Pathophysiology of migraine
activation of trigem nerve
–>substance P and calcitonin GRP causes inflammation of meninges
How do triptans work?
5HT1B/1D AGONist
- -Block vasoactive peptide release from neuron
- -vasoconstriction
Bupropion mechanism
Dopa and NE reuptake inhibitor
Use of buproprion
depression and smoking cessation
TCA mechanism
Serotonin/NE reuptake inhibitor
Migraine prophylaxis
b-blocker
TCA and venlafaxine
Phenytoin mechanism
Inhibits Na channels from recovering from inactivation
phenytoin tox
lymphadenopathy
–hirsuitism/rash/gingival hypertrophy
carbamazepine tox
agranulocytosis
valproic acid tox
hepatotoxicity
lamotrigine tox
steven johnson hypersensitivity rash
phenobarbital tox
Acute intermittent prophyria
Benefits of zolpidem
less tolerance/addiction
Unlike benzos, it is missing the following
- –No anticonvulsant properties
- –No muscle relaxation
Syphilis destroys what part of CNS
tabes dorsalis
–posterior columns. Also happens in B12 deficiency
alar plate
dorsal sensory roots
basal plate
motor ventral roots
Forebrain
telencephalon and diencephalon
lateral ventricle
telencephalon
third ventricle
diencephalon
mesencephalon
midbrain
aqueduct
mesencephalon
Hindbrain (rhombencephalon)
metencephalon
myelencephalon
pons/cerebellum
metencephalon
medulla
myeencephalon
fourth ventricle derived from
- Metencephalon=upper
2. Myelencephalon=lower
you suspect NTD in a fetus with elevated AFP–how to confirm?
AChE
anencephaly assoc’d with
maternal diabetes
holoprosencephaly
left and right hemispheres don’t separate
holoprosencephaly caused by
hedgehog signaling pathway
cystic enlargement of 4th ventricle with hydrocephalus/spina bifida
dandy walker
cause of dandy walker
agenesis of cerebellar vermis (central area)
chiari II
aqueductal stenosus and hydrocephalus from cerebellar herniation
how does chiari II present?
paralysis and thoraco/lumbar myelomeningocele
syningomyelia is associated with
Chiari I
Muscles of tongue are derived from
occipital myotomes
anterior 2/3 of tongue from:
1st branchial arch
posterior 1/3 of tongue from:
3rd/4th branchial arch
taste goes to which nucleus?
solitary nucleus
PNS and schwann cells come from
neural crest cells. everything else comes from neuroectoderm except microglia (from mesoderm)
GFAP is a marker for
astrocytes
role of astrocytes
- BBB
- K metabolism
- Removing extra neurotransmitter
Multinucleated giant cells in the CNS are made of
microglia that are fused. Caused by HIV
Myelin effects on space and time constant
Increases space constant (distance signal will spread before dying)
Decreases time constant
which cells are destroyed in MS?
oligodendrocytes (white matter of CNS)
fried egg on H&E of brian matter
oligodendrocytes
large myelinated sensory fibers that adapt quickly
meissner’s
large myelinated fibers that adapt slowly
merkel’s discs
merkel’s discs sense:
pressure, position sense in hair follicles
C fibers
slow, unmyelinated pain fibers
Ad fibers
fast myelinated temperature fibers
endoneural inflammation
guillain barre
perifascicular/endomysial inflammation
polymyositis
Nucleus accumbens
reward center, fear
locus ceruleus
stress and panic
anxiety neurotransmitter
Increased NE, decreased 5HT, decreased GABA
schizophrenia neurotransmitter
increased dopamine
depression neurotransmitter
decreased NE
Decreased dopamine
Decreased serotonin
alzheimer’s neurotransmitter
decreased Ach
Huntington’s neurotransmitter
decreased Ach
decreased Gaba
REM sleep neurotransmitter
increased Ach
Synthesis of dopamine
ventral tegmentum and Snc (midbrian)
Synthesis of serotonin
raphe nucleus
Synthesis of Gaba
nucleus accumbens
Synthesis of Ach
basal nucleus of Meynert
Lateral hypothalamus
hunger
leptin inhibits
ventromedial hypothalamus
satiety
anterior hypothalamus
cooling
posterior hypothalamus
heating
VPL
ALS and DC-ML fibers going to somatosensory cortex
VPM
trigeminal and gustatory pathway
LGN
CNII fibers to calcarine sulcus (lateral light)
MGN
superior olive and inferior colliculus fibers to auditory cortex (medial music)
VL
Motor fibers from basal ganglia to motor cortex
LImbic system responsible for
feeding fleeing fighting feeling (emotion) sex
structures of the limbic system
hippocampus amygdala fornix mamillary bodies cingulate gyrus
Inputs to cerebellum through which peduncle?
middle and inferior
Input to cerebellum carries:
Middle: contralateral cortex info
Inferior: ipsilateral proprioceptive info from climbing/mossy fibers
Outputs from cerebellum:
Superior peduncle carrying info to contralateral cortex
Damage to lateral cerebellum:
impaired coordinated movement of extremities, with falling towards ipsilateral side
Effect of dopamine in basal ganglia
Stimulates D1
Inhibits D2 receptors
–>overall will facilitate movement through the direct pathway
Describe the direct pathway arc
Increased putamen stimulus
Decreased GPi
Increased thalamus
Increase cortex
Describe indirect pathway ard
Increased putamen Decreased GPe Increased STN Increased GPi Decreased thalamus Decreased cortex
parkinson’s changes in brain
lewy bodies with alpha synuclein and loss of Substantia nigra pars compacta dopaminergics
Huntington Sx
chorea, aggression, depression, dementia
Huntington causes neuronal death through:
NMDA-R binding and glutamate toxicity
Huntington=degeneration of:
striatal nucleus (putamen plus caudate
intention tremor seen in
cerebellar dysfunction
dystonia is:
sustained involuntary muscle contractions
Lesion in hemibalismus
contralateral subthalamic nucleus
–>STN normally stimulates the GPi to inhibit the thalamus. Loss of inhibition in basal ganglia!
kluver bucy
hyperorality
hypersexuality
disinhibited behavior
Kluver bucy lesion
amygdala
kluver bucy is associated with
HSV-1
Lx: Re-emergence of primitive reflexes
frontal lobe
left sided spatial neglect
right parietal lobe
lx: wernicke-korsakoff
mamillary bodies
intention tremor lesion:
cerebellar hemisphere lesion. (fall to ipsilateral side)
PPRF lesion
Eyes look away from side of lesion
Frontal eye fields
Eyes look toward lesion
Which area of the brain are damaged first in severe HTN? examples of deficits?
watershed regions:
- -upper leg/arm weakness
- -visual processing
Cerebral perfusion is primarily driven by
CO2
Only driven by hypoxemia when po2 < 50
Charcot bouchard
chronic HTN, affects small vessels in basal ganglia and thalamus
Causes of berry aneurysm
ADPKD
marfant’s
ehler danlos
site of berry aneurysm
communicating arteries
Acomm stroke
visual field defect
Pcomm stroke
CN III palsy (eye is down and out)
PCA stroke
contralateral hemianopia with macular sparing
Stroke lesion:
vertigo, facial paralysis, loss of lacrimation and salivation and taste from anterior tongue, decreased corneal reflex
Face has loss of pain and temperature sensation, ipsilateral horner’s
AICA
–FACIAL NUCLEUS lesion
–vestibular nuclei, cranial nerve nuclei, spinal trigeminal nuclei also affected
“Facial droop means AICA’s pooped”
Stroke lesion:
vertigo; decrealsed pain and temperature to limbs/face
DYSPHAGIA and HOARSENESS, ipsilateral horner’s
PICA
–NUCLEUS AMBIGUOUS
“Don’t pica hoarse that can’t eat (dysphagia)”
stroke lesion:
contralateral hemiparesis of lower limbs
Tongue deviates ipsilaterally
Decreased contralateral proprioception
ASA
- -lateral corticospinal
- -DCML
- -caudal medulla
lateral striate artery supplies the
striatum and internal capsule. Damage causes contralateral hemiparesis and hemiplegia
–Caused by HTN
Stroke lesion:
contralateral paralysis and loss of sensation in the lowerlimb
ACA
Lesion: aphasia and loss of motor and sensory from upper limb and face
MCA
Which intracranial hemorrhage gives a bloody tap?
subarachnoid hematoma.
worst headache of my life
subarachnoid
Other causes of intraparenchymal hemorrhage besides HTN
amyloid angiopathy, vasculitis, neoplasm
Which parts of the brain are most susceptible to hypoxic damage?
hippocampus
neocortex
cerebellum
watershed
red neurons
12-28 hours after injury
necrosis and neutrophils in brain
24-72 hrs after injury
macrophages in brain
3-5 days
reactive gliosis and vascular proliferation
1-2 weeks later
What connects the 4th ventricle to the subarachnoid space?
foramina of luschka (lateral) and foramina of magendie (medial)
Symptoms of normal pressure hydrocephalus
“wet wobbly and wacky” in elderly. Ventricles expand and cortex contracts
communicatin hydrocephalus
caused by decreased arachnoid granulation absorption
hydrocephalus ex vacuo
degeneration of cortex results in expanded hydrocephalus
fasciculations seen in UMN or LMN lesion?
LMN
atrophy seen in UMN or LMN lesion?
LMN
Werdnig hoffman disease
Like polio, affects anterior horns
Mutation in ALS
superoxide dismutase
subacute combined degeneration caused by:
Vit B12/E deficiency
Which areas damaged in SubacuteCD?
Dorsal columns Lateral corticospinal spinocerebellar --Ataxia, paresthesia --Lost position/vibration
Infarction of anterior spinal artery damages which parts of spinal cord?
everything but dorsal columns of upper thoracic region
How does riluzole work?
Decrease glutamate (excitatory) release
floppy baby with hypotonia and tongue fasciculations. Death at 7 months
Werdnig hoffman, autosomal recessive inheritance
Friedreich’s ataxia caused by
GAA repeat (autosomal recessive)
How does Friederich’s ataxia present?
Kyphoscoliosis in childhood
- -pes cavus
- -staggering and falling
Loss of pain and temperature on one side, and propioception/vibration on the other side
Brown sequard syndrome. Lesion will be contralateral to the pain and temperature side
Contralateral loss of pain and Temp with ipsilateral paralysis of CN V, IX, X, XI
lateral medullary syndrome
contralateral paralysis
ipsilateral paralysis of tongue
medial medullary syndrome
Some common causes of horner’s
Pancoast tumor, brown sequard above T1
Describe the pathway for horner’s
Hypothalamus__.Spinal cord–>Exit at T1 to sympathetic ganglion–>Pupil
Gallbladder pain refers to which area?
the right shoulder (phrenic nerve)
C2/C3/C4 dermatomes
C2: skull cap
C3: tutleneck
C4: low cut shirt
S2/S3/S4 dermatomes
Penis
Anal zones
Biceps reflex
C5/6
Triceps reflex
C7/8
Patella reflex
L3/L4
Galant reflex
Stroking along one side of spine causes newborn to flex lower body toward that side
Cranial nerves that come out medially at the brain stem
3, 4, 12
medial to lateral: 3, 4 5 (pons) 6, 7, 8 9, 10 11 12
Superior colliculus
conjugate vertical gaze
Inferior colliculus
auditory
parinaud syndrome
paralysis of conjugate vertical gaze
Cause of parinaud
lesion in superior colliculi
Innervation of submandibular/sublingual
facial nerve
innervation of stapedius muscle
facial
innervation of stylopharyngeus
CN IX
Innervation of carotid body/sinus
CN IX
innervation of parotid gland
CN IX
Midbrain CN nuclei
CN 3, 4
Pontine CN nuclei
CN 5, 6, 7, 8
Medullary CN nuclei
CN 9, 10, 12
Spinal cord nuclei
CN 11
Corneal reflex afferent/efferent
V1 opthalmic
VII efferent
Lacrimation afferent/efferent
V1 afferent
VII efferent
Three vagal nuclei
Solitarius
Ambiguous
Dorsal motor nucleus
Innervation to nucleus solitarius
7, 9, 10 (taste, baroreceptors, gut)
nucleus ambiguus sends what fibers
9, 10 (motor innervation of pharynx, larynx, and upper esophagus)
dorsal motor nucleus sends what fibers
10 (parasympathetic fibers to heart, lungs, GI)
Optic canal contents
CN II, opthalmic, central retinal vein
Superior orbital fissure contents
III, IV< V1, VI, ophthalmic vein
Foramen spinosum contents
Middle meningeal
Internal auditory meatus
CN VII, VIII
Jugular foramen
CN 9, 10, 11
Foramen magnum
CN 11
Hypoglossal canal
CN 12
Cavernous sinus drains blood from:
eye and superficial cortex
Which nerves travel through the cavernous sinus?
3, 4, V1, V2, 6
Opthalmoplegia with normal vision
-decreased corneal and maxillary sensation
cavernous sinus syndrome
CN V motor lesion sign
Jaw deviates toward lesion
CN X lesion
uvual deviates away
CN XI lesion
weakness turning head away from lesion
CN XII lesion
tongue deviates toward lesion (lick the lesion)
Conductive hearing loss finding
Abnormal rinne, localization to affected hear in weber
Sensorineural hearing loss finding
Normal rinne, localizes to unaffected ear
Which muscle opens the jaw?
lateral pterygoid
which muscles close the jaw?
masster, temporalis, medial pterygoid
if near sighted, light focuses…
in front of retina
hyperopia/myopia
far/nearsighted
Uveitis is inflammation of:
uveal coat (iris, ciliary body, choroid)
Causes of retinitis
viral (CMV, HSV, HZV)
Sx of open angle glaucoma
Painless Peripheral then central vision loss
Cause of open angle glaucoma
Block of trabecular meshwork. Angle between the iris and cornea is “open”
Sx of chronic closed angle glaucoma
asymptomatic usually. May lose peripheral vision
Sx of acute closed angle glaucoma
painful sudden vision loss with a rock hard eye
What should you NOT give in acute closed angle glaucoma?
epinephrine–causes mydriasis and constriction of pupillary dilator muscle
pupillary dilator innervated by
Alpha 1
Pupillary sphincter innervated by
M3
Ciliary epithelium innervated by
Beta receptors–will produce more aqueous humor
Signs of CN IV damage
Eyes move up when looking contralateral or when tilting head down (cannot see when walking down stairs)
Miosis pathway
EW nucleus to ciliary ganglion by CN III
–Short ciliary nerve to pupillary sphincter
Mydriasis pathway
Hypothalamus to center of budge
- -Exit T1 to superior cervical ganglion
- -Travel along internal carotid, long ciliary nerve to pupillary dilator
Light compression of CN III results in
Blown pupil. Parasympathetics travel on the outside
“curtain drawn down” on eyes preceded by flashes and floaters
retinal detachment
Loss of central vision not caused by stroke
Macular degeneration
dry vs wet MD
dry most common: with yellow material beneath retinal pigment (drusen).
Wet: rapid loss of vision from bleeding off of choroidal neovascularization. Will see gray subretinal membrane
treatment for dry AMD
multivitamin and antioxidants
Meyer’s loop travels through
Temporal lobe carrying visual fibers
Dorsal optic radiation travels through
parietal lobe
Rapidly progressive dementia with startle myoclonus
Creutzfeldt-Jakob dz
Dementia, aphasia, parkinsonism and change in personality
Pick’s disease
Which areas of the brain are affected in Pick’s disease?
frontotemporal lobes
histology of creutzfeldt-jakob
spongiform cortex with prions
Spherical tau protein aggregates
pick bodies
which genes cause early onset alzheimer’s?
APP (chromosome 21), presenilin-1/2 (chromosome 14), and ApoE4 (chromosome 19)
Which gene is protective against alzheimer’s?
ApoE2
Lab findings in multiple sclerosis
Increased protein IgG
Oligoclonal bands
MRI
Treatment for multiple sclerosis:
Beta interferon
immunosuppression
natalizumab
Symmetric ascending muscle paralysis
Acute inflammatory demyelinating polyradiculopathy (Guillain barre)
Treatment for GBD
respiratory support
–consider IV globulins and plasmapheresis
Dx of GBD
Increased protein in CSF
Progressive multifocal leukoencephalopathy
demyelination of CNS from destruction of oligodendrocytes
PML is associated with
JC virus
Multifocal pervenular inflammation and demyelination after infection
Acute disseminated encephalomyelitis
Metachromatic leukodystrophy
Auto-recessive lysosomal storage disease caused by arylsulfatase A deficiency. Sulfatides build up and impair myelin sheath
Krabbe’s disease
Lysosomal storage disease with deficiency of galactocerebrosidase. Build up of galactocerebroside destroys the myelin sheath
Charcot marie-tooth disease
Weakness of dorsiflexion from demyelination of common fibular nerve
–Defect in myelin protein gene
Prophylactic for migraines
propranolol and topiramate
Inheritance of sturge weber
sporadic
Sx of sturge weber
port wine stain AVM (leptomeningeal angiomas) Pheos glaucoma seizures
Sx of tuberous sclerosis
Hamartomas Cutaneous angiofibromas Ash leaf spots Cardiac rhabdomyomas Tubers retardation seizures renal angiomyolipoma AUTO DOM
Sx of NF 1
Cafe au lait Lisch nodules neurofibromas Optic gliomas Pheo AutoDOM --Mutation on NF-1 of CHROM 17
Sx of VHL
Cavernous hemangioma bilateral renal cell carcinoma Retinal Hemangioblastomas pheo AUTO DOM VHL on chromosome 3
Butterfly looking tumor
gliblastoma multiforme
GFAP + tumor
glioblastoma multiforme in adults
pilocytic astrocytoma in kids
Pseudopalisading tumor
gbm
What is the most common and 2nd most common primary brain tumor?
GBM then meningioma
spindle cells in a whorled pattern with psamomma bodies
meningioma
bilateral acoustic schwannoma
NF-2
S-100 positive
Schwannomas
Slow growing, Fried egg tumor
Oligodendroglioma.
1p:19q deletion tumor
Oligodendroglioma
Pituitary adenoma presents as
Prolactinoma usually.
Rosenthal fibers
pilocytic astrocytoma
pilocytic astrocytomas found in
posterior fossa
pilocytic astrocytoma good or bad prognosis?
good
homer wright rosettes
medulloblastoma
tumor that compresses 4th ventricle, causing hydrocephalus
medulloblastoma and ependyoma
tumor sends drop metastases to spinal cord
medulloblastomsa
PNET tumor
medulloblastoma
Most childhood tumors are found in cerebellum except
ependyoma and craniopharyngioma
perivascular pseudorosettes and rod-shaped blepharoplasts
ependyoma
Childhood tumor associated with VHL and EPO producing
hemangioblastoma
Foamy cells and high vascularity tumor
hemangioblastoma
verocay bodies
NF-2
brimonidine
alpha 2 agonist, decreases aqueous humor synthesis
epinephrine treats glaucoma by….
decreasing aqueous humor through vasoconstriction
Timolol, betaxolol, carteolol
Decrease aqueous humor synthesis without vision change
Side effect of alpha agonists for glaucoma
Alpha receptors dilate the pupil, causing mydriasis
Acetazolamide mechanism for glaucoma
decreased aqueous humor synthesis by inhibition of carbonic anhydrase
–no pupillary/vision change
pilocarpine/carbachol for glaucoma
Increase outflow of aqueous humor by contraction of ciliary muscle (M3) and opening trabecular meshwork. Causes miosis and cyclospasm
–Pilocarpine esp good for emergencies (acute closed angle)
Physostigmine, echothiophate
Indirect cholinergics, also used for glaucoma by contracting ciliary muscles and opening trabecular network
Latanoprost for glaucoma
Increase outflow of aqueous humor
Side effect of latanoprost
Darkens color of iris
Class: meperidine, dextromethorphan, diphenoxylate
Opioids
Mechanism of opioids
Bind to receptors
- -open K channels, close Ca channels
- -Decrease transmission
- -inhibits release of Ach, Ne, Serotonin, glutamate, sub P
Use of loperamide and diphenoxylate
diarrhea
Butorphanol
Partial mu agonist and kappa opioid agonist
use: butorphanol
severe pain, good b/c less respiratory depression
Problem with using butorphanol
cannot reverse overdose as well with naloxone
Tramadol side effect
decrease seizure threshold + normal opioid side effects
Use of tramadol
chronic pain
Mechanism tramadol
weak opioid agonist that inhibits serotonin and NE reuptake
First line for partial seizure
carbamazepine
First line for tonic clonic
phenytoin
valproic acid
carbamazepine
First line for prophylaxis against status epilepticus
phenytoin
Which drugs are only for partial seizures (most are for both)
tiagabine and vigabatrin
First line for trigeminal neuralgia
carbamazepine
mechanism phenytoin
sodium channel inactivation
mechanism carbamazepine
sodium channel inactivation
mechanism lamotrigine
Blocks voltage gated Na channels
Gapapentin mechanism
Inhibits voltage Ca channels
Other uses of gapapentin besides seizures
postherpetic neuralgia
peripheral neuropathy
bipolar disorder
migraines
First line drug for seizures in children
Phenobarbital
Mechanism of topiramate
Blocks Na channels and increases GABA action
Mechanism of phenobarbital
Increases GABAa action by increasing duration of Cl- channel opening
Mechanism of ethosuximide
Blocks thalamic T type calcium channels
Benzo mechanism
Increase GABA by increasing frequency of Cl- channel opening
Tx for seizures of eclampsia
Mg SO4
Tigabine mechanism
Inhibits GABA
Vigabatrin mechanism
Inhibits GABA transaminase to increase GABA
Stevens Johnson syndrome occurs with which drugs
Carbamazepine
Ethosuximide
phenytoin
lamotrigine
Sx of stevens johnson
purpuric macules–>epidermal necrosis and sloughing
Carbamazepine side effects
agranulocytosis
teratogen
SIADH
Which seizure drugs induce p-450
carbamazepine
phenobarbital
phenytoin
Which seizure drugs are contraindicated in pregnancy
carbamazepine
phenytoin
valproid acid
Lateral horn of spinal cord
Carries sympathetic fibers. Starts at T1. Knocked out in an expanded syringomyelia
Frataxin gene normally regulates:
iron
Friedreich ataxia is associated with what heart defect?
Hypertrophic cardiomyopathy
the last stage of a healed stroke is
A gliotic cyst
Xanthochromia
yellow spinal tap from hemoglobin
Which chromosome is amyloid precursor protein found on?
Chromosome 21!
Which layers of the cortex consist of the pyramidal neurons?
3,5,6. these are most susceptible to damage with a stroke
tau protein normally does what?
makes microtubules in cells
MTPT causes
Parkinson’s
how do you tell apart lewy body dementia from parkinsons?
In Parkinson’s, dementia is a VERY late finding. early onset dementia suggests lewy body dementia.
Lewy bodies are found in cortex in lewy body dementia
how do you treat Normal pressure hydrocephalus?
Shunt the CSF. Sx will improve with lumbar puncture (decrease CSF pushing on brain tissue)
Spongiform encephalopath histology
White open bubbles (spongy!)
Side effects of phenytoin
Ataxia Gingival hyperplasia hirsuitism megaoblastic anemia SLE syndrome osteopenia fetal hydantoin syndrome
Side effect of valproic acid
Hepatotoxicity (check LFTs)
GI distress
weight gain
neural tube defects
Side effect of topiramate
sedation
mental dulling
kidney stones
weight loss
Which benzos have a higher addictive potential?
short acting
- triazolam
- oxazepam
- midazolam
uses of benzos
anxiety (blue jasmine) status epilepticus delirium tremens night terrors/sleep walking insomnia
How do you treat a benzo overdose
flumenazil, a competitive GABA antagonist. Generally less addictive than barbiturates
How do the non-benzo hypnotics work?
BZ1 subtype of GABA receptor. effects are also reversed by flumenazil
Rapid induction anesthetics have what property?
Decreased solubility in blood
Potent drugs have what property?
Increased solubility in lipids, determined by 1/MAC. Therefore a SMALL MAC means a highly potent drug
tox: halothane
hepatotoxicity
tox: methoxyflurane
nephrotox
tox: enflurane
convulsant
tox: inhaled anesthetics
malignant hyperthermia (except nitrous oxide). Nitrous oxide can expand trapped gas in a body cavity
Thiopental
IV barbiturate used to induct anesthesia
IV benzo
midazolam. used for endoscopy
side effect of midazolam
severe respiratory depression
Ketamine mech
blocks NMDA receptors. analog of PCP
Side effect of ketamine
hallucination/bad dreams
Propofol use
sedation in ICU, rapid anesthesia induction. less nausea than thiopental.
How does propofol work?
Potentiates GABAa
Local anesthetics: two types?
esters: procaine, cocaine, tetracaine
Amides: lidocaine, mepivacaine, bubivacaine
How do local anesthetics work?
Block Na channels on INNER portion of channel. Often combined with epinephrine to enhance action
Side effect of bupivacaine
cardiovascular toxicity
Other side effects of local anesthetics
Hypertension, hypotension, arrythmias
two phases of succinylcholine?
Phase I: depolarization: No antidote
Phase II: repolarized but blocked. Antidote=cholinesterase inhibitor like neostigmine
Side defect of succinylcholine
hypercalcemia
hyperkalemia
malignant hyperthermia
Nondepolarizing NMJ blockers
“-curiums”
–These are NMJ ACh receptor competitive antagonists
Dantrolene mechanism
prevents release of Ca from SR of muscle.
Clinical use of dantrolene
Treatment of malignant hyperthermia. A side effect of inhaled anesthetics and succinylcholine
Also for neuroleptic malignant syndrome
What predisposes you to malignant hyperthermia?
Genetics
Dopamine agonists for parkinson’s
Bromocriptine (ergot)
pramipexole (non-ergot)
Non-ergots are better
Parkinson drug that increases dopamine
Amantadine
L-dopa/carbidopa (converted to dopamine in CNS)
Toxicity of amantadine
ataxia
Selegiline mechanism
Prevents dopamine breakdown by blocking MAO
entacapone, tolcapone mechanism
COMT inhibitors preventing L dopa degradation in parkinsons
Benztropine
For parkinsons, an antimuscarinic that improves tremor and rigidity
“Park your benz”
What’s the role of carbidops in the levodopa/carbidopa combo?
L dopa is converted to dopamine in the CNS. Carbidopa is a decarboxylase inhibitor that STAYS in the peripheral circulation and prevents L dopa activation in the periphery.
Side effects of levodopa
dyskinesia and arrhythmias
Memantine
NMDA antagonist for alzheimers
Donepezil, rivastigmine, galantamine
Acetylcholinesterase inhibitors for alzheimer’s
Side effects of memantine
dizziness/confusion/hallucination
Side effect of donepezil
nausea/dizziness/insomnia
treatment for huntington
tetrabenzine and reserpine inhibit the VMAT limiting dopamine release
Also haloperidol, a dopamine antagonist
Sumatriptan mechanism
5HT/1b1d agonist that inhibits trigeminal nerve activation.
Sumatriptan is contraindicated in
coronary vasospasm (CAD or prinzmetal’s angina)
cherry red spot on macula
retinal artery occlusion
Negative rinne test
Louder outside the ear than in the mastoid bone.
Abnormal Rinne
Conductive hearing loss
Normal Rinne
Sensorineural hearing loss
Medulloblastoma sx
Gait and limb ataxia
bursts of conjugate eyemovements in many directions with hypotonia and myoclonus. Also an abdominal mass. and HTN
Neuroblastoma in kids. Generated in the adrenal medulla causing secretion of catecholamines
gene responsible for neuroblastoma
c-myc
Signs of guillain barre on microscopy
segmental demyelination and endoneural inflammation
Loss of vibration/position
Paresis (spastic)
Ataxia
Subacute combined degeneration
Dorsal column loss
Lateral cerebrospinal tract loss
Demyelination of peripheral nerves withOUT perineural inflammation
Beriberi (thiamine deficiency).
–pain and paresthesia with muscle weakness and areflexia
Which sensory pathway is the only one that does not go through the thalamus?
smell
Where would you find the area postrema?
Dorsal medulla, at the caudal end of the fourth ventricle
Marcus Gunn pupils
Light shown in one eye fails to show pupillary constrict on both sides.
–Note that NASAL portion of the retina contributes more input to the pretectal nucleus….so an optic tract defect could cause marcus gunn (even though light input to both eyes! so tricky!)
neurofibromas are made of
schwann cells, derived from neural crest
inhaled anesthetics have what system wide effect?
Increased cerebral blood flow Myocardial depression hypotension respiratory depression decreased renal function
CN III: compression vs ischemia?
Compression damages parasympathetics first. Ischemia only affects somatic fibers (ptosis, down and out eye) with intact parasympathetics (PERRLA)
Ergot compounds
bromocriptine and pergolide
nonergot componds
pramipexole and ropinirole
How do ergot/nonergot compounds work?
They directly stimulate the dopamine receptors