Neuro 3 pt1 Flashcards
(25 cards)
Most common disorder of Neuromuscular transmission
Cardinal features are weakness and fatigability of the skeletal muscles
Weakness increases with activity and improves c rest
Myasthenia Gravis
Myasthenia Gravis
Peak incidence is what age range in males/females/
Peak incidence women in 20s/30s and men in 50s/60s
hyperthyroidism hypokalemic periodic paralysis(HPP) RA Sjogren’s syndrome SLE DM these are all associated disorders with:
Myasthenia Gravis
Acetylcholine Receptors are either __ or __
nicotinic or muscarinic
The fundamental defect of Myasthenia Gravis is:
decrease in available acetylcholine receptors
“Myasthenic fatigue” is caused by
inefficiency of NM transmission causing increasing weakness c activity
– if you do the same thing over and over you will be less and less able to function. this term is called ____; what is this associated with?
Presynaptic rundown
associated with Myasthenia Gravis
What is MuSK? What does it stand for?
Muscle Specific tyrosine Kinase (MuSK) is protein involved in AChR clustering at NM junction mostly bulbar
Reduces the amt. of AChRs
IgG and T-cell mediated
Cranial nerve exercise: what's the principle eye function of each of these CN? Abducens Oculomotor Facial Oculomotor
Abducens: LATERAL eye movement
Oculomotor: MEDIAL eye movement
Facial: Lower the eyelid
Oculomotor: Raise the eyelid
What two nerves are involved with swallowing?
Vagus & Glossopharyngeal
Face muscles are tired and you can’t smile correctly. This is called:
Myasthenic “snarl” of Myasthenia Gravis
MG weakness:
~85% have ______ weakness.
How are their DTR’s? Why?
proximal limb weakness
DTRs preserved. Reflexes are fine because it doesn’t involve the spine’s reflex arc. –use this to differentiate between MG and some other disorders.
weakness restricted to extraocular muscles for >3yrs
Pupillary function is still good
Ocular MG
How do you dx Ocular Myathenia Gravis?
ice test (your eye will work better with the cool temperature), tensilon test; same as generalized MG PLUS: you have a thymoma
What is the most common symptom of Ocular MG?
ptosis (whether it is uni or bilateral)
MG testing (it’s highly sensitive & specific)
Acetylcholine receptor antibodies
He showed us a video of a dog that could barely walk, but then after they did some test it could. What was the dog’s conditinon and test?
What did it do?
Tensilon Test in a dog with MG
Tensilon test- IV edrophonium inhibits acetylcholinesterase and transiently reverses ptosis & EOM weakness(relatively contraindicated in CAD or bronchiole asthma), need antidote atropine ready
Tx of Myasthenia Gravis (2 types)
Thymectomy if there’s a thymoma
or
Aceytlchoinesterase, and then try prednisoneW
What does ALS stand for? (what is each initial’s definition)?
Amyotrophy: muscle atrophy
Lateral(and anterior): white matter corticospinal tracts
Sclerosis: resultant firm gliosis – scarring and damage seen on MRI.
Is ALS UMN, LMN, or both?
BOTH
ALS- cause unknown, other than gene mutation identical in both inherited and sporadic forms.
Name 2 things that increase risk in these genetically susceptible pts
smoking
lead exposure
Most common presentation of ALS
asymmetric distal limb weakness (80%)
what is a bulbar symptom?
sx relating to the medulla oblongata
What is the most common ALS bulbar sx? (2)
Dysarthria or dysphagia
