Neuromuscular disorders Flashcards
What are upper motor neurons?
pathways completely contained within the CNS
cerebral cortex –> ventral horn of spinal cord
Primary role of upper motor neurons
influence
- reflex arcs,
- low-level control centers &
- motor neurons (some sensory)
Corticospinal tract supplies what
voluntary muscles of the trunk and extremities
corticospinal pathway
precentryal gyrus
internal capsule - midbrain - pons
90% decussate in medulla –> lateral corticospinal
10% decussate low @ s/c –> ventral corticospinal
corticospinal synapse w/
spinal nerves
ventral corticospinal tract ?
posture
corticobulbar tract supplies what
voluntary muscles of head
same pathway of corticospinal UNTIL brainstem
corticobulbar pathway
precyntral gyrus
CN 3, 4, 6, 9, 10, 11 bilaterally
CN 7, 13 unilaterally (facial & hypoglyssal)
where are lower motor neurons located?
brain stem or spinal cord
what do lower motor neurons do?
direct influence on muscles! they send out axons via nerves in PNS to synapse on sk. muscles
lower motor neurons passing through spinal nerves control…
muscles of limbs/trunk
lower motor neurons passing through cranial nerves control….
sk muscles of head/neck
umn (pyramidal cells) motor cortex
- muscle groups affected, mild weakness, minimal disuse muscle atrophy
- no fasiculations
- hypertonia & spasticity
- increased stretch reflex, + babinski
lmn ventral horn (S/C) and motor nuclei (brainstem)
individual muscles affected
- mild weakness, marked muscle atrophy
- fasciculations
- decreased stretch, hypotonia, flaccid
- no babinski
name 5 umn diseases
cp, cva
ms
parkinson’s
huntington’s
cp patho
non-progressive disorder caused by injury/abnormal development in the immature brain before, during, or after birth for up to a year
what path is affected by cp
corticospinal
s/s cp
muscle weakness
no speech, drooling
exaggerated DTR, spasticity, rigidity
scoliosis, contractures
vision/hearing
swallowing , sz, slow
gerd
cp treatment (4)
no cure - s/s treatment only dorsal rhizotomy antireflux intrathecal baclofen botulinum toxin
cp anesthesia
hold sedatives, opioids (short acting only) vascular access sucks difficult airway RSI sux - usually ok, but 30% do have extrajunctional receptors ndmr - if on anticonvulsants, resistant mac decreased 20 - 30% bleeding - antisz meds hypothermia - no fat dry slow emergence high risk for latex no regional d/t scoliosis etc
m/s patho
autoimmune
demyelination, inflammation, axonal damage of CNS
PNS ok
s/s ms
paresthesia muscle fatigue muscle spasms visual problems ans dysfunction bulbar muscle dysfunction cognitive dysfunction - advnaced
tx m/s
diazepam dantrolene baclofen steroids immunosuppresants cd20 monoclonal abs, interferons, glatiramir
s/s of m/s exacerbated by
stress
hyperthermia
infection
hyponatremia
anesthesia & m/s
no sux, scopolamine, atropine nmdr: be careful no spinal block epidural is ok aspiration, dvt risk stress dose steroids exaggerated hypotensive effect
anterior cerebral artery
contralateral leg weakness
mca
contralateral hemiparesis and hemisensory deficit
(face & arm > leg)
contralateral visual defect
posterior ca
contralateral visual defect + hemiparesis
penetrating arteries
contralateral hemiparesis & hemisensory deficits
basilar artery
oculomotor deficits
ataxia
crossed sensory/motor
vertebral artery
lower cranial nerve deficits
ataxia
crossed sensory
cva tx
asa
tpa (ischemic)
surgery
cva anesthesia
rsi dvt risk (use regional!) b/s b/p initially, pt has htn - don't rapidly decline their bp b/c cpp
parkinson’s patho
loss of dopaminergic fibers in basal ganglia
unopposed ach
s/s parkinsons
tremor during rest
rigid, akinesia
diaphragmatic spasm, dementia
facial immobility
parkinson’s tx
levodopa carbidopa amatadine selegiline + rasagiline (avoid meperidine, check b/s) COMti (lfts) antiviral amantadine prolongs QT
anesthesia & Parkinsons
levodopa continue dos hypotension + arrhythmias or htn RSI, airway risk (post extubation stridor) hard sticks if on anticholinergic, ndmr less effective SEVOFLURANE ketamine if on ldopa direct acting pressors sux?
huntington’s patho
degenerative disease of CNS
marked atrophy of caudate nucleus + putamen + globus
s/s huntington’s
dementia - progressive
chorea, tremors, rigid
mood swings
cant talk or swallow
anesthesia & huntingtons (3)
rsi
sux + nmdr prolonged
avoid reglan, anticholinergics. atropine
lmn (6)
mg muscular dystrophy myotonic dystrophy mitochondrial d/o g/b spinal muscular atrophy
myasthenia gravis
autoimmune (igg) against the nachr
m/g s/s
diplopia, ptosis
fluctuating fatigue/weakness imrpoves w/rest
face weakness
m/g tx
pyridostigmine (cholinesterase inhibiotr) plasmapheresis steroids immunosuppresants thmectomy
m/g and anesthesia
aspiration risk
ndmr sensitivity
regional preferred (amides)
resistant to sux
lems s/s (3)
proximal muscles are affected most
weakness worse in a.m., gets better during the day
resp/diaphragm weakness and dysfunction
lems & anesthesia
sux and ndmr sensitivity
bad reversal w/acei
lots have small cell carcinoma
duchenne s/s
kyphoscoliosis degeneration of cardiac muscles/impaired conduction gi hypomotility/decr. airway reflex pulm htn cognitive impairment
becker s/s
less slowness
proximal muscle weakness
tx of musc. dystrophy
steroids, biphosphates
mystatin or protease inhibitors
m/d anesthesia
tiva
sensitive to ndmr
local/regional yay
aspiration risk
myotonic dystrophy
hereditary disease of sk. muscle resulting in dysfunctional ca+ sequestration by SR. na/chl also involved
myotonic dystrophy s/s
distal limb weakness, myotonia, face/thorax/intercostal/diaphragm
cardiomyopathy, conduction defects endocrine central sleep apnea ptosis male triad (balding, cataracts, sm. testes)
myotonic dystrophy tx
procainamide/phenytoin
baclofen/dantrolene
carbamezepine/cardiac pacemaker
myotonic dystrophy & anesthesia
no sux
do a tiva
myotonia aggravated by neo/physo
have pacing at bedside, they vagal lots
mitochondrial d/o
heterogenous group of d/o of sk. muscle energy metabolism
mitochondria produce energy required by sk. muscle cells through the oxidation-reduction reactions of etc and oxidative phopohrylation
mitochondrial d/o s/s
fatigue, muscle pain
hearing loss
balance, sz, learning deficits
organ problems
mitochondrial d/o tx
give metabolites & cofactors
sodium bicarb/dichlloroacetate
ketogenic diet
mitochondrial d/o anesthesia
acidosis, dehydration lactate high avoid sux, LR, prop gtt nmdr&LA - be careful no bupi
GB
sensory deficits, ans dysfunction
GB tx
plasmapheresis
ivig
NO STEROIDS
gb & anesthesia
no sux sensitive to ndmr dvt increased risk siadh don't use indirect sympathomimetics
spinal muscle atrophy
d/t deletions or mutations in the survival motor neuron gene. this gene product is involved in the formation of rna complexes & their trafficking out of the nucleus
loss of smn function promotes apoptosis of lmn & affect anterior horn of s/c
sma & tx
spinraza/zolgensma/evrydsi
give abx early
sma. & anesthesia
difficult intuation
no sux
nmdr prolonged
als s/s
atrophy in hands
resting tachycardia
snesation ok
als tx
riluzole, edavaone
spasmolytics
analgesics
als anesthesia
avoid sux
nmdr prolonged
ans dysfunction
no spinal anesthesia
