Neuromuscular Dysfunction Flashcards
What is myasthenia gravis?
Antibody to post-synaptic AcH receptors - autoimmune, and type 2 hypersensitivity. So not able to bind AcH - weakness in often used muscles, eyes, jaw, vocal, facial, worse throughout the day.
Crisis - respiratory weakness!!
R/out thymoma and do a Tensilon test
What is inflammatory myositis?
Is a systemic autoimmune disease - T-cell mediated, cellular damage and atrophy of muscles, multiple variants, large and proximal muscles - high CK - polymyositis
To help augment prednisone - what can be used to help taper
Methotrexate, Imuran, and tacrolimus
What is MS?
Demyelination of neurons = leads to slowing of the nerve impulses, higher in areas away from the equator and might be related to the HLADR
Only effects the CNS, one or more clinically distinct CNS dysfunction with some resolution
Lesions spaced in time and space - and do and MRI - needed 2 different things
Weakness due to LMN vs UMN vs neuro-motor unit
LMN - the peripheral nerve, anterior ventral horn, etc. Looking for a localized disease, hyporeflexia, atrophy, flaccid paralysis, and fasciculations
UMN - spinal cord, cerebral cortex, hyperflexia , increased tone, consider B12 deficiency (rare)
- forehead spared
NEURO-motor unit - where the nerve connects to the muscle - will follow anatomical distribution, fatiguable weakness, functional loss of muscle fibres.
How does lead effect neuromuscular disease?
Damages the axon in the anterior horn cells
Gullain-Barre presentation
Ascending paralysis - can do a CSF analysis - watch for respiratory failure, post-viral, weak and tired
Don’t treat with steroids tx with IVIG or plasma exchange, fine to vaccinate but avoid vaccinations that may have triggered the initial event
Weakness questions?
Figure out function - ADLs, what is effected
Progressive or sudden, and onset vs recognition
Is there associated sensory loss, vision changes, mental changes
What worsens it - use, heat?
Along with regular full interview and exam
Muscle strength grading?
5 - muscle contracts against full resistance
4 - reduced but still against resistance
3- reduced but against gravity only
2 - movement against gravity
1- flicker of movement
0- nothing
Generalized vs Localized weakness
Generalized - look for cachexia, periodic paralysis
Localized - look for asymmetry, then for LMN disorders, if symmetric then look for other causes as well - not neuro disorders
Lambert- Eaton
Pre-synaptic AcH inhibition
What is dermatomyositis
Dermatomyositis - this is the one that you need to know - has a rash WITH symmetric muscle weakness, heliotrope rash, serious
Dermatomyositis - screen for cancer (everything) from 40s onwards
Polymyositis - screen for cancer (everything) from 60s onwards
Sx of B12 deficiency
Peripheral neuropathy, fatigue, parasthesias, glossitis, confusion, delirium, dementia
Wernicke’s encephalopathy
Ataxia, confusion, nystagmus (thiamine deficiency)
Korsakoff encephalopathy
Anterograde amnesia, problems with learning things, confabulation
