muscle

Question 1

what is happening here and what are these muscle fibres called

Answer 1

muscle reinnervation after injury to motor neurone
target fibres

Question 2

what do muscle fibres look like when they are de-innervated

Answer 2

flat and de-inflated

Question 3

infantile myopathic hypotonia has two types. Explain the differnece seen in histology

Answer 3

classic CFTD: type 1 small, type 2 large

non-classic: large type 2, small type 1

Question 4

which stain for muscle fibres in babies

Answer 4

ATP-ase

Question 5

slow type 1 muscle fibres stain

Answer 5

pale

Question 6

quick type 2 fibres stain

Answer 6

dark

Question 7

which muscle fibres are predominatly lost in ageing

Answer 7

fast type 2

Question 8

signs of dermatomyositis

Answer 8

V sign rash on chest
red rash over eyes with oedema
Gottron’s papules on knuckles

Question 9

which is the most common ANA in dermatomyositis

Answer 9

Anti-Jo1

Question 10

sequalea of untreated dermatomyositis

Answer 10

calcifications in skin and muslces

Question 11

tx dermatomyositis acute

Answer 11

1mg/kg prednisolone until creatine kinase normalised and then add 2 weeks to avoid rebound

Question 12

maintenance tx dermatomyositis

Answer 12

azathioprine
methotrexate
rituximab

Question 13

inclusion body myositis which muscles, which demographic

Answer 13

elderly men
quadriceps
finger and wrist flexors

Question 14

inclusion body myositis, which big problem

Answer 14

dysphagia because of skeletal muscle in oesophagus

Question 15

histology of inclusion body myositis(4)

Answer 15

amyloid plaques, tau bodies, presinilin 1, apolipoprotein E deposits in the muslce

Question 16

what is inclusion body myosistis

Answer 16

legzheimers

Question 17

which enzyme affected by Duchenne and Beckers musculodystrophies

Answer 17

dystrophin

Question 18

Duchenne which MOI

Answer 18

X linked recessive

Question 19

which groups of muscles affected by Duchenne and Becker

Answer 19

proximal

Question 20

what do you see on dystrophin staining in Duchenne vs Becker

Answer 20

Becker - decreased ring
Duchenne - absent ring

Question 21

what is this consequesnce of muscular dystrophies

Answer 21

endomysial fibrosis

Question 22

which common drug increases risk of statin induced rhabdomyolysis

Answer 22

Amiodarone increases risk of statin induced rhabdomyolysis

Question 23

drug induced myopathies

Answer 23

Corticosteroids
Fluorinated steroids
Dose dependent
Type 2 fibre atrophy
Statins
Approx 10% of patients
Rhabdomyolysis
Seems to affect type II fibres more
Alcohol
Chronic - slow progressive proximal weakness
Acute - single heavy session
Hydroxychloroquine
Not dose dependent