Neuromuscular Disorders

Question 1

skeletal muscle fibres are innervated by __ neurons whose cell bodies arise in the __ horn of the spinal cord

Answer 1

motor

ventral/anterior

Question 2

define the motor end plate

Answer 2

synapses formed between terminal motor neurons and skeletal muscle

Question 3

this enzyme breaks down Ach into ___ and ____

Answer 3

acetylcholinesterase
acetone
choline

Question 4

is acetate or choline sequestered into presynaptic vesicles?

Answer 4

choline

Question 5

clostridium botulinum exists where?

Answer 5

soil

Question 6

MoA of botox?

Answer 6

cleaves presynaptic proteins involved in vesicle formation

Question 7

lambert eaton myaesthenic syndrome involves an inflammatory response against what structure?

Answer 7

presynaptic Ca channels

Question 8

Tx of lambert eaton myeasthenic syndrome?

Answer 8

3,4- diaminopyridine

Question 9

LEMS is associated with what condition?

Answer 9

small cell carcinoma

Question 10

myaesthenia gravis is a __-synaptic disorder

Answer 10

post

Question 11

most common disorder of the NMJ

Answer 11

myaesthenia gravis

Question 12

myaesthenia gravis is an autoimmune condition T or F

Answer 12

T

Question 13

pathophysiology of myaesthenia gravis

Answer 13

antibodies made against ACh receptors causing muscle weakness and fatigue

Question 14

symptoms of MG begin when ACh receptors are reduced to __% of normal

Answer 14

30

Question 15

what gland plays a particular role in myaesthenia gravis?

Answer 15

thymus

Question 16

name the 2 peaks of incidence of MG and the genders they appear in

Answer 16

females in 30s

men in 60s/70s

Question 17

clinical presentation of MG

Answer 17

fluctuating weakness worse during day
extraocular, facial, bulbar weakness
mainly proximal limb weakness

Question 18

limb weakness is worst __lly

Answer 18

proximally

Question 19

Tx of MG acutely?

Answer 19

acetylcholinesterase inhibitor eg pyridostignmine
IV Ig’s and/or plasma exchange
thymectomy if thymus involved

Question 20

mainstay Tx of MG?

Answer 20

immunomodulators
steroids
azathioprine (immunosuppressant)

Question 21

what antibiotic should be avoided in MG?

Answer 21

gentamicin

Question 22

smallest contractile unit in skeletal muscle

Answer 22

muscle fibre

Question 23

which type of muscle has no sarcomeres?

Answer 23

smooth muscle

Question 24

actin myosin ratio of smooth muscle?

Answer 24

10:1

Question 25

fasciculations can be triggered by what?

Answer 25

stress caffeine fatigue

Question 26

fasciculations are indicative of disease where?

Answer 26

motor neurone (NOT muscle)

Question 27

where is the problem in myotonia?

Answer 27

chloride channels

Question 28

define myotonia

Answer 28

failure of muscle relaxation after use

Question 29

symptoms and signs of muscle disease?

Answer 29

myalgia muscle weakness wasting hyporeflexia

Question 30

immune mediated muscle disorders?

Answer 30

dermatomyositis | polymyositis

Question 31

inherited muscle disorders?

Answer 31

muscular dystrophies dystrophinopathies myotonic dystrophies

Question 32

congenital muscle disorders?

Answer 32

myaesthenic syndromes | congenital myopathies

Question 33

describe the pattern of muscle weakness in polymyositis

Answer 33

symmetrical progressive proximal weakness that has a chronic onset

Question 34

best marker for polymyositis?

Answer 34

CK

Question 35

slowly progressive weakness in a patient in their 60s with sparing of their thumb...

Answer 35

inclusion body myositis

Question 36

commonest MD

Answer 36

myotonic MD

Question 37

how is myotonic MD inherited?

Answer 37

AD

Question 38

clinical presentation of myotonic MD

Answer 38

``` myotonia weakness cataract ptosis frontal badling cardiac defects ```

Question 39

muscular dystrophies are non inflammatory T or F

Answer 39

T

Question 40

central and peripheral nerve dysfunction is a symptom of muscular dystrophy T or F

Answer 40

F, central and peripheral nerves not affected

Question 41

infective causes of MD?

Answer 41

coxsackie trpanosomiasis cistercercosis borrelia

Question 42

patient with new onset myotonia after eating uncooked pork....

Answer 42

cistercercosis

Question 43

what electrolyte imbalance can cause a myopathy?

Answer 43

hypokalemia

Question 44

describe rhabdomyolysis?

Answer 44

skeletal muscle causes leakage of large quantities of toxic intracellular contents into plasma

Question 45

triad of symptoms of rhabdomyolysis?

Answer 45

myalgia muscle weakness myoglobinuria

Question 46

scoring a 4 on muscle grading means what?

Answer 46

movement against resistance but not full strength

Question 47

scoring a 3 on muscle grading means what?

Answer 47

movement against gravity but not against resistance

Question 48

scoring a 1 in muscle grading means what?

Answer 48

flicker of movement when attempting to contract muscle