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.
Histologic features of ischemia in brain.
NOTHING from 3-6h. Red neurons 12-48 hrs. Necrosis + neutrophils from 24-72h. Macrophages from 3-5 days. Reactive gliosis + vascular proliferation from 1-2 weeks. >2 weeks is a glial scar.
TIA definition?
Brief, reversible focal neurologic dysfunction lasting <24 hrs with NEG MRI findings of infarction.
Superior sagittal sinus vs. inferior saggital sinus
Superior on top. Inferior is inside off of the straight sinus as a branch (other being Great cerebral vein of Galen)
Phenytoin vs. phenobarbital SE’s?
Generalized lymphadenopathy w/ hirsuitsm, coarsened features, gingival hyperplasia vs. acute intermittent porphyria, sedation
Neurofibromatosis-1
AD (Chromosome 17). Cafe-au-lait. Neurofibromas. Lisch nodules (hamartomas of iris). Pseudoarthrosis.
CN’s in medulla
CN IX-XII
CN’s in Pons
CN V-VIII
CN’s above the Pons
CN I-IV
Restless legs syndrome treatment
First nonpharm (limit aggravating factors), Fe supplement, Dopamine agonists (pramipexole, ropinirole)
Valproic acid pregnancy risk?
NEURAL tube defects. 1-3%
By what age should a child be able to play cooperatively?
Age 4
By what age able to copy circle and use utensils?
Age 3
By what age have friends?
Age 5
Steps for hearing from TM
Stapes to TM -> oval window (amplification) -> fluid displacement of endolymph of scala media -> bending of cilia of hair cells (basilar vs. tectorial membranes) -> inc. OR dec. K+ conductance = dpol. or repol. -> dpol to Ca2+ release of repol to no Ca2 -< release of neurotransmitter or not -> CN VIII; Higher frequency closer to stapes (stiff) while lower frequency at compliant near apex.
Purpose of the foramina of Luschka and Magendie?
Connect 4th ventricle to the subarachnoid space. Luschka = Lateral. Magendie = Medial.
NPH
Expansion fo ventricles distorts fibers of the CORONA RADIATA -> urinary incontinence, ataxia, cognitive dysfunction
Communicating hydrocephalus
Decreased CSF absorption by arachnoid graduation lead to inc. ICP, papilledema, herniation
Hydrocephalus ex vacuo
Apparent increase of CSF 2/2 atrophy. ICP is normal. (e.g. Alzheimer’s, adv. HIV, Pick)
Noncommunicating hydrocephalus
Due to a structural blockage within the CSF system
How many spinal nerves are there?
31 spinal nerves. “Have the spine of a man walking outside on January 31st.”
Which nerves exit above their corresponding vertebra?
C1-C7.
To what vertebrae does the spinal cord extend to? And where do you do a LP?
Lower border of L1-L2. LP usu. between L3-L4 or L4-L5. Subarachnoid space down to S2.
Dorsal column body organization
Fasciculus gracilis (lower body and legs) are inside. Fasciculus ceunatus (upper body, and arms)
Anterolateral system body organization
Lateral spinothalamic tract. Sacral outside to cervical inside.
Corticospinal tract body organization
Sacral lateral. Cervical medial.
Anterolateral system pathway
Free nerve endings synapse in ipsilateral gray matter and decussates within 2-3 levels in anterior white commisure, ascending CONTRlaterally, synapsing at VPL -> sensory cortex
Dorsal column pathway
Fine touch, vibration, pressure, propioception enter spinal cord and ascend ipsilaterally until it synapses at the nucleus cuneatus (lateral) or gracilis (medial) -> decussates at the MEDULLA and ascends contralaterally up the medial lemniscus -> synapses at VPL -> sensory cortex
Spastic paralysis vs. flaccid paralysis
UMN vs. LMN signs
ALS
Combined UMN and LMN w/ NO sensory, cognitive, or oucular motor deficits. Some etio = defective superoxide dismutase I. Riluozole tx modest (dec. presynaptic glutamate release).
Tabes dorsalis
Tertiary syphilis -> demyelination of dorsal columns and roots -> impaired sensation, propioception, coordination. Charcot joints, Argyll Robertson pupils (small pupils that accommodate but do not react to light). Absent DTRs and POS romberg
Syringomyelia
Syrinx damages anterior white commisure -> b/l loss of pain and temperature
Poliomyelitis
Poliovirus (oropharynx and SI replication before spreading hematogenously to CNS). Destruction of anterior horn cells -> LMN death. Weakness, hypotonia, flaccid paralysis, fasciculations. CSF shows inc. WBCS and slight increased protein w/ NO CSF glucose change.
Spinal muscular atrophy (Werdnig-Hoffmann disease)
Congenital degeneration of anterior horn cells. AR.
Friedreich ataxia
AR GAA on Chromosome 9 (frataxin) -> mt dysf(x). Muscle weakness and loss of DTRs. Staggering, frequent falls,nystagmus, pes caves, hypertrophic cardiomyopathy
Brown-Sequard syndrome
Hemisection. Ipsilateral UMN signs (corticospinal). Ipsilateral dorsal column. Contralateral anterolateral. (pain and temperature). At the level of lesion, loss of all sensation. Above T1, could have Horner’s syndrome
Horner syndrome and its pathway.
Ptosis (superior tarsal m.), Anhidrosis and flushin, Miosis. Hypothalamus to synapse in lateral horn of intermediolateral column of spinal cord (T1) -> superior cervical (sympathetic) ganglion (which is near bifurcate of common carotid) synapse -> sweat glands of face, opthalmic division of trigeminal nerve for pupillary dilator, sweat glands of forehead + smooth muscle of eyelid
C2 vs. C3
Posterior part of skull cap vs. high turtleneck
Spinal cord lvls that would affect erection
S2,3,4
Biceps reflex
C5,6
Triceps reflex
C7,8
Patellar reflex
L3,4
Achilles reflex
S1,2
Cremaster reflex
L1,L2
Anal wink reflex
S3,S4
When are primitive reflexes exhibited?
Before age 1. Or “frontal release” (adult with frontal lobe lesions)
Galant reflex
Stroking one side of spine while ventral suspension causes lateral flexion of lower body toward stimulated side
Parinaud syndrome
Paralysis of conjugate VERTICAL gaze 2/2 lesion in superior colliculi (e.g. pinealoma)
Inferior colliculi
auditory
What are the cranial nerves that have both sensory and motor nerves?
CN V, VII, IX, X. “Some say marry money, but my brother says big brains matter most.”
Midbrain vs. Pons vs. Medulla CN nuclei
Midbrain = CN III, IV. Pons = V, VI, VII, VIII. Medulla = IX, X, XII. Pons 5-8. Generally, lateral nuclei are sensory while medial nuclei are motor.
Corneal reflex?
Afferent V1, efferent VII (orbicularis oculi)
Lacrimation reflex
Afferent V1, efferent VII.
Jaw jerk reflex
Afferent V3 (masster spindle), efferent V3 (masseter)
The vagal nuclei
Nucleus solitarius, nucleus ambiguus, dorsal motor nucleus
Nucleus solitarius
S for Sensory. Visceral sensory (taste, baro, gut distenstion. CN VII, IX, X.
Nucleus ambiguus
M for MOTOR - pharynx, larynx, upper esophagus. IX, X, XI.
Dorsal motor nucleus
Parasympathetics of heart, lungs, upper GI. CN X
Parotid, submandibular, and sublingual gland innervation?
Parotid = CN IX. Other two are CN VII.
Superior orbital fissure
CN III, IV, V1, VI, opthalmic vein, sympathetic fibers. Standing room only, but the spinster is meningeal.
Foramen rotundum
CN V2 = Standing room only, but the spinster is meningeal.
Foramen ovale
V3. CN V = Standing Room Only, but the spinster is meningeal.
Foramen spinosum
Middle meningeal artery
Internal auditory meatus
CN VII, VIII
Jugular foramen
CN IX, X, XI, jugular vein
Hypoglossal canal
CN XII
What’s in the cavernous sinus?
CN III, IV, V1, V2, VI, post-ganglionic sympathetics.
Cavernous sinus syndrome
Opathlmoplegia , decreased corneal and maxillary sensation with NORMAL VISUAL acuity. CN VI common.
Middle ear ossicles
Malleus, incus, stapes
Rinne test
Abnormal in conductive hearing loss (Bone > air) but normal in sensorineural (air > bone).
Weber test
Localizes to affected ear in conductive hearing loss. Localizes to unaffected ear in sensorineural hearing loss.
Muscles of Mastication
Masseter, Temporalis, Medial pterygoid CLOSE. Only opener is lateral pterygoid. M’s munch. Lateral lowers.
Uveitis
Inflamation of anterior urea and iris. Sterile pus, conjuctival redness. Associated with sarcoid, RA, JIA, TB, HLA-B27
Hyperopia vs. myopia vs. presbyopia?
Myopia = short-sighted b/c eye is too long (football!). Hyperopia = far-sighted b/c eye is too compressed. Presbyopia = decreased focusing ability during accommodation 2/2 sclerosis and decreased elasticity
Retinitis
Retinal edema and necrosis that can lead to a scar. Often viral and associated with immunosuppresion.
Central retinal artery occlusion
Acute, PAINless, monocular vision loss. Cloud retina and cherry-red spot at the fovea.
Retinal vein occlusion
Retinal hemorrhage and edema
Diabetic retinopathy
Non-proliferative type is due to leakage of of blood, lipids, and fluid (tx w/ blood sugar control and macular laser). Proliferative type is due to angiogenesis b/c of chronic hypoxia (tx w/ peripheral retinal photocoagulation, anti-VEGF injections)
Aqueous humor pathway
Ciliary epithelium produces aqueous humor (Beta stimulation). Aqueous soln moves through posterior chamber in the space between the iris and the lens, then moves into the anterior chamber where it is collected via trabecular meshwork into the Canal of Schlemm.
Glaucoma
Optic disc atrophy and progressive PERIPHERAL visual field loss associated w/ increased IOP
Open angle glaucoma
Associated with in creased age, AA, family. Painless. Primary - unknown. Secondary - blocked trabecular meshwork b/c of WBC’s (uveitis), RBCs (vitreous hemorrhage), retinal elements (retinal detachment)
Closed/narrow angle glaucoma
Primary - enlargement or forward movt of lens against the central iris leads to OBSTRUCTION of aqueous flow. Fluid build-up behind iris also pushes peripheral iris against cornea to impede trabecular meshwork flow. Secondary - hypoxia from retinal disease induces a vasoproliferation in the iris that contracts the angle. Acute closure from increased IOP is PAINFUL, frontal headache. No Epi b/c mydriatic.
Cataract
Painless often b/l opacification of the lesion. RF include age, smoking EtOH, excessive sunlight, cortico, classic galatosemia, galactokinase deficiency, DM, trauma, infection
How does miosis happen?
Edinger-Wetphal nucleus to ciliary ganglion piggy-backing CN III. After synapse, short ciliary nerves to pupillary sphincter
How does mydriasis happen?
From hypothalamus to ciliospinal center of Budge (C8-T2!). Exit T1 to superior cervical ganglion. Then move through plexus on internal carotid, through cavernous sinus, through long ciliary nerve to pupillary dilators
Pupillary light reflex
From retina to CN II to pretectal nuclei - activates b/l Edinger-Westphal -> miosis.
Marcus Gunn pupil
Afferent pupillary defect
Cranial nerve III anatomy
Is fed from outside in. Motor components INSIDE are vulnerable to DM. Parasympathetic output (outside) are vulnerable to compression (blown pupil)
Internuclear opthalmoplegia
lesion in MLF leads to lack of coordination between eyes.. CN III talking to opposite CN VI. So, when Left eye moves left and right eye does not, the R oculo III isn’t syncing with L abducens, so it is the Right MLF that is NOT working. (III is priority) for a Right INO (refers to eye that is paralyzed)
Ciliary muscle, pupillary dilator, pupillary sphincter, ciliary epithelium innervation?
Cholinergic (parasympathetic) M3’s for sphinter and ciliary muscle. Alpha-1 for dilator. Beta for ciliary epithelium
Entacapone
A Catechol-O-methyl-transferase (COMT) inhibitor that helps increase the bioavailability of levodopa by inhibition PERIPHERAL methylation. Tolcapone does both peripheral and central but associated with hepatotoxicity.
Carbamazepine mech and SE’s?
Blocks voltage-gated Na+ channels in cortical neurons. Bone marrow suppression, hepatotoxic, SIADH.
Two major mechs of diabetic neuropathy?
Glycoslyation leads to thickness, hyalinization, and narrowing of arterial walls -> ischemic damage. Accumulating glucose as sorbital -> inc. cell osmolarity -> osmotic dmg to axons and Schwann cells. Retina, renal papilla, and scwhann cells have DEC. activity of sorbitol dehydrogenase, which prevents clearance of sorbitol into fructose.
Genetics affecting course of Alzheimers?
Early onset associated with APP (21), presenilin-1 (14), and preseinili-2 (1). Late onset with ApoE4 (19). ApoE2 (19) appears to be protective
Senile plaques vs. neurofibrillary tangles
Senile plaques are extracellular Beta-amyloid core. amyloid-Beta comes from cleavage of amyloid precursor protein (APP). Neurofibrillary tangles are INTRAcellular, hyperphosphorylated TAU protein = insoluble. Tangles correlate to degree of dementia.
Frontotemporal dementia vs. Lewy body dementia
Personality and parkinsonian vs. Visual hallucination -> parkinsonian. Pick bodies (spherical tau protein aggregates) + fonrtotemporal atrophy vs. alpha-synuclein defect.
Acute inflammatory demyelinating polyradiculopathy
Most common Guillan-Barre variant. Autoimmune condition associated w/ infection (Campy and CMV) -> destruction of Schwann cells leading to a simmering ascending muscle weakness/paralysis starting from lower extremities. Autonomic findings! Tx - respiratory support, plasmapheresis, IVIG. LP shows increased protein with NORMAL cell count and increased protein.
PML
Progressive multifocal leukoencephalopathy. Destruction of OLIGO’s associated with JC. Found in AID’s and inc. risk with natalizumab (MS drug). Usu. fatal.
ADEM
Acute disseminated encephalomyelitis. After infection (measles, VZV) or vaccination (rabies, smallpox), multifocal perivenular inflammation and demyelination
Metachromatic leukodystrophy
AR, arylsulfatase A deficiency -> buildup of sulfatides -> impaired myelin sheet production -> central and peripheral demyelintation with ATAXIA and dementia. Many-colored Arya becomes ataxic in the sulfur pits.
Charcot-Marie-Tooth
Progressive hereditary nerve disorder 2/2 defective protein production for structure or function of peripheral nerves or myelin. Typically AD, scoliosis, high or flat arches
Krabbe disease
Galactocerebrosidase (Gaucher is glucocerebrosidase) -> buildup of galactocerebroside and pyschosine -> myelin destruction -> peripheral neuropathy, dvpt delay, optic atrophy, globoid cells. Krabs are delayed.
Adrenoleukodystrophy
X-linked! Metabolism of VLCFA’s -> buildup in nervous, adrenals (crisis), testes. ADRENO! luekodystrophy.
Status epilepticus
Continuous seizure for > 30 minutes or recurrent sz without regaining consciousness between sz. Emergency
Myoclonic vs. tonic-clonic vs. tonic vs. atonic sz.
Myoclonic are quick, repetitive jerks while tonic-clonic are grand mal alternating stiffening and movement. Tonic sz = stiffening. Atonic sz = “drop” sz.
Etios of sz for children?
Genetic, infection (febrile), trauma, congenital, metabolic
Cluster vs. Tension vs. Migraine HA’s regarding DURATION
Cluster - 15min-3 hrs repetitive. Tension HA > 30 min and constant. Migraines are 4-72 hours.
Cluster HA vs. trigeminal neuraglia
TN produces repetitive shooting pain in distribution of CN V typically lasting < 1 min. Cluster HA pain is > 15 min.
Tx for cluster headaches?
Inhaled oxygen and sumatriptan vs. analgesics or amitriptyline for chronic pain
Peripheral vs. central vertigo
Peripheral is more common (inner ear etio). Positional testing leads to a delayed horizontal nystagmus. Central is brain stem or cerebellar with directional change of nystagmus, dipolopia, dymetria, immediate nystagmus with positional testing
Sturge-Weber
Sporadic, port-wine Stain, Tram track, Unilateral, Retardation, Glaucoma, GNAQ, Epilepsy. (SSTURGGE). Activating mut -> dvpt anomaly of neural crest derivatives. Port-winte in V1/V2 distribution. Ispsi leptomeningeal angioma -> sz/epilepsy. Congenital NON-inherited. GNAQ sporadic.
Tuberous sclerosis
HAMARTOMAS = Hamartomas in CNS/skin, Angiofibromas, MR, Ash-leaf spots, cardiac Rhabdomyoma, TS, autosomal dOminant, Mental retardation, renal Angiomyolipomas, Sz, Shagreen patches. Increased subependymal astrocytomas.
NF-1
Cafe-au-lait, Lisch nodules, NF’s in skin, optic gliomas, pheochromocytomas. NF1 is a tumor suppressor gene (Ras regulator) on chromosome 17.
VHL
Cavernous hemangiomas in skin, mucosa, organs, b/l RCC, hemangioblastoma in retina, brainstem, cerebeullum, and pheochromocytomas. AD. VHL is tumor suppressor on chromsome 3 -> constitutive HIF (transcription factor) expression -> angiogenic growth factors
Gliobastoma multiforme
Hemispheres, “Butterfly glioma,” Astrocytes stain’d for GFAP, pseudopalisading pleomorphic tumor cells with central areas of necrosis
Meningioma
Arachnoid cells, EXTRA-exial. Dural-tail. Often asymptomatic with sz or focal neuro. Path w/ spindle cells concentrically and Psammoma bodies
Hemangioblastoma
VHL associated when w/ retinal angiomas. Cerebellar. Often produce EPO => secondary polycythemia. Path - closely arranged, thin-walled caps with minimal parenchyma
Schwannomas
Cerebellopontine angle. Schwann cell. S100 POS. B/l acoustic schwannomas found in NF-2.
Oligodendoglioma
Rarer, slower growing. Frontal lobe. Path - fried egg cells (oligo’s) and chicken-wire capillary pattern. Often calcified.
Pilocytic astrocytoma
In children, often found in posterior fossa. Well-circumscribed. Benign w/ good prognosis. Path - GFAP POS, Rosenthal fibers (corkscrew, eosinophilic), cystic on gross.
Medulloblastoma
PNET. Highly malignant cerebellar. Compress 4th ventricle; Drop metastases into spinal cord. Path - Homer-Wright rosettes. Solid, small blue cells.
Ependymoma
Usu. FOURTH ventricle. Hydrocephalus. Poor prognosis. Path - perivascular rosettes. Rod-shaped blepharoplasts (basal ciliary bodies) near nucleus.
Craniopharyngioma
Most common childhood supratentorial tumor derived from Rathke’s pouch (evagination of ectoderm that lines fetal oral cavity -> adenohypophysis; neurohypophysis from neuroectoderm). Often calcified. CYSTS filled with yellow, viscous fluid rich in cholesterol crystals.
Uncal herniation
Ipsilateral CN III (blown and down and out), ipso PCA (contralateral homonymous hemianopsia), contralateral crus cerebra (ipsi paralysis)
Adrenergic glaucoma drugs
Epinephrine decreases aqueous humor synthesis via vasoconstriction (se of mydriasis so don’t use in closed-angle). Brimonidine (alpha-2, decreases synthesis) w/ se of blurry vision, hyperemia, foreign body sensation, allergy, ocular. The beta-blockers are timlol, betaxolol, and carteolol.
Cholinomimetics used for glaucoma
Direct (pilocarpine, carbachol) and indirect (physostigmine, echotiophate). Contract ciliary muscle and open trabecular meshwork to increase outflow. SE include miosis and cyclospasm.
Prostaglandin used for glaucoma
Latanoprost (PDG2alpha) increases aqueous humor outflow and browns the iris.
Mechanism of opioid analgesics
Opioid receptors (mu = morphine, delta = enkephalin, kappa = dynorphin) to open K+ channels, close Ca2+ channels -> DECREASED synaptic transmission. Inhibit release of ACh, NE, 5-HT, glutamate, and substance P.
Butorphanol
PARTIAL mu-opioid receptor agonist and kappa-opioid receptor agonist. Used for severe pain (migraine and labor) with LESS reparatory depression. H/e, withdrawal symptoms if patient on full opioid agonist. Overdose hard to reverse with naloxone.
Tramadol
VERY weak opioid agonist that also inhibits 5-HT and NE reuptake. Chronic pain. Similar tox profile as opioids, decreases sz threshold, serotonin syndrome.
Ethosuximide
Absence sz. Blocks t-type Ca2+ channels in thalamic neurons. SE’s fatigue, GI, HA, Itching, Stevens-Johnson
1st line acute tx for status vs. 1st line ppx for status?
Benzos (diazepam, lorazepam) vs. Phenytoin
Phenytoin
1st line tonic-clonic and ppx for status. Na+ channel inactivation. 0-order kinetics. Induces P450. Lots of SE (nystagmus, dipolpia, gingival hyperplasia, teraogeneis w/ fetal hydantoin syndrome, ale-like). Fosphenytoin is IV.
Carbamazepine
1st line for simple, complex, tonic-clonic sz, and trigeminal neuralgia. Na+ channel inactivation. SE diplopia, ataxia, blood dyscrasia, liver, teratogenesis, induces P-450, SIADH, Stevens
Valproic acid
1st line for tonic clonic. Used for partial sz and absence. Na+ channel inactivation and inhibition of GABA transaminase to increase GABA. GI, hepatotoxicity (rare but fatal, Neural tube defects, tremor, wt gain. Myoclonic sz and bipolar.
Gabapentin
Partial and tonic-clonic, peripheral neuropathy, postherpetic neuralgia, migraine ppx, bipolar. Inhibits high-voltage activated Ca2+ channels. SE - sedation and ataxia
Phenobarbital
Partial, tonic-clonic. Increases GABA action. 1st-line for neonates! sedation, tolerance, induce P-450, CV dep.
Topiramate
Partial and tonic-clonic. Blocks Na+ channels and increases GABA. Migraine prevention. Sedation, mental dulling, kidney stones, wt loss.
Lamotrigine
Partial, tonic-clonic, absence. Blocks voltage-gated Na+. Stevens-Johnson syndrome.
Levetiracetam (Keppra)
Partial, tonic-clonic. Unknown mech. No SE’s noted.
Barbiturates - Mech and Tox
Increase DURATION of Cl- channel opening (GABA), decrease neuron firing. Contra’d in porphyria. Used for anxiety, sz, insomnia, induction of anesthesia (thiopental). Tox - CV depression, dependence, induces P450. Overdose tx is supportive. “Barbies are durable.”
Benzos - Mech and Tox
Increase FREQUENCY of Cl- channel opening. Decreases REM sleep. Tox - dependence, CNS depression with alcohol, but less resp depression than barbiturates. Tx overdose w/ flumazenil. “Ppl that buy Benz’s (and do benzos) are flippant.”
Nonbenzo hypnotics - mech and tox
Zolpidem, Zaleplon, Eszopiclone. Act on BZ1 subtype of GABA receptor. Tox - ataxia,HA, confusion. Short duration b/c rapidly metabolized by LIVER. dec. dependence
What properties of anesthetics do we care about?
Solubility in lipids and blood. MAC - minimal alveolar concentration req. to prevent 50% from moving in response to noxious stimuli. Inc. solubility in lipids = greater potency (lower MAC). Inc. solubility to blood = slower cross to CNS = slower induction and recovery
Toxicities of inhaled anesthetics
Heptotoxicity (halothane), nephrotoxicity (methoxyflurance), proconvulsant (enflurane), expansion of trapped gas in body cavity (NO). All of these except NO and the addition of succinylcholine can cause malignant hyperthermia which is life-threatening HEREDITARY condition with fever and severe muscle contractions. Tx = dantrolene
IV anesthetics
Barbiturates, Benzos, Ketamine, Opioids, Propofol
Propofol
Sedation in ICU, rapid anethesia induction, short procedures. Less postop nausea than thiopental. Potentiates GABA.
Thiopental
IV barbiturate of high potency and rapid entry into brain. Induction and short surgical procedures. Rapid redistribution into skeletal muscle and fat (recovery quick). Decreased cerebral blood flow
IV midazolam
Commonly used for endoscopy. Used w/ gaseous anesthetics and narcotics. May cause severe post-op respiratory depression, decreased pressure, and anterograde amnesia
Ketamine
PCP analog that blocks NMDA (dissociative anesthetic). CV stimulant. Disorientation, hallucination, bad dreams. Inc. cerebral blood flow.
Local anesthetics
Amides are lidocaine, mepivacaine, bupivacaine. Esters are procain, cocaine, tetracaine.
Mech of local anesthetics
Block Na+ channels (inner portion) and preferentially bind to activated ones. Tertiary amines penetrate membrane uncharged, then after charge, bind ions.
Factors affecting the effectiveness of local anesthetics?
It’s hard for charged, alkaline anesthetics to get into infected (acidic) tissue. Order of nerve blockade small diameter > large diameter. Then myelinated > unmyelinated. Lose pain, temp, touch, then pressure. Can give with vasoconstrictors like epi to enhance local action via dec bleeding and dec. systemic conc.
Local anesthetic toxicity
CNS excitation, CV tox (bupivacaine), HTN, hypotension, arrhythmias (cocaine)
Basic overview of paralytics
Used for surgery or mech ventilation. Selective for motor nicotinic receptors. Depolarizing vs. nondepolarizing = agonist vs. competetive antagonist
Succinylcholine
Strong ACh receptor agonist -> sustained depolarization and prevents muscle ctx. Complications - hyperCa, hyperK, malignant hyperthermia. Phase 1 block is prolonged depol. w/ no antidote. Phase 2 block is repolarized but AChR desensitized and req. cholinesterase inhibitors. Patients with hyperK (crush/burn, denervating injuries, myopathies) -> depolarizing agents
Dantrolene
Ryanodine receptor. Prevents release of Ca2+ from SR in skeletal muscle. Used for malignant hyperthermia and NMS.
Parkinsons drugs
BALSA = Bromocriptine, Amantadine, Levodopa, Selegiline, Antimuscarinics.
Selegeline
MAO-B inhibitor that prevents DA breakdown (MAO-B prefers to breakdown DA > NE and 5-HT). Other DA breakdown inhibitors are COMT inhibitors (entacapone and tolcapone)
Benztropine
Curbs excess cholinergic activity in Parkinsons as an antimuscarinic.
Memantine
Alzheimer’s drug. NMDA receptor antagonist. Tox includes dizziness, confusion, hallucinations
AChE inhibitors for Alzheimer’s
Donepezil, galantamine, rivastigmine.
HD drugs
Haloperidol (DA receptor antagonist). Inhibitors of vesicular monoamine transporter (VMAT) - tetrabenazine and reserpine.
Sumatriptan
5-Ht1b/1d agonist. Inhibits treigeminal n. activation and prevents vasoactive peptide release. t1/2 <2hrs. Used for acute migraines and cluster headaches. Tox = coronary vasospasm CONTRA = CAD or Prinzmetal angina
Myotonic muscular dystrophy
Myotonia = slow relaxation of muscles. Difficulty loosening one’s grip. AD. CTG (myotonia-protein kinase). Anticipation. Cataracts. Atrophy of type 1> type 2.
Meniere’s disease
Increased volume of endolymph. Tinnitus, vertigo, hearing loss is sensorineural (Weber will lateralize to HEALTHY side)
Fluorinated anesthetics effect on CV, Resp, Cerebral blood flow, Kidney, hepatic blood flow?
Myocardial depression leads to decreased CO. Hypotension. Respiratory depressant (dec. TV and minute ventilation -> hypercapnea and dec. mucociliary clearance). Halothane and sevolurane have bronchodilation prop’s - asthma. Decreased vascular resistance -> increased cerebral blood flow -> ICP. Dec. GFR, increased renal vascular resistance, and decreased RPF. Decreased hepatic blood flow.
How does solubility of anesthetic in peripheral tissues effect anesthetic concentration?
If peripheral tissue solubility is high (AV gradient high), then it takes more anesthesia to saturate the blood and the brain.
How does pulmonary ventilation rate affect anesthetic concentration?
Rise of gas tension in alveoli is proportional to the rate AND depth of respiration.
How does the blood/gas partition coefficient affect the action of anesthetics?
Higher blood/gas partition coefficient means highly SOLUBLE –> blood saturates slowly leading to delayed rise in partial pressure -> increasing onset of time. (e.g. halothane)
MS path
Plaques. Demyelination w/ relative preservation of axons. Accumulation of lipid-laden macrophages. Astrocytosis. Infiltration by lymphocytes and mononuclear cells.
Pheochromocytoma
PNET tumor of chromatin cells of sympathetic nervous system (90% from adrenal medulla).
HD location
AD 100% penetrance. Loss of neurons in caudate nucleus and putamen (striatum). STN lesion = hemiballismus.
Side effects for 1st gen antipsychotics?
Generally, low-potency (Chlorpromazine and thioridazine) have more non-neuro SE’s (sedation, Antichol, orthostatic hypotension). High-potency (haloperidol, fluphenazine) will have EPS - acute dystonia, akathisia, parkinsonism.
Congenital torticollis
Etio - birth trauma or malposition of head in utero -> SCM injury and fibrosis. Develops by wk 2-4. Head tilted toward AFFECTED side with CHIN pointed AWAY. Good prognosis. Tx = conservative and stretching
Alcoholic cerebellar degeneration
Chronic thiamine deficiency. Gait ataxia, truncal instability, intention tremor. Atrophy of anterior lobes and cerebellar vermis.
Two ways that tumors increase ICP?
Blockage. Breakdown of the BBB.
How does NPH lead to urinary incontinence?
Disrupts paraventricular fibers from cortex which normally inhibit the SACRAL micturition center (responsible for bladder contraction and found in S2-S4 level)
Causes of exacerbations of myasthenia gravis?
(1) Myasthenic crisis 2/2 not enough Ach in cleft (e.g. not enough drug). Dx with edrophonium improvement. (2) Cholinergic crisis 2/2 TOO much Ach -> refractory muslce. Dx with no improvement with edrophonium.
Neuroblastoma
Most common extra cranial cancer of children. Found in any neural crest deviated. Associated with N-myc. Paraneoplastic syndrome includes opsoclonus and myoclonus. Often see increased excretion of catecholamines in urine.
Protein 14-3-3
CSF protein helpful in diagnosing Cretuzfeldt-Jakob
Narcolepsy CSF findings?
Decreased hypocretin-1 (orexin-A) and hypocretin-2 (orexin-B)
Arachnoid granulations vs. choroid plexus?
Choroid plexi MAKE CSF. Arachnoid granulations ABSORB CSF. Communicating hydrocephalus 2/2 dysfunction of subarachnoid villi (e.g. meningeal infection or SAH)
Length constant vs. time constant?
Length constant = how far down an axon an AP can go. Time constant = how quickly it takes for a membrane to reset. Myelination increases length constant and decreases time constant.
