Penn tests

Question 1

brainstem auditory evoked potentials

Answer 1

Wave I – ipsilateral auditory (VIIIth) nerve action potentials; Wave II – ipsilateral proximal VIIIth nerve; Wave III – bilateral superior olivary nucleus (3 for 3 words-lower pons); Wave IV – bilateral lateral lemniscus (mid to upper pons); Wave V – bilateral lateral lemniscus and inferior geniculate (upper pons).

Question 2

SSEPs

Answer 2

• N or P indicates a “negative”/upward or “positive”/downward deflection from baseline. number -time, in milliseconds, in which this response should occur.

The slowed P37 could occur with any central lesion of the somatosensory pathway, however the normal central median responses indicate the lesion must be below the cervical spine. The normal popliteal and N22 responses indicate transmission of the sensory signal through the leg and lumbar spine respectively. Therefore this lesion is localized to the thoracic spine.

Question 3

musk

Answer 3

NO thymus pathology
-sensitive to rituximab
-female predominant

Question 4

lems

Answer 4

Baseline CMAP amplitudes are typically depressed.

-Marked increment of the CMAP amplitudes is seen with fast (50 Hz) repetitive stimulation or brief (10 sec) exercise
-distinct from post-synaptic NMJ disorders (MG).
- slow (2 Hz) repetitive stimulation decrement is seen in both pre and post-synaptic disorders.

Low VGCC Ab titers can be seen in up to 23% of patients with ALS, 24% of patients with cancer without LEMS

Question 5

MG diagnosis

Answer 5

highest sensitivity: single fiber emg - increased jitter (not the most specific)

more specific: ACHR antibodies, but not the most sensitive

anti-striational Ab- positive in 80% of ppl with thymoma

MUSK - women and no thymoma

Question 6

Wernicke-Korsakoff

Answer 6

thiamine is a critical co-factor multiple enzymes involved in carbohydrate metabolism.

Question 7

asymmetric stepwise progression of painful cranial and/or peripheral neuropathies

Answer 7

mononeuritis multiplex

Question 8

innervation flexor pollicis longus?

Answer 8

AIN median
[flexor pollicis brevis deep head ulnar]

Question 9

monoclonal gammopathies

Answer 9

MGUS - IgG or IgA
Waldenstrom- IgM
MM - IgG in 50% ,IgA 21%, kappa/lambda light chain Bence jones 16%

Question 10

martin gruber anastamosis emg

Answer 10

stimulate median and record at ADM getting robust response

Question 11

Delirium tremens inhospital mortality rate

Answer 11

5%

Question 12

Parinaud’s syndrome

Answer 12

4 components: Parinaud dorsal midbrain
-pupillary near- light dissociation (ciliary ganglion causes a tonic pupil)
-impaired bilateral upgaze
-bilateral eyelid retraction
-convergence-retraction nystagmus

Answer 13

The left oculomotor nucleus has the dorsal median subnucleus that sends fibers to the right superior rectus. Injury of this subnucleus causes impaired right eye elevation. The right oculomotor nucleus has the dorsal median subnucleus that sends axons to the left superior rectus muscle by passing through the left oculomotor nucleus. Therefore injury of the left oculomotor nucleus injures axons from the right oculomotor dorsal median subnucleus causing impaired right eye elevation. Finally, the left oculomotor nucleus has subnuclei that send axons to the left medial rectus, inferior rectus, and inferior oblique muscles. Injury to these subnuclei cause impaired left eye adduction and depression.

-left ventral midbrain would involve the left 3rd nerve fascicle. Injury to the left 3rd nerve fascicle or the left 3rd nerve as it runs between the posterior cerebral and superior cerebellar arteries would cause left ptosis and impaired left eye elevation, adduction and depression.

Question 14

etoh effects

Answer 14

Acutely alcohol acts as a CNS depressant by reducing glutamate activity and increasing GABA activity, Cocaine primarily acts as a CNS stimulant by blocking presynaptic uptake of dopamine and norepinephrine and blocking the dopamine transporter. No drugs of abuse inhibit dopamine receptors.

Question 15

poisoning

Answer 15

Acute toluene-confusion and ataxia. Hypokalemia and weakness with a non-anion gap acidosis

Chronic abuse -leukoencephalopathy - white matter in medial temporal lobes and corpus callosum

Nitrous oxide abuse can cause a relative B12 deficiency, which can result in a myeloneuropathy

Alcohol/propane abuse could cause a similar ataxia/confusion, no hypokalemia or the white matter changes seen here.

Question 16

opioids receptors

Answer 16

Salvia Divinorum- kappa opioid receptors-Spice is a synthetic cannabinoid.

Bath Salts are synthetic cathinones, which are derivatives of the naturally occurring beta-ketone amphetamine analogue.
GHB (Gamma Hydroxybutyrate) is GABA agonist.

Question 17

cocaine vs amphetamine

Answer 17

hydroxyamphetamine-3rd order presynaptic release of NE - distinguishes 1st + 2nd from 3rd
Cocaine -block reuptake DA, NE and blocking DA reuptake transporter DAT NET

Question 18

vertigo provoked by loud noises, Valsalva - direction of ear and canal

Answer 18

anterior canal -upbeating beats away, downbeating beats towards

Question 19

optic neuropathy + branch retinal artery occlusion

Answer 19

giant cell arteritis

APD + white disc

Question 20

orbital apex structures

Answer 20

CN II-enters through optic canal
CN VI-enters skull through superior orbital fissure

CN II and CN VI

(cav sinus = 3, 4, v1, v2, 6)

Question 21

Localization RAPD

Answer 21

ipsilateral optic neuropathy or contralateral optic tract

Question 22

bilateral abducens + bilateral optic neuropathy

Answer 22

bilateral papilledema and bilateral abduction deficits-bilateral orbital apex syndromes or false localizing sign b/c papilledema + abducens BL palsy just means elevated intracranial pressure
-compressed at clivus of the temporal bones.

-arachnid granulations clogged-increase ICP

Question 23

junctional -optic nerve + chiasm

Answer 23

A lesion at the junction of the right optic nerve and chiasm would cause a right optic neuropathy and superior lateral visual field loss in the left eye from involvement of left inferior nasal fibers that entered the chiasm and right optic nerve in Wilbrand’s knee.

Question 24

localization incongruent homonymous hemianopia

Answer 24

incongruent right homonymous hemianopsia. This is most consistent with an optic tract lesion. As the visual pathway proceeds posteriorly, the fibers from a particular visual location for each eye run closer together increasing the congruency of the visual field loss when a lesion occurs. Therefore a left occipital lobe visual field cut is usually nearly identical in each eye. A visual field cut from a lesion of the left temporal optic radiations should cause relatively congruent superior visual field loss. A visual field cut from a lesion of the left lateral geniculate nucleus should cause either a quadruple quadrantanopsia if the anterior choroidal artery is affected or a horizontal sectorpsia if the posterior choroidal artery is affected. A lesion at the junction of the right optic nerve and chiasm would cause a right optic neuropathy and superior lateral visual field loss in the left eye from involvement of left inferior nasal fibers that entered the chiasm and right optic nerve in Wilbrand’s knee. A right optic neuropathy would not cause visual field loss that affects superior and inferior retinal fibers and respects the vertical meridian since the superior retinal fibers run together to enter the top of the optic nerve and the inferior retinal fibers run together to enter the bottom of the optic nerve.

Question 25

ocular abnormalities NF1 vs NF2

Answer 25

NF1-ocular pathway glioma; lisch nodules

NF-2 include juvenile posterior subcapsular cataracts, epiretinal membranes, and retinal astrocytic hamartomas

sturge weber - glaucoma, choroidal/conjunctival hemangiomas

Question 28

Superior oblique vs inferior rectus

Answer 28

SO: depresses and intorts
IR: depresses and extorts

IO: elevates and extorts
SR: elevates and