neuro uworld

Question 1

subacute sclerosing encephalitis of Measles

Answer 1

Measles virus
-helical, envelopped RNA virus, which is a member of the Paramyxoviridae family. Measles manifests with prodromal fever, cough, coryza (runny nose), conjuctivitis and erethematous maculopapular rash.

complications later:
Subacute sclerosing encephalitis--> a certain measles virus that is missing an antigen (M protein). The missing antigen causes failure of the meales virus to be cleared by the immune system and allows its persistence in the CNS.
-inflammation
-demyelination
-gliosis 
-neurons and glial cells display viral nuclear inclusions
-progressive but fatal
-dementia, neuro defecits

Question 2

patients that survive an initial subarachnoid hemorrhage more than 50% develop secondary arterial vasopasm

Answer 2

• the vasopspam occurs around the ruptured aneurysn
• cause cerebral ischemia presenting with a new onset confusion, and or focal neur deficit 4-12 after
• it may not show on CT
• transcranial color doppler is needed

prevent: use nimodipine a selective calcium channel blocker

Question 3

valproate exposed neonates

Answer 3

valproate inhibits intestinal folic acid absorption

neural tube defects =(

Question 4

Tardive dyskinesia is a possible side effect of antipsychotic use

Answer 4

-involuntary perioral movements:
biting, chewing, grimacing, tongue protrusions. and possible involuntary choreoathetoud movements of head, limbs, trunk

4 months to 4 years after treatment
may be irreversible

Question 5

transpeptidases =

Answer 5

penicillin-binding proteins
targets for penicillins and cephalosporins

a change in structure of the pbp prevents binding –> resistance

Question 6

endothelium-dervied relaxing factor EDRF =

Answer 6

NO!
-cholinergic agonists bind to muscarinic receptors on endothelial cells and promote release of NO, NO activates GC –> cGMP –> vasodilation

Question 7

phenytoin increases expression of PDGF as a side effect

Answer 7

when gingival macrophages are exposed to increased amounts of PDGF, they stimulate proliferation of gingical cells and alveolar bone. –> gingival hyperplasia

Question 8

first line benzos for alcohol withdrawal?

Answer 8

chlordiazepoxide and diazepam - long acting

Question 9

first line treatment for patients with advance liver dysfunction benzos?

Answer 9

lorezapam and oxazepam

Question 10

NF1, neurofibromas are tumors of schwann cells

Answer 10

neurocrest cells

Question 11

Calcified cystic mass = craniopharyngioma

Answer 11

• suprasellar region
• calcifications visible on neuroimaging
• macroscopic: cystic or partially cystic with solid areas
• LM: lines with sqaumous epithelium, keratin pearls may be seen
• cysts are usally filled with a yellow, viscous fluid that is rich in cholesterol crystals

remnant of rathkes pouch an evagination o the ectoderm that lines the fetal oral cavity this protrusion becomes the anterior pituitary, note the posterior pituitary is formed from the neuroectoderm

Question 12

rathkes pouch

Answer 12

evagination of ECTODERM that lines the fetal oral cavity. This protrusion eventually becomes the anterior pituitary (adenopyhophysis)
notes the posterior pituitary develops from the NEUROECTODERM

Question 13

diapragmatic contraction is responsible for most of the intrapeural pressyre fall during inspiration

Answer 13

lets say we have a physiograph and we see decreasing amplitude of the cyclic intrapleural pressure and we compare with a phrenic nerve stimulation graph that is normal, then the decrease is dye to weakening inspiration diaphragmatic contractions due to a pathology at the NMJ! examples include myasthenia gravis, restrictive lung disease or chest wall disease which could cause normal diaphragm to fatigue rapidly.

Question 14

Pancoast tumor

Answer 14

cancer of apex of lung can affect the superior sympathetic cervical ganglion leading to horners syndrome
-it can also cause an ipsilateral compressive brachial plexopathy

Question 15

treat narcolepsy

Answer 15

modifinil
-a non-amphetamine stimulant
-

Question 16

A chronically progressive pre-senile demential with cortical atrophy but no other radiological or laboratory abnomralities permits a clinical diagnosis of Alzheimers which is a diagnosis of exclusion

Answer 16

treat:
Cholinesterase inhibitor: donepezil
Antioxidants: vitamin E
NMDA receptor antagonist -memantine

Question 17

NMDA receptor

Answer 17

n-methyl-d-aspartate receptor for glutamate

-controls synaptic plasticity and memory function

Question 18

thiorizadine antipsychotic

Answer 18

retinal deposits –> retinitis pigmentosa

Question 19

specific antispychotic side effects:

Answer 19

Chlorpromazine - corneal deposits
haloperiodol - EPS
Ziprasidone- prolongue QT
Olanzapine- wt gain
-clclozapine - agranulocytosis and seizures

Question 20

nictonic receptors

vs muscarinic

Answer 20

ligand-gated ion channels that open after binding ACh

• influx of Na and Ca
• Efflux of K

M1 and M3 - IP3 pathway to increase intracellular Ca –> PKC
Md- cAMP second messenger system and when activated decreased cAMP! they are g protein coupled

Question 21

How does flow travel from the third ventricle to the 4th?

Answer 21

the cerebral aqueduct of sylvius

Question 22

What should we use to cover the organisms that could cause a neonatal meningitis?

Answer 22

ceftriaxone to get most

but to get that pesky listeria we need to use Ampicillin!!!!

Question 23

Friedreich ataxia

Answer 23

Autosomal recessive

• chromosome 9 protein frataxin - needed for mitochondria function
  1. ascending and descending spinocerebellar tract degeneration –> gait ataxia
  2. degeneration of the dorsal columns and dorsal root ganglia cause loss of position and vibration sensation
  3. kyposcoliosis and foot abnormalities (pes cavus) are common
• heart –> hypertrophic cardiomyopathy and gCHF
• DM in about 10%

Question 24

MS

Answer 24

reduced saltatory conduction

Question 25

alzheimers atrophy

Answer 25

temporoparietal lobes and hippocampus

Question 26

Dopamine agonists preferentially stimulate D2 receptors (inhibit the indirect pathway leading to motion, normal is decreased motion)

Answer 26

ergot compounds: bromocriptine and pergolide

nonergot compounds: -pramipexole and ropinirole

Question 27

HSV-1 esephalitis

Answer 27

early symptoms: headache and fever
mental status changes, CN defictits, seizures may follow.
-temporal lobe –> aphasia , olfactory hallucinations (olfactory cortex involement) and personality changes due to amygdala damge

histo: eosinophillic intranuclear inclusion (cowdy type A) are present in glial cells and neurons, multinucleated giant cells may also be found.

Question 28

main side effect of benzodiazepines is daytime drowsiness

Answer 28

• the hangover effect–> impaired judgment, and concentration and assoc ataxia –> risk of falling
• shorter acting benzos are more addictive
• shorter benzos would decrease the risk of day time drowsiness

short benzos:alprazolam, triazolam, oxazepam
medium estazolam, lorazepam, temazepam
long: chlordiazepoxide, chlorazepate, diazepam, flurazepam

long acting will be assoc with daytime drowsiness but less withdrawal

Question 29

Lesions of the macula cause central scotomas

Answer 29

age related macular degeneration

• macula is the central area of the retina
• degeneration causes distortion(metamorphorphopsia) and even loss of central vision (scotomas)
• dry non excitative - deposition of yellows extracellular material in and beneath the bruch membrane and retinal pigment epithelium
  2. wet exudatitve, rapid loss of vision due to bleeding secondary to choroidal neovasculazation

Question 30

radial head subluxation “nursemaids elbow”

Answer 30

• common injury in children resulting from sudden outward pulling on an extended and pronated arm.
• but could happen to adults too
• the radial head subluxatuon can damage the deep branch of the radial nerve leading to weakness or parylysis of forearm extensors compartment muscles
• the deep branch of the radial nerve does not carry the somatic sensory innervation. The superficial branch is sensory

the deep branch arises near the lateral epicondyle of the humerus , where the humerus articulates with the head of the radiums

Question 31

solubility of anesthetic in the peripheral tissues negatively affects brain saturation

Answer 31

higher peripheral tissue solubility means more anesthetic is extracted from the arterial blood. this increases the arteriovenous concentration gradient, meaning that more anesthetic must be absorbed to saturate the blood and then the brain!

Question 32

hyperpyrexia

Answer 32

recall PGE2 leads to an increase in the thermoregulatotey set point in the anterior hypothalamus –> fever
NSAIDS and acetominophen will reduce this
-dont give aspirn to kid
-acetominophen ok
-but in the setting of extreme fever give cold blankets first

Question 33

myoclonic - brief arrhythmic jerking movements, last < 1 second, usally occur in clusters for a few mins, no loss of consciousness

Answer 33

1st line valproic acid

Question 34

cholinergic agonists:

Answer 34

• increase GI tract smooth muscle tone to produce nausea, vomiting, abdominal cramps and diarrhea
• decrease heart rate, cardiac conduction and contractility –> bradycardia, partial or complete heart block and hypotension
• decrease BP by stimulation of endothelial NO synthesis
• they increase secretions–> leading to excessive sweating, salivation and lacrimation.
• dyspnea via bronchoconstriction due to increased smooth muscle tone in the tracheobronchial tree

use them for?
Bethanechol - used to stimulate peristalsis in postoperative ileus
Bathanechol - treat non-obstructive urinary retention (atonic bladder)

Carbachol and pilocarpine - decrease IOP in glaucoma