Muscle pathology Flashcards

(45 cards)

1
Q

What is the epimysium?

A

The fibrous sheath which surrounds the entire skeletal muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the endomysium?

A

The fibrous sheath which surrounds individual muscle fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the perimysium?

A

The fibrous sheath which surrounds groups of muscle fibres to create a fascicle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the indications for muscle biopsy?

A

Evidence of muscle disease - weakness, atrophy, raised CK
Presence of neuropathy
Presence of vascular disorder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What histological changes might be seen in muscular dystrophy?

A
Variability in size of muscle fibres
Endomysial fibrosis
Fatty infiltration
Increased central nuclei
Segmental necrosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are muscular dystrophies?

A

A group of inherited diseases that cause progressive weakening of muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the pathophysiology of muscular dystrophies?

A

There is destruction of single muscle fibres in the muscles, which are then regenerated
This causes fibrosis of the muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

When does Duchenne Muscular Dystrophy typically present?

A

2-4 years old

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the pathophysiology of Duchenne muscular dystrophy?

A

There is a mutation of the dystrophin gene on the long arm of chromosome X
Actin fibres don’t adhere properly to the basement membrane, leaving fibres liable to tearing
There is uncontrolled Ca2+ entry into cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is myositis ossificans?

A

A condition where heterotopic ossification (bone forming outside the skeleton) occurs in muscles usually after an injury

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are polymyositis and dermatomyositis?

A

Idiopathic inflammatory myopathies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Which gender do polymyositis and dermatomyositis affect?

A

Female:male 2:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the peak age of incidence in polymyositis and dermatomyositis?

A

40-50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are patients with polymyositis and dermatomyositis at increased risk of?

A

Malignancy, particularly dermatomyositis (15%)

Lung, breast, ovarian, stomach, colon and bladder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which patients with polymyositis and dermatomyositis in particular are at risk of malignancy?

A

Men >45

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What cutaneous signs may be present in dermatomyositis?

A

Gottrons sign (fingers and knuckles)
Heliotrope rash
Shawl sign

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What other organs may be involved in polymyositis and dermatomyositis?

A

Lungs: respiratory muscle weakness and interstitial lung disease, breathlessness, cough
Heart: myocarditis
Oesophagus: dysphagia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What general systemic symptoms may be present in polymyositis and dermatomyositis?

A

Fever
Weight loss
Raynaud’s
Non-erosive polyarthritis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What other diseases are polymyositis and dermatomyositis associated with?

A

Diabetes mellitus

Thyroid disease

20
Q

What drugs are development of polymyositis and dermatomyositis associated with?

A

Steroids

Statins

21
Q

What tests on examination can be done to investigate polymyositis and dermatomyositis?

A

Confrontational testing - direct testing of power

Isotonic testing - 30 second sit to stand test

22
Q

What blood tests should be done to investigate polymyositis and dermatomyositis?

A

Creatine kinase
Inflammatory markers
Electrolytes, calcium, PTH, TSH to exclude other causes

23
Q

What auto-antibodies may be present in polymyositis and dermatomyositis?

A

ANA

Anti-Jo-1

24
Q

What investigations should be done to confirm polymyositis and dermatomyositis?

A

Electromyography (EMG)
Muscle biopsy
MRI

25
What would be seen on electromyography in polymyositis and dermatomyositis?
Increased fibrillations Abnormal motor potentials Complex repetitive discharges
26
What would be seen in muscle biopsy in polymyositis and dermatomyositis?
Perivascular inflammation and muscle necrosis
27
What would be seen on MRI of polymyositis and dermatomyositis?
Muscle inflammation, oedema, fibrosis and calcification
28
What is the treatment for polymyositis and dermatomyositis?
``` Glucocorticoids Azathioprine Methotrexate Ciclosporin IV immunoglobulin ```
29
What is inclusion body myositis?
An inflammatory muscle disease, characterized by slowly progressive weakness and wasting of mostly distal, but some proximal muscles, most apparent in the muscles of the arms and legs
30
Which gender is inclusion body myositis most apparent in?
Males 3:1
31
At what age are patients affected by inclusion body myositis?
>50
32
Which muscles are most commonly affected by inclusion body myositis?
Wrist and finger flexors in upper limbs | Quadriceps and anterior tibial muscles in legs
33
Which has higher levels of CK: polymyositis or inclusion body myositis?
Polymyositis
34
What is polymyalgia rheumatica?
Polymyalgia rheumatica (PMR) is a condition that causes pain, stiffness and inflammation in the muscles around the shoulders, neck and hips
35
At what age does polymyalgia rheumatica occur?
>50
36
What condition is polymyalgia rheumatica associated with?
Giant cell arteritis
37
What are the symptoms of polymyalgia rheumatica?
Ache in shoulder and hip girdle Morning stiffness Fatigue, anorexia, weight loss and fever Reduced movement of shoulders, neck and hips
38
Is muscle strength affected in polymyalgia rheumatica?
No
39
What is the treatment for polymyalgia rheumatica?
Low dose steroids | Gradual reduction at 18months - 2years
40
What is the commonest cause of musculoskeletal pain in women aged 22-50 years?
Fibromyalgia
41
What gender is fibromyalgia most common in?
Females 6:1
42
What may trigger fibromyalgia?
Emotional or physical trauma
43
Is fibromyalgia associated with inflammation?
No
44
What are the clinical manifestations of fibromyalgia?
Chronic pain: neck, shoulders, lower back, chest wall 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
45
What is the treatment for fibromyalgia?
``` Patient education Graded exercise programme Cognitive behavioural therapy Complementary medicine eg. acupuncture Antidepressants Analgesia e.g. tramadol Gabapentin and pregabalin ```