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Flashcards in Muscle and NMJ Deck (24)
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1
Q

What are hte features of lower motor neurone disorders?

A

weak; low tone and fasciculations

2
Q

What is the motor end plate?

A

the synapse formed between motor neurons and muscle

3
Q

How does botulinum toxin affect the presynaptic cleft?

A

cleaves presynpatic proteins involved in vesicle formation and block vesicle docking with the presynpatic memrbane

4
Q

What happens in lambert-eaton myasthenic syndrome/

A

antibodies to presynaptic calcium channels leads to less vesicle release

5
Q

What is lambert-eaton syndrome associated with?

A

small cell carcinoma

6
Q

What happens in myasthenia gravis?

A

antibodies to acetyl choline receptors reducing number of receptors and triggering an inflammatory cascade flattening of endplate folds

7
Q

What is other organ is found to be involved with myasthenia gravis?

A

thymus- 85% have hyperplasia or thymoma

8
Q

When are the 2 peaks of incidence for myasthenia gravis?

A

females in the 3rd decade and males in 6th or 7th decade

9
Q

What are the lcinical features of myasthenia gravis?

A

wekaness getting worse over the day; proximal limb weakness; commonly extraocular weakness; facial and bulbar weakness

10
Q

What is the acute treatment for myasthenia graivs?

A

acetylcholinesterase inhibitor- pyridostigmine; IV immunoglobulins

11
Q

What is the chronic treatment fro myasthenia gravis?

A

thymectomy; steroids/ azathioprine

12
Q

What are the common causes of morbidity in myasthenia gravis?

A

resp failure and aspiration pneumonia; porblems with immunosuppression and steroids in the elderly

13
Q

What connective tissue are individual muscles surrounded by?

A

epimysium

14
Q

What is a sarcomere?

A

from one Z line to another- smallest contractile unit of muscle

15
Q

What are fasciculations?

A

visible, fast, fine, spontaneous twitches

16
Q

When do fasciculations occur pathologically?

A

in denervated msucle which has become hyperexcitable- usually problem in motor neurone not muscle

17
Q

What is mytonia?

A

failure of muscle relaxaion after use due a problem with chloride channels

18
Q

What are the features of polymyositis?

A

symmetrical, progressive proximal weakness developing over weeks to months with raised CK

19
Q

What are the features of inclusion body myositis?

A

similar to sarcopenia but arises earlier than normal but has chracteristic thumb sparing

20
Q

What is the inheritance of myotonic dystrophy?

A

autosomal dominant

21
Q

What are the features of myotonic dystrophy?

A

myotonia; weakness; cataracts; ptosis; frontal blading; cardiac defects

22
Q

What happens in rhabdomyloysis?

A

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

23
Q

What are the features of rhabdomylosis?

A

myalgia; msucle weakness and myoglobinuria

24
Q

What are the complications of rhabdomyolysis?

A

acute renal failure and DIC