Neuro Flashcards
a. Which part of the CNS/PNS originates from mesoderm?
b. Which part originates from neural crest?
a. Microglia
b. PNS neurons, Schwann cells
Why would Acetylcholinesterase be elevated from neural tube defects?
The fetal AchE in CSF transudates across defect in amniotic fluid
Anencephaly associations
Maternal type 1 diabetes
Decreased maternal folate
Holoprosencephaly mutation signaling
Mutation in sonic hedgehog pathway
Which conditions is holoprosencephaly seen in?
Patau syndrome (trisomy 13) Fetal alcohol syndrome
What sensation is lost with Syringomyelia?
Cape-like bilateral loss of PAIN and TEMP sensation in upper extremities
Syringomyelia associations
Chiari malformations
Trauma
Tumors
Which muscle elevates posterior tongue during swallowing? Innervated by?
Palatoglossus innervated by CN X
What is a Wallerian degeneration? What does this allow for?
When there is injury to axon there is degeneration distal to injury and axonal retraction proximally that allows for potential regeneration of axon (if in PNS)
Which axons are unmyelinated?
Autonomic post ganglionic
Afferent heat sensation
Afferent slow burning pain
1st order bipolar olfaction nerves
Role of Schwann cells
Myelinate ONE PNS axon
Promote axonal regeneration
Location of acoustic neuromas
Internal acoustic meatus
Which cell is injured in MS, PML and leukodystrophies?
Oligodendroglia
Where are Meissner corpuscles located? What do they sense?
Glabrous (hairless) skin - senses dynamic, light touch, position sense
Where are Merkel discs located? What do they sense?
Finger tips, superficial skin - senses pressure, deep static touch (shapes, edges), position sense
Which sensory receptors adapt quickly?
Which adapt slowly?
Meissner corpuscles and Pacinian corpuscles adapt quickly
Merkel discs and Ruffini corpuscles adapt slowly
What is synthesized in Locus ceruleus?
NE
What is synthesized in Ventral tegmentum and substantial nigra pars compacta? (Midbrain)
Dopamine
What is synthesized in Raphe nuclei of pons, medulla and midbrain?
Serotonin (5-HT)
What is synthesized in Basal nucleus of Meynert?
Ach - Basal nucleus of Meynert degenerates in Alzheimers
What is synthesized in nucleus accumbens?
GABA
Which areas of brain don’t have blood brain barrier?
This allows molecules in blood to affect brain function or neurosecretory products to enter circulation
Area postrema - vomiting after chemo
OVLT - osmotic sensing
Neurohypophysis - ADH release
How do infarction and neoplasm affect the blood brain barrier?
They destroy the endothelial cell tight junctions –> this leads to vasogenic edema
Where is area postrema located? Important for what?
Located in dorsal medulla at caudal end of 4th ventricle
Which hypothalamic nucleus makes ADH?
Supraoptic nucleus
Which hypothalamic nucleus makes oxytocin?
Paraventricular nucleus
Which hypothalamic nucleus might be damaged in an anorexic person?
Lateral area (also causes failure to thrive)
Which hypothalamic nucleus is damaged in hyperphagia?
Ventromedial area
Hypothalamic nucleus for cooling, parasympathetic
Anterior (think of A/C)
Hypothalamic nucleus for sympathetic, heating
Posterior (Zap your posterior you become poikilotherm)
Hypothalamic nucleus responsible for Circadian rhythm
Suprachiasmatic nucleus (Master clock)
Hypothalamic area that secretes GnRH
Pre-optic
Hypothalamic area causing savage behavior, obesity
Dorsomedial nucleus
What regulates suprachiasmatic nucleus?
What does SCN activation cause?
SCN regulated by environment
SCN –> NE release –> pineal gland –> melatonin
Causes of decreased REM sleep
Alcohol, BDZs, Barbiturates
Norepinephrine
Treatment for sleep enuresis
Oral desmopressin (ADH) Imipramine (second line bc of S/E)
Treatment for night terrors and sleepwalking
BDZs
a. Beta waves
b. Alpha waves
c. Theta waves
d. Sleep spindles and K complexes
e. Delta waves
a. Awake and REM sleep (high frequency, low amplitude)
b. Awake with eyes closed
c. Light sleep (Stage 1)
d. Stage 2 - Bruxism
e. Stage 3/4 nonrem - sleepwalking, night terrors, bedwetting (lowest frequency, highest amplitude)
What happens during REM sleep?
Loss of motor tone Increased brain O2 use Variable BP and pulse Dreaming Penile/clitoral tumescence
Sleep changes in depressed patients
Decreased slow wave
Increased REM
Decreased REM latency
Which info does VPL relay?
Sensory info from body (Very Painful Legs mnemonic)
Which info does VPM relay?
Sensation from face (Very Painful Mouth)
Which info does LGN relay?
Vision (Lateral = Light)
Which info does MGN relay?
Hearing (Medial = Music)
Function of Limbic system
Fucking, Feeding, Feeling, Fighting, Fleeing
a. Correcting hypernatremia too quickly
b. Correcting hyponatremia too quickly
a. Cerebral edema/herniation
b. Osmotic demyelination syndrome (central pontine myelinolysis)
Vascular lesion resulting in complete contralateral sensory loss and proprioceptive defects that lead to falls
Thalamic syndrome (damage to VPL and VPM)
Lesion location causing athetosis
Basal ganglia (Huntington)
Lesion location causing chorea
Basal ganglia (Huntington)
Treatment of essential tremor
Beta blocker, Primidone
Lesion causing hemiballismus
Contralateral subthalamic nucleus
Loss of neurons in substantia nigra pars compacta
Parkinson disease
Atrophy of caudate nuclei with ex vacuo dilation of frontal horns on MRI
Huntington disease
Increased dopamine, decreased GABA, decreased Ach
Huntington disease
CAG repeats = Caudate loses Ach and GABA (CAG)
Hyperphagia, hypersexuality, hyperorality
Kluver Bucy syndrome (bilateral amygdala lesion)
Hemispatial neglect syndrom
Lesion in non-dominant parietal temporal cortex
Gerstmann syndrome
Agraphia, acalculia, finger agnosia, left-right disorientation
DOMINANT parietal temporal cortex lesion
a. Damage to Paramedian pontine reticular formation
b. Damage to frontal eye fields
a. Eyes look AWAY from side of lesion
b. Eyes look TOWARD lesion
pCO2 effects on cerebral blood flow
Increased CO2 –> VASODILATION –> increased blood flow
Decreased CO2 –> decrease in cerebral perfusion (can cause neurologic signs)
(Patients with cerebral edema hyperventilate to decrease ICP)
pO2 effects on cerebral blood flow
Perfusion is constant between pO2 50-100 Severe hypoxia (
Common location of lacunar infarcts secondary to unmanaged HTN
Lenticulostriate arteries in striatum, internap capsule
ASA stroke - Area of lesion and symptoms
- Lateral corticospinal tract - contralateral hemiparesis of upper and lower limbs
- Medial lemniscus - Decreased contralateral proprioception
- Caudal medulla - Hypoglossal nerve - Causes ipsilateral hypoglossal dysfunction
Medial medullary stroke cause
Infarct of paramedian branches of ASA and vertebral arteries
Lateral medullary (Wallenberg) syndrome cause
PICA stroke
Don’t PICA horse (hoarseness) that can’t eat (dysphagia)
PICA stroke -
a. area of lesion
b. symptoms
a. Lateral medulla - vestibular nuclei, Lateral spinothalamic tract, Spinal trigeminal nucleus, Nucleus ambiguus, Sympathetic fibers, Inferior cerebellar peduncle
b. Vomiting, vertigo, nystagmus, decreased pain/temp from ipsi face and contra body; dysphagia, hoarseness, decreased gag reflex, ipsi Horner syndrome, ataxia, dysmetria
Lateral pontine syndrome
AICA lesions - Facial nucleus effects specific to AICA lesion
AICA stroke -
a. area of lesion
b. symptoms
a. lateral pons (vestibular nuclei, facial nucleus, spinal trigeminal nucleus, cochlear nuclei, sympathetic fibers) and middle inferior cerebellar peduncles
b. Vomiting, vertigo, nystagmus, paralysis of face, decreased lacrimation, salivation, decreased taste from anterior 2/3 of tongue; Ipsi loss of pain/temp from face, contra loss of pain temp from body; ataxia/dysmetria
Where is lesion of stroke causing contralateral hemianopia with macular sparing?
PCA
Where is stroke causing locked in syndrome?
Basilar artery
Where is stroke causing CN III palsy (down and out with ptosis and mydriasis)?
PCom (lesions typically aneurysms, not strokes)
Complication after subarachnoid hemorrhage
Vasospasm due to blood breakdown (treat with Nimodipine)
Rebleed
When do you see Xanthochromic spinal tap?
2-3 days after subarachnoid hemorrhage
Most vulnerable areas
Hippocampus, Neocortex, Cerebellum, Watershed areas
When do you see red neurons after ischemic event?
12-48 hours after
When do you see necrosis + neutrophils after ischemic event?
24-72 hours
When do you see macrophages and microglia after ischemic event?
3-5 days
When do you see reactive gliosis + vascular proliferation after ischemic event?
1-2 weeks
After 2 weeks what does an ischemic infarct look like?
Glial scar
Most common site of intracerebral hemorrhage
Hemorrhagic stroke
Where do the dural venous sinuses drain into?
Internal jugular vein
Risk factors for idiopathic intracranial HTN (pseudotumor cerebri)
Woman of childbearing age
Vitamin A excess
Danazol
Treatment for pseudo tumor cerebri
Weight loss
Acetazolamide
Topiramate
Urinary incontinence, Ataxia, Cognitive dysfunction
Normal pressure hydrocephalus (expansion of ventricles distorts the corona radiate fibers)
Where do nerves exit spinal cord corresponding to vertebrae?
Nerves C1-C7 exit ABOVE corresponding vertebrae
C8 spinal nerve exits below C7 and above T1
All other nerves exit BELOW corresponding vertebrae
What herniates in vertebral disc herniation?
The nucleus pulposus (soft central disc) herniates through annulus fibrosus (outer ring) - usually posterolaterally
Area affected in Werdnig Hoffmann disease
Anterior horn - LMN lesions only Flaccid paralysis (floppy baby)
Defect in superoxide dismutase 1
Amyotrophic Lateral Sclerosis
Treatment for ALS
Riluzole - decreases presynaptic glutamate release
Occlusion of anterior spinal artery affects which parts of spinal cord?
Spares dorsal column and Lissauer tract (pain pathway in dorsal column)
Charcot joints, shooting pain, Argyll Robertson pupils
Tertiary syphilis - Tabes dorsalis
Autosomal recessive trinucleotide repeat disorder (GAA)
Friedrich ataxia - on chromosome 9; gene that encodes frataxin (iron binding protein) –> impaired mitochondrial functioning –> degeneration of multiple spinal cord tracts
Symptoms of Friedreich ataxia
Muscle weakness, loss of DTRs, vibratory sense and proprioception
Staggering gait, frequent falling, nystagmus, dysarthria, hammer toes, diabetes mellitus, hypertrophic cardiomyopathy
Cause of death in Friedreich ataxia
Hypertrophic cardiomyopathy
Child with kyphoscoliosis
Friedreich ataxia - AR GAA trinucleotide repeat - chr. 9 that encodes frataxin iron binding protein
Reflexes:
a. Biceps
b. Triceps
c. Patella
d. Achilles
a. C5
b. C7
c. L4
d. S1
Galant reflex
Stroking along one side of spine while baby is face down causes lateral flexion of lower body toward stimulated side
CN nuclei that lie medially at brainstem
III
IV
VI
XII
Function of each:
a. Pineal gland
b. Superior colliculi
c. Inferior colliculi
a. Melatonin secretion, circadian rhythms
b. Conjugate vertical gaze center
c. Auditory
(Your eyes are above your ears and superior is above inferior colliculus)
What is Parinaud syndrome?
Dorsal midbrain syndrome; Paralysis of conjugate vertical gaze (inability to move eyes UP or down) due to lesion in superior colliculi (stroke, hydrocephalus, pinealoma)
What CNs go through the following
a. Cribriform plate
a. CN I
Middle cranial fossa - which CNs go through the following?a. Optic canal
b. Superior orbital fissure
c. Foramen rotundum
d. Foramen ovale
e. Foramen spinosum
a. CN II, ophthalmic artery, central retinal vein
b. CN III, IV, V1, VI, ophthalmic vein, sympathetic fibers
c. V2
d. V3
e. Middle meningeal artery
Posterior cranial fossa - which CNs go through the following?
a. Internal auditory meatus
b. Jugular foramen
c. Hypoglossal canal
d. Foramen magnum
a. CN VII, VIII
b. CN 9, 10, 11, jugular vein
c. CN 12
d. spinal roots of CN 11, brain stem, vertebral arteries
Functions of oculomotor nerve
Motor - superior rectus, inferior rectus, medial rectus, inferior oblique
Pupillary constriction (sphincter pupillae, Edinger Westphal nucleus, muscarinic receptors)
Accommodation
Eyelid opening (elevator palpebrae)
Functions of trigeminal nerve
Motor - mastication
Facial sensation
Somatosenation from anterior 2/3 of tongue
Functions of facial nerve
Facial movement Taste from anterior 2/3 tongue Lacrimation Salivation (submandibular, sublingual) Eyelid closing (orbicularis oculi) Stapedius muscle in ear
Does Facial nerve innervate parotid gland?
No but it courses THROUGH it; parotid is innervated by CN 9
Glossopharyngeal nerve functions
Taste and sensation to posterior 1/3 tongue
Swallowing
Salivation (parotid gland)
Monitoring carotid body and sinus chemo and baroreceptors
Stylopharyngeus (branchial arch 3)
Vagus nerve functions
Taste from epiglottic region Swallowing Soft palate elevation Midline uvula Talking Coughing Thoracoabdominal viscera Monitoring aortic arch chemo and baroreceptors
Which nerves innervate Nucleus solitarius and what info does it provide?
CNs 7, 9 and 10 –> visceral SENSORY information
Which nerves innervate nucleus aMbiguus and what info does it provide?
CNs 9, 10 and 11 –> MOTOR innervation of pharynx, larynx, upper esophagus
Which nerve innervates dorsal motor nucleus and what info does it provide?
CN 10 –> sends autonomic (PARASYMPATHETIC) fibers to hear, lungs, upper GI
Which nerves make up gag reflex?
Afferent - CN 9
Efferent - CN 10
Lacrimation reflex?
Afferent - V1
Efferent - 7
Pupillary reflex?
Afferent - 2
Efferent - 3
CN 5 motor lesion
Jaw deviates TOWARD side of lesion due to unopposed force from the opposite pterygoid muscle
CN 10 lesion
Uvula deviates AWAY from side of lesion (weak side collapses and uvula points away)
CN 11 lesion
Weakness turning head to contralateral side of lesion
Shoulder droop on side of lesion
CN 12 lesion
Tongue deviates TOWARD side of lesion
Weber - lateralizes to left ear
Rinne - normal
Sensorineural hearing loss in right ear
Weber - lateralizes to left ear
Rinne - can’t hear it in left ear
Conductive hearing loss in left ear
Rinne - normal in both ears
Weber - lateralizes to right ear
Sensorineural hearing loss in left ear
What is cholesteatoma?
Overgrowth of desquamated keratin debris within middle ear space - may erode ossicles or mastoid air cells –> conductive hearing loss
gray white pearly lesion behind tympanic membrane, conductive hearing loss and vertigo
Cholesteatoma
Facial nerve palsy associations
Lyme disease Herpes simplex or Herpes zoster (ramsay hunt) Sarcoidosis Tumors Diabetes AIDS
Which mastication muscle is responsible for opening jaw?
Lateral pterygoid
What produces aqueous humor?
Ciliary epithelium of eye
a. Innervation of dilator pupillae muscle
b. Innervation of sphincter pupillae muscle
a. alpha 1 receptors (IP3) - parasympathetic
b. M3 receptors (IP3) - parasympathetic
a. Loss of peripheral vision
b. Loss of central vision
a. Glaucoma
b. Age related macular degeneration
Causes of secondary closed angle glaucoma
Diabetes or vein occlusion -> induces vasoproliferation in iris that contracts angle
Rock hard eye, frontal headache, vision loss
Acute closure glaucoma = EMERGENCY
DON’T give epinephrine because of mydriasis effect
Treatment of glaucoma
a. Increase outflow
b. Decrease aqueous humor production
c. acute angle closure
a. Prostaglandins, alpha agonists, cholinergic agonists (Pilocarpine)
b. Beta blockers, carbonic anhydrase inhibitors, alpha agonists
c. add Mannitol
Types of Diabetic nephropathy
- Nonproliferative - damaged capillaries leak blood –> lipids and fluid seep into retina –> hemorrhages and macular edema (treat with blood sugar control and macular laser)
- Proliferative - chronic hypoxia results in formation of new vessels with resultant traction of retina –> treat with peripheral retinal photocoagulation or anti-VEGF (bevacizumab)
Schwannomas and Meningiomas
Neurofibromatosis 2
Painless monocular vision loss with cherry red spot at fovea
Central retinal artery occlusion
Risk of early ONSET alzheimers
APP, Presenilin 1 and Presenilin 2
Increased risk of alzheimers
ApoE4
Where is there decreased Ach activity in Alzheimers?
Decreased choline acetyltransferase activity in nucleus baseless of Meynert and hippocampus
What makes up neurofibrillary tangles? What do they correlate with?
They are intracellular hyperphosphorylated tau protein; number of tangles correlates with degree of dementia
Silver staining spherical tau protein aggregates
Pick bodies
alpha synuclein defect
Lewy body dementia
Increased protein (IgG) in CSF Oligoclonal bands
Multiple sclerosis
Oligoclonal bands are diagnostic
Mechanism of Baclofen
Inhibits GABAb receptors at spinal cord level –> leads to skeletal muscle relaxation
-Can treat MS, spasticity
LP findings for Guillain Barre syndrome
Increased CSF protein with NORMAL cell count
Most common cause of viral meningitis
Coxsackievirus A virus
LP with increased lymphocytes and low glucose
Fungal
Scoliosis and foot deformities
Charcot Marie Tooth disease (autosomal dominant)
=hereditary motor and sensory neuropathy
Galactocerebrosidase deficiency
Krabbe disease (autosomal recessive lysosomal storage disease) Build up of galactocerebroside destroys myelin sheath
Peripheral neuropathy, developmental delay, optic atrophy, globoid cells
Krabbe disease
Arylsulfatase A deficiency
Metachromatic Leukodystrophy (autosomal recessive) buildup of sulfates destroys myelin sheath; central AND peripheral demyelination with ataxia, dementia
Central and peripheral demyelination with ataxia, dementia
Metachromatic Leukodystrophy
Progressive multifocal leukoencephalopathy
Demyelination of CNS due to destruction of oligodendrocytes; associated with JC virus
Drugs that cause increased risk of PML
Natalizumab (anti alpha 4 integrin), Rituximab (anti CD20)
Build up of very long chain fatty acids in nervous system, adrenal gland and testes
Adrenoleukodystrophy (X linked recessive)
Treatment for focal (partial) seizures
Carbamazepine
Gabapentin
Phenobarbital
Phenytoin
Drugs that treat broad spectrum of seizure disorders
Valproic acid
Topiramate
Lamotrigine
Cause of migraine
Irritation of CN V, meninges or blood vessels –> release of Substance P, calcitonin gene related peptide, vasoactive peptides
Prophylatic treatment of migraines
Propranol
Topiramate
Ca channel blockers
Amitriptyline
Abortive treatment of migraines
Triptans
NSAIDs
Delayed horizontal nystagmus
Peripheral vertigo
Tinnitus, vertigo, hearing loss
Meniere disease (Increased volume of endolymph)
Developmental anomaly of neural crest derivatives due to activating mutation of GNAQ gene
Sturge Weber syndrome
Port wine stain of face
Seizures/epilepsy
Intellectual disability
Episcleral hemangioma
Sturge Weber Syndrome (non-inherited)
Nevus flammeus, a non-neoplastic birthmark in V1-V2 distribution
Port Wine stain (seen in Sturge Weber syndrome)
STURGE mmnemonic
Sporadic, port wine Stain Tram track calcifications (opposing gyri) Unilateral Retardataion GNAQ mutation, Glaucoma Epilepsy
Tuberous Sclerosis findings (HAMARTOMAS)
Hamartomas in CNS, skin Angiofibromas Mitral regurgitation Ash-leaf spots cardiac Rhabdomyoma Tuberous sclerosis autosomal dOminant Mental retardation renal Angiomyolipoma Seizures, Shagreen patches
Cafe au lait spots
Lisch nodules
Optic gliomas
Pheochromocytomas
Neurofibromatosis type 1 (von Recklinghausen)
Also see cutaneous neurofibromas
Mutation in Neurofibromatosis type 1
Neurofibromin - a negative regulator of RAS - on chromosome 17
von Hippel Lindau findings
Hemangioblastomas
Bilateral renal cell carcinoma
Pheochromocytoma
Angiomatosis (hemangioblastomas in skin, organs)
What does histology of hemangioblastoma look like?
High vascularity with hyperchromatic nuclei
Pseudopalisading pelomorphic tumor cells with necrosis and hemorrhage - brain tumor
Glioblastoma multiforme (grade 4 astrocytoma)
Brain tumor - spindle cells arranged in whorled pattern; psammoma bodies (laminated calcifications)
Meningioma
Brain tumor arising from arachnoid cells and has dural attachment
Meningioma
Location of hemangioblastomas
Most often cerebellar
Histology of hemangioblastomas
Closely arranged, thin walled capillaries with minimally intervening parenchyma
S-100 +
Schwannoma
Synaptophysin stain
in CNS tumors of NEURONAL origin
Brain tumor with rosenthal fibers
Pilocytic astrocytoma
Highly malignant cerebellar tumor seen in childhood
Medulloblastoma (primitive neuroectodermal tumor)
Drop metastases to spinal cord
Medulloblastoma
Brain tumor with Homer Wright rosettes
Medulloblastoma
Brain tumor with perivascular rosettes
Ependymoma
Supratentorial tumor with cystic spaces filled with brownish fluid rich in cholesterol
Craniopharyngioma
Herniation that compresses anterior cerebral artery
Cingulate herniation (subfalcine) under falx cerebri
Herniation causing duret hemorrhage (rupture of paramedian basilar artery branches)
Downward transtentorial herniation
Herniation causing ipsilateral blown pupil, contralateral homonymous hemianopia, ipsilateral paresis
Uncal herniation
CN III = ipsilateral blown pupil
ipsilateral PCA = contralateral homonymous hemianopia
contralateral crus cerebri = ipsilateral paresis
Herniation causing coma and death
Cerebellar tonsillar herniation into foramen magnum compressing brainstem
