Neuromuscular Junction Disorders Flashcards Preview

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Flashcards in Neuromuscular Junction Disorders Deck (22)
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1
Q

MG

A
  • ai d/o pf post-synpatic NMJ (AChR are degraded or blocked)

- also get abnormalities of thymus (glandular enlargement or hyperplasia)

2
Q

LEMS

A

pre-NMJ voltage gated calcium channel

3
Q

what are the most common initial symptoms of MG

A
  • ptosis (eye lid drooping)
  • diplopia (dbl vision from asymmetrically weal extraocular muscles)
  • dysarthria (slurred speech)
  • dysphagia (weakness of swallowing)
4
Q

more on MG

A
  • asymmetrical weakness is common

- some ppl improve with rest

5
Q

ocular myasthenia

A

10-20% of ppl who ONLY have visual s/s after 2-3yrs

-restricted form of MG

6
Q

generalized MG

A

majority: 80-90%

7
Q

neonatal myasthenia

A

healthy newborns of myasthenic moms may have MG s/s for a few days until mom’s Ab wash out of their system

8
Q

myasthenic crisis

A
  • profound weakness may cause quadriplegia
  • pt unable to speak, swallow, breathe
  • may be triggered by a serious infection or other systemic illness
  • tx with IVIG or plasmapheresis
9
Q

diagnosis of MG

A

*clinical history

10
Q

most specific diagnostic test for MG

A

presence of serum AChR Ab

11
Q

treatment of ai MG

A
  • anticholinesterase drugs: Pyridostigmine (monitor dose for r/o cholinergic crisis)
  • thymectomy
  • corticosteroids (*prednisone) and some other immunosuppressants
12
Q

LEMS muscle fatigue and weakness

A
  • affect proximal muscles of shoulder, hip, trun
  • autonomic s/s: dry mouth, orthostatic hypotension, ED
  • ai dysfunction is related to an underlying cancer (small cell carcinoma of the lung)
13
Q

LEMS tx

A
  • tx underlying ca

- enhance ACh release: guanidine or 3,4-diaminopyridine

14
Q

depending on distribution of clinical findings muscle weakness can be caused by disorders of:

A
  • UMN
  • LMN
  • peripheral nerve
  • NMJ
  • muscle fibers
15
Q

LMN/anterior horn cells

A
  • spinal muscular atrophy
  • ALS
  • paraneoplastic syndromes
  • poliomyelitis
16
Q

UMN

A
  • leukodystrophies
  • vasculitis
  • brain mass
  • vit B12 deficiency
17
Q

peripheral nerves

A
  • hereditary primary motor sensory neuropathy
  • GBS
  • diabetic neuropathy
  • amyloid neuropathy (myeloma)
  • lead poisoning
18
Q

NMJ

A
  • MG
  • LEMS
  • OPP poisoning
  • botulism
19
Q

muscle fibers

A
  • muscular dystrophies
  • polymyositis and dermatomyositis
  • hypothyroidism
  • corticosteroids
  • HIV myopathy
20
Q

MG s/s

A
  • fluctuating and fatigable proximal muscle weakness that is worse later in the day
  • ocular (diplopia, ptosis)
  • bulbar (dysphagia, dysarthria)
  • respiratory muscles (myasthenic crisis)
21
Q

what test is highly specific for MG

A

Acetycholine receptor antibodies

22
Q

eval of spinal cord compression

A

MRI of the spine

-s/s: UMN dysfunction distal to site of compression