Stroke & Cerebrovascular Disease Scores

Hunt and Hess Scale Calculator – Subarachnoid Hemorrhage Severity

Clinical calculation support · Verify results before clinical use

Clinical assessment

Select the single grade that best matches the patient's neurological examination.

—Grade

—HH grade

Clinical severity classification

Not yet assessed

Select a neurological presentation to display the grade.

Clinical interpretation

The scale describes clinical severity in patients with aneurysmal subarachnoid hemorrhage; it does not establish the diagnosis or provide an individualized mortality estimate.

About the Hunt and Hess Scale

The Hunt and Hess Scale classifies initial neurological severity in aneurysmal subarachnoid hemorrhage (aSAH). It is an ordinal grade from I to V, not a sum of independent findings. Higher grades generally indicate greater clinical severity and worse prognosis.

Clinical grading criteria

Grade	Clinical presentation
I	Asymptomatic or minimal headache with slight nuchal rigidity.
II	Moderate to severe headache and nuchal rigidity; no neurological deficit except cranial nerve palsy.
III	Drowsiness, confusion, or a mild focal neurological deficit.
IV	Stupor, moderate to severe hemiparesis, possibly early decerebrate rigidity or vegetative disturbance.
V	Deep coma, decerebrate rigidity, or moribund appearance.

Clinical considerations

Grades I–III and IV–V are sometimes grouped as lower-grade and high-grade aSAH, respectively. This grouping does not replace individualized clinical assessment. The original historical classification described worsening by one category for serious systemic disease or severe angiographic vasospasm; this tool implements the commonly used five-grade clinical presentation classification without automatic comorbidity adjustment.

Assess confounders such as sedation, intubation, seizures, hydrocephalus, and other reversible causes of impaired consciousness. Grade at a documented clinical time point and reassess when indicated.

References

Hunt WE, Hess RM. (1968).Surgical risk as related to time of intervention in the repair of intracranial aneurysms. J Neurosurg. 28(1):14–20.
doi:10.3171/jns.1968.28.1.0014

Hoh BL, Ko NU, Amin-Hanjani S, et al. (2023).2023 Guideline for the Management of Patients With Aneurysmal Subarachnoid Hemorrhage. Stroke. 54:e314–e370.
doi:10.1161/STR.0000000000000436

National Institute of Neurological Disorders and Stroke.Hunt and Hess scale. Common Data Elements Repository.
NINDS clinical definitions

Clinical disclaimer: Intended for qualified healthcare professionals. The Hunt and Hess grade supports initial severity assessment and prognostic communication; it must not be used alone to diagnose SAH, predict individual survival, determine treatment futility, or delay urgent neurovascular evaluation and treatment.