Acute Stroke Assessment: The NIHSS Standard
The NIH Stroke Scale (NIHSS) is the definitive tool used in emergency departments worldwide to quantify the neurological impairment caused by an acute ischemic stroke. Rapid and accurate NIHSS scoring is the cornerstone of the "Time is Brain" philosophy.
Why NIHSS Matters for tPA
Alteplase (tPA) and Tenecteplase are highly effective but carry a risk of intracranial hemorrhage. The NIHSS helps determine if the benefit of reperfusion outweighs the risk. A score of 4 or greater is generally the threshold for considering thrombolysis, while lower scores are treated if the deficit is disabling (e.g., loss of speech).
Predicting LVO (Large Vessel Occlusion)
Stroke specialists use the NIHSS to predict if a patient has a massive blockage in a major artery like the MCA or ICA. An NIHSS score ≥6 is a strong predictor of LVO, potentially qualifying the patient for Endovascular Thrombectomy (EVT)—a mechanical procedure to remove the clot.
Clinical Interpretation Summary
- 1 - 4Minor Stroke
- 5 - 15Moderate Stroke
- 16 - 20Moderate to Severe
- 21 - 42Severe Stroke