disorders of the NMJ

Question 1

presynaptic disorders

Answer 1

Botilism

Lambert eaton myasthenia syndrome

Question 2

Botulism

Answer 2

clostridium botulinum found in soil- food and wounds can become infected
Toxin cleaves presynaptic proteins involved in vesicle formation and block vesicle docking with presynaptic membrane

Question 3

symptoms of botulism

Answer 3

rapid onset weakness without sensory loss

Question 4

who gets botulism and why

Answer 4

IV drug users- black tar heroin

Question 5

Lambert eaton myasthenic syndrome

Answer 5

antibodies to presynaptic calcium channels leads to less vesicle release- slowly increasing muscle fatigue

Question 6

What is associated with Lambert eaton

Answer 6

underlying small cell carcinoma

Question 7

Post synaptic disorders- myasthenia gravis

Answer 7

autoimmune antibodies to acetyl choline receptors
decrease number of functioning receptors leads to muscle weakness
symptoms start when ACh receptors fall to 30%of normal

Question 8

clinical features of myathenia gravis

Answer 8

weakness- fluctuating- worse throughout the day
Most common presentation- extraoccular weakness, facial and bulbar weakness
limb weakness typically proximal

Question 9

treatment of myasthenia gravis

Answer 9

acetylcholinesterase- pyridostigmine
thymectomy
steroids
emergency plasma exchange/ immunoglobulin

Question 10

symptoms of muscle disease

Answer 10

myalgia
muscle weakness
wasting
hyporeflexia

Question 11

inflammatory muscle disease

Answer 11

dermatomyositis

polymyositis

Question 12

inherited muscle disease

Answer 12

muscular dystrophies

myotonic dystrophies

Question 13

congenital muscle disease

Answer 13

congenital myasthenia disease, congenital myopathies

Question 14

polymyositis and dermatomyositis

Answer 14

symmetrical, progressive, proximal weakness developing over weeks- months
Raised CK
dermatomyositis is the same but with skin lesions- heliotrope rash

Question 15

degenerative muscle disease

Answer 15

inclusion body myositis
little response to steroid, typically slowly progressive weakness in 6th decade of life with characteristic thumb sparing

Question 16

myotonic dystrophy

Answer 16

AD
most common muscular dystrophy, multisystem involvement
myotonia, weakness, cataracts, ptosis, frontal balding, cardiac defects
trinucleotide repeat disorder with anticipation

Question 17

rhabdomyolosis

Answer 17

dissolution of muscle

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

Question 18

cause of rhabdomyolosis

Answer 18

trauma, toxins, post convulsion

Question 19

triad of symptoms in rhabdomyolosis

Answer 19

myalgia, muscle weakness and myoglobinuria

Question 20

complications of rhabdomyolosis

Answer 20

acute renal failure, DIC