Neurology Flashcards
Neural tube development
1) Notochord induces ectoderm to differentiate into neuroectoderm and form neural plate
2) Neural plate gives rise to neural tube and neural crest cells
3) Notochord becomes nucleus pulposus of intervertbral disc
Alar plate- dorsal, sensory
Basal plate- ventral, motor
Regionalization of the brain
PRimary vesicles: prosencephalon (forebrain), mesencephalon (midbrain), rhombencephalon (hindbrain)
Secondary vescles
-prosencephalon – telencephalon (cerebral hemispheres and lateral venticles) and diencephalon (thalamus and third ventricle)
-mesencephalon – midbrain and cerebral aqueduct
rhombencephalon –metencephalon (pons and cerebellum) and myelencephalon (medulla); both contribute to fourth ventricle
Neuroectoderm derivatives
CNS neurons, epednymal cells that line the ventricles and make CSF, oligodendroglia, astrocytes
Neural crest derivatives
PNS neurons and schwann cells
mesoderm derivatives
microglia (hematopoietic lineage)
Testing for neural tube defects
Elevated AFP in maternal serum and amniotic fliud
Elevated AChE in amniotic fluid
Spina bifida occulta
Failure of bony spinal canal to close without any structural herniation and with dura intact. AFP is normal. Least severe neural tube defect.
Meningocele and Meningomyelocele
Meningocele: meninges only herniate through bony defect
Meningomyelocele: meninges and nural tissue hernate through bony defect; associated with chiari II malformation
both have risk of ascending infection
Look like plaquode on skin
Holoprosencephaly
Not a neural tube defect. Failure of left and right hemispheres to separate. Can be caused by sonic hedgehog mutations. Associated with Patau syndrome and FAS. Associated with cleft palate/lip, cyclopia
Chiari II
Hernation of cerebellar tonsils and vermis through foramen magnum. Aqueductal sternosis and hydrocephalus as result. Meningomyelocele (neural tube defect) is associatd
Dandy Walker malformation
Agenesis of cerebellar vermis with cystic enlargement of the fourth ventricle. Associated with hydrocephalus and spina bifida
Syringomyelia
Cystic cavity in spinal cord. Typicall damages corssing anterior spinal commisurral fibers leading to cape like loss of pain and temp in upper extremities. Associated with chiari I
Chiari I malformation
Cerebellar tonsils herniate. Associated with syringomyelia. Usually asymptomatic in childhood
Tongue development
1st and second branchial arches: anterior 2/3 with sensation from V3, taste from VII
3rd and 4th arches form posterior 1/3 with sensation and taste from IX and X
Motor from X (palatoglossus) and XII (all others)
Nissl stain
Stains RER and can be used to visualize cell bodies and dendrites of neurons. Doesn’t stain axon as RER is not present: proteins are synthesized in the cell body and transported down the axon
Wallerian degeneration
In response to axonal injury, the nerve degenerates distal to the injury and the axon retracts proximally, allowing for regeneration if in the PNS. Regeneration occurs slowly over weeks to months.
Astrocytes
Functions: physical support, repair, potassium metabolism, removal of excess neurotransmitter (take up glutamate and convert to glutamine), component of BBB, reactive gliosis in response to neuronal injury, match cerebral blood flow to synaptic activity
Marker: GFAP
Derivative of neuroectoderm
HIV in the brain
Infect microglia, which fuse to form multinucleated giant cells in the CNS
Scwann cells
Each Schwann cell myelinates 1 PNS axon. Promote axonal regeneration. Derived from neural crest
Oligodendroglia
Myelinate axons of CNS. Each oligodendrocyte can myelinate many axons. Derived from neuroectoderm. Fried egg appearance
Types of sensory receptors: free nerve endings, meissner corpuscles, pacinian corpuscles, merkel discs, ruffini corpuscles
Free nerve endings: Carry pain on C fibers, temp on Adelta fibers. Located in skin and seome viscera
Meissner corpuscles: Carry fine touch and position on large myelinated fibers that adapt quickly. Found on hairless skin
Pacinian corpuscles: Carry vibration and pressure on large myelinated fibiers that adapt quickly. Found in deep skin layers, ligaments, and joints.
Merkel discs: Carry pressure, deep touch, and position on large myelinated fibers that adapt slowly. Found in fingertips and superficial skin
Ruffini corpuscles: Carry pressure information on slow adapting dendritic endings within the capsule
Layers of a peripheral nerve
Endoneurium: surrounds single nerve fibers
Perineurium: surround fasicle of nerve fibers
Epineurium: dense connective tissue surrounding entire nerve
Location of neurotransmitter synthesis: NE, DA, 5-HT, ACh, GABA
NE: locus ceruleus of the pons Dopamine: ventral tegmentum and substantia niagra of midbrain 5-HT: Raphe nuclei in brainstem ACh: Basal nucleus of Meynert GABA: nucleus accumbens
Components of BBB
- Tight junctions between nonfenestrated capillary endothelial cells
- Basement membrane
- Astrocyte foot processes
OVLT
Area of hypothalamus not protected by BBB that senses changes in osmolarity.
Area postrema
Area of hypothalamus not protected by BBB that responds to emetics
Supraoptic nucleus
Part of hypothalamus that makes ADH
PAraventricular nucleus
Part of hypothalamus that makes oxytocin
Hypothalamus: lateral, ventromedial, anterior, posterior, suprachiasmic nucleus
Lateral area: hunger, inhibited by leptin
Ventromedial area: Satiety, stimulated by leptin
Anterior hypothalamus: Cooling, parasympathetic
Posterior hypothalamus: Heating, sympathetic
Suprachiasmic nucleus: Circadian rhythm
Circadan rhythm
Controlled by suprachiasmic nucleus. Drives nocturnal release of ACTH, prolactin, melatonin, norepinephrin.
Effect of CNS depressants on sleep
EtOH, benzos, and barbs decrease REM sleep and delta wave sleep
Pathology of different sleep stages
Non-REM stage N2: bruxism (teeth grinding)
Non-REM stage N3: sleepwalking, night terrors, bed wetting
Thalamic nuclei
VPL: Spinothalamic tract and dorsal column relay to sensory cortex
VPM: Trigeminal and taste relat to sensory cortex
LGNL Received vision info from CNII and sends to calcarine sulcus
MGN: Reveives auditory info from sup olive and inf collicular and sends to auditory cortex
VL: Reveives motor info from basal ganglia and cerebellum and relays to motor cortex
Limbic system
Includes hippocampus, amygdala, fornix, mamillary bodies, and cingulate gyrus
Central pontine myelinolysis
Result of overly rapidly correcting hyponatremia. Results in acute paralysis, LOC, locked in syndrome
Pathways through basal ganglia
Excitatory: Cortical inputs stimulate striatum; striatum stimulates release of GABA which disinhibits the thalamus via GPi/SNr
Inhibitors: Cortical inputs stimulate striatum, disinhibits STN via GPe, STN stimulates GPI/SNr to inhibit thalamus.
Dopamine receptors
D1: stimulates excitatory pathway
D2: inhibits inhibitory pathway
both increase motion
Hemiballismus
Decreased activity of subthalamic nucleus decreasing GPint activity, increasing thalamic activity and causing flailing. Sudden wild flailing of 1 arm and sometimes ipsilateral leg due to damage to contralateral subthalamic nucleus
Athetosis
Slow writhing movements of the fingers seen with lesions to basal ganglia, such as in Huntington
Treatment of essential tremor
beta blcokers
primidone
Myoclonus
Sudden, brief, uncontrolled muscle contraction seen iwth metabolic abnormalities
Pathology of PD
Lewy bodies of alpha synuclein which have intracellular eosinophilic inclusions. Loss of dopaminergic neurons of substantia niagra
Neurotransmitters in HD
DA increased
GABA decreased
ACh decreased
Broca aphasia
Nonfluent aphasia with intact comprehension, impaired repetition.
Broca area in inferior frontal gyrus of frontal lobe
Wernicke aphasia
Fluent aphasia with impaired comprehension and repetition.
Wernicke area is in superior temporal gyrus of termporal lobe
Conduction aphasia
Poor repetition but fluent speech and intact comprehension
Can be caused by damage to arcuate fasciculus
Global aphasia
Nonfluent aphasia with impaired comprehension
Transcortical motor aphasia
Nonfluent, good comprehension, intact repetition
Transcortical sensory aphasia
Poor comprehension, fluent speech, intact repetition
Mixed transcortical aphasia
Nonfluent speech, poor comprehension, intanct repetition
Kluver Bucy syndrome
Bilateral damage to amygdalae. Disinhibited behavior with hyperphagia, hypersexuality, hyperorality. Associated with HSV-1
Frontal lobe lesions
Cause disinhibition, problems with concentration, orietnation, judgement, possible reemergence of primitive reflexes
Parietal-temporal cortex lesions
Nondominant: hemispatial neglect syndrome
Dominant: Gerstmann syndrome of agraphia, acalculia, finger agnosia, left-right disorientation
Reticular activating system lesions
Reduced levels of arousal and wakefulness
Wernicke-Korsakoff syndrome
Pathology: affects mammillary bodies
Presentation: confusion, ophthalmoplegia, ataxia, memory loss, personality changes, confabulation
Basal ganglia lesions
Resting tremor, chorea, athetosis
Cerebellar lesions
Hemisphere: Intention tremor, limb ataxia, loss of balance. Ipsilateral defects; fall toward side of lesion
Vermis: Truncal ataxia, dysarthria
Hippocampal lesions
Anterograde amnesia
Defects to paramedian pontine reticular formation vs frontal eye fields
Paramedian pontine reticular formation: eyes look away from side of lesion
Frontal eye fields: eye look toward lesion
Regulation of cerebral perfusion
Driven by Pco2. Po2 modulates only in severe hypoxemia. Increased Pco2 increases cerebral perfusion pressure. Decreased O2
Therapeutic hyperventilation
Decreases Pco2 which helps to decrease intracranial pressure in acute cerebral edema via vasoconstrtion (brain thinks it has plenty of oxygen if CO2 is low). Hypventilation in panic attacks decreases perfusion leading to fainting.
Cerebral perfusion pressure
CPP = MAP - ICP
So, hypotension or incresaed intracranial pressure can decrease cerebral perfusion
Presentation of MCA stroke
Can get contralateral paralysis of upper limb and face due to effect on motor cortex
Can get contralateral sensory loss of uppper limb and face due to effect on sensory cortex
Can get aphasia or hemineglect due to effect on ermporal lobe and frontal lobe
Presentation of lenticulostriate artery stroke
Affects striatum and internal capsule. Contralateral hemiparesis/hemiplegia. Often lacunar infarct secondary to unmanaged hypertension
Presentation of anterior spinal artery stroke
Affects lateral corticospinal tract: contralateral hemiparesis of upper and lower limbs
Affects medial lemniscus: loss of contralateral proprioception
Affects caudal medulla: ipsilateral hypoglossal dysfunction with tongue deviating ipsilaterally
Presentation of PICA stroke
Affects lateral medulla: vomiting, vertigo, nystagmus due to cerebellar dysfunction and effect on vestibular nuclei. Decreased pain and temp sensation from ipsilateral face, contralateral body due to effect on lateral spinothalamic tract. Dysphagia and hoarseness due to effect on nucleus ambiguus. Ipsilateral horner syndrome due to effect on sympathetic fibers
Presentation of AICA stroke
Affects lateral pons including middle and inferior cerebellar peduncles. Presents with vomiting, vertigo, nystagmus, face paralysis, ataxia, dysmetria
Presentation of PCA stroke
Affects occipital cortex and visual cortex. Contralateral hemianopia with macular sparing
Presentation of basilar artery stroke
Locked in syndrome. Preserved consciousness and blinking with quadriplegia and loss of mouth, face, tongue movements
Presentation of anterior communicating artery stroke
Most often due to aneurysm. Presents with visual field defect
Presentation of posterior communicating artery stroke
Saccular aneurysms. CNIII palsy.
Saccular aneurysms
Also called berry aneurysms. Occur at bifurcations of circle of willis, most commonly junction of ACA and ant comm a. Rupture leads to SAH or hemorrhagic stroke. May compress optic chiasm.
Diseases associated with saccular aneurysms
ADPKD, Ehlers-danlos
Charcot-Bouchard microaneurysm
Associated with chronic HTN. Affects small vessels of basal ganglia and thalamus
Central post-stroke pain syndrome
Neuropathic pain due to thalamic lesions. Parasthesias followed by allodynia and dysesthesia
Epidural hematoma
Caused by middle meningeal artery rupture secondary to fracture. Classic lucid interval followed by expansion and transtentorial herniation with CNIII palsy. Biconvex blood collection that doesn’t cross suture lines, can cross falx, tentorium
Subdural hematoma
Caused by rupture of bridging veins. Slow venous bleeed over time. Seen in eldery, alcoholics, blunt trauma, shaken baby. Crescent shaped hemorrhage that crosses suture lines. Cannot cross tentorium
SAH
Caused by rupture of an aneurysm or AVM. Rapid ime course. Worst headache of life. Bloody or yellow spinal tap. Risk of vasospasms 2-3 days afterward due to blood breadown and rebleed
Intraparenchymal hemorrhage
Associate dwith systemic HTN or amyloid angiopathy, vascultitis, neoplasm. Basal ganglia and internal capsule are most common locations
Ischemic brain diesease
irreversible damage 5 mins of hypoxia. Hippocampus, neocorex, and cerebellum most vulnerable.
Imaging: noncontrats CT to exclude hemorrhage. Will detect ischemic changes in 6-24 hours. Diffusion-weighted MRI can detect ischemia much sooner
Histologic changes seen after ischemic stroke
12-48 hrs: red neurons 24-72 hrs: necrosis and neutrophils 3-5 days: macrophages/microglia 1-2 weeks: reactive gliosis and vascular proliferation over 2 wks: glial scar
CSF flow
Made by ependymal cells of choroid plexus. Flows from lateral ventricles through R and L interventricular foramina of monroe into 3rd ventricle, through cerebral aqueduct to 4th ventricle, into subarachnoid space through foramina of luschka (lateral) and foramen of magendie (medial). Reabsorbed by arachnoid granulations. Drains into dural venous singuses
Idiopathic intracranial HTN
Also called pseudotumor cerebri. Increased ICP without apparent cause on imaging. Presents with headaches and diplopia without mental status change. Papilledema present. Increased opening pressure on LP.
Risk factors: woman of childbearing age, vitamin A excess, danazol
Treatment: weight los, acetazolamide, topiramate
Normal pressure hydrocephalus
Idiopathic condition seen in elderly. CSF pressure elevated episodically. Expansion of ventricles, distorting fibers of corona radiata. Wet, wobbly, and wacky: urinary incontinence, ataxia, cognitive dysfunction
Ex vacuo ventriculomegaly
Appearance of increased CSF on imaging due to decreased brain tissue. Normal ICP
Spinal nerve naming
C1-C7 exit above corresponding vertebra. C8 exits below C7. Rest exit below their corresponding vertebra
Vertebral disc herniation
Nucleus pulposus herniates through annulus fibrosus.
Lower extension of spinal cord
Adults: lower border of L1-L2 vertebra. Subarachnoid space to loer border of S2. LP performed between L3/L4 or L4/L5
Medial lemniscus
Carries sensory fibers from the nucleus gracilis and cuneatus to LGN
Poliomyelitis
Destruction of anterior horns. LMN lesions only (flaccid paralysis). Replicates in oropharynx and sm intestine; then spreads to CNS by blood stream
CSF: increased WBCs and slight increased protein
Spinal muscular atrophy
congenital degeneration of anterior hormones. LMN lesions only (flaccid paralysis). Floppy baby with tongue fasciculations. AR inheritance
Multiple sclerosis effect on spinal cord
Demyelination mostly of white matter in cervical region. Random and asymmetric lesions
Riluzole
Glutamate antagonist used to treat ALS
Tabes dorsalis
Caused by tertiary syphilis. Degeneration of dorsal columns and nerve roots resulting in impaired sensation and proprioception and poor coordination. Absent DTRs, pos romberg
Vitamin B12 def - effect on spinal cord
Subacute combined degeneration: demyelination of dorsal columns, lateral corticospinal tracts, spinocerebellar tracts resulting in ataxic gait, paresthesia, impaired pos and vibration sense
Friedreich ataxia
AR GAA repeat on chromosome 9. Gene encodes iron binding protein frataxin. Leads to impairment of mitochondrial function.
Degeneration of spinal tracts resultingin weakness, loss of DTRs, vibratory sense, and proprioception.
Associated with diabetes and hypertrophic cardiomyopathy. Also kyphoscoliosis
Brown Sequard syndrome
Hemisection of cord. If above T1 can cause Horner syndrome as well as spinal cord findings
Key dermatomes: C2, C3, C4, T4, T7, T10, L1, L4, S2, S3, S4
C2: posterior half of skull cap C3: high turtleneck shirt C4: low collar shirt T4: nipple T7: xiphoid process T10: umbilicus L1: inguinal ligament L4: kneecap S2, S3, S4: erection and sensation of penis and anus
Pineal gland
Located above the superior colliculi. Responsible for melatonin secretion and circadian rhythms
Supeiror and inferior colliculi
Superior: conjugate vertical gaze
Inferior: auditory function
Locations of cranial nerve nuclei
Midbrain: III and IV
Pons: V, VI, VII, VIII
Medulla: IX, X, XII
Spinal cord: XI
Latearl nuclei are sensory, originating from alar plate
Medial nuclei are motor, originating from basal plate
Optic canal: what travels through
CNII, ophthalmic artery, central venous vein
Superior orbital fissure: what passes through
CNIII, IV, V1, VI (all nerve to eye except optic) + opthalmic vein and sympathetic fibers
Foramen rotundum
Carries CN V2
Foramen ovale
Carries CN V3
Foramen spinosum
Holds middle meningeal artery
Internal auditory meatus
Carries CN VII and VIII
Jugular foramen
Carries CN IX, X, XI, jugular vein
Hypoglossal canal
Carries CN XII
Foramen magnum
Carries spinal roots of CN XI, brainstem, vertebral arteries
Function of CN IV and XI
IV (trochlear) innervates superior oblique
VI (abducens) innervates lateral rectus
Sensation of tongue
Somatosensory for anterior 2/3: CNV
Taste for anterior 2/3: CNVII
Taste and somatosensory for posterior 1/3: CNIX
Taste from epiglottic region: CNX
Carotid and aoritc body monitoring
CNIX monitors carotid body and sinus chemo and baroreceptors
CNX monitors aortic arch chemo and baroreceptors
Nucleus solitarius
Visceral sensory information for CNVII, IX, X - taste, baroreceptors, gut distention
Nucleus ambiguus
Motor information for pharynx, larynx, upper esophagus. CNIX, X, XI
Dorsal motor nucleus
Autonomic fibers of CNX to heart, lungs, upper GI tract
Gag reflex
Afferent: IX
Efferent: X
Cavernous sinus
Collection of venous sinuses on either side of pituitary. Blood from eye and superficial cortex drains into cavernous sinus which drains into internal jugular vein.
CN III, IV, V1, VI pass through to get to orbit
Cavernous sinus syndrome
Ophthalmoplegia, decreased corneal sensation, Horner syndrome due to pituitary tumor mass effect, fistula, cavernous sinus thrombosis affecting nerves that pass through
Tonotopy of basilar membrane
Low freq heard at apex which is wide and flexible
High freq heard at base of cochlea which is thin and rigid
Test results for conductive vs senorineural hearing loss
Conductive hearing loss: Rinne test abnormal with bone greater than air. Weber test localizes to affected ear
Sensorineural hearing loss: Rinne test normal wiht air greater than bone conduction. weber localizes to unaffected ear
Noise induced hearing loss
Damages hair cells. Leads to loss of high freq hearing loss first
Cholesteatoma
Overgrowth of desquamated keratin debris within middle ear. May errode ossicles and mastoid air cells leading to conductive hearing loss
UMN vs LMN lesion of face
UMN: causes contralateral paralysis of the face. upper face is spared because it gets bilateral UMN innervation
LMN: causes ipsilateral paralysis of upper and lower face
Muscles of mastication
Masseter, temporalis, and medial pterygoid close the jaw
Lateral pterygoid opens
Aqueous humor pathway
Produrced by ciliary epithelium. Collected by trabecular meshwork, then goes into canal of schlemm to drain
Refractive errors: hyperopia, myopia, astigmatism, presbyopia
Hyperopia: eye too short; light focused behind retina
Myopia: eye too long; light focused in front of retina
Astigmatism: abnormal curvature of cornea
Presbyopia: age-related impaired acommodation due to decreased lens elasticity
Glaucoma
Opitc disc atrophy with cupping. Elevated IOP, progressive peripheral vision loss
Open angle glaucoma
Painless and more common. Associated with age, african america, famiy history. Can be secondary to blocked trabecular meshwork with WBCs, RBCs, retinal elements
Tetrodotoxin
Toxin found in puffer fish. Binds to NA+ channels, inhibiting influx
Morphine effect on ion channels
Binds to mu receptors and causes G protein coupled acivation of K+ channels to increase K+ efflux, hyperpolarizing post-synatpic neurons and terminating pain transmission
Kinesin
MT associated motor protein that does anterograde transport of intracellular vesicles and organelles toward plus end of MTs.
Valproate during pregnancy
Increases risk of neural tube defects because inhibits folic acid absorption
Length constant vs time constant
Length constant: How far long an axon an impulse can propagate. Increased by myelin so that conduction occurs faster.
Time constant: How long it takes for a change in membrane potential to occur. Reduced by myelination so that conduction occurs faster.
POMC
Polypeptide precursor that goes through enzymatic modification to produce beta endorphins, ACTH, and MSH
Tetrahydrobiopterin
BH4. Cofactor in synthesis of serotonin, DOPA, and tyrosine
CSF findings in MS
Increased protein in CSF - oligoclonal bands diagnostic
Treatment of MS
Disease modifying therapies: beta-interferon, natalizumab
Acute flares: IV steroids
Treatment of Guillan Barre
Respiratory support. Plasmapheresis. IVIG
Acute disseminated encephalomyelitis
Multifocal periventricular inflammation and demyelination after infection or certain vaccinations. Commonly seen after measles or VZV
Charcot-Marie-Tooth disease
Progressive hereditary nerve disorders due to defective protein production. AD inheritance. Associated with scoliosis and foot deformities
Krabbe disease
AR lysosomal storage disease due to def of galactocerebrosidase. Causes galactocerebroside to build up and destroy myelin. Presents with peripheral neuropathy, developmental delay, optic atrophy, globoid cells
Metachromatic leukodystrophy
AR lysosomal storage disease. Arylsulfatase A def. Central and peripheral demyelination with ataxia and dementia
Progressive multifocal leukoencephalopathy
Demyelination of CNS due to oligodendrocyte destruction. Associated with JC virus - seen in AIDS patients. Radpily progressive and fatal.
Adrenoleukodystrophy
X-linked genetic disorder. Disupted metabolism of VLCFA causing build up in NS, adrenal, testes.
Positional testing for nystagmus
Delayed horizontal nystagmus suggests peripheral (inner ear) vertigo
Immediate nystagmus in any direction suggests central vertigo
Sturge-Weber syndrome
Congenital anomaly of neural crest derivatives due to acivating GNAQ mutation. Affects capillaries leading to port-wine stain on face. Ipsilateral leptomeningeal angioma causes seizures. Intellectual disability. Episcleral hemangioma leads to elevated IOP and early onset glaucoma
Tuberous sclerosis
Hamartomas in CNS and skin. Angiofibromas Mitral regurg Ash-leaf spots Cardiac rhabdomyoma mental retardation renal angiomylolipoma seizures shagreen patches Autosomal dominant inheritance
Cancers seen with von hippel lindau
hemangioblastomas of retina, brain stem, cerebellum, and spine
angiomatosis
bilateral renal cell carcinoma
pheochromocytoma
Glioblastoma multiforme pathology
Found in cerebral hemispheres and can cross the corpus callosum. Stains positive for GFAP. Pseudopalisading, pleomorphic tumors cells: tumor cells border areas of necrosis and hemorrhage
Meningioma presentation and pathology
Presentation: Seizures or focal neurologic signs due to compression of brain tissue
Pathology: spindle cells in whorled paterns; psammoma bodies
Hemangioblastoma
Associated with VHL syndrome. Usually cerebellar. Can make EPO leading to polycythemia.
Schwannoma: location and tumor marker
Found at cerebellopontine angle. S-100 positive.
Oligodendroglioma
Slow growing, usually in frontal lobes. Fried egg cell appearance. Often calcified
Pilocytic astrocytoma
Well circumscribed posterior fossa tumor of childhood. GFAP +. Benign with good prognosis. Rosenthal fibers
Medulloblastoma histology
Homer-Wright rosettes. Solid small blue cells
Ependymoma
Ependymal cell tumor found in 4th ventcile. Can cause hydrocephalus. Poor pronosis. Perivascular rosettes on histology
Craniopharyngioma
Benign tumor of childhood in sella turcica. Presents with bitemporal hemianopia. Derived from Rathke pouch remnants. Commonly calcified
Cingulate herniation
Cingulate gyrus herniates under falx cerebri. Can compress ACA
Transtentorial herniation
Can displace brain stem leading to duret hemorrhages; usually fatal
Uncal hernation
Uncus herniates downward and compresses CNIII and PCA
Cerebellar tonsilar herniation
Herniates into foramen magnum. Can compress brainstem resulting in coma and death
MOA of opioids
Agonize opioid recetpors. Open K+ channels and close Ca++ channels to reduce synaptic transmission. Inhibit release of ACh, NE, 5-HT, glutamate, substance P
Butorphanol
MOA: kappa opioid agonist, mu opioid partial agonist
Less resp depression than full opioid agonist
Can cause withdrawal in someone also taking full agonist due to competition at mu receptor
Tramadol
MOA: weak opioid agonist; inhibits 5-HT and NE reuptake
Toxicity: decreased seizure threshold, serotonin syndrome
Ethosuximide toxicity
Itching, stevens johnson syndrome
Phenytoin: MOA, pharmacokinetics, side effects, use
MOA: Increases Na+ channel inactivation
Kinetics: 0 order kinetics
Side effects: gingival hyperplasia, P450 induction, stevens johnson
Use: First line for tonic-clonic seizures and prophylaxis of status epilepticus; can be used for everything except absence
Carbamazepine: MOA, side effects, use
MOA: Increases Na+ channel inactivation
Side effects: agranulocytosis and aplastic anemia, teratogenic, P450 induction, SJS
Use: First line for partial seizures and tonic-clonic seizures, first line for trigeminal neuralgia
Valproic acid: MOA, side effects, use
MOA: Increases Na+ channel inactivation, increases GABA
Side effects: hepatotoxicity, neural tube defects
Use: First line for tonic clonic seizures, effective against all seizure types. Myoclonic seizures, bipolar
Gabapentin: MOA, side effects, use
MOA: inbhits VG Ca++ channels
Side effects: sedation and ataxia
Use: Partial seizures, peripheral neruopaty
Phenobarbitol for seizures: MOA, side effects, use
MOA: Increases GABAa action
Side effects: sedation, tolerance and dependence, resp depression, P450 induction
Use: First line in neonatal seizures
Topiramate: MOA, side effects, use
MOA: blocks Na+ channels, increases GABA
Side effects: Sedation, mental dulling
Use: Partial and tonic-clonic seizures. Migraine prophylaxis
Lamotrigine
MOA: blocks VG Na+ channels
Side effects: SJS
Use: All seizure types, including absence
Levetiracetam use
Partial and tonic-clonic seizures
Tiagabine MOA and use
Inhibits GABA reuptake. Used for partial seizures
Vigabatrin
Increases GABA. Used for partial seizures
