Potpourri

Question 1

What CNS neuropeptide is altered in narcolepsy? Is it increased or decreased?

Answer 1

Hypocretin (orexin) is decreased in patients with narcolepsy.

Question 2

What stages of sleep are increased in the two nights following prolonged sleep deprivation?

Answer 2

The first night consists of increased N3 (SWS) sleep. The second night may have increased REM, especially in younger patients.

Question 3

What is monoadenylate deaminase deficiency?

Answer 3

Myoadenylate deaminase deficiency is an inherited disorder of muscular energy metabolism with a lack of AMP deaminase activity in skeletal muscle. It is characterized by exercise-induced muscle pain, cramps and/or early fatigue. Can be diagnosed by a low ammonia response to the forearm ischemia test.

Question 4

What causes the increased risk of stroke for patients with Fabry disease?

Answer 4

Fabry disease is an X-linked storage disorder with features of proteinuria, renal failure, painful small fiber stocking-glove neuropathy, skin angiokeratomas, and corneal dystrophy. Increased stroke risk is caused by accumulation of fatty deposits in blood vessels, increasing risk of small vessel ischemic stroke. There may also be contribution in some patients from hypertension due to kidney disease.

Question 5

Name the gene, location, and type of mutation involved in Freidrich’s ataxia.

Answer 5

AR trinucleotide GAA repeat on the FXN gene located on 9q21.11

Question 6

A patient with REM sleep behavior disorder is most likely to develop what condition?

Answer 6

Parkinson disease

Question 7

What is the mechanism of action of triptans?

Answer 7

5HT1B and 5HT1D agonist

Question 8

Hurler syndrome (mucopolysaccharidosis type 1) has a deficiency of what enzyme?

Answer 8

Deficiency of A-L-iduronidase, which causes buildup of dermatan and heparan sulfate

Question 9

Describe characteristic features of pilocytic astrocytoma

Answer 9

Occurrence in the posterior fossa, large cystic portion with an enhancing mural nodule. Pathology can show compact regions with microcystic components, Rosenthal fibers. This is the most common glioma in children.

Question 10

What MRI feature distinguishes WHO grade II and III tumors?

Answer 10

Enhancement (WHO II don’t enhance)

Question 11

This “fried egg” appearance is characteristic of what tumor type?

Answer 11

Oligodendroglioma

Question 12

What genetic change is favorable in oligodendroglioma?

Answer 12

1p19q deletion is favorable, occurs in 50-80%

Question 13

Where does the olfactory nerve synapse?

Answer 13

First order neurons synapse at olfactory bulb, second order project directly to olfactory cortex (only CN that doesn’t synapse in the thalamus). Olfactory cortex is pyriform cortex = lateral olfactory stria, uncus, and medial parahippocampal lobe.

Question 14

Where are amacrine cells found?

Answer 14

Inner plexiform layer of the retina. Secrete dopamine and GABA.

Question 15

What is anterior ischemic optic neuropathy?

Answer 15

Most common optic nerve disorder in adults > 50.

Can be arteritic (due to inflammation like GCA) or non-arteritic (due to cardiovascular risk factors, non-inflammatory).

Symptoms are unilateral painless vision loss, often wtih altitudinal visual field deficit.

Question 16

What is the function of the Edinger Westphal nucleus?

Answer 16

Provides parasympathetic innervation to the iris sphincters and ciliary muscles

Question 17

Tell me about the trochlear nerve

Answer 17

Cranial nerve IV, has the longed intracranial course, only nerve to exit the brainstem dorsally. Decussates after leaving the brainstem, so innervates contralateral side.

Innervates the superior oblique, which functions to pull the eye down and rotate in.

Question 18

A right INO will have what symptoms?

Answer 18

Rightward gaze is normal. Upon looking left, left eye will abduct but with nystagmus, right eye cannot adduct.

Caused by lesion of RIGHT MLF.

Question 20

Where does achromotopsia localize?

Answer 20

Inability to see colors, localizes to the inferior lip of the calcarine fissure

Question 21

Where does a Horner syndrome with facial anhidrosis localize?

Answer 21

Lesion must be proximal to the carotid bifurcation

Question 22

What nerves travel through the superior orbital fissure?

Answer 22

3, 4, 6, V1 and sympathetics

Question 23

Where does the maxillary (V2) nerve exit the skull?

Answer 23

Foramen rotundum

Question 24

Where does the mandibular (V3) nerve exit the skull?

Answer 24

Foramen ovale

Question 25

What is Kearns-Sayre syndrome?

Answer 25

Mitochondrial disorder with onset before age 20, characterized by progressive external ophthalmoplegia, ptosis, pigmentary retinopathy, ataxia, elevated CSF protein, cardiac conduction abnormalities.

Can have diabetes, dementia, weakness, renal failure.

Muscle biopsy shows ragged red fibers

Question 26

What is abetalipoproteinemia?

Answer 26

Rare autosomal recessive disorder resulting in poor absorption of fat and fat-soluble vitamins.

Symptoms include failure to thrive, diarrhea, weakness, ataxia, intellectual disability, retinitis pigmentosa.

Many symptoms can be referred specifically to Vitamin E deficiency.

Question 27

What disease is characterized by deficient alpha-N-acetyl neuraminidase?

Answer 27

Sialidosis, a lysosomal storage disease

Question 28

Which nerve roots are injured in Erb-Duchenne palsy? Klumpke palsy?

Answer 28

Erb-Duchenne C5-6

Klumpke C8-T1

Question 29

What brain tumor shows strong immunoreactivity to synaptophysin?

Answer 29

Central neurocytoma