For healthcare professionals

Hunt and Hess scale

The Hunt and Hess scale grades the clinical severity of an aneurysmal subarachnoid hemorrhage (bleeding around the brain from a burst aneurysm) from grade I to grade V, using headache, neck stiffness, level of consciousness and neurological deficits. This tool is written for clinicians caring for a patient with a diagnosed bleed. It is not a self-check and not a diagnosis.

Last reviewed: 2026-11-03 By the uncovermyrisk.com editorial team Educational only, not medical advice.

A sudden, severe headache with no known cause: call 911 now.General safety advice (not part of the published scale). A sudden severe headache is one of the emergency signs of stroke (CDC). A bleed needs a brain scan in hospital; do not wait for a grade.

Clinical findings

For a patient with a diagnosed aneurysmal subarachnoid hemorrhage. Choose the one description that best fits the patient now. Nothing you enter leaves this page.

Hunt and Hess grade

Grade I. Asymptomatic or minimal headache and slight nuchal rigidity Grade II. Moderate or 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 disturbance Grade V. Deep coma, decerebrate posturing, moribund appearance

Result appears here

What you will see

The Hunt and Hess grade from I to V with its definition as printed in the source.

Educational only, not medical advice. A grade never replaces the judgment of the treating team.

Source

The Hunt and Hess classification by Hunt WE and Hess RM, Journal of Neurosurgery 1968, with the grade definitions as printed in the open access Table 5 of Patel and colleagues, International Journal of Emergency Medicine 2021 (CC BY 4.0), and cross-checked against the table in Marcolini and Hine, Western Journal of Emergency Medicine 2019 (CC BY 4.0). The tests check every grade against the printed wording.

Validated in

Patients with an aneurysmal subarachnoid hemorrhage. The original 1968 paper, which we cite but do not quote because its license does not allow reuse here, related the grade to surgical risk. Patel and colleagues write that the classification was established in 1968 to estimate mortality based on a specific list of criteria.

Limits

For a diagnosed subarachnoid hemorrhage only: the scale does not diagnose a bleed and is not for a headache that has not been investigated. The grade rests on clinical judgment, and the words in each grade (such as mild, moderate or severe) are not defined by exact thresholds, so two clinicians can choose different grades for the same patient. The two open reviews also print different outcome figures next to the grades (mortality in one, survival in the other), so this tool gives the grade only and no outcome estimate.

The grades

Hunt and Hess classification, as printed in Patel and colleagues 2021, Table 5 (Patel 2021) (Hunt 1968):

Grade I: Asymptomatic or minimal headache and slight nuchal rigidity
Grade II: Moderate or 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 disturbance
Grade V: Deep coma, decerebrate posturing, moribund appearance

Marcolini and Hine print the same five grades with small wording differences (Marcolini 2019): grade I reads "Asymptomatic or mild headache with slight nuchal rigidity", grade IV ends "or vegetative disturbance" and grade V reads "Deep coma, decerebrate rigidity, moribund appearance".

Reading the result

Marcolini and Hine write that the Hunt and Hess score and the World Federation of Neurological Surgeons grading system are both used to predict patient outcome, and that the Fisher grade helps to predict vasospasm (Marcolini 2019). They also note that patients with Hunt and Hess grades I and II are more commonly missed, because their symptoms are milder (Marcolini 2019). A low grade therefore does not mean a minor problem: a subarachnoid hemorrhage of any grade needs urgent specialist care.

Related tools

To decide which patients with a sudden severe headache need testing for a subarachnoid hemorrhage, see the Ottawa SAH rule. The WFNS grade grades the same bleed from the Glasgow Coma Scale and motor deficit, and the modified Fisher scale grades it on the initial CT. To score level of consciousness, use the Glasgow Coma Scale calculator. For a bleed into the brain tissue, see the ICH score. Other bedside scores are listed under For healthcare professionals.

Sources

Patel S, Parikh A, Okorie ON. Subarachnoid hemorrhage in the emergency department. Int J Emerg Med. 2021;14(1):31. doi:10.1186/s12245-021-00353-w. PMID 33980142. Open access (CC BY 4.0). Table 5 (Hunt and Hess classification). pmc.ncbi.nlm.nih.gov/articles/PMC8117305/
Marcolini E, Hine J. Approach to the diagnosis and management of subarachnoid hemorrhage. West J Emerg Med. 2019;20(2):203-211. doi:10.5811/westjem.2019.1.37352. PMID 30881537. Open access (CC BY 4.0). Table (Hunt and Hess grading for subarachnoid hemorrhage). pmc.ncbi.nlm.nih.gov/articles/PMC6404699/
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. doi:10.3171/jns.1968.28.1.0014. PMID 5635959. Original grading (cited, not quoted). doi.org/10.3171/jns.1968.28.1.0014
Centers for Disease Control and Prevention. Signs and Symptoms of Stroke. www.cdc.gov/stroke/signs-symptoms/index.html

Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-11-03. Spotted an error? See About.