Neuro Day 2 Flashcards
communicating hydrocephalus
- due to decreased CSF absorption by arachnoid granulations, which can lead to increased intracranial pressure, papilledema and herniation
- ex: arachnoid scarring post-meningitis
NPH
- no increase in subarachnoid space volume
- expansion of ventricles distorts the fibers of the corona radiata and leads to clinical triad of urinary incontinence, ataxia and cognitive dysfunction
- urinary incontinence 2/2 stretching of descending cortical fibers
noncommunicating hydrocephalus
caused by structural blockage of CSF circulation within the ventricular system (stenosis of the aqueduct of Sylvius)
spinal cord - lower extent
goes to L2, so do a LP between L3-L5 to keep the spinal cord alive
dorsal column orientation
organized the way you are, legs in the middle, arms on the outside
- decussates in the medulla
descending lateral corticospital tract orientation
Legs are Lateral, head is medial
- decussates at the caudal medulla
ascending lateral spinothalamic tract orientation
Legs are Lateral, head is medial
- decussates in the anterior white commissure and ascends contralaterally
polio and spinal muscular atrophy SC lesion
- affects anterior horns –> flaccid paralysis
LMN lesions only
ALS SC lesion, pathogenesis and treatment
- combined UMN and LMN lesions
- affects the anterior horn and lateral corticospinal tract
- can be caused by a defect of copper-zinc superoxide dismutase
- commonly presents with fasciculations,
- riluzole treatment modestly increases survival by increasing presynaptic GABA release
- usually die from aspiration pneumonia
ASA stroke SC lesion
- affects everything except the dorsal columns
tabes dorsalis SC lesion
- affects dorsal columns and roots
- impaired proprioception –> sensory ataxia and poor coordination
- absence of DTRs and + Romberg
Vit B12 or E deficiency
- subacute combined degeneration
- demyelination of dorsal columns, lateral corticospinal tracts and spinocerebellar tracts
- ataxic gait, paresthesias, impaired position and vibratory sense and affects voluntary movement of limbs
spinal muscular atrophy (Werdnig-Hoffman Disease)
- congenital degeneration of anterior horns of spinal cord –> LMN lesion
- “floppy baby” with marked hypoxia and tongue fasciculations
- infantile type has median age of death at 7 months
- autosomal recessive inheritance
friedreich ataxia
- AR trinucleotide repeat (GAA) on chromosome 9
- gene that encodes frataxin, leads to impairment of mitochondrial functioning
- degeneration of muscle spinal cord tracts leads to muscle weakness and loss of DTRs, vibratory sense and proprioception
- staggering gait, frequent falling, nystagmus, dysarthria, pes cavus (foot abnormality), and hypertrophic cardiomyopathy (cause of death)
- presents in childhood with kyphoscoliosis
- 10% get diabetes
- “frat” brother who is always stumbling, staggering and falling, but has a big heart
Brown Sequard syndrome
- loss of contralateral pain and temp
- loss of ipsilateral position and vibration 1-2 levels below the lesion
Horner syndrome
- ptosis, anhydrosis and miosis
- associated with a SC lesion above T1
- due to Pancoast tumor, Brown-Sequard syndrome, late-stage syringomyelia
landmark dermatomes
T4 nipple, T10 umbilicus, L1 inguinal ligament, S234 keeps the penis off the floor
clinical reflexes
S1,2 - achilles - buckle my shoe L3,4 - patellar - kick the door T5,6 - biceps - pick up sticks T7,8 - triceps - lay they straight L1,2 - cremasteric - testicles move S3,4 - anal wink
parinaud syndrome
- paralysis of conjugate vertical gaze due to lesion in superior colliculi
- can be due to germinoma (most common pineal tumor)
which colliculi are which
ears are below your eyes
- superior - vision (conjugate vertical gaze center)
- inferior - auditory
CN I - olfactory - S
smell
CN II - optic - S
vision
CN III - oculomotor - M
- eye movement - SR, IR, MR, IO
- pupillary constriction, accomodation, eyelid opening
CN IV - trochlear - M
- eye movement - SO
CN V - trigeminal - B
- mastication (V3), facial sensation, somatosensation from ant 2/3 of tongue
CN VI - abducens - M
- eye movement - LR
CN VII - facial - B
- facial movement, taste to ant 2/3 of tongue, lacrimation, salivation, eyelid closing, stapedius (hyperacusis with palsy)
CN VIII - vestibulocochlear - S
hearing, balance
CN IX - glossopharyngeal - B
- taste and somatosensation from post 1/3 of tongue
- swallowing, salivation, carotid body chemo and baroreceptors
- stylopharyngeus
CN X - vagus - B
- taste from epiglottic region
- swallowing, soft palate elevation
- midline uvula, talking, coughing
- thoracoabdominal viscera, monitoring aortic arch chemo/baroreceptors
CN XI - accessory - M
- SCM, trap
CN XII - hypoglossal - M
- tongue movement
corneal and lacrimal reflex
- afferent - CN V1
- efferent - CN VII
pupillary reflex
- afferent - CN II
- efferent - CN III
gag reflex
- afferent - CN IX
- efferent CN X
vagal nucleus solitarius
- visceral Sensry information (taste, baroreceptors, gut distention)
vagal nucleus aMbiguus
- Motor innervation of pharynx, larynx, and upper esophagus
vagal dorsal motor nucleus
- sends autonomic (parasympathetic) fibers to heart, lungs, upper GI
- bronchoconstriction
what goes through the optic canal
CN III, opthalmic artery, central retinal vein
what goes through the superior orbital fissure
- CN III, IV, V1, VI, opthalmic vein and sympathetic fibers
what goes through the foramen rotundum
- V2
what goes through the foramen ovale
- V3
what goes through the foramen spinosum
- middle meningeal artery and recurrent branch of V3
what goes through internal auditory meatus
- CN VII, VIII
what goes through the jugular foramen
- CN IX, X, XI, jugular vein
what goes through the hypoglossal canal
CN XII
what goes through the foramen magnum
spinal roots of CN XI, brain stem, vertebral artery
where are high/low frequency sounds heard best
- low frequency at the apex near the helicotrema (wide and flexible)
- high frequency at the base of the cochlea (thin and rigid)
conductive hearing loss
Rinne test abnormal (bone > air)
Weber test localizes to the affected ear
sensorineural hearing loss
Rinne test is normal
Weber test localizes to the normal ear
- in sensoriNeural, webber points to Normal
noise induced hearing loss
- damage to sterociliated cells in the organ of Corti
- loss of high frequency hearing 1st, sudden extremely loud noises can rupture tympanic membrane
facial nerve palsy
- ipsilateral facial paralysis, decreased lacrimation and salivation, hyperacusis and loss of taste sensation to first 2/3 of tongue
- idiopathic or associated with Lyme disease, HSV, herpes zoster, sarcoidosis, tumors or DM
hyperopia
- eye to short for refractive power of the cornea and lens–> light focused behind the retina
myopia
- eye too long for refractive power of the cornea, light focused in front of the retina
astigmatism
- abnormal curvature of cornea resulting in different refractive power at different axes
presbyopia
decreased focusing ability during accommodation due to sclerosis and decreased elasticity
central retinal artery occlusion
acute, painless monocular vision loss
- retina cloudy with attenuated vessels and “cherry red” spot at the fovea
- often permanent
retinal vein occlusion
- blockage of central or branch retinal vein due to compression by nearby arterial atherosclerosis
- retinal hemorrhage and edema in affected area
diabetic retinopathy
- non-proliferative: damaged capillaries leak, lipis and fluid seep into retina leading to hemorrhages and retinal edema. treat with blood sugar control and macular laser
- proliferative: chronic hypoxia results in new blood vessel formation with resultant traction on retina. treat with peripheral retina photocoagulation, anti-VEGF injections
open angle glaucoma
- associated with increased age, AA race, family history
- painless, more common in US
- primary has unclear etiology, but secondary can be due to blocked trabecular meshwork from WBCs (uveitis), RBCs (vitreous hemorrhage), retinal elements (retinal detachment)
primary closed angle glaucoma
- enlargement or forward movement of lens against central iris (pupil margin) leads to obstruction of normal aqueous flow through pupil –> fluid builds up behind the iris, pushing peripheral iris against cornea and impeding flow through trabecular meshwork
secondary closed angle glaucoma
- hypoxia from retinal disease (diabetes, vein occlusion) induces vasoproliferation in the iris that contracts the angle
miosis (constriction) control
- 1st neuron: Edinger- Westphal nucleus to ciliary ganglion via CN III
- 2nd neuron: short ciliary nerves to pupillary sphincter muscles
mydriasis (dilation) control
- 1st neuron: hypothalamus to ciliospinal center of Budge (C8-T2)
- 2nd neuron: exit at T1 to superior cervical ganglion (travels along cervical sympathetic chain near lung apex)
- 3rd neuron: plexus along internal carotid, through cavernous sinus, enters orbit as long ciliary nerve to pupillary dilators
Marcus Gunn pupil
- afferent pupillary defect
- due to optic nerve damage (optic neuritis) or severe retinal injury
- both eyes constrict when light shone in healthy eye, neither constrict when light shone in affected eye
- “swinging flashlight test”
age-related macular degeneration
- causes distortion and loss of central vision
- dry –> deposition of yellowish extracellular material (fatty tissue) in and beneath Bruch membrane and retinal pigment epithelium with gradual decrease in vision. prevent progression with multivitamin and antioxidant
- wet –> rapid loss of vision due to bleeding 2/2 choroidal neovascularization. “grey subretinal membrane”. treat with anti-VEGF
Meyer loop lesion (temporal lobe) lesion
pie in the sky
Dorsal optic radiation (parietal lobe) lesion
pie on the floor
right peri-chiasmal lesion
- R nasal hemianopia, can be due to calcification of the carotid artery
INO
MLF lesion
- lack of communication between CN VI and CN III nuclei
- abducting eye gets nystagmus, convergence is normal
