Grading Scales in Subarachnoid Hemorrhage
SAH grading serves two distinct purposes: clinical scales (Hunt-Hess, WFNS) capture the patient's neurological condition at presentation and predict outcome, while the radiographic scale (modified Fisher) quantifies the blood burden on CT and predicts vasospasm / delayed cerebral ischemia (DCI). The VASOGRADE combines both to stratify DCI risk. For the disease background see Overview & Pathophysiology.
Bottom Line: SAH Grading
- Clinical → prognosis: Hunt-Hess and WFNS (GCS-based) grade severity 1–5; higher grade = worse outcome.
- Radiographic → vasospasm risk: the modified Fisher scale (0–4) rises with cisternal blood thickness and IVH — risk increases monotonically, unlike the original Fisher scale.
- VASOGRADE merges modified Fisher + WFNS into Green / Yellow / Red to predict DCI; Red (poor clinical grade) carries the highest risk.
- Always record a clinical and a radiographic grade on admission — they drive prognosis discussions, DCI surveillance intensity, and trial enrollment.
1. Hunt & Hess Scale (clinical)
The oldest and still widely used clinical scale (1968); grade correlates with surgical risk and mortality.
| Grade | Clinical findings |
|---|---|
| I | Asymptomatic, or mild headache and slight nuchal rigidity |
| II | Moderate-to-severe headache, nuchal rigidity; no neurological deficit other than a cranial-nerve palsy |
| III | Drowsiness, confusion, or mild focal deficit |
| IV | Stupor, moderate-to-severe hemiparesis, early decerebrate posturing |
| V | Deep coma, decerebrate rigidity, moribund appearance |
Mortality rises steeply with grade — low for I–II and very high for IV–V. (A common modification adds +1 grade for serious systemic disease, e.g., severe hypertension, COPD.)
2. WFNS Scale (clinical, GCS-based)
The World Federation of Neurosurgical Societies scale (1988) anchors grading to the Glasgow Coma Scale plus the presence of a major focal deficit, making it more reproducible than Hunt-Hess.
| Grade | GCS | Major focal deficit |
|---|---|---|
| I | 15 | Absent |
| II | 13–14 | Absent |
| III | 13–14 | Present |
| IV | 7–12 | Present or absent |
| V | 3–6 | Present or absent |
3. Modified Fisher Scale (radiographic)
Graded on the first non-contrast CT, the modified Fisher scale (Frontera, 2006) predicts symptomatic vasospasm. It improved on the original Fisher scale by accounting for both cisternal blood thickness and intraventricular hemorrhage (IVH), so that risk increases monotonically across grades (the original scale's risk paradoxically peaked at grade 3).
| Grade | CT findings | Vasospasm risk |
|---|---|---|
| 0 | No SAH and no IVH | Lowest |
| 1 | Focal or thin diffuse SAH, no IVH | Low |
| 2 | Focal or thin diffuse SAH with IVH | Intermediate |
| 3 | Thick SAH (filling a cistern/fissure), no IVH | High |
| 4 | Thick SAH with IVH | Highest |
4. VASOGRADE (combined DCI risk)
The VASOGRADE (de Oliveira Manoel, 2015) combines the radiographic and clinical grades into a simple traffic-light tool validated to predict delayed cerebral ischemia.
| VASOGRADE | Definition | DCI risk |
|---|---|---|
| Green | Modified Fisher 1–2 and WFNS 1–2 | Low |
| Yellow | Modified Fisher 3–4 and WFNS 1–3 | Intermediate |
| Red | WFNS 4–5 (any modified Fisher grade) | High (~3× vs Green) |
5. Using the Scales Together
- On admission: record a clinical grade (Hunt-Hess and/or WFNS) and the modified Fisher grade.
- Prognosis: clinical grade is the strongest early predictor of functional outcome and mortality.
- DCI surveillance: modified Fisher (blood burden) and VASOGRADE guide how intensively to monitor for vasospasm/DCI over days 4–14 — see Vasospasm & DCI.
- Communication & research: standardized grades enable consistent handoffs and trial eligibility.
References
- Hunt WE, Hess RM. Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg. 1968;28(1):14–20.
- Report of World Federation of Neurological Surgeons Committee on a Universal Subarachnoid Hemorrhage Grading Scale. J Neurosurg. 1988;68(6):985–986.
- Frontera JA, et al. Prediction of symptomatic vasospasm after subarachnoid hemorrhage: the modified Fisher scale. Neurosurgery. 2006;59(1):21–27.
- de Oliveira Manoel AL, et al. The VASOGRADE: a simple grading scale for prediction of delayed cerebral ischemia after subarachnoid hemorrhage. Stroke. 2015;46(7):1826–1831.
- Hoh BL, et al. 2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage. Stroke. 2023;54(7):e314–e370.
