Neurology Flashcards
what does the neural plate develop into?
neural tube and the neural crest cells
what does the notochord become?
nucelus polposus and eventually the intervertebral discs
what are the alar and basal plates?
alar- dorsal-sensory
basal-ventral-motor
what findings do you get with neural tube defects?
when neuropores fail to close during 4th week so you get opening between amniotic fluid and spinal canal. high AFP and high acetylcholinesterase (except spina bifida occulta- normal AFP)
what are the types of neural tube defects?
- spina bifida occulta- hole in neurpore, but no herniation so dura intact- tuft of hair or sacral dimple
- meningocele- meninges herniate, but no neural tissue
- myelomeningocele- meninges and neural tissue
- myeloschisis- exposed neural tissue with no meningeal or skin covering
- ancencephaly- failure of rostral neurpore to close so no forebrain
- holoencephaly- failure of right and left hemispheres to fuse (5-6 weeks)
what is the difference between type 1 and type 2 chiari malformations?
- ectopia of the cerebellar tonsils
2. vermis and tonsils through foramen magnum and stenosis of aqueduct
what is a dandy walker malformation?
agenesis of cerebellar vermis so get big 4th ventricle, non communicating hydrocephalus, spina bifida
what are the symptoms of a syringomyelia?
cape like loss of pain and temp sensation upper extremities, fine touch usually preserved
what are astrocytes?
glial cells- support, repair, extracellular K buffer, remove excess neurotransmitter
-derived neuroectoderm, GFAP is marker
where is myelin made?
oligodendrocytes in the CNS and schwann cells in the PNS
what types of cells are affected in guillian barre? what about multiple sclerosis
- Schwann cells in the PNS
2. Oligodendrocytes in the CNS
what are the three layers of the meninges?
- Dura mater (mesoderm)
- Arachnoid mater (neural crest)
- Pia mater (neural crest)
Epidural space (between skull and dura-blood vessells and fat)
CSF runs between arachnoid and pia
what makes up the blood brain barrier?
astrocyte foot process, tight junctions between non fenestrated capillary endothelial cells and basement membrane
- non polar lipid soluble get through rapidly with diffusion and
- glucose and AA’s get through with carrier mediated transport
what does the preoptic nucleus in the hypothalamus do?
thermoregulation and sexal urges-, GnRH (when the neurons don’t migrate, you get Kallman’s syndrome)
what are beta waves?
awake with eyes open, high frequency, low amplitude
what does the thalamus do? VPL and VPM?
major center for all ascending sensory information
VPL-spinothalamic and medial meniscus/dorsal column
VPM-gustatory and trigeminal
-all go to primary somatosensory cortex
what goes the lateral geniculate nucleus do?
all from CN2, optic tract, optic chiasm- goes to calcarine sulcus
medial geniculate nucleus?
hearing, everything from superior oliver and inferior colliculus of tectum
what does the ventral lateral nucleus do?
everything from basal ganglia and cerebellum- goes to motor cortex
what are the 4 dopaminergic pathways?
- Mesocortical- negative symptoms
- Mesolimbic- positive symptoms
- Nigrostriatal- decreased activity gives extrapyramidal symptoms-dystonia, akathisia, parkinsonism, tardive dyskinesia
- Tubuloinfindibular- dec activity= inc prolactin, dec libido, inc galactorrhea, gynecomastia
Is cerebral perfusion pressure more controlled by CO2 or O2?
CO2 until you get O2 less than 50mmHg, the CPP is proportional to pCO2 until it gets over 90mmHg
where is CSF made? where does it drain?
ependymal cells of choroid plexus
-drains into the arachnoid granules and then into the dural venous sinuses
what does the pineal gland do?
melantonin secretion and circadian rhythm
what are the vagal nuclei?
- nucleus solitarius- visceral sensory (taste, gut distension, baroreceptors) 7, 9, 10
- nucleus ambiguus-motor for the pharynx, larynx 9,10,11
- dorsal motor nucleus- autonomic (parasym) to heart, lungs, upper GI
at what vertebrae does the spinal cord terminate?
L1-L2
where do the eyes look when there is a lesion? where do the eyes look for seizures?
lesion- toward
seizures-away
what is a common lesion seen in MS?
medial longitudinal fasiculus, can’t adduct the eye with the side of the lesion and the contralateral eye gets nystagmus with abduction
what is the timeline for hypoxic damage in brain?
5 mins
- CT can detect changes 6-24hr (noncontrast to look for hemorrhage)
- diffusion weighted MRI (3-30mins)
what is horners syndrome?
miosis (constriction of the pupil), anhidrosis (no sweating face) and ptosis (drooping of eyelid)
what is trigeminal neuralgia?
CN V, shooting pain unilateral face, caused by chewing, talking, touching sides
-tx with carbamazepine
what is athetosis?
snake-like writhing movements- basal ganglia
what is syndenham chorea?
dance like purposeless movements associated with rheumatic fever
what is hemiballismus?
flailing arm and ipsilateral leg-contralateral stroke, subthalamic nuceli-lacunar stroke
what is the pathology of parkinsons?
lewy bodies with alpha synuclein- intracellular eosinophilic inclusion
what is huntingtons?
AD CAG repeat in chr 4 HTT gene- get inc dopamine, dec GABA and Ach, degeneration of neurons in caudate and putamen
what is Creutzfeldt Jakob disease?
Prion PrPc and PrPsc- periodic sharp waves on EEG, myoclonus, 14-3-3 protein on CSF
what is communicating hydrocephalus?
decreased absorption of CSF by arachnoid granules
what is normal pressure hydrocephalus?
wet, wobbly, wacky, increase ICP causes distortion of corona radiata so you get urinary incontinence, gait apraxia and cognitive dysfunction
what is Charcot-Marie Tooth disease?
AD- hereditary sensory and motor neuropathy- lower extremity weakness, foot abnormalities (hammer toe), foot drop, sensory deficits
- problem making proteins for peripheral nerves and myelin sheath
- CMT1A PMP22 gene duplication
what is STURGE weber?
sporadic, port wine stain, tram track calcifications in gyri, intellectual retardation, GNAQ gene, epilepsy
-affects small capillary sized blood vessels
What is tuberous sclerosis?
TSC1 on Chr 9 or TSC2 on Chr16, AD
- hamartomas on skin and CNS
- angiofibromas
- MR
- ash leaf spots
- cardiac rhabdomyomas, mental retardation, angiomyolipoma, seizures, shagreen patches
What is NF1?
mutation in NF1 tumour suppressor gene, inhibitor of RAS, chr 17
- subcutaneous neurofibromas, cafe au lait spots, optic gliomas, pheochromocytomas, lisch nodules
- AD
What is NF2?
mutation chr 22, NF2
1. bilateral acoustic schwannomas, juvenile cataracts, meningomas and ependymomas,2 ears, 2 eyes, 2 parts brain
What is Von hippel lindau?
deletion of VHL, chr 3p
- hemangioblastomas of retina, brain stem, cerebellum and spine
- renal cell carcinomas, pheochromocytomas, angiomastosis (hemangiomas of the skin
how does a prolactinoma present in males and females?
males- infertility and low libido
females; galactorrhea, amenorrhea, low bone density
tx- dopamine agonist (bromocriptine, cabergoline
what are the primary childhood brain tumours?
- pilocytic astrocytoma
- medulloblastoma
- ependymoma
- craniopharyngioma
- pinealoma
what kind of cells do you see in medulloblastoma?
homer wright rosettes, primitive neuroectoderm tumour
where is ependymoma usually found?
4th ventricle- get perivascular pseudorosettes
where is craniopharygioma usually found?
supratentorial tumour, calcified
- remnants of Rathke pouch (ectoderm)
- cholesterol crystals found in motor oil like fluid into the tumour
what can uncal herniation cause?
medial temporal lobe
-contralteral CN3 palsy and ipsalateral hemiparesis (false localizing sign
what is spinal muscular atrophy?
AR
- anterior horn degeneration
- symmetrical weakness, LMN, marked hypotonia and fasiculations
what is tabes dorsalis and what do you get?
tertiary syphilis- get knocked out dorsal column so dec proprioception, ataxia
what does syringomelia cause?
bilateral cape like loss pain and temp
B12 deficiency
knocks out dorsal columns and corticospinal tracts so you get ataxia, gait disturbance, impaired vibration, parathesias
what is brown sequard?
hemisection of the spinal cord
- ipsalateral UMN, LMN and vibration, proprioception and fine touch
- contralateral pain and temp loss
what is friedrich’s ataxia?
degeneration of lateral corticospinal, spinocerebellar and dorsal columns
- AR, nucleotide repeat disorder (GAA) frataxin (iron binding protein)
- diabetes, dilated cardiomyopathy, staggering gait, dysarthria, falling, nystagmus, hyphoscoliosis
What is presbycusis?
age-related hearing loss
- loss high frequency
- bilateral, symmetrical
- destruction of hair cells in cochlear base
what is astigmatism?
abnormal curvature of the cornea- different refractive power on different axes, need cylindrical lens
what is presbyopia?
age related change in lens so you can’t accommodate as well
-need reading glasses
what is miosis?
constriction of the pupil (parasympathetic)
mydriasis?
dilation (sympathetic)
what is horner syndrome?
loss of sympathetic denervation of the face-miosis, ptosis and anhidrosis
what is internuclear opthalmoplegia?
in MS-medial longitudinal fasiculus-so CN6 lateral rectus goes lateral, but can’t communicate for medial rectus on opposite eye to also coordinate inward to get the same direction of horizontal gaze
what is first line for trigeminal neuralgia?
carbamazepine
what is ethosuximide used for?
thalamic T type Ca channels blocked- absence seizures
how does sumatriptan work?
5HT IB/ID agonist- for migraine, cluster headache, inhibits trigeminal nerve activation, prevents vasoactive peptide release and induces vasoconstriction
how does levodopa work? what about carbidopa?
levodopa crosses BBB and converted by dopa decarboxylase to dopamine in CNS
carbidopa is a peripheral dopa decarboxylase inhibitor which is given with it to increase bioavailability of L dopa
what is malignant hyperthermia and what do you give to treat it?
AD usually- mutation in genes for ryanodine receptors so you get increased Ca release in sarcoplasmic reticulum and give dantrolene
