Neuro 2 (Brainstem, PNS) Flashcards
C1 dermatome
hairline
T4 dermatome
nipple line (male)
T10 dermatome
umbilicus
L1 dermatome
inguinal ligament
S1 dermatome
sole of foot
S4/5 dermatome
perianal
large cells/axons mediate
vibration and joint position sense
small cells/axons mediate
pain and temperature sensation
monomelic amyotrophy
Wasting in myotome
Self-limited
Electromyographic exam
May see MRI T2 signal
location of C6 root
between C5, C6
location of C8 root
between C7, T1
location of L4 root
between L4, L5
central protrusion in lumbar cord
affect descending root
lateral protrusion in lumbar cord
affects lateral roots
how to know it’s a radiculopathy?
Sensory and motor symptoms and signs in same dermatome and myotome
C5 radiculopathy = weakness in
Deltoid (C5, axillary)
Biceps (C5, musculocutaneous)
Infraspinatus (C5, suprascapular)
Rhomboid (C5, dorsal scapular)
Erb’s Palsy
upper plexus injury
Stretch upper roots (C5, C6)
Waiter’s tip
Musculocutaneous out
Klumpke’s Palsy
lower plexus traction injury
Pulling arm away from neck
Or nursemaid’s injury
Extensors out
How to know it’s a plexus injury
® Clinical-sensory, and motor deficits which do not fit a particular dermatoma/myotomal distribution or single nerve distribution
associated pain
usually unilateral
Parsonage Turner syndrome
□ Hereditary neuralgic amyotrophy
® Males»Females
® SEPT9 gene on chromosome 17w
® Septins are involved in formation of cytoskeleton
® Recurrent
Episide precipitated by physical activity
neuropraxia
temporary loss of motor and sensory function due to blockage of nerve conduction- focal demyelination
axonotmesis
disruption of axon w/ little disruption of CT
neurotmesis
disruption of axon and CT
Wallerian degeneration
degeneration of axon from distal to proximal. Associated w/ metabolic insufficiency
How to know it’s a mononeuropathy?
Sensory and motor symptoms and signs confined to distribution of one nerve
most common cause of polyneuropathy in US
diabetes
classification of polyneuropathy
vascular infectious neoplastic degenerative inflammatory congenital autoimmune trauma/toxins endocrine something else
how do we know it is a polyneuropathy?
Symptoms and signs in multiple nerves
Early neuropathy may not yet show motor or autonomic sxs
Symptoms and signs are length dependent, distal, symmetrical, dying back over time
Guillain-Barre syndrome (AIDP)
Bystander mechanism- antibody made against something else cross-reacts w/ myelin
Autoimmune process
Ascending weakness
Attacking the myelin- inflammatory mediators, damage the axon itself
Miller Fisher Variant
5% of GBC
Descending paralysis w/ triad: opthalmoplegia, ataxia (gait/trunk), areflexia
Anti GQ1B Ab in 85-90%
Tx: IVIg, PEx
Bickerstaff’s Encephalitis
Ataxia, cranial neuropathy, opthalmoplegia, altered mental status, hyperreflexia/Babinski
Anti-GQ1B Ab in 66%
Tx w/ steroids, IVIg, PEx
asymmetric polyneuropathy
demyelinating mononeuritis
multifocal motor neuropathy
small fiber neuropathy
Slow motor unit
Smaller forces
Maintain composure longer- resistant to fatigue due to subcellular anatomy
Important for posture, maintaining position
fast fatigable motor unit
Larger forces
Less myoglobin, fatigue easier
i.e. sympathetic response, standing jump (brief large forces)
fast fatigue resistant
Intermediate
Good for transition movements
2 ways to increase force (motor recruitment)
Enlist more friends –> increase number of motor units firing
Tell your friends to work harder –> increased firing frequency
Hallmarks of ALS Diagnosis
Combination of UMN and LMN signs
Can occur in 4 body regions: bulbar, cervical, thoracic, lumbosacral
Research requires 3/4 areas- may delay diagnosis and treatment
Rule out potentially treatable conditions mimicking this disorder
Upper motor neuron signs
Hyperreflexia
□ clonus
Spascicity
Upgoing toes (plantar extensor response)
Lower motor neuron signs
Weakness
Muscle atrophy
Fasciculations
Decreased/absent reflexes
Important negatives of ALS
Sensory systems in tact
Bowel/bladder dysfunction is spared
Ocular motor problems not effected
Poliomyelitis
□ Caused by RNA enterovirus
□ Eventually spreads to alpha motor neurons in spinal cord and brain stem
□ Causes focal atrophy and LMN findings
Spinal muscular atrophy
Bucket of autosomal recessive disorders
Survival motor neuron gene- important for alpha motor neuron to live
Looks like a LMN disease
Wernbig-Hoffman disease- huge spectrum of disease
muscular dystrophy
disease in muscle membrane or supporting proteins
ongoing muscle degeneration and regeneration
Duchenne/Becker MD
x-linked: mytation in dystrophin gene important for structural integrity of muscles Duchenne (absent), Beckers (low levels) eventually lose walking ability pseudohypertrophy Gower's sign
Myotonic dystrophy Type 1
most common in adults
trinucleotide repeat disease in myotonin protein kinase
symptoms of myotonic dystrophy
ptosis, cataracts at early age (slit lamp needed)
Weakness- distal muscles get weak first
hypogonadism (reduced testosterone, testicular atrophy), reduced GH, insulin resistance, frequent loss of pregnancy
Afib, tachyarrhythmia, ectopic beats and cardiomyopathy late
dysphagia, hypokinetic tract w/ pseudo-obstruction, constipation
Fascioscapulohumeral MD
face, shoulder, arm
Reduction or deletion of DNA sequence- thought to be activator
70-90% AD inheritance
Highly penetrant- 90% of patients w/ weakness by age 20 w/ sizable deletion
CK values normal (creatine kinase- enzyme in muscles)
Fascioscapulohumeral MD Symptoms
Facial weakness early
Horizontal smile, wide palpebral fissures, difficulty burying eyelids and pursing lips
Weakness in arms –> medical attention –> anterior axillary folds
Scapular winging
Triple hump sign- fierce atrophy of deltoid, but trapezius and biceps are in tact
Abdominal laxity
Asymmetry- sometimes.
C fibers
nociception
slow conduction velocity
not tested by EMG
When to order an EMG
Useful to exclude any peripheral cause of sensory or motor abnormalities on neurological exam when there is a diagnostic uncertainty
what is on an NCS report
amplitude
conduction
latency
duration
how to diagnose myopathy
EMG
sensory NCS is normal, as it conduction velocity and distal latency
target fibers
seen in chronic denervation
dysimmune/inflammatory myopathies
polymyositis
dermatomyositis
inclusion body myositis
polymyositis
Cell mediated
Adults 40-70 yo
Proximal, symmetrical weakness and myalgia evolving (several months)
Lymphocytes (CD8+ T cells): w/in fascicules, surround, invade, and destroy myofibers
dermatomyositis
Children and adults Microvasculature Association w/ malignancy Proximal muscle weakness Infiltrates B & CD 4+ T lymphocytes in interfascicular distribution Heliotrope rash
inclusion body myositis
mostly men
Pathology: inflammation, rimmed vacuoles
Congo red positive inclusions:
No effective treatment
mitochondrial myopathies
ragged-red fiber
GSE
somites- efferent
GVE
sympathetic/parasympathetic
SVE
branchial motor- derived from pharyngeal arch muscles
GSA
sensation of external environment
GVA
sensation of internal environment
carotid bodies, feedback system.
SSA
vision
hearing
vestibular function
SVA
chemical transmission:
olfaction, taste
lesion on XII in cortex
contralateral tongue deviation
lesion on XII nucleus, fascicles, or nerve
ipslateral tongue deviation
lesion on XI in R cortex
L trapezius, R SCM weakness
head deviates toward the R
lesion on R XI nerve itself
R trapezius, R SCM weakness
if anything, deviation toward R
vagus nerve nuclei
Dorsal motor nucleus
Nucleus ambiguus
Solitary tract/nucleus
Spinal trigeminal nucleus
Dorsal motor nucleus
parasympathetic
Nucleus ambiguus
branchial motor supply (arch 4-6)
Solitary nucleus
visceral sensation, taste
Uvular deviation
deviates towards the good side (away from the lesion)
Dysphagia: cortical lesion
Focal swallowing dysfunction/hoarseness: nerve lesion
rostral part of nucleus solitarius
gustatory nucleus- taste
caudal part of nucleus solitarius
cardiorespiratory nucleus- chemo and baroreceptors
from aortic arch, cardiorespiratory system, digestive tract
big difference between IX and X
parasympathetics:
IX: from inferior salivatory nucleus to parotid gland. Sympathetics synapse in otic ganglion
area postrema
open BBB
center for vomiting, closely related to CN X
CN VIII- type of fibers
all SSA
pathway of sound
cochlear nuclei decussation in trapezoid body superior olivary nucleus lateral lemniscus inferior colliculus medial geniculate body of thalamus auditory cortex- frontal lobe
nuclei of facial nerve
spinal trigeminal
solitary nucleus
superior salivatory nucleus
VII: branchial motor
facial motor nucleus and nerve fascicle
to muscles of facial expression, posterior belly of digastric, stylohyoid, stapedius
upper face innervation
ipslateral and contralateral contribution
lower face innervation
only contralateral side
VII lesion in UMN
contralateral weakness of lower face only
VII lesion in LMN
all fibers to one side of face (upper and lower face)
VII parasympathetics
from superior salivatory nucleus
via greater petrosal nerve
synapse in sphenopalatine ganglion
all salivary glands except for parotid
IX parasympathetics
inferior salivatory nucleus
VII taste
nucleus solitarius (rostral)–> geniculate ganglion–> central tegmental tract –> thalamus –> insularr cortex –>…
VII GSA
cell bodies in geniculate ganglion
exit of CN VI
superior orbital fissure
does V have parasympathetics?
no, just motor and sensory
location of VI, 2, 3 cell bodies
trigeminal ganglion
V1 exit
superior orbital fissure
V2 exit
foramen rotundum
V3 exit
foramen ovale
does NOT pass through cavernous sinus
what is alone in the cavernous sinus?
VI
SVE of VII
to muscles of mastication, a nterior belly of digastric, tensor tympani, tensor velli palatini
lesion in V3
jaw deviation toward the weak side (due to pterygoids)
V for proprioception
GVA for fine touch- mesencephalic nucleus and tract
where is the cell body for V proprioceptive neurons?
mesencephalic nucleus
corneal reflex
in on V –> blinking VII
types of fibers in IV
GSE
parasympathetic nucleus for III
edinger-westphall
DRG history
Pain and numbness in dermatomal distribution
Decreased sensation in dermatomal distribution
Trouble with balance/coordination
No weakness- no motor
APD
○ Damage to the optic nerve or bad retinal disease
○ Not seen with cataracts, vitreous or corneal disease, refractive error
○ Not seen in functional (non-organic disease)
cocaine test
blocks reuptake of NE. Dilation is normal.
with Horner’s syndrome, nothing happens.
apraclonidine
alpha adrenergic agonist
reversal of Horner’s syndrome
denervation supersensitivity
Adie’s Pupil
Occurs in young woman, benign, probably viral
Unlike pharm blockage, you constrict to near
Also reacts to dilute pilocarpine (1/8%) unlike the normal pupil
no response to light, but response to near
absent reflexes
binocular vision
sign of issue on efferent side, likely ocular misalignment
worse diplopia at a distance
VI
worse diplopia near
III, medial rectus
vertical diplopia
III, IV
myasthenia gravis
thyroid eye disease
benign positional vertigo
last less than a minute- positional
Meniere’s disease
lasts hours usually with tinnitus (ringing noise) and hearing loss
Vestibular neuritis
inflammation of the inner ear- last days to weeks
Acoustic neuroma
evolves over weeks to months
pathologic nystagmus characteristics
amplitude greater than 4 degrees
asymmetry
commonly caused by drugs and anti-seizure meds
doesn’t fatigue with prolonged gaze
peripheral nystagmus
beats in one direction regardless of gaze
central nystagmus
vertical component, direction changing
