Neurology: Localization, Vascular Syndromes, and Emergencies
Core concepts
The neurology section rewards a disciplined anatomic localization before any diagnostic leap. Work top-down: mental status and language, cranial nerves, motor (tone, power, reflexes), sensory, coordination, and gait. Distinguish upper vs lower motor neuron signs (spasticity, hyperreflexia, Babinski vs atrophy, fasciculations, areflexia). Know the classic stroke syndromes: middle cerebral artery (contralateral face/arm weakness, aphasia if dominant), posterior circulation (vertigo, diplopia, dysarthria, crossed findings), and lacunar patterns (pure motor, pure sensory). Be fluent in seizure semiology (focal vs generalized, postictal confusion), headache red flags (thunderclap, fever with meningismus, positional, neurologic deficit), and altered mental status framing (AEIOU: alcohol, endocrine, insulin, oxygen, uremia, plus infection, stroke, seizure, drugs).
Traps in questions
Questions often tempt you toward imaging before stabilization or toward a rare diagnosis when the stem describes a common emergency. Remember time-critical priorities: acute ischemic stroke within the thrombolysis window, bacterial meningitis (antibiotics before imaging if stable), and status epilepticus (benzodiazepine first). Do not confuse delirium with dementia-acute onset and fluctuating attention point to delirium. Watch for peripheral vs central vertigo cues (direction-changing nystagmus, vertical nystagmus, and focal deficits favor central).
Worked example / rule of thumb
A patient with sudden right arm and face weakness plus expressive aphasia localizes to the left MCA territory; the priority is rapid imaging and thrombolysis eligibility, not outpatient workup. Rule of thumb: localize first, then ask "is this time-critical?" before choosing a test.