Neuro Flashcards
Age-related macular degeneration types and therapies
Dry = sub retinal drusen deposits or pigment changes. Wet = abnormal blood vessels w/ sub retinal fluid/hemorrhage, gray subretinal membrane, or neovascularization (acute over days to weeks). Tx of acute = anti-VEGF inhibitors (prevent neovascular membrane formation), laser, photo
1st line drug for partial seizures
Carbamazepine; regardless of simple or complex
1st line drug for tonic-clonic sz
Phenytoin, carbamazepine, valproate
1st line drug for myoclonic sz
Valproic acid
1st line drug for absence sz
Ethosuximide, blocks T-type Ca2+ channels that trigger and sustain pulsed discharges in thalamic neurons. (2nd = valproate)
Gene defect in Friedreich’s ataxia?
Frataxin gene - mitochondrial protein for respiratory f(x) and Fe homeo. GAA repeat.
Drug after SAH to prevent vascular spasm?
Nimodipine
Viral CSF pattern?
Lymphocytic pleocytosis, normal glucose, elevated protein.
Bacterial CSF pattern?
Neutrophilic predominance, low glucose, high protein.
Early-onset familial Alzheimer’s associated w/ what mutations?
APP (21- Down’s!), presenilin 1 (14), and presenilin 2 (1). Apo E4 w/ late.
Path associated with lacunar infarcts?
Small vessel lipohyalinosis and atherosclerosis ->fluid-filled cavities
Alzheimer’s path
Decreased ACh lvl (deficient choline acetyltransferase) found in basal nucleus. Hippocampus. Neurofibrillary tangles, senile plaques, amyloid angiopathy.
Myasthenia gravis
Circulating Ab’s against post-synaptic Ach receptors -> complement-mediated destruction -> weakness (late in day). Associated with thymoma or thymic hyperplasia.
Two types of dopamine agonists
Ergot compounds (bromocriptine and pergolide) and nonergot compounds (pramipexole and ropinirole).
Phenytoin mech
Blocks Na+ channels and prolongs their rate of recovery. Inhibits high-frequency firing. Tonic-clonic and status.
Triptan mechanism
Serotonin 5-HT1b/5-HT1d AGONISTS that counter release of vasoactive peptides
Migraine mech
Pain due to activation of trigeminal afferents that innervate meninges -> release of vasoactive neuropeptides (substance P and calcitonin gene-related peptide) -> neurogenic inflammation due to vasodilation and plasma protein extravasation. Neuronal sensitization
How does ketamine block morphine tolerance?
NMDA receptor antagonist to block actions of glutamate.
Subfalcine herniation
Cingulate gyrus herniates under falx cerebri –> ACA compression
Uncal herniation
Ipsi oculomotor, ipsi PCA -> contralateral homonymous hemianopsia w/ macular sparing, compression of contra cerebral peduncle -> ipsilateral hemipareses. brainstem hemorrhages
Dmg to putamen vs. globus pallidus
Putamen initiates movt so lesions –> tremor, bradykinesia, and rigidity. GP external dmg = less movt. Internal dmg = excessive motion/movt. Think of damage to globus as the normal pathways through them b/c they are inhibited in their pathways.
Nucleus ceruleus?
NE-secreting neurons for flight or fight. Dorsal pons.
Raphe nuclei?
Serotonergic neurons. Sleep-wake, lvl of arousal. Lesion -> insomnia and depression. Sir Raphe the sleepy.
Nucleus basalis of Meynert?
Cholingergic cells. Decreased amounts in Alzheimer’s disease. Cholling Mr. Meynert?
Red nucleus?
In anterior midbrain. Important for motor coordination of upper extremities.
Monocular scotoma?
A partial lesion in the retina, optic disk, or optic nerve. etio - macular degeneration and optic neuritis
Homonymous superior quadrantanopia?
Lesion or stroke involving temporal lobe (Meyer’s loop)
Homonymous inferior quadrantanopia
Lesion or stroke involving PARIETAL lobe (DORSAL optic radiation)
Korsakaoff syndrome damages what particular nuclei?
Anterior and dorsomedial thalamic nuclei -> confabulation. Anterograde amnesia (usu. permanent).
Role of the notochord?
Induces overlying ectoderm to form the neural plate, which gives rise to the neural tube and neural crest cells (dy 18). Notochord becomes the nucleus puposus of the intervertebral discs.
Forebrain structures
Forebrain = prosencephalon = telencephalon + diencephalon = cerebral hemispheres + lateral ventricles + thalamus + third ventricle
Midbrain structures
Mesencephalon = midbrain + aqueduct
Hindbrain structures
Rhombencephalon = Metencephalon + myeloncephalon = (Pons + Cerebellum + Upper part of 4th ventricle) + (Medulla + lower part of 4th ventricle)
Neuroectoderm gives rise to?
CNS neurons, ependymal cells, oligodendroglia, astrocytes
Neural crest cells give rise
PNS neurons and Schwann cells. Neural crest is PNS-only!
Mesoderm gives rise
Microglia (resident macrophages of the CNS). MESO for MICRO.
Neuropore failing to fuse when? Connects what structures?
Wk 4. Pore is FOUR. Connects spinal canal with amniotic cavity. increased alpha-fetoprotein in fluid and serum. Increased AChE in amniotic fluid is confirmatory
Spina bifida occulta vs. meningocele vs. meningomyelocele?
Spina bifidia = failure of bony canal to close but NO herniation and intact dura. Associated w/ tuft of hair or skin dimple (lower vertebrae). Meningocele has meningial herniation (normal AFP) whereas meningomyelocele has both meninges and spinal cord herniation.
Anencephaly vs. holoprosencephaly
No forebrain and open calvarium vs. failure of hemispheres to separate. Anecephaly findings include increased AFP, polyhdramnios (b/c don’t swallow). Associated with DMT1. Holoprosencephaly has complex multifactorial etio. Mod. form has cleft lip/palate while severe form -> cyclopia
Chiari II vs. Dandy-Walker
Significant herniation of cerebellar tonsils and versus w/ aqueductal stenosis and hydrocephalus. Often w/ myelomeningocele. Dandy is AGENESIS of vermis with cystic enlargement of 4th ventricle. Hydrocephalus and spin bifida.
Syringomyelia
Cape-like b/l loss of pain and temperature but OK fine touch. Most common at C8-T1. Associated with Chiari I (>3-5 mm tonsillar octopi and asymptomatic till older).
Tongue development overview
Anterior 2/3 with 1st and 2nd branchial arches (Sensation V3 and taste VII). Posterior 1/3 from 3-4th branchial arches (sensation and taste IX, X in back). XII is muscle.
Nissl substance located where?
Dendrites and cell body. NOT axon.
Astrocyte vs. Microglia
Support cell with reactive gliosis derived from NEUROECTODERM VS CNS phagocytes from MESODERM.
Pain and temperature sensory?
Free nerve endings found in skin, epidermis, and some viscera. C nerves are slow, unmyelinated. Adelta are fast myelinated.
Meissner corpuscle
Dynamic, fine touch, propioception. Glabrous (hairless skin). Large, myelinated, adapt quickly. “A fine hairless adaptable miss.”
Pacinian corpuscle
Vibration and pressure. Deep skin, ligaments, joints. Large, myelinated, adapt quickly. “Deeply packed and pressurized Pacinian corpuscle.”
Merkel discs
Pressure, deep static touch, propio. Basal epidermal layer, hair follicles. Large, myelinated fibers, adapt slowly.
Name the three parts of peripheral nerve?
Endoneurium, Perineurium, Epineurium
Endoneurium
SINGLE nerve fiber layer. Infiltrate in Guillan Barre.
Perineurium
Surrounds fascicle of nerve fibers. Permability barrier. Rejoined by microsurgery for limb reattachment.
Epineurium
Dense CT surrounding entire nerve.
NE change in disease? and location of synthesis?
Increased in anxiety and decreased in depression. Locus ceruleus (pons)
DA change in disease? and location of synthesis?
Inc. in HD. Dec. in Parkinson’s and depression. Ventral tegmentum and SNc (midbrain)
5-HT change in disease? and location of synthesis?
Inc. in Parkinsons. Dec. in depression and anxiety. Raphe nucleus (pons, medulla, midbrain)
ACh change in disease? and location of synthesis?
Inc. in Parkinsons. Dec. in Alzheimers and HD. Basal nucleus of Meynert. “Need A/C during Mey?”
GABA change in disease? and location of synthesis?
Decreased in HD and anxiety. Nucleus accumbens.
Three major structures for BBB?
Tight junctions between NONfenestrated capillary endothelial cells, BM, astrocyte foot processes.
Carrier-mediated transport for BBB?
Glucose and amino acids.
Major areas of the hypothalamus
Lateral area, ventromedial area, anterior, posterior, suprachiasmatic, OVLT, area postrema, supraoptic nucleus (makes ADH), paraventricular nucleus
Lateral area of hypothalamus?
Hunger. Inhibited by LEPTIN = appetite suppressant. Lesion = anorexia/FTT. HUNGRY for LATE’s.
Ventromedial area of hypothalamus?
Satiety. Stimulated by leptin. Destruction (e.g. craniopharyngioma -> hyperphagia).
Anterior area of hypothalamus?
Cooling and parasympathetics. A for A/C.
Posterior hypothalamus?
Heating, sympathetic.
Suprachiastmatic nucleus
Circadian rhythm. Need to sleep to be charismatic.
OVLT
Organum vasuclosum of the laminal terminals senses changes in osmolarity. NOT protected by BBB.
Area postrema
Responds to emetics. NOT protected by BBB. (Toxin sensor). Located on dorsal surface of medulla at caudal end of 4th ventricle
What makes oxytocin and ADH?
Paraaventricular = oxytocin. Supraoptic = ADH. “A DH needs super good eyes!” “Vent the room after using Oxy-clean.”
Melatonin production?
From pineal gland stimulated by NE made from the suprachiasmatic nucleus.
EEG waveforms phrase
BATS Drink Blood.
Theta waves
Non-REM 1. Light sleep
Alpha waves
Awake with eyes-closed. Alpha: First things first, close your eyes.
Beta waves
Awake and alert AND REM sleep (loss of motor tone, dec. oxygen use, variable pulse and pressure, dreaming, tumescence, memory?)
Delta waves
Delta = Deepest non-REM sleep (Slow-wave with HIGH amplitude) Stage N3 where night errors, sleepwalking, and bedwetting occur.
Sleep spindles and K complexes?
N2 (45% of sleep). N2 is when bruxism occurs.
Neuro vs. adenohypophysis?
Neurohypophysis = POSTERIOR. Neuro for ADH and oxytoxcin
Five nuclei of the thalamus
VPL, VPM, LGN, MGN, and VL
VPL
Ventral posterolateral nucleus - spinothalamic, dorsal column; pain and temperature, pressure, touch, vibration, propioception; headed toward primary somatosensory cortex. P for posterior column (dorsal) and L for anteroLateral system.
VPM
Ventral posteromedial nucleus - trigeminal and gustatory pathway; face sensation and taste; primary somatosensory cortex. “Make-up for the face.”
LGN
Relay for LIGHT. CN II, vision headed toward Calcarine sulcus.
MGN
M for MUSIC. Superior olive and inferir colliculus of tectum, hearing -> auditory cortex of temporal lobe
Limbic system
5 F’s - Feeding, Fleeing (autonomics), Fighting (autonomics), Feeling. Emotion, long-term memory, olfaction, behavior modulation, ANS
Input into the cerebellum?
Contralateral cortex via the middle cerebellar peduncle. Ipsilateral propioceptive information via inferior cerebellar peduncle (climbing and mossy fibers)
Cerebellar outputs?
Contralateral cortex (Purkinje -> deep nuclei -> contralateral cortex via superior cerebellar peduncle)
Cerebellar deep nuclei?
From lateral to medial: Dentate, Emboliform, Globose, Fastigial (DEGF)
Lateral cerebellar vs. medial cerebellar lesions?
Lateral lesions -> fall ipsilaterally. Medial lesions -> truncal ataxia, nystagmus, head tilting, b/l motor deficits.
Basal ganglia structures
Striatum = putamen and caudate. Lentiform = putamen and globus pallidus.
Excitatory pathway of basal ganglia
Cortex stimulates striatum (GABAerg) which inhibits the GPi/SNr to disinhibits the thalamus (VA/VL).
Inhibitory pathway of basal ganglia
Cortex stimulates striatum to inhibit the GPe, which disinhibits the sub-thalamic nucleus, which activates the GPi/SNr to inhibit the VA/VL thalamus.
Substantia nigra pars compacta’s role in Parkinson’s
Acts via D1 on excitatory pathway to reinforce and acts via D2 on inhibitory pathway to oppose. These neurons degenerate in Parkinson’s
GPe vs. GPi/SNr
GPi/SNr tonically inhibits the VA/VL. GPe tonically inhibits the sub-thalamic nucleus (which activates the GPi/SNr). Globus = globally tonically active in inhibiting. Internal segment INHIBITS movt. External = EXTRA and inhibits STN, which normally inhibits GPi)
Chorea vs. athetosis?
Sudden jerky movts vs. slow writhing movts (esp. fingers). Both seen in basal ganglia lesions (HD).
Essential vs. resting vs. intention tremor?
Action tremor exacerbated by holding posture/limb vs. alleviation by movt (Parkinson’s) vs. poor finger2nose (cerebellar)
General homunculus
Medial to lateral = Toes to hand to face to tongue and swallowing
Amygdala lesions
B/l - Kluver-Bucy = hyperorality, hypersexuality, disinhibied behavior. Associated with HSV-1
Mammillary body lesion?
B/l lesions in Wernicke-Korsakoff syndrome (confusion, opthalmoplegia, ataxia, memory, confab, personality)
STN lesion?
STN activates GPi to inhibit movt. So lesion = contralateral hemiballismus.
Hippocampus lesion?
B/l lesions lead to anterograde amnesia.
Central pontine myelinolysis
Massive axonal demyelination in pontine white matter 2/2 osmotic forces and edema (Na+ from low to high correction). Acute paralysis, dyarthria, dysphagia, dipolopia, LOC. (Pseudobulbar symptoms)
Where do the ICA’s come from?
Right one from the brachiocephalic artery. Left one straight from the aortic arch.
Basilar artery into Circle of Willis anatomy?
Superior cerebellar arteries come off 1st, THEN the posterior cerebral arteries!
Where do the vertebral arteries come from?
Right one from braciocephalic artery (after R ICA). Left one from the subclavian artery.
AICA vs. PICA?
PICA’s off the vertebral arteries. AICA’s at junction with basilar artery.
A1 vs. A2 ACA?
A1 between MCA and ACom. A2 after Acom.
P1 vs. P2 PCA?
P2 after PCom. P1 between Pom and Basilar before Superior cerebellar arteries.
Two numbers to know for cerebral blood flow.
PO2 < 50 mmHg —> increased cerebral perfusion pressure. PCO2 > 90 mmHg is LIMIT to increasing cerebral blood flow (via vasodilation) in proportion to PCO2.
Therapeutic hyperventilation?
By decreasing PCo2, we decreased cerebral blood flow and therefore intracranial pressure. Used for stroke, trauma.
MCA stroke
Contralateral paralysis of upper limb and face. Contralateral loss of sensation in upper and lower limbs, and face. Aphasia if dominant or hemineglect if non-dominant.
ACA stroke
Contralateral paralysis and loss of sensation in the LOWER limb. (B/c ACA perfuses in the middle-inside portion of brain.
Common location of lacunar stroke?
Internal capsule of the striatum supplied by lenticulotriate artery.
ASA (anterior spinal artery) stroke
Complete motor paralysis. Loss of pain and temp b/l. Retained propioception.
PICA stroke
Lateral Medullary syndrome - dec. pain and temp from ipsilateral face and contralateral body, dysphagia, hoarseness, dec. gag, ipsilateral Horner, ataxia
AICA stroke
Lateral pontine syndrome - vertigo, vomiting, nystagmus, falling over to side, ipsi facial paralysis and loss of sensation
PCA stroke
Contralateral hemianopia w/ macular sparing
Basilar artery stroke
Locked-in syndrome.
ACom lesion
Most commonly from aneurysm. Visual field deficits.
PCom lesion
Saccular aneurysm. CN III palsy.
Berry aneurysm
Occurs at bifurcations in Circle of Willis. e.g. Acom and ACA. Rupture to SAH. Associated with ADPKD, Ehlers-Danlos, Marfan. Age, HTN, smoking.
Charcot-Bouchard microaneurysm
Associated with chronic HTN, affecting small vessels
Crossing hematomas. Epidural vs. subdural?
Epidural will cross Falx and tentorium but NOT sutures. Subdural is exact opposite.
Most vulnerable areas of the brain for hypoxia?
Hippocampus, neocortex, cerebellum, watershed.