Neurology Flashcards
What are the primary vesicles?
1) Prosencephalon (forebrain)
2) Mesencephalon (midbrain)
3) Rhombencephalon (hindbrain)
How are the alar & basal plates organized?
In closed spinal cord, alar plate (sensory) is dorsal & basal plate (motor) is ventral.
In the medulla & pons, the basal plate is medial & the alar plate is lateral. Within these, the visceral nuclei are generally closest to the sulcus limitans.
What are the secondary vesicles?
1) Telencephalon
2) Diencephalon
3) Mesencephalon
4) Metencephalon
5) Myelencephalon
What does the telencephalon give rise to?
Cerebral hemispheres & lateral ventricles
What does the diencephalon give rise to?
Thalamus
Hypothalamus
Retina
Third ventricle
What does the mesencephalon give rise to?
Midbrain & cerebral aqueduct
What does the metencephalon give rise to?
Pons
Cerebellum
Top half of 4th ventricle
What does the myelencephalon give rise to?
Medulla
Bottom half of fourth ventricle
When does the neural tube develop?
Day 18-day 21
What is seen in the amniotic fluid with a neural tube defect?
^AFP
^AChE
What are the caudal neural tube defects?
Spina bifida occulta –> bony canal not closed, tuft of hair
Meningocele –> meninges herniate through spinal canal defect
Meningomyelocele –> meninges & spinal cord
What is seen with anencephaly
^AFP
Polyhydramnios (no swallowing center in brain)
No forebrain, open calvarium
“Frog-like appearance”
What causes anencephaly?
Maternal T1DM
Lack of folate
Anterior neural tube does not close
What causes holoprosencephaly?
Failure of R & L hemispheres to separate
May be due to sonic the hedgehog defect
What is seen with holoprosencephaly?
Cleft lip/palate
Severe form –> cyclopia
What is seen with congenital cerebral aqueduct stenosis?
Enlargement of lateral & third ventricles
Enlarging head circumference (sutures not yet fused)
What is seen with Arnold-Chiari malformation?
Type I - modest herniation, usually clinically silent
Type II: Tonsillar herniation Hydrocephalus Meningomyelocele Syringomelia
What is seen with Dandy-Walker malformation?
Agenesis of cerebellar vermis –> cystically enlarged 4th ventricle
The cerebellum is basically missing.
Hydrocephalus & spina bifida can be seen
Where is the most common site of a syringomyelia?
C8-T1
What is seen with a syringomyelia?
Bilateral loss of pain & temperature sensation in upper extremities
“Cape-like”
Later stages –> LMN signs of arms; Horner’s syndrome
Can extend downward
Fine touch & proprioception are spared
What causes syringomyelia?
Trauma
Chiari I malformation
Scoliosis is a hint that syringomyelia may be present
What is the sensory innervation of the tongue?
Anterior 2/3:
Sensation - V3
Taste - VII
Posteior 1/3:
Sensation & taste - IX or X (extreme posterior is X)
What neural cells arise from the neuroectoderm?
Neural crest?
Mesoderm?
Neuroectoderm: CNS neurons Ependymal cells Oligodendrocytes Astrocytes
Neural crest:
PNS neurons
Schwann cells
Mesoderm:
Microglia
How can one stain for the cell bodies of neurons?
Stain for Nissl substance (RER). Only present in the cell body.
What do Meissner’s corpuscles sense?
Dynamic touch
Fine touch
Position sense
Found on hairless (glabrous) skin
What do Pacinian corpuscles sense?
Vibration
Pressure
What do Merkel’s discs sense?
Pressure
Deep static touch
What are the layers surrounding a PNS nerve?
Epineurium surrounds whole nerve
Perineurium surrounds fascicle of nerve fibers
Endoneurium surrounds individual fibers
Where is NE synthesized?
Locus ceruleus
pons
Where is dopamine produced in the brain?
Ventral tegmentum (VTA) Substantia nigra (pars compacta)
Where is serotonin produced in the brain?
Raphe nucleus (pons)
Where is ACh produced in the brain?
Basal nucleus of Meynert
Where is GABA produced in the brain?
Nucleus accumbens
What is the BBB composed of?
1) Tight junctions between endothelial cells
2) Basement membrane
3) Astrocyte foot processes
What are the circumventricular organs?
Area postrema - chemo induced vomiting
OVLT - osmolarity sensing
Neurohypophysis
Median eminence of hypothalamus
They have fenestrated capillaries to circumvent the BBB
Where is ADH produced?
Supraoptic nucleus
Hypothalamus
Where is Oxytocin produced?
Paraventricular nucleus
Hypothalamus
Where does Leptin act in the brain?
Acts at the hypothalamus: Lateral area (hunger) --> inhibited by leptin --> satiety Ventromedial area (satiety) --> stimulated by leptin --> satiety
Destruction of the Lateral area –> anorexia
Destruction of the Ventromedial area –> hyperphagia
What parts of the hypothalamus control body temperature?
Anterior hypothalamus (parasympathetic) –> cooling
Posterior hypothalamus (sympathetic) –> heating
What in the CNS controls sleep/wake cycles?
Suprachiasmatic nucleus
hypothalamus
What is secreted by the neurohypophysis?
Oxytocin & Vasopressin
What are the inputs & outputs of these Thalamic nuclei? VPL VPM LGN MGN VL
VPL - STT & DCP from body –> sensory cortex
VPM - Trigeminal & gustatory pathway –> sensory cortex
LGN - CNII (SLO AIM) –> calcarine sulcus
MGN - Hearing (SLO AIM) –> Auditory cortex
VL - Motor input from basal ganglia –> motor cortex
What structures make up the limbic system?
Hippocampus Amygdala Fornix Mamillary bodies Cingulate gyrus
What does the cerebellum control?
Ipsilateral coordination of movement.
It generally makes sure that the movement you get is the one that you want.
What are the inputs & outputs of the cerebellum?
Inputs:
Contralateral cortex via middle cerebellar peduncle
Ipsilateral proprioceptive input via inferior cerebellar peduncle
Outputs:
Purkinje fibers –> deep nuclei of cerebellum –> contralateral cerebral cortex via superior cerebellar peduncle
What are the deep nuclei of the cerebellum?
Medial–>Lateral “Fat Guys Eat Donuts”
Fastigial
Globose
Emboliform
Dentate
What is the homunculus of the cerebellum like?
Medial - balance & truncal coordination
Lateral - voluntary movement of extremities (ipsilateral)
Floculus/Nodulus - Truncal balance & vestibulo-ocular reflexes
What are climbing & mossy fibers?
They are inputs to the cerebellum. Climbing fibers originate in the inferior olivary nucleus, while mossy fibers carry everything else.
What dopamine receptors correspond to the direct & indirect pathway of the basal ganglia?
What are the effects of each pathway?
D1 = D1rect (D2 = indirect)
INdirect = INhibitory (Direct = excitatory)
Dopamine normally stimulates the excitatory pathway & inhibits the inhibitory pathway –> ^movement
What is the direct basal ganglia pathway?
SN activate Putamen (D1 receptor) –> Putamen inhibits Globus Pallidus interna –> releases thalamus from GPi inhibition –> ^movement
What is seen histologically with Parkinson’s disease?
Lewy bodies (intracellular, round, pink; alpha-synuclein) Loss of Substantia Nigra pars compacta
What is seen clinically with Parkinson’s disease?
Your body becomes a TRAP: Tremor (resting; pill-rolling tremor) Rigidity (cogwheel) Akinesia (slowed voluntary movement; expressionless face) Postural instability --> shuffling gait
Dementia seen late in disease process.
What is the striatum composed of?
Putamen + Caudate
What are the lentiform nuclei?
Putamen + Globus pallidus
What causes Huntington’s disease?
Autosomal dominant expansion (during spermatogenesis) of CAG repeats on chrom. 4
“Hunting 4 CAGs”
Caudate loses ACh & GABA (CAG) –> Caudate atrophy
(Neuronal death occurs via glutamate toxicity)
(Direct basal ganglia pathway predominates)
What is seen clinically with Huntington’s disease?
Choreoathetosis
Aggression
Depression (suicide)
Dementia
What causes Hemiballismus?
Contralateral subthalamic nuclei lesion
(no indirect basal ganglia pathway)
Either flailing or rotatory movement of 1 arm & 1 leg (both same side)
What is myoclonus?
What is it seen in?
Jerks; hiccups
Often seen in matabolic diseases (liver failure, renal failure, etc.)
What is seen with essential tremor?
What is the treatment?
Active tremor
Exacerbated by holding a position
Genetic predisposition
Pts often self medicate with EtOH. Treatment is propranolol.
What causes intention tremor?
Intention tremor is a slow zigzag movement when extending arm toward a target. Seen in cerebellar dysfunction.
What is the organization of the homunculus?
Feet are medial
Head is lateral
What causes Kluver-Bucy syndrome?
What is seen?
Bilateral amygdala destruction. Can be associated with HSV-1.
Symptoms:
Hyperorality
Hypersexuality
Disinhibition
What is seen with frontal lobe lesions?
Disinhibition
Concentration deficits
Poor judgement
Reemergence of primitive reflexes
What is seen with lesions in the right parietal lobe?
Contralateral hemineglect
What is seen with a lesion to the reticular activating system?
Reduced levels of arousal (coma)
It is located in the midbrain.
What side do cerebellar defects cause a fall towards?
Patients fall toward the side of their lesion (ipsilateral defects)
What is seen with a lesion to the paramedian pontine reticular formation?
PPRF lesion –> eyes look away from side of lesion
What is seen with a lesion in the frontal eye fields?
Eyes look toward lesion
Where is Broca’s area?
Wernicke’s area?
Broca’s - inferior frontal gyrus
Wernicke’s - Superior temporal gyrus
What is seen with conduction aphasia?
What causes it?
Fluent speech & intact comprehension but impaired repetition
Caused by a lesion to the arcuate fasciculus (connects Broca’s & Wernicke’s)
What is the brain autoregulatory range for CO2?
O2?
CO2 –> ^ in perfusion up to 90 mmHg of CO2
O2 –> ^ in perfusion if PO2 < 50 mmHg
Thus normally CO2 drives cerebral autoregulation. Hyperventilation can decrease ICP.
What is seen with a MCA infarction?
Contralateral paralysis & loss of sensation of upper limb & face
Aphasia if in left (dominant) hemisphere
Hemineglect if in right (nondominant) hemisphere
What is seen with an ACA infarction?
Contralateral paralysis & loss of sensation in leg
What can be caused by lacunar strokes?
What arteries are involved?
Lenticulostriate arteries are typically involved –> Striatum, Thalamus, or Internal capsule (deep structures)
Internal capsule –> pure motor stroke
Thalamus – pure sensory stroke
What causes lacunar infarcts?
Unmanaged HTN –> hyaline arteriolosclerosis (of lenticulostriate vessels) –> lacunar infarcts (little hollow “lakes”)
What can cause Medial Medullary Syndrome?
What is affected?
Anterior spinal artery occlusion or paramedian branches
Affected:
Lateral CST –> contralateral hemiparesis
Medial lemniscus –> contralateral proprioceptive defect
Hypoglossal nerve –> Lick your wounds
What can cause Lateral Medullary Syndrome?
What is affected?
Lateral Medullary = Wallenberg = PICA syndrome
Affects:
Nucleus ambiguus –> dysphagia & hoarseness (PICA specific)
Vestibular nuclei –> vertigo & vomiting
STT & Trigeminal nuc. –> no pain/temp to limbs/face
Sympathetic fibers –> ipsilateral Horner’s
Inferior cerebellar peduncle –> ataxia
What is seen with AICA occlusion?
Paralysis of face is specific to AICA
“Facial droop means AICA’s pooped”
What can PCA occlusion cause?
Contralateral hemianopsia with macular sparing.
If bilateral –> cortical blindness (pupillary light reflex intact)
What can be seen clinically with Saccular aneurysms?
Berry aneurysms:
Rupture –> subarachnoid hemorrhage
Bitemporal hemianopia (compression of optic chiasm)
What are the risk factors for saccular aneurysms?
Berry aneurysms:
ADPKD
Ehlers-Danlos
Marfan’s
Age
HTN
Smoking
Blacks
Where is the most common site of a berry aneurysm?
Anterior communicating artery branch points
Where are Charcot-Bouchard microaneurysms found?
The lenticulostriate arteries
They are due to HTN and can cause intracerebral hemorrhage.
What arteries arise from the vertebral arteries?
Anterior spinal artery
Posterior spinal arteries
PICA
What is the shape of an epidural hematoma?
Subdural hematoma?
Epidural - biconvex (lens) shape, crosses falx/tent but not sutures
Subdural - crescent shape, crosses sutures but not falx/tent
What is seen in epidural hematoma?
Temporal bone fracture --> ruptured middle meningeal artery Lucid interval CNIII palsy (transtentorial herniation)
Who is at risk for subdural hematoma?
Neonates (shaken-baby)
Elderly (brain atrophy)
Often caused by whiplash-like injury
What is seen with subarachnoid hemorrhage?
WHOML
Xanthochromatic (yellow) spinal tap
Risk of vasospasm 2 days afterward (Tx: Nimodipine)
What is the timeline of histology following a stroke?
12h - Red neurons appear 24h - PMN's 3 days - Macs 1 week - Gliosis 2 weeks+ - Glial scar
What is the treatment for an ischemic stroke?
tPA within 4.5h if no risk of hemorrhage
What is a TIA?
Focal neurologic dysfunction lasting < 24h
No acute infarction seen on MRI
What is the path of CSF?
Ependymal cells of lateral ventricles –> Interventricular foramina of Monroe –> 3rd ventricle –> Cerebral aqueduct –> 4th ventricle –> Foramina of Luschka & Foramen of Magendie –> subarachnoid space –> Arachnoid granulations
What is seen with normal pressure hydrocephalus?
Urinary incontinence (wet) Ataxia (wobbly) Cognitive dysfunction (wacky)
Results from overproduction of CSF. Treatment is a VP shunt.
What can cause hydrocephalus ex vacuo?
Alzheimer’s
Advanced HIV
Pick’s disease
Any condition with brain atrophy.
How many spinal nerves are there & from what divisions?
8 cervical 12 thoracic 5 lumbar 5 sacral 1 coccygeal
31 total
Where do spinal nerves exit?
C1-C7 exit above the corresponding vertebrae
All others exit below the corresponding vertebrae
Where does disc herniation occur most commonly?
What is breached?
Occurs most commonly at L4-L5 or L5-S1
Nucleus pulposus herniates through anulus fibrosis
Where does the spinal cord end?
The Subarachnoid space?
Where should LP be performed?
Cord ends at L2
Subarachnoid ends at S2
LP between L3-L4 or L4-L5
“L3-L5 keeps the spine alive”
What comprises the DCP in the spinal cord?
Fasciculus gracilis (legs; medial)
Fasciculus cuneatus (arms; lateral)
Describe the dorsal column pathway
1st order:
Cell body in DRG, enters cord & ascends in ipsilateral dorsal column, synapse in nucleus cuneatus/gracilus (medulla)
2nd order:
Decussates in medulla, ascends in contralateral medial lemniscus, synapses on VPL (thalamus)
3rd order:
Goes from VPL to sensory cortex
Describe the spinothalamic tract
1st order:
Sensory nerve ending has cell body in DRG, enters cord & synapses on ipsilateral nucleus proprius
2nd order:
Decussates at anterior commissure (at level where it entered) & ascends contralaterally. Synapses on VPL
3rd order:
VPL –> sensory cortex
What do the anterior & lateral spinothalamic tracts do?
Lateral - pain & temperature
Anterior - crude touch & pressure
Describe the lateral corticospinal tract
1st order:
UMN cell body in primary motor cortex. Descends ipsilateral through internal capsule & decussates at pyramidal decussation (caudal medulla). Then descends contralaterally & synapses on cell body of anterior horn.
2nd order:
LMN leaves spinal cord & synapses on neuromuscular junction
What are the classical deficits in MS?
SIIIN
Scanning speech Intention tremor Internuclear ophthalmoplegia Incontinence Nystagmus
What tracts are affected by ALS?
Lateral CST –> UMN signs
Anterior horns –> LMN signs
Both are seen, with no sensory, cognitive, or oculomotor deficits.
What causes familial ALS?
Mutation in superoxide dismutase 1 –> free radical injury of neurons
What is seen with ALS?
40-70y males
Atrophy & hand weakness is often early sign (motor only)
Mixed UMN & LMN signs
No sensory, cognitive, oculomotor defects (Stephen Hawking)
What is the treatment for ALS?
Riluzole –> inhibits presynaptic glutamate release
“Give Lou Riluzole”
Where is the watershed area for the anterior spinal artery?
Upper thoracic area
Below T8, artery of Adamkiewicz supplies ASA
What is seen with Anterior Spinal Artery syndrome?
The most common result of spinal ischemia.
Back pain at the level of the lesion
Loss of sensory motor function (LMN shock then eventual UMN)
Preservation of proprioception & vibratory sense
What tracts are affected by Tabes dorsalis?
What is seen?
Demyelination of dorsal roots & DCP
Symptoms: Impaired sensation & proprioception Progressive sensory ataxia Charcot's joints (injuries go unnoticed --> ulcers) Radicular pain Argyll-Robertson pupils (accommodation but no light reflex) Absent DTR's Positive Romberg
What tracts are affected by B12 deficiency?
Subacute combined degeneration = demyelination of:
Dorsal columns
Laeral CST
Spinocerebellar tracts
Combined = ascending & descending tracts affected
What is seen in subacute combined degeneration?
Poor proprioception (DCP) Spastic paresis (CST) Gait ataxia (spinocerebellar)
How is Werdnig-Hoffman disease inherited?
What is seen?
Autosomal recessive
Congenital degeneration of anterior horn cells
Hypotonia (floppy baby)
Tongue fasciculations
Prognosis = 7mo
What causes Friedreich’s Ataxia?
Autosomal recessive expansion of GAA in frataxin gene –> impaired mitochondrial iron regulation –> free radical damage
What is seen in Friedreich’s Ataxia?
Degeneration of cerebellum & multiple cord tracts Death by hypertrophic cardiomyopathy Childhood kyphoscoliosis (both coronal & saggital plane) Ataxia Frequent falls Nystagmus Dysarthria Pes cavus Hammer toes
“Friedreich is fratastic, slurring & falling, but he’s got a big heart.
What causes Brown-Sequard syndrome?
What is seen?
Hemisection of the spinal cord
At level of lesion - Ipsilateral LMN signs & loss of all sensation
Below lesion:
Ipsilateral UMN signs (CST) & loss of proprioception & vibration sense (DCP)
Contralateral loss of pain & temperature (STT)
What level must a spinal cord lesion be to cause Horner’s syndrome?
Above T1
What do are the dermatomes of these structures? Kneecaps Penis Umbilicus Nipples Arms Posterior head
Kneecaps - L4 Penis - S2,3,4 keeps the penis off the floow Umbilicus - T10 at the belly butTEN Nipples - T4 (teat pore) Arms - C5,6,7,8,T1 Posterior head - C2
What are the clinical DTR’s & their nerve roots?
S1,2 - achilles
L3,4 - patella
C5,6 - biceps
C7,8 - triceps
What are the primitive reflexes?
Moro reflex - flail out limbs when scared (hold on for dear life)
Rooting - turn when stroke cheek
Sucking - suckling when roof of mouth is touched
Palmar - fingers curl when palm is touched
Plantar - Babinsky sign (not considered as such when infant)
Galant - lying face down, stroke one side of spine, flexes toward
What is Parinaud syndrome?
What causes it?
Parinaud syndrome is paralysis of conjugate upward vertical gaze due to a lesion in the superior colliculi (often pinealoma, MS, stroke). Downward gaze is normally preserved.
What nucleus controls the pupillary sphincter & ciliary muscle?
Edinger-Westphal nucleus
What is mediated by the trigeminal nerve?
Muscles of mastication
Sensation of the face & anterior 2/3 of tongue
What is mediated by the facial nerve (CNVII)?
Facial movement Taste from anterior 2/3 of tongue Lacrimation Salivation (sublingual & submandibular) Stapedius muscle in ear Orbicularis oculi
What is mediated by the glossopharyngeal nerve (CNIX)?
Taste & sensation from posterior 1/3 of tongue Swallowing Salivation (parotid) Carotid body & sinus Stylopharyngeus
Where are the CN nuclei located?
Midbrain = 3-4
Pons = 5-8
Medulla = 9,10,12
Spinal cord = 11
What cranial nerves facilitate the gag reflex?
In on IX
Out on X
Describe the path of the carotid sinus & aortic arch baroreceptors
Carotid sinus –> Hering’s nerve –> CNIX –> Nucleus solitarius
Aortic arch baroreceptors –> CNX –> Nucleus solitarious
What is nucleus solitarius for?
What are its cranial nerves?
Visceral sensory information
CNVII, CNIX, CNX
What is nucleus ambiguus for?
What are its cranial nerves?
Motor innervation of pharynx, larynx, upper esophagus
CNIX, CNX
What is the dorsal motor nucleus for?
What are its cranial nerves?
Parasympathetics to heart, lungs, upper GI
CNX
What passes through the cavernous sinus?
EOM nerves (III, IV, VI) and V1, V2 Portion of internal carotid
What is seen in cavernous sinus syndrome?
What causes it?
Ophthalmoplegia (CNIII,IV,VI run through it)
Impaired corneal (V1) & maxillary sensation (V2)
Normal vision
It can be caused by:
Neoplasm
Internal carotid aneurysm or fistula
Which way will the jaw deviate from a CNV lesion?
Toward the defect, due to unopposed pterygoids
Which way does the uvula deviate with a CNX lesion?
Away from the side of the lesion
Which way will there be weakness in head turning with a CNXI lesion?
Contralateral head turn will be weak (SCM aids in opposite head turn). Trapezius will droop on same side of lesion.
What is damaged in noise-induced hearing loss?
Stereociliated cells within the organ of corti are damaged. High frequencies are lost first.
What is seen with an UMN facial lesion?
LMN facial lesion?
UMN (cortex-facial nucleus) –> contralateral lower face paralysis
LMN (facial nucleus-muscle) –> ipsilateral whole face paralysis
What is Bell’s Palsy seen in?
AIDS Lyme disease HSV Sarcoisosis Tumors Diabetes
What muscles open the mouth?
Close it?
Open - Lateral pterygoid (“Lateral lowers”)
Close - Masseter, temporalis, medial pterygoid
What is the clinical term for nearsighted?
Farsighted?
Nearsighted = you can see near only = myopia
Farsighted = you can only see far = hyperopia
What occurs within the eyeball during accomodation?
Ciliary muscles contract –> zonular fibers relax –> lens becomes fatter –> you can see close
What is uveitis?
What conditions is it seen with?
Inflammation of iris, ciliary body, & choroid (all anterior chamber)
Associated with chronic inflammatory conditions:
Sarcoidosis
RA
HLA-B27 conditions
What causes retinitis?
Usually viral (CMV, HSV, HZV)
Associated with immunosuppression
What is the pathway of aqueous humor in the eye?
Produced by ciliary epithelium (ciliary body) –> around lens –> through pupil into anterior chamber –> trabecular meshwork –> Canal of Schlemm
What type of receptor dilates the pupil?
Constricts?
A1 dilates
M3 constricts
What are the causes of open angle glaucoma?
What are the risk factors?
Caused by blockage of trabecular meshwork:
WBC’s (uveitis)
RBC’s (hemorrhage/trauma)
Retinopathy
Risk factors: Age, Black race, family history
What are the symptoms of chronic glaucoma?
Painless
Loss of peripheral vision
Cupping on optic exam
What causes closed angle glaucoma?
What is seen?
Lens moves forward & blocks pupil –> aqueous humor builds up behind iris –> pushes iris forward which blocks trabecular meshwork
Symptoms: Ophthalmic emergency Pain Rock hard eye Sudden vision loss Halos Frontal headach
What type of drugs are used to treat glaucoma?
Cholinomimetics
You want to contract the pupil (closed angle) & contract the ciliary muscle (open angle).
What are the risk factors for cataracts?
Age Galactokinase deficiency or classic galactosemia Diabetes Corticosteroid use Smoking EtOH Excessive sunlight Trauma Infection
What is seen with CNIII damage?
Eye looks down & out
Ptosis
Dilated pupil
What is seen with CNIV damage?
Eye moves upward (especially w/ contralateral gaze)
Problems while walking down the stairs
What is the pathway to cause mydriasis?
1) Hypothalamus –> Ciliospinal center of Budge (C8-T1)
2) Exit at T1 –> Superior cervical ganglion
3) Plexus along internal carotid –> through cavernous sinus (with V1) –> long ciliary nerve in the orbit –> pupillary dilator muscles
What is the pathway to cause miosis?
Edinger-Westphal nucleus –> Ciliary ganglion (via CNIII) –> Short ciliary nerves –> pupillary sphincter muscles
What is the pathway for the pupillary light reflex?
CNII –> Pretectal nucleus –> Bilateral Edinger-Westphal nuclei –> CNII –> constriction
What is a Marcus Gunn pupil?
Relative Afferent Pupillary Defect
By using the swinging light test, you will see that when the light is moved to the impaired eye, it will dilate some rather than re-constrict as is seen in a normal eye. Caused by damage to the retina or early optic tract.
What is seen with vascular vs compression damage to CNIII?
Vascular impairment –> O2 can’t diffuse to inner motor components –> Ptosis, down & out gaze
Compression –> peripheral parasympathetic fibers affected first –> blown pupil
What is seen with retinal detachment?
What are the risk factors?
Retina detaches from choroid –> retinal ischemia –> sudden monocular loss of vision (“like a curtain drawn down”)
Risk factors:
Diabetes
Myopia
Inflammation
What causes age-related macular degeneration?
Dry (nonexudative; 85%) - deposition of yellow material beneath pigmented epithelium –> gradual loss in central vision (scotoma)
Wet (exudative; 15%) - choroidal neovascularization –> bleeding –> rapid loss of vision
How is age-related macular degeneration treated?
Nonexudative - multivitamin & antioxidants
Exudative - anti-VEGF injections or laser
What genes are associated with Alzheimer’s?
Early onset:
Amyloid precursor protein (APP; chrom 21)
Presenilin-1, Presenilin-2
Late onset:
ApoE4
Protective:
ApoE2
What is seen histologically with Alzheimer’s?
Grossly?
Senile/Neuritic plaques - Extracellular beta-amyloid core with surrounding neuritic processes
Neurofibrillary tangles - Intracellular aggregations of hyperphosphorylated Tau protein (MT-associated protein)
Amyloid angiopathy may be present
Gross:
Widespread cortical atrophy (narrow gyri, wide sulci)
Hydrocephalus ex vacuo
What is seen clinically in Pick’s disease?
Change in personality
Aphasia
Parkinsonian aspects
Dementia
What is seen histologically with Pick’s disease?
Grossly?
Intracellular Pick bodies - ROUND aggregates of tau protein
Grossly:
Frontotemporal atrophy
Spares parietal lobe & posterior 2/3 of superior temporal gyrus
What causes Lewy body dementia?
What is seen clinically with Lewy body dementia?
Defect in alpha-synuclein –> Lewy body deposition
Parkinsonism
Dementia
Hallucinations
What causes Creutzfeld-Jakob disease?
Sporadic, inherited, or transmitted misfolding of PrPc –> PrPsc
Assumes a beta-pleated sheet form –> converts more copies of itself to altered form –> vacuole formation
What is seen clinically with CJD?
Creutzfeldt-Jakob disease
Rapidly progressive dementia Startle myoclonus Ataxia Spike wave complexes on EEG Death in <1y
What is seen with familial fatal insomnia?
A type of inherited spongiform encephalopathy
Insomnia
Startle myoclonus
Neck flexion –> shocklike sensation down spine & into extremities
What is it called?
What can cause it?
Lhermitte’s sign
Caused by MS
What are the findings on labs with MS?
Oligoclonal IgG bands in the CSF
Periventricular plaques on MRI (gold standard)
Who is affected by MS?
White women in their 20’s-30’s with HLA-DR2 far from the equator
What is the treatment for MS?
Long term:
IFN-beta
Natalizumab (prevents immune cells from penetrating the CNS)
Acute –> Corticosteroids
What infections are associated with Guillan-Barre syndrome?
Campylobacter jejuni
CMV
Leads to autoimmune attack on Schwann cells due to molecular mimicry.
What is seen in Guillan-Barre syndrome?
Ascending paralysis
Facial paralysis in 50%
Autonomic dysfunction
What is the treatment for Guillan-Barre?
Respiratory support
Plasmapheresis
IVIg
What is the gold standard in diagnosing Guillan-Barre?
Increased CSF protein with normal cell count
albuminocytologic dissociation
What causes Progressive Multifocal Leukoencephalopathy?
AIDS –> Reactivation of JC virus in oligodendrocytes –> central demyelination –> rapid progression & death
What is the cause of Charcot-Marie-Tooth disease?
What is seen?
aka Hereditary Motor & Sensory Neuropathy
Various inherited etiologies affecting peripheral nerves or Schwann cells
Symptoms:
Leg weakness/atrophy
High arches & hammertoes
What is seen with partial temporal seizures?
Most common point of origination:
Funny feeling in stomach rising up
Weird smells
What is seen with frontal partial seizures?
They occur at night
What is the difference between simple partial & complex partial seizures?
Complex = loss of consciousness
What is seen with juvenile myoclonic epilepsy?
Myoclonic seizures shortly after arising in the morning
Seen in teens
Precipitates by lack of sleep & EtOH (college lyfeee)
What is seen with absence seizures?
What is the treatment?
EEG = 3 Hz
Ages 4-10
No postictal state
Tx: Ethosuximide
What are the types of generalized seizures?
Absence (petit mal)
Myclonic - quick, repetitive jerks
Tonic-clonic (grand mal) - alternating stiffening & movement
Tonic - stiffening
Atonic - “drop seizures” often mistaken for fainting
What is the treatment for myoclonic seizures?
Valproic acid
What is status epilepticus?
Continuous seizure for >30 mins or recurrent seizures for >30 mins without regaining consciousness
What is seen with a patient’s eyes in a seizure?
Patients look away from a seizure & into a stroke
What causes peripheral vertigo?
Inner ear pathology:
Semicircular canal debris (BPPV)
Vestibular nerve infection
Ménière’s disease
Positional testing –> delayed horizontal nystagmus
What causes central vertigo?
What is seen?
Brainstem or cerebellar lesion –> central vertigo
Findings:
Position testing –> immediate nystagmus in any direction
What is seen in Tuberous Sclerosis?
HAMARTOMAS: Hamartomas in CNS & skin Adenoma sebaceum Mitral regurgitation Ash-leaf spots Rhabdomyoma in heart Tuberous sclerosis aut. dOminant Mental retardation Angiomyolipoma in kidney Seizures
What is seen in Neurofibromatosis Type I?
Cafe-au-lait spots Lisch nodules Neurofibromas in skin Optic gliomas Pheochromocytomas
What is seen in Neurofibromatosis Type 2?
Bilateral Schwannomas
Meningiomas
What is seen in von Hippel-Lindau disease?
Bilateral renal cell carcinoma
Cavernous hemangiomas in skin & organs
Hemangioblastoma
Pheochromocytomas
Autosomal dominant mutation of VHL on Chromosome 3
What is seen grossly with glioblastoma?
Histologically?
What should be stained for?
“Butterfly glioma” with necrosis
Histology:
Pseudopalisading cells surrounding necrotic area
Stain for GFAP
What is seen on histology in meningioma?
Psammomas and whorls in middle-aged girls
often calcified, estrogen receptor positive
What stain should be used for Schwannoma?
S-100
What is seen histologically with oligodendroglioma?
OligoHENdroglioma:
Chicken wire capillary pattern
Fried egg cells
Often calcified
What is seen grossly with Pilocytic astrocytoma?
Histologically?
What stain should be used?
Grossly - cystic portion & solid portion (piloCYSTic astrocytoma)
Histology - Rosenthal fibers (eosinophilic corkscrews)
GFAP+
What is seen on histology of medulloblastoma?
Small blue cells (primitive neuroectodermal)
Homer-Wright rosettes
What are drop metastases?
What are they seen in?
Medulloblastoma can send drop metastases down to the spinal cord through CSF.
What is seen histologically with an ependymoma?
Perivascular rosettes
Rod-shaped blepharoplasts found near the nucleus
Where is the most common site for an Ependymoma?
4th ventricle. Can cause hydrocephalus
What are the tumors found in adults?
GBM = Metastasis > Meningioma > Schwannoma > Pituitary adenoma > Oligodendroglioma
What are the primary CNS tumors found in children?
Pilocytic astrocytoma = Medulloblastoma > Craniopharyngioma = Ependymoma = Hemangioblastoma
What is seen with Hemangioblastoma?
Arise during middle age
Associated with von Hippel-Lindau syndrome
Can produce EPO –> polycythemia
What toxicities are seen with opioid analgesics?
Addiction Respiratory depression Constipation Biliary colic (sphincter of Oddi constriction) Miosis Additive CNS depression
What changes are seen on CBC following glucocorticoid administration?
Increased serum neutrophil count
All other WBC’s are diminished
This is due to demargination of PMN’s that were previously attached to a vessel wall (in the lung).
Why does aspirin use decrease the incidence of CRC?
COX-2 activity is seen to be high in som adenomatous polyps.
What chemical exposure is a cause of Parkinson’s disease?
MPTP
MPPP is a synthetic opioid used in a prior time. One of the byproducts of its production was MPTP. In the body, MPTP is converted to MPP+ by MAO. This substance is toxic to dopaminergic neurons.
What composition of bile is pro-gallstone?
High cholesterol
Low phosphatidylcholine
Low bile salts
What causes pituitary apoplexy?
Hemorrhage into a preexisting pituitary adenoma. Presents much like a subarachnoid hemorrhage but has a history of pituitary adenoma symptoms.
Cardiovascular collapse can occur secondary to ACTH deficiency –> acute adrenal insufficiency.
