Stroke Assessment and Diagnosis
The NIHSS
Eleven items, maximum 42 points, covering level of consciousness (1a-1c), gaze, visual fields, facial palsy, arm and leg motor function, limb ataxia, sensation, language, dysarthria, and extinction/inattention. Score what the patient actually does, not what you think they can do. If item 1a is 3 (unarousable), score 3 on every remaining item and 0 for ataxia. Items that cannot be tested (amputation, intubation) are recorded as untestable, not as zero.
Imaging and workup
The noncontrast CT excludes hemorrhage and is the only study required before thrombolysis; target door-to-CT within 20 minutes and door-to-needle within 60 minutes in most centers. CTA identifies large-vessel occlusion and guides thrombectomy; CT perfusion or MRI mismatch selects late-window candidates. MRI diffusion-weighted imaging detects acute infarction within minutes but should never delay treatment.
Mimics and timing
Check glucose first - hypoglycemia is the classic mimic. Also consider seizure with postictal deficit, complicated migraine, conversion disorder, sepsis, and toxic-metabolic states. Establish the last known well time, not the time of discovery; wake-up strokes are timed from when the patient was last seen normal.
Traps: the NIHSS underestimates posterior circulation and small brainstem strokes. Dysarthria and aphasia are scored on separate items. A normal CT does not exclude ischemic stroke. TIA is a transient deficit without infarction on imaging - it still requires urgent evaluation (ABCD2 supports risk stratification but does not replace workup).
Rule of thumb: glucose, then CT, then drug. Screen swallowing before anything by mouth.