Penn tests Flashcards
brainstem auditory evoked potentials
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).
SSEPs
- 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.
musk
NO thymus pathology
-sensitive to rituximab
-female predominant
lems
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
MG diagnosis
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
Wernicke-Korsakoff
thiamine is a critical co-factor multiple enzymes involved in carbohydrate metabolism.
asymmetric stepwise progression of painful cranial and/or peripheral neuropathies
mononeuritis multiplex
innervation flexor pollicis longus?
AIN median
[flexor pollicis brevis deep head ulnar]
monoclonal gammopathies
MGUS - IgG or IgA
Waldenstrom- IgM
MM - IgG in 50% ,IgA 21%, kappa/lambda light chain Bence jones 16%
martin gruber anastamosis emg
stimulate median and record at ADM getting robust response
Delirium tremens inhospital mortality rate
5%
Parinaud’s syndrome
4 components: Parinaud dorsal midbrain
-pupillary near- light dissociation (ciliary ganglion causes a tonic pupil)
-impaired bilateral upgaze
-bilateral eyelid retraction
-convergence-retraction nystagmus
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.
etoh effects
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.
poisoning
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.