Neurology

Question 1

Locus ceruleus significance

Answer 1

Found in pons, source of Norepinephrine

Question 2

Raphe nuclei significance

Answer 2

Found in pons, medulla, midbrain. Source of serotonin

Question 3

Striatum & lentiform defined

Answer 3

Striatum: Putamen (motor) + caudate (cognitive)
Lentiform: Putamen + globus pallidus

Question 4

Two important causes of locked-in syndrome

Answer 4

1) Central pontine myelinolysis (rapidly corrected hyponatremia)
2) Basilar artery stroke (think of the paramedian reticular formation)

Question 5

Brain area most vulnerable to ischemia

Answer 5

Hippocampus (neocortex, cerebellum, watershed areas as well)

Question 6

Clasp-knife spasticity, and fasciculations. Signs of what?

Answer 6

Clasp-knife - upper motor neuron sign (increased tone and resistance to movement that suddenly releases)
Fasciulations - lower motor neuron sign

Question 7

Superoxide dismutase 1 significance?

Answer 7

Defect in SD1 can be associated with ALS

Side note: ALS can be treated with Riluzole (Glutamate antag)

Question 8

Patient presents with isolated inability to look upward. Lesion and cause?

Answer 8

Parinaud syndrome from lesion in superior colliculus. Can be caused by tumor in the pineal gland, just superior to superior colliculus (caudal to cerebellum, on posterior surface of midbrain). Remember inferior colliculus is for hearing

Question 9

Foramen spinosum

Answer 9

Skull base entry point for the middle meningeal artery

Question 10

Stapedius muscle in inner ear. Innervation?

Answer 10

CN VII. Thus branchial arch 2 derivative

Question 11

Cholesteatomas composed of what

Answer 11

Keratin overgrowth within middle ear space

Question 12

CN IV lesion

Answer 12

Trochlear palsy, patient has difficulty with depression of eye when looking medially (superior oblique). Hypertropy that’s worse when looking medially

Question 13

MOA of sumatriptan

Answer 13

5-HT agonist specifically in CNS vasculature. This causes vasoconstriction of these arteries and decreases the inflammation thought to be responsible for cluster headaches and migraines

Question 14

Neurofibromatosis type 1 genetics

Answer 14

NF-1 mutation on chromosome 17. NF-1 usually inhibits Ras pathways.
Skin neurofibromas usually derived from neural crest cells

Question 15

MOA of opioid analgesics

Answer 15

Agonist of opioid receptors, results in decreased synaptic transmission by opening K channels and closing Ca channels necessary for release of neurotransmitters.

Question 16

Two epilepsy drugs associated with Stevens-Johnson syndrome

Answer 16

Lamotrigine (when titrated too quickly) and Ethosuximide (for absence seizures). Also, phenytoin, carbamazepine (just btw)

Question 17

Ethosuximide MOA

Answer 17

Blocks T-type Ca channels in the thalamus. Indicated for absence seizures

Question 18

Benzos with shortest half-lives?

Answer 18

ATOM: alprazolam, triazolam, oxazepam, midazolam. Highest abuse potential

Question 19

3 main embryonic structures that give rise to CNS?

Answer 19

Prosencephalon: forebrain
Mesencephalon: midbrain
Rhombencephalon: hindbrain (i.e. cerebellum)

Question 20

Memantadine MOA

Answer 20

NMDA receptor antag used in treatment of Alzheimers. NTBCw/ Amantadine a stimulator of dopamine release and inhibitor of dopamine reputake (Parkinsons)

Question 21

Pramipexole, ropinirole MOA?

Answer 21

Non-ergot direct dopamine agonists used in treatment of Parkinson’s disease

Question 22

Selegiline MOA

Answer 22

Inhibition of central MAO-B which degrades dopamine to 3-MT

Question 23

Anterior choroidal artery. Origin and structures it supplies

Answer 23

Branch of the internal carotid just before it gives off ACA and MCA. Supplies posterior limb of internal capsule, LGN, choroid plexus (hence the name), hippocampus, amygdala, uncus

Question 24

Weber test for hearing loss

Answer 24

Conductive hearing loss: localizes to the affected ear

Sensorineural hearing loss: localizes to unaffected (contralateral) ear