Y4 Myopathy

Question 1

what are features of myopathy?

Answer 1

Gradual onset
􏰀 Symmetrical, proximal weakness: difficulty combing
hair, climbing stairs, getting up from chairs

Question 2

what are the reflexes of myopathy?

Answer 2

preserved - normal

Question 3

what is the difference in locations affected between myopathy and neuropathy ?

Answer 3

neuropathy - distal

myopathy - proximal

Question 4

what two conditions have fatiguablity ?

Answer 4

MG, LEMS

Question 5

what type of myopathy would be indicated by pain on exercise ?

Answer 5

ischaemia or metabolic myopathy

Question 6

what type of myopathy would be indicated by pain at rest ?

Answer 6

inflammyopathy

Question 7

what investigations should be done for myopathies?

Answer 7

ESR, CK, AST, LDH

􏰀 EMG

Question 8

state two inflammatory myopathies ?

Answer 8

Polymyositis

􏰀 Dermatomyositis

Question 9

what metabolic conditions can cause myopathies ?

Answer 9

Hyperthyroidism, Cushing’s, ↑/↓Ca2+

Question 10

what medication can cause myopathies ?

Answer 10

steroids, statins, EtOH

Question 11

state the two common types of muscular dystrophies ?

Answer 11

Duchennes

Beckers

Question 12

what is the genetic inheritance of muscular dystrophies ?

Answer 12

X linked

Question 13

what age does duchennes present ?

Answer 13

4years

Question 14

what are the features of duchennes?

Answer 14

Difficulty standing
􏰁 Calf pseudohypertrophy 􏰁
Respiratory failure

Question 15

what one investigation apart from genetics can confirm duchennes?

Answer 15

↑↑CK

Question 16

is duchennes or beckers more severe?

Answer 16

duchennes

Question 17

what muscular dystrophies has Difficulty puffing cheeks and raising arms above head?

Answer 17

Facioscapulohumeral MD

Question 18

what is the genetic inheritance of Facioscapulohumeral MD ?

Answer 18

Autosomal dominant

Question 19

what are three signs of Facioscapulohumeral MD ?

Answer 19

Weakness of face, shoulders and upper arms
(often asymmetric ̄c deltoids spared)
􏰁 Winging of scapula
􏰁 Foot drop.

Question 20

what is the cause of Myotonic Dystrophy?

Answer 20

Cl- channelopathy

Question 21

what does the face look like with myotonic dystrophy ?

Answer 21

Myopathic facies: long, thin, expressionless 􏰁
Wasting of facial muscles and SCM
􏰁 Bilateral ptosis
􏰁 Dysarthria: myotonia of tongue and pharynx

Question 22

what is myotonia ?

Answer 22

Myotonia: slow relaxation

Question 23

what do the hands look like in myotonic dystrophy?

Answer 23

Myotonia: slow relaxation
􏰂 E.g. inability to release hand after shake
􏰁 Wasting and weakness of distal muscles + areflexia → wrist drop
􏰁 Percussion myotonia: percuss thenar eminence → involuntary thumb flexion

Question 24

state some other features of myotonic dystrophy?

Answer 24

􏰁 Frontal balding
􏰁 Cataracts
􏰁 DM
􏰁 Cardiomyopathy, tachy- / brad-arrhythmias
􏰁 Dysphagia
􏰁 Testicular atrophy

Question 25

what medication can improve myotonia during myotonic dystrophy?

Answer 25

phenytoin

Question 26

what is the pathophysiology of myasthenia gravis ?

Answer 26

Autoimmune disease mediated by Abs vs. nicotinic Ach receptors.

Question 27

what are the reflexes like with myasthenia gravis?

Answer 27

normal

Question 28

state the presenattion of myasthenia gravis ? - extra ocular - bulbar - face - neck - limb

Answer 28

Extra-ocular: bilateral ptosis, diplopia 􏰁 Bulbar: voice deteriorates on counting to 50 􏰁 Face: myasthenic snarl on attempting to smile 􏰁 Neck: head droop 􏰁 Limb: asymmetric, prox. weakness

Question 29

what two abs are present in myasthenia gravis ?

Answer 29

Anti-AChR Abs | MuSK abs

Question 30

what investigations should be done for myasthenia gravis ?

Answer 30

``` Tensilon Test 􏰁 Give edrophonium IV 􏰁 +ve if power improves w/i 1min 􏰀 Anti-AChR Abs 􏰀 EMG ```

Question 31

what gender is myasthenia gravis associated with <50 and >50yrs ?

Answer 31

``` <50 = women >50 = males ```

Question 32

what condition is myasthenia gravis associated with <50yrs ?

Answer 32

thymic hyperplasia.

Question 33

what condition is myasthenia gravis associated with >50yrs ?

Answer 33

thyme tumour/atrophy

Question 34

what medication can be given for myasthenia gravis?

Answer 34

Anticholinesterase: e.g. pyridostigmine.

Question 35

what is the management of myasthenia gravis ?

Answer 35

``` steroids anti cholinesterase immunosuppression (methotrexate) IV Ig plasma exchange (plasmapheresis) thymectomy ```

Question 36

what is a Myasthenic Crisis?

Answer 36

Weakness of respiratory muscles during relapse may be lethal.

Question 37

how is a myasthenic crisis monitored ?

Answer 37

Monitor FVC: vent support if <20ml/kg

Question 38

what does LEMS stand for

Answer 38

Lambert-Eaton Myasthenic Syndrome

Question 39

what is the pathophysiology of LEMS ?

Answer 39

Abs to VGCC ↓ influx of Ca2+ during presynaptic excitation → ↓ presynaptic ACh-vesicle fusion. therefore less ACh being released and binding to receptors

Question 40

what does VGCC stand for in LEMS ?

Answer 40

voltage-gated calcium channels

Question 41

what are two common causes of LEMS ?

Answer 41

Paraneoplastic: e.g SCLC 􏰀 | Autoimmune

Question 42

what abs are present in LEMS ?

Answer 42

anti VGCC abs

Question 43

what is the presentation of LEMS ?

Answer 43

``` same as myasthenia gravis + 􏰁 Leg weakness early (before eyes) 􏰁 Extra: Autonomic and areflexia 􏰁Movement improves symptoms 􏰁Small response to edrophonium ```

Question 44

what treatment is available for LEMS?

Answer 44

3,4-diaminopyridine or IVIg

Question 45

how does botulism toxin work?

Answer 45

prevents ACh vesicle release

Question 46

what is the presentation of botulism ?

Answer 46

Descending flaccid paralysis ̄c no sensory signs

Question 47

what is the treatment for botulism ?

Answer 47

benpen + antiserum