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Updated: Know ThySHELF: Neurology

Shelves! How beautiful and circuitous is our relationship with shelves? We hang them on the wall to hold up the books that we need to study for these tests that bear the same name. The neurology shelf is a particularly difficult test, especially given its lack of a reputation.  (This blog post was updated July 2019.)

Mention the surgery shelf or internal medicine shelf, and students tend to become hypervigilant and step up their games. But neurology doesn’t come with the same weight, though it certainly deserves devoted study and an action plan. While the lot of neuro pathology is more circumscribed than the other heavy-hitting subjects, the questions are just as difficult. Here are some special considerations to help focus your plan of attack.

Ain’t nothin gonna slow you down, oh no, you’ve got to keep on moving.

Time is as short as a neuron’s refractory period on the test. 110 questions over 165 minutes means you have to move quickly. And similarly to the psychiatry shelf, your stems will be LONG. Your classic dementia question often goes above and beyond to tell you how Mr. Johnson can no longer balance his checkbook, is getting lost on the way home from his child’s house, still finds enjoyment in the things in life he loves, hasn’t lost any weight, has normal vitals, performs well on this part of the mini-mental status exam but poorly on others, etc.

Remember not to get bogged down by these verbose blocks of text, and focus on the high yield information that comes from the first sentence of the stem. It is here you will usually find the age of the patient, the time course of the disease, if they went to a primary care office or were brought into the ED, or were brought in by a concerned family member. A patient with bacterial meningitis is probably not going to a routine office visit. And a patient with Alzheimer’s disease should not have an urgent issue so much as a subacute to chronic decline in functioning.

Given the time constraint, once you are comfortable with your answer, go with it, don’t vacillate, and move on. There will also be questions that you should identify with a very low probability of getting correct. If despite your best efforts, you simply could not get the knack of upper extremity innervations, it is unlikely that you will figure it out now under pressure. Select a decent answer, and move onto questions with a higher probability of correctness.

Drugs, drugs, and more drugs.

Neurologists have quite an armament of drugs for a myriad of conditions. Migraines alone have loads of options for both abortive therapy and prophylaxis. Combine that with a score of antiepileptic drugs and meningitis algorithms that are age-dependent, and you’ve got a solid chunk of medications that you are responsible for. Like most tests, in a world where there are so many appropriate first line choices for a prescription, side effects and nuances become key. Think about that patient with migraines. Given that you can choose between beta blockers, antidepressants, calcium channel blockers, anticonvulsants, and NSAIDs (yes, there are more), what other condition might the patient’s physiology appreciate coverage for? Concomitant depression? Tricyclic antidepressant sounds great. A hypertensive patient with migraines? Go with propranolol!

Consider a patient with epilepsy. You need to know that their gingival hyperplasia and cerebellar ataxia is probably not idiopathic — phenytoin is the likely culprit. If they instead present with controlled seizures but new onset transaminitis and thrombocytopenia, then we can blame valproic acid. (Both Valproic acid and liVer have a “V” to remember this connection. This same “V” can be a dagger into the platelets.)

The name of the game is lesion localization.

While the MRI machine takes some of the burden off of the clinician in diagnosis, a huge portion of the exam comes down to lesion localization. You should absolutely practice this art in your studying and clinical work, and develop a systematic approach to figuring out where a defect is. For a motor problem, some anatomical structure from the brain to the muscle itself is to blame.

It is paramount to have an excellent understanding of the complete pathway of signal from the motor cortex of the brain, working its way through the internal capsule, decussating down the medulla, coursing down the corticospinal tract to synapse at the lower motor neuron (anterior horn cell) in the grey matter, working its way to the neuromuscular junction, and finally the muscle. Sensory pathways naturally begin at distal receptors near the skin, work their way through the dorsal root ganglion onto their particular tract the spinal cord, decussate at different levels depending on their tract, work their way into the thalamus, and finally the sensory strip along the cortex in the parietal lobe. Knowledge of these pathways and tracts INSIDE AND OUT will be crucial and make your neurological life so much easier. As a corollary…

Know your anatomy, both intra- and extracranially.

By this point you have learned that Parkinson’s disease stems from pathology in the substantia nigra. But can you point to that on an MRI slice? Is foot drop a result of a tibial or common peroneal nerve injury? What abilities will be affected by a middle cerebral artery (MCA) stroke? Get your anatomy mastered as you prepare for the test. Be comfortable with the structure of the brain in axial, coronal, and sagittal slices. Remember the pain of drawing and redrawing the brachial plexus? The better you know it, the better you can explain upper extremity pathologies. Knowledge of spinal cord, especially your marquee tracts (corticospinal, spinothalamic, and dorsal columns) is also key.

Revisit an old friend to master the bread and butter.

Think about the classic conditions in a neurologist’s wheelhouse: strokes, seizures, meningitis, headaches, dementias, peripheral nerve problems, and cranial trauma all come to mind. You know that you will be tested on these topics. That dusty old copy of First Aid for Step 1 is definitely worth revisiting in preparation for the test. It will be a prime refresher in the basics of these conditions’ presentations, as well as their pathophysiology. The pharmacology section is pointed while being all-encompassing, and the anatomy review is spot on. First Aid alone can probably get you about 75% of the way there. Instill your clinical clerkship knowledge into this framework, use review books to put together the inbetweens, and head into test day with confidence.



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