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Year 2 - Musculoskeletal (DP) > Pathology > Flashcards

Flashcards in Pathology Deck (76)
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1

What are some indications for a muscle biopsy?

Evidence of muscle disease:
- Weakness
- Symptoms (Atrophy, Fasciculation)
- Increased CK
Presence of neuropathy (Do nerve biopsy too)
Presence of vasculitis

2

In what disorders is CK high? How do we class high CK?

Dystrophies
200-300 times normal

3

In what disorders is CK intermediate? How do we class intermediate CK?

Inflammatory myopathies
20-30 times normal

4

In what disorders is CK relatively low? How do we class relatively low CK?

Neurogenic disorders
2-5 times normal

5

What can be seen in muscle dystrophy on biopsy?

Variable fibre size
Endomysial fibrosis
Fatty infiltrate + replacement:
- Clear spaces on histology
Myocyte hypertrophy
Fibre splitting
Increased central nuceli

6

Why is segmented necrosis seen in muscle dystophy biopsies?

Parts of individual muscle fibres controlled by different nuclei

7

What are ring fibres?

Striated anulets on histology

8

What are some general pathological features seen in all muscular dystrophies?

Destruction of single fibres
Prolonged
Regeneration of fibres
Fibrosis

9

A 3 year old patient is brought to you by his father. He is concerned about the fact that his son has been walking on his tiptoes a lot and falls a lot when he tries to run. On examination, the boy stands up by walking his hands towards his feet and has swollen 'woody' calves. What is the diagnosis and genetic cause of this disease?

Duchenne Muscular Dystrophy:
- Dystrophin gene mutation
- X linked recessive

10

What are pathogenic features of DMD?

Anchorage of actin to basement membrane
Uncontrolled calcium entry into cells

11

What investigations could be requested in DMD and what would the expected results be?

Serum creatinine phosphokinase:
- Raised
Muscle biopsy:
- Fibre necrosis and phagocytosis
- Regeneration
- Chronic inflammation and fibrosis
- Hypertrophy

12

What is Becker Muscular Dystrophy and how does it differ from DMD?

Essentially a variant of DMD but:
- Later onset
- Slower progress

13

At what age to DMD patients tend to die?

20

14

What tends to cause death in DMD?

Dilated cardiomyopathy

15

How is BMD inherited?

X-Linked recessive

16

'Hatchet-like' face?

Myotonic dystrophy

17

What are the two most common types of myotonic dystrophy?

DM1
DM2

18

How is myotonic dystrophy inherited?

Autosomal dominant:
- Ch19 (DM1)
- Ch3 (DM2)

19

What muscles are affected in the following stages of myotonic dystrophy:
1. Adolescent
2. Late

1. Face and distal limbs
2. Respiratory muscles

20

What are the histological features of myotonic dystrophy?

Atrophy of Type i skeletal muscle fibres
Central nuclei
Fibre necrosis
Fibrofatty replacement

21

What is the immunopathogenesis of polymyositis?

Cell-mediated immune response to muscle antigens:
- CD8+ T cells in endomysium

22

What type of fibre necrosis is seen in polymyositis?

Segmental

23

What are the clinical signs of polymyositis?

Progressive proximal muscle weakness
Pain
Tenderness

24

A patient present with difficult climbing the stairs and brushing her hair. You notice a purple heliotrope rash around her eyes.

Dermatomyositis

25

Where are immune complexes and complement deposited in dermatomyositis?

Within and around muscle capillaries

26

What sort of fibre injury is seen in dermatomyositis?

Perifascicular

27

Why lymphocytes infiltrate the muscle fibres in dermatomyositis?

B cells
CD4+ T cells

28

What is the general histological appearance of a muscle biopsy in neurogenic muscle disorders?

Small, angulated fibres (adults)
Small, round fibres (kids)
Target fibres
Fibre type grouping
Grouped atrophy

29

What causes motor neurone disease?

Progressive degeneration of anterior horn cells

30

What are signs of motor neurone disease?

Denervation atrophy
Fasciculation
Weakness