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The Hunt and Hess scale classifies the clinical severity of aneurysmal subarachnoid hemorrhage into five grades based on headache, nuchal rigidity, level of consciousness, and focal deficits. Higher grades predict higher mortality.
Grade assigned from clinical presentation: I (no or minimal symptoms) through V (coma with decerebrate posturing); higher grade = worse prognosis
Grade I is the least severe; Grade V is moribund. Historical mortality: I 1–3%, II 3–5%, III 9–19%, IV 23–42%, V 70–77%.
The Hunt and Hess scale was published by William Hunt and Robert Hess in 1968 (Journal of Neurosurgery) to grade the surgical risk in 275 patients with aneurysmal subarachnoid hemorrhage. Grade I denotes no or minimal symptoms; grade II moderate to severe headache with nuchal rigidity and no deficit other than cranial nerve palsy; grade III drowsiness, confusion, or mild focal deficit; grade IV stupor with moderate to severe hemiparesis and possible early decerebrate rigidity; and grade V deep coma with decerebrate rigidity. A 1974 modification added grades 0 and 1a and the rule to add one grade in the presence of serious systemic disease.
Specialty
NeurologyCategory
NeurologyDifficulty
Basic
Estimated Time
30 seconds
Version
1.0
Last Updated
2026-08-16
Formula
Keywords
Normal Range
Grade I is the least severe; Grade V is moribund. Historical mortality: I 1–3%, II 3–5%, III 9–19%, IV 23–42%, V 70–77%.
| Classification | Range |
|---|---|
Grade I Asymptomatic or minimal headache with slight nuchal rigidity | I |
Grade II Moderate–severe headache with nuchal rigidity; no deficit other than cranial nerve palsy | II |
Grade III Drowsy or confused, with mild focal deficit | III |
Grade IV Stupor, moderate–severe hemiparesis, possible early decerebrate rigidity | IV |
Grade V Deep coma, decerebrate rigidity, moribund | V |
Classifies the clinical severity of aneurysmal subarachnoid hemorrhage into five grades (I–V) based on headache, nuchal rigidity, level of consciousness, and focal deficits, and is used to estimate prognosis.
Lower grades predict better outcomes. Grades I–III are generally candidates for early aneurysm securing; grades IV–V require stabilization before treatment. Historical mortality ranged from 1–3% (grade I) to 70–77% (grade V), though modern outcomes are better.
Hunt and Hess grading provides a rapid, universally recognized language for SAH severity that guides the timing and intensity of aneurysm treatment and supports prognostication.
A 55-year-old woman with a confirmed posterior communicating artery aneurysm is drowsy, disoriented, and has a mild right hemiparesis after her SAH.
Inputs:
Hunt and Hess grade III — drowsy/confused with mild focal deficit; historical mortality ≈ 9–19%.
Historically 70–77%, but modern series with aggressive neurointensive care report substantially better outcomes.
Yes, it is commonly combined with the WFNS grade and the modified Fisher scale for a fuller assessment of SAH severity.
Pre-diagnosis triage of acute headache
Serial neurologic monitoring
Disclaimer: This calculator is intended for educational and clinical decision support purposes only. Mortality figures are historical; treatment decisions must follow current guidelines and the patient's full clinical picture.