Neurologic System
The neurologic domain tests acute stroke, seizures, headache, neuropathy, multiple sclerosis, and dementia, emphasizing time-sensitive treatment and recognition of emergencies.
Core rules
- Acute ischemic stroke: check glucose immediately, obtain noncontrast head CT to exclude hemorrhage, and determine last known well. IV thrombolysis is generally given within 4.5 hours if no contraindications; mechanical thrombectomy may be offered up to 24 hours in selected large-vessel occlusion.
- Seizure: protect the airway, check glucose, and give a benzodiazepine for prolonged seizure. Status epilepticus requires timely second-line antiseizure medication.
- Headache red flags include thunderclap onset, fever with neck stiffness, focal deficit, papilledema, cancer history, and age over 50 with new headache.
- Migraine with aura is a contraindication to combined oral contraceptives because of stroke risk.
Worked example
A 63-year-old woman has sudden right arm weakness. Last known well was two hours ago. Glucose is normal and head CT shows no hemorrhage. She has no contraindications, so give IV thrombolysis and arrange thrombectomy evaluation. Do not delay for an MRI, and do not lower blood pressure aggressively unless it exceeds thrombolysis thresholds.
Traps
- Missing hypoglycemia as a stroke mimic.
- Performing lumbar puncture before CT in suspected subarachnoid hemorrhage.
- Lowering blood pressure too rapidly in acute ischemic stroke.
- Attributing new focal deficits to migraine without imaging.