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Standardized neurological assessment for acute stroke severity
Activate stroke code immediately. Time last known well. Target door-to-needle <60 minutes for tPA. Target door-to-groin <90 minutes for thrombectomy. This calculator is for trained medical professionals only.
| Score | Severity | Clinical Implications | Prognosis |
|---|---|---|---|
| 0 | No stroke | No neurological deficits | Excellent |
| 1-4 | Minor | Consider tPA if within window | Good (70-80% favorable) |
| 5-15 | Moderate | Strong tPA/thrombectomy candidate | Variable (50-70% favorable) |
| 16-20 | Mod-Severe | Likely LVO - consider thrombectomy | Guarded (30-50% favorable) |
| 21-42 | Severe | High hemorrhagic risk, likely LVO | Poor (<20% favorable) |
LVO = Large Vessel Occlusion. Favorable outcome = mRS 0-2.
Significant improvement. May indicate successful reperfusion or spontaneous recanalization.
No significant change. Continue monitoring and supportive care.
Neurological decline. Consider hemorrhagic transformation, reocclusion, or stroke extension. Urgent head CT.
The NIH Stroke Scale is a 15-item (11 domains) standardized neurological exam used to objectively quantify stroke severity. Scores range from 0-42, with higher scores indicating more severe deficits.
Most centers use NIHSS ≥4 as a threshold, though some use ≥6. Very mild strokes (NIHSS 1-3) are controversial - risk vs. benefit must be weighed. Scores >22 have higher hemorrhagic risk.
NIHSS ≥6, especially with cortical signs (aphasia, neglect, gaze deviation). LVO strokes benefit most from mechanical thrombectomy. Use rapid LVO screening tools in conjunction with NIHSS.
At baseline, q15min × 2hrs after tPA, then q30min × 6hrs, then q1hr × 16hrs, then at 24hrs. More frequent if neurological changes. Serial scores track improvement or worsening.
Yes. Higher baseline NIHSS predicts worse functional outcome. NIHSS >20 has <20% chance of favorable outcome (mRS 0-2). Early improvement (↓4+ points) is a good prognostic sign.
Posterior circulation strokes may score low despite severe disability. Doesn't assess cognition, memory, or executive function well. Left hemisphere bias (language weighted). Examiner variability without training.