprine or methotrexate

Question 36

What are the classical cutaneous features of dermatomyositis?

Answer 36

1. V-shaped rash over chest 2. Gottron's papules 3. Heliotrope rash

Question 37

There is an associated risk of malignancy with dermatomyositis patients, which types of cancer are most common?

Answer 37

* Breast * Ovarian * Lung * Colon * Oesophagus * Bladder

Question 38

What is fibromyalgia?

Answer 38

An unexplained condition causing widespread muscle pain and fatigue

Question 39

Fibromylagia is most common in which sex and age?

Answer 39

Females Young and middle aged

Question 40

What is fibromyalgia thought to be?

Answer 40

Disorder of central pain processing or Syndrome of central sensitivity

Question 41

Patients with fibromyalgia tend to have a lower threshold of which things?

Answer 41

* Pain * Heat * Noise * Strong odours

Question 42

Fibromyalgia can occur as a primary or secondary condition. When it occurs as a secondary condition, which conditions is it associated with?

Answer 42

1. RA 2. SLE

Question 43

How does fibromyalgia clinically present?

Answer 43

1. **Persistant widespread pain** (\> 3 months) on bopth sides of the body, above and below the waist and including the axial spine 2. **Fatigue** and unrefreshing sleep 3. Cognitive difficulties 4. Anxiety, depression, IBS and migraine

Question 44

Which conditions may present similiarly to fibromyalgia?

Answer 44

* Hypothyroidism * RA * SLE * Polymyalgia rheumatica * Other inflammatory autoimmune conditions

Question 45

What is the management of fibromyalgia like?

Answer 45

1. Education of self-management techniques 2. Graded exercise 3. Atypical analgesia (amitriptyline) 4. Gapapentin 5. Pregabalin 6. Cognitive behavioural therapy