Grades the clinical severity of aneurysmal subarachnoid hemorrhage, from grade I (mild headache) to grade V (deep coma).
Result
The grade appears here.
With in-hospital mortality for that grade.
In-hospital mortality by grade
1,200 consecutive patients with subarachnoid hemorrhage, Columbia University, New York, 1996–2009. Lantigua et al., Crit Care 2015 (PubMed)
Grade I
3.5%
12 of 342
Grade II
3.2%
6 of 186
Grade III
9.4%
30 of 319
Grade IV
23.6%
41 of 173
Grade V
70.5%
127 of 180
Group averages from published cohorts, not a prediction for one patient. Age, CT blood, hydrocephalus, rebleeding and complications change the outlook. All outcomes
Sources
AHA/ASA 2023: Class 1 · 6 studies
Class 1AHA/ASA 2023 recommends a clinical grade such as Hunt and Hess.
6
studies
3,371
citations
2,174
PubMed papers
Evidence
Guideline recommendation
“In patients with aSAH, use of clinical scales (eg, the Hunt and Hess [HH] grade or World Federation of Neurosurgical Societies [WFNS] grade) is recommended to determine initial clinical severity and predict outcome.”
Known limitations
In 1,200 consecutive patients, in-hospital mortality was 18%, rising from 3% at grades I and II to 71% at grade V. The leading causes of death were the effects of the initial hemorrhage, rebleeding and medical complications.
Crit Care: Journal Metrics Score 7.4, Q1 · cited 380 times
PubMed · Free full text · DOI
In 291 consecutive patients, the admission Hunt and Hess grade was the best of three scales at predicting mortality (odds ratio 3.39 in a logistic model), while a grade based on the Glasgow Coma Scale best predicted the Glasgow Outcome Score at discharge. Interrater kappa in 15 prospectively graded patients was 0.41 for Hunt and Hess.
Neurosurgery: Journal Metrics Score 0.9, Q3 · cited 176 times
Across 103 paired assessments of 50 patients by 57 raters, agreement was lowest for Hunt and Hess (weighted kappa 0.48, 95% CI 0.36–0.59), compared with 0.60 for WFNS and 0.64 for PAASH.
The terms for the level of consciousness used by Hunt and Hess were significantly less consistent between observers than the Glasgow Coma Scale, and grading headache severity caused the most disagreement.
J Neurosurg: Journal Metrics Score 2.9, Q1 · cited 103 times
Over 15 years at one neurocritical care unit, outcomes improved for good-grade and grade III patients but not for grades IV and V, and the admission grade became a weaker predictor of outcome as care improved.
Neurosurgery: Journal Metrics Score 0.9, Q3 · cited 70 times
PubMed · Free full text · DOI
A systematic review of grading scales found that most were derived retrospectively and that intra- and interobserver variability had seldom been assessed. The authors recommend reporting at least the admission Glasgow Coma Scale score and other known prognostic factors.
Neurocrit Care: Journal Metrics Score 2.5, Q1 · cited 348 times
The original paper has been cited 3,371 times, and 2,174 PubMed articles mention the Hunt and Hess scale in their title or abstract. Citation counts from OpenAlex and article counts from PubMed, retrieved November 4, 2026. Journal Metrics Scores and quartiles are from this site’s current release; follow the journal name for details.
Prognosis
In-hospital mortality 3.5% (grade I) to 70.5% (grade V)
Outcomes by grade
Mortality rises steeply from grade III to grade V. The figures are copied from the tables of two large modern cohorts and are group averages for the admission grade, so decisions about life-sustaining treatment should not rest on the grade alone. The 1968 surgical series is not shown, because its mortality reflects surgery of that era.
In-hospital mortality
1,200 consecutive patients with subarachnoid hemorrhage, Columbia University, New York, 1996–2009.
Admission grade. Most deaths followed brain death or withdrawal of life support.
Lantigua H et al., Crit Care 2015 · PubMed · Free full text · DOI
In-hospital mortality, treated aneurysm
1,586 patients whose ruptured aneurysm was coiled or clipped, Emory University, Atlanta, 2007–2016.
Samuels OB et al., Neurosurgery 2021 · PubMed · Free full text · DOI
Independent at discharge (modified Rankin Scale 0–2), treated aneurysm
1,586 patients whose ruptured aneurysm was coiled or clipped, Emory University, Atlanta, 2007–2016.
Samuels OB et al., Neurosurgery 2021 · PubMed · Free full text · DOI
After grading
Advice · Management · Critical actions
Treat the aneurysm within 24 hours and start nimodipine early.
Next steps
From the 2023 AHA/ASA guideline for aneurysmal subarachnoid hemorrhage:
Avoid common errors
6 common errors to avoid
and 4 more
Before you record the grade
1Grade after resuscitation
Hydrocephalus, a seizure or the post-ictal state, hypoxia and hypotension can make a patient look a grade or two worse. Grade again once they are corrected, for example after an external ventricular drain.
2Sedated or intubated patients
Sedation hides the level of consciousness. Use the grade recorded before intubation, or record that the grade could not be assessed.
3Aphasia is not confusion
A patient who cannot speak but follows commands may be aphasic rather than drowsy or stuporous. Grade the level of consciousness, not the speech.
4Grade again when things change
A rebleed, new hydrocephalus or delayed cerebral ischemia can change the grade within hours. Keep the admission grade for research and prognosis, and record each later grade with its time.
5A third nerve palsy alone is grade II
Hunt and Hess allowed a cranial nerve palsy in grade II. It moves the patient to grade III only with drowsiness, confusion or another focal deficit.
6Not interchangeable with WFNS
There is no official conversion from the Glasgow Coma Scale to Hunt and Hess. Record both grades rather than translating one into the other.
Formula
Five grades from the 1968 paper, as used in practice today.
Five grades from the 1968 paper, as used in practice today.
Scoring rules
| Grade | Criteria (Hunt and Hess, 1968) |
|---|---|
| I | Asymptomatic, or minimal headache and slight nuchal rigidity |
| II | Moderate to severe headache, nuchal rigidity, no neurologic deficit other than cranial nerve palsy |
| III | Drowsiness, confusion, or mild focal deficit |
| IV | Stupor, moderate to severe hemiparesis, possibly early decerebrate rigidity and vegetative disturbances |
| V | Deep coma, decerebrate rigidity, moribund appearance |
Original 1968 modifier (not used here)
Choosing a grade
Later additions
History
William E. Hunt and Robert M. Hess Jr, 1968
William E. Hunt and Robert M. Hess JrOhio State University, 1968
About the creators
1921–1999 · Chief of Neurological Surgery, Ohio State University
Hunt earned his medical degree at Ohio State in 1945, trained in neurosurgery with Henry Schwartz at Washington University in St. Louis, and led the Division of Neurological Surgery at Ohio State from 1963 until he retired in 1989. Besides the Hunt and Hess scale, his work on cerebrovascular disease gave its name to Tolosa–Hunt syndrome.
1931–2019 · Neurosurgeon, Ohio State University
Hess worked with Hunt, his mentor, on the Ohio State aneurysm series while training in neurosurgery there. Their 1968 paper adapted the earlier Botterell classification to estimate surgical risk in 275 patients, and the five grades it described became the Hunt and Hess scale.
Test cases
7 published cases, each also a test case
7 published cases; the calculator reproduces every grade.
Worked examples
A 51-year-old man with severe headache for 8 hours, a stiff neck and full strength in all limbs, who obeyed commands. No history of hypertension or diabetes. The report gives Hunt–Hess grade II.
“the patient could obey the orders and had a stiff neck. His upper and lower limbs had grade V muscle strength. The patient’s Hunt–Hess scale score was Grade II.”
Entered as: Moderate to severe headache and stiff neck, no neurological deficit.
Source: Yu J, Int J Surg Case Rep 2025 (PubMed · Free full text · DOI)
A 57-year-old man with a four-hour history of severe headache and vomiting, neck stiffness and full strength, who followed commands. No history of hypertension or diabetes. The report gives Hunt–Hess grade II.
Entered as: Moderate to severe headache and stiff neck, no neurological deficit.
Source: Zheng L et al., Front Surg 2026 (PubMed · Free full text · DOI)
A 50-year-old woman with six hours of thunderclap headache, nausea, dysphasia and deterioration of consciousness; examination found a complete right third nerve palsy and 4/5 left hemiparesis. The report gives Hunt and Hess grade 3.
Deteriorating consciousness with dysphasia and 4/5 hemiparesis fits grade III (drowsiness, confusion or mild focal deficit). The third nerve palsy alone would only be grade II.
Entered as: Drowsy or confused, or a mild focal deficit.
Source: Riley Moguel AE et al., Cureus 2024 (PubMed · Free full text · DOI)
A 39-year-old man found unconscious at home, with a Glasgow Coma Scale score of 9 (E2V1M6) and left hemiparesis. The report gives Hunt and Hess grade 4.
E2V1M6 is a borderline picture: a patient who obeys commands but makes no sounds may be aphasic rather than stuporous, and some would grade this patient III. The authors graded IV, which the depressed eye opening and the hemiparesis support.
Entered as: Stuporous, or moderate to severe hemiparesis.
Source: Lopes D et al., Cureus 2025 (PubMed · Free full text · DOI)
Hunt and Hess define grade I as asymptomatic, or minimal headache and slight nuchal rigidity.
In grade II a cranial nerve palsy is allowed: moderate to severe headache, nuchal rigidity, and no neurologic deficit other than cranial nerve palsy.
Hunt and Hess define grade V as deep coma, decerebrate rigidity and moribund appearance.
FAQ
10 questions and answers
and 8 more answers
Questions
The Hunt and Hess scale is a five-grade clinical classification of patients with aneurysmal subarachnoid hemorrhage, from grade I (no symptoms or a minimal headache) to grade V (deep coma). William Hunt and Robert Hess published it in the Journal of Neurosurgery in 1968 to estimate surgical risk, and it is still one of the two most used clinical grades with the WFNS scale.
Grade I: asymptomatic, or minimal headache and slight nuchal rigidity. Grade II: moderate to severe headache, nuchal rigidity, no neurologic deficit other than cranial nerve palsy. Grade III: drowsiness, confusion, or mild focal deficit. Grade IV: stupor, moderate to severe hemiparesis, possibly early decerebrate rigidity and vegetative disturbances. Grade V: deep coma, decerebrate rigidity, moribund appearance.
Grades IV and V. The 2023 AHA/ASA guideline notes that most of the literature defines high-grade (poor-grade) subarachnoid hemorrhage as Hunt and Hess grade 4 and 5 or WFNS grade 4 and 5. Grades I to III are usually grouped as good grade.
In the original scale, yes. Hunt and Hess placed patients with serious systemic disease, such as hypertension, diabetes, severe arteriosclerosis or chronic pulmonary disease, or with severe vasospasm on arteriography, in the next less favorable grade. Many later studies report the grade without this adjustment, so state which version you used. This calculator uses the version without it, as most clinicians and studies do.
Hunt and Kosnik added them in 1974. Grade 0 is an unruptured aneurysm. Grade Ia is a patient with no acute meningeal or brain reaction but with a fixed neurological deficit. They are rarely used in current studies of ruptured aneurysms.
The Hunt and Hess scale uses descriptive terms such as drowsiness, stupor and coma. The World Federation of Neurosurgical Societies (WFNS) scale grades the Glasgow Coma Scale score and the presence of a motor deficit instead. In a study of 103 paired assessments, agreement between observers was lower for Hunt and Hess (weighted kappa 0.48) than for WFNS (0.60).
No. The Hunt and Hess scale grades the patient’s clinical condition, while the Fisher and modified Fisher scales grade the amount and distribution of blood on the CT scan and are used to estimate the risk of vasospasm. Papers usually report one clinical grade and one CT grade together.
There is no official conversion, because the Hunt and Hess scale was defined with descriptive terms before the Glasgow Coma Scale was published. If you have the GCS, record it and use the WFNS scale alongside the Hunt and Hess grade.
In 1,200 consecutive patients treated at Columbia University between 1996 and 2009, in-hospital mortality by admission grade was 3.5% for grade I, 3.2% for grade II, 9.4% for grade III, 23.6% for grade IV and 70.5% for grade V (Lantigua 2015). In 1,586 patients whose aneurysm was treated at Emory University between 2007 and 2016, in-hospital mortality was 5.4% for grades I and II, 11.5% for grade III and 37.0% for grades IV and V (Samuels 2021). These are group averages, not a prediction for one patient.
Higher grades go with higher mortality and worse functional outcome. In a series of 291 patients, the admission Hunt and Hess grade was the strongest of the three scales tested for predicting mortality. In the Emory cohort, 69.1% of treated grade I and II patients were independent at discharge, compared with 40.3% at grade III and 8.4% at grades IV and V. Outcome figures from the 1968 surgical series are much worse than in modern series and should not be used to counsel patients today.
Further reading
13 references with PubMed and DOI links
13
references
6
free full text
From Hunt WE et al., J Neurosurg 1968 to the newest case reports.
References
Contributed by Dr. Meng Zhao (MD · Former Neurosurgeon · Medical AI Researcher), from the original publications listed here. Last updated November 4, 2026. LinkedIn
The calculator code is tested against every worked example on this page before each release.
This calculator supports, and does not replace, clinical judgment. It is meant for healthcare professionals and is not medical advice for patients. Report an error through the contact page.
The journal that published the original scale, with its current metrics.
Compare journals before you submit a subarachnoid hemorrhage paper.