NIHSS Score: Ischemic Stroke Severity Calculator
Calculate the NIH Stroke Scale (NIHSS) online to objectively assess ischemic stroke severity. A crucial tool for thrombolysis decision-making and neurological prognosis.
Understanding the NIHSS Scale
The National Institutes of Health Stroke Scale (NIHSS) is the cornerstone of clinical evaluation in emergency neurology. It provides a standardized method to quantify neurological deficits.
The 11 Domains of Neurological Evaluation
The scale consists of 11 items (total score 0-42):
- Consciousness: Alertness, orientation, and commands.
- Vision: Gaze and visual fields.
- Motor Function: Facial palsy and limb strength.
- Ataxia: Cerebellar involvement.
- Sensation & Language: Sensory loss, aphasia, dysarthria, and neglect.
Therapeutic Implications: Thrombolysis
The NIHSS score guides reperfusion therapy decisions:
- A score between 4 and 25 is typically an indication for IV thrombolysis.
- Very low scores (1-3) may preclude thrombolysis unless deficits are disabling.
- Scores > 25 indicate a massive infarction with a high risk of hemorrhage.
Stroke Severity Classification
| NIHSS Score | Clinical Severity |
|---|---|
| 0 | Normal neurological exam |
| 1 - 4 | Minor stroke |
| 5 - 15 | Moderate stroke |
| 16 - 20 | Moderate to severe stroke |
| 21 - 42 | Severe stroke |
Clinical Limitations
The NIHSS tends to over-score left-hemisphere strokes (due to aphasia points) and under-score right-hemisphere or brainstem strokes. It must always be correlated with urgent brain imaging.
References:
1. Brott T, Adams HP Jr, Olinger CP, et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke. 1989.
[Stroke Journal]
2. National Institute of Neurological Disorders and Stroke (NINDS). NIH Stroke Scale Training.
[NIH / NINDS]
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