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Flashcards in Pathology Deck (44):
1

Describe type 1 muscle fibres

Red, large mitochondria and increased myoglobin

2

Describe type 2 muscle fibres

White, small mitochondria & large motor end plates

3

What are some indications for performing a muscle biopsy?

Evidence of muscle disease-weakness, atrophy, fasciculation, elevated CK, presence of neuropathy (+nerve biopsy), presence of vascular disorder (vasculitis)

4

Describe high, medium and low CK levels

High: 200-300x normal (dystrophies). Medium:20-30x (inflammatory myopathy). Low : 2-5x (neurogenic disorder)

5

Describe some dystrophic changes in histology

Variability in muscle fibre size, endomysial fibrosis, fatty infiltration and replacement, myocyte hypertrophy & fibre splitting, increased central nuclei, segmental necrosis, regeneration, ring fibres

6

What occurs to muscles and CK in DMD?

Proximal weakness, pseudohypertrophy of calves. Raised CK

7

What mutation occurs in DMD?

Mutations in dystrophin gene on long arm of ChX

8

What changes occur regarding cell structures in DMD?

Alterations in anchorage of actin cytoskeleton to basement membrane. Fibres liable to tearing, uncontrolled Ca2+ entry

9

What histological changes occur in DMD?

Muscle fibre necrosis & phagocytosis
Regeneration
Chronic inflammation and fibrosis
Hypertrophy

10

Describe the onset, mutation and progress of BMD

Later onset, mutation in dystrophin (like DMD), slower progress

11

What are the most common types of myotonic dystrophy?

DM1 (distal), DM2(proximal)

12

What symptons occur in myotonic dystrophy?

Muscle weakness, myotonia, non-muscle features- cataracts, frontal baldness in men, cardiomyopathy, low intelligence

13

What inheritance occurs in myotonic dystrophy?

Autosomal dominant-Ch19/3

14

What areas are affected by myotonic dystrophy?

Adolescence- face, distal limbs. Later-respiratory muscles

15

What histological changes occur in myotonic dystrophy?

Atrophy of type 1 fibres, central nuclei, ring fibres, fibre necrosis, fibrofatty replacement

16

What is polymyositis?

Cell-mediated immune response to muscle antigens

17

What pathological changes occur in polymyositis?

Endomysial lymphocytic infiltrate, invasion of muscle by CD8+ T cells, segmental fibre necrosis

18

What is the difference between dermatomyositis and polymyositis?

Dermatomyositis is polymyositis plus skin changes

19

What changes occur in dermatomyositis?

Upper body erythema, swelling of eyelids with purple discolouration

20

What are the pathological changes that occur indermatomyositis?

Immune complex and complement deposition within and around capillaries within muscle. Perifascicular muscle fibre injury. B-cells/CD4+ T cells > polymyositis

21

What is MND?

Progressive degeneration of anterior horn cells. Denervation atrophy, fasciculation and weakness

22

What is the genetic mutation behind spinal muscular atrophy?

Inherited autosomal recessive-Ch5

23

What occurs in spinal muscular atrophy?

Degeneration of anterior horn cells in spinal cord, and denervation of muscle

24

What type of disorder is Myasthenia Gravis?

Autoimmune

25

What symptoms occur in Myasthenia Gravis?

Weakness, proptosis, fatigue and dysphagia

26

Who does myasthenia gravis commonly effect?

Women between 20-40

27

What percentage of people with Myasthenia Gravis have thymoma, and what may others have alternatively?

25%- others may have thymic hyperplasia

28

What is Rhabdomyolysis, and what occurs systemically?

Breakdown of skeletal muscle- myoglobinuria, hyperkalaemia, necrosis and shock

29

What is the outcome of rhabdomyolysis?

Acute renal failure, hypovolaemia, hyperkalaemia, metabolic acidosis, disseminated intravascular coagulation

30

What is SLE?

AI multisystem disorder, involving ANA's, has genetic factors and may be drug induced (hydralazine and pracainamide). F-M 9:1

31

What symptoms/conditions occur as a result of SLE?

Butterfly rash, discoid lupus erythematosus (DLE), arthralgia, glomerulonephritis, psychiatric symptoms, focal neurological symptoms, peri/myocarditis, necrotizing vasculitis, lymphadenopathy, splenomegaly, pleuritis, pleural effusions, anaemia, leucopenia, thrombophilia

32

What hypersensitivity presentations occur in SLE?

Visceral lesions (Type III), Haematological effects (Type II)

33

What is polyarteritis nodosa (PAN)?

Inflammation and fibrinoid necrosis of small/medium arteries?

34

What is the aetiology of PAN?

Unknown

35

What are the target organs of PAN?

Kidneys, heart, liver, GI tract, skin, joints, muscles, nerves, lungs

36

What are the clinical features of PAN?

Non-specific +/- organ specific features- HT, haematuria, abdo pain, melaena, diarrhea, mononeuritis multiplex, rash, cough, dyspnoea

37

How is PAN diagnosed?

Biopsy; fibrinoid necrosis of vessels. Serum contains pANCA (perinuclar antineutrophil cytoplasmic autoantibody)

38

How does polymyalgia rheumatica present?

In elderly commonly- pain, stiffness in shoulder & pelvic girdles. No muscle weakness

39

What is Temporal arteritis?

Inflammation affecting cranial vessels.

40

What are the symptoms of temporal arteritis?

Headache and scalp tenderness. Risk of blindness if terminal branches of ophthalmic artery affected

41

How is temporal arteritis diagnosed?

Raised ESR- temporal artery biopsy; inflammation, +/- giant cells, fragmentation of internal elastic lamina

42

What is scleroderma?

Excessive fibrosis of organs and tissues (excessive collagen production)

43

What symptoms/conditions occur due to scleroderma?

Skin is tight, tethered, decreased joint movement. GIT-fibrous replacement of muscularis. Pericarditis and myocardial fibrosis. Interstitial fibrosis. Kidneys-affects arteries > HT, MSK- polyarteritis and myositis

44

What syndrome is scleroderma associated with?

CREST