Hunt & Hess Scale Calculator — Subarachnoid Hemorrhage Grading
The Hunt & Hess Scale is a clinical grading system used to classify the severity of subarachnoid hemorrhage (SAH) based on the patient's neurological status at presentation, providing prognostic information on mortality risk.
About
The Hunt & Hess classification system was introduced by William E. Hunt and Robert M. Hess in 1968 in an article published in the Journal of Neurosurgery. It was developed to provide a standardized method for grading the surgical risk and prognosis of patients with intracranial aneurysms presenting with subarachnoid hemorrhage. The scale consists of five grades based on clinical severity, ranging from Grade 1 (asymptomatic or minimal symptoms) to Grade 5 (deep coma with decerebrate rigidity). Despite the development of more recent grading systems such as the WFNS (World Federation of Neurological Surgeons) scale, the Hunt & Hess classification remains widely used due to its simplicity and strong correlation with outcomes.
Formula
Grade 1-5 based on clinical severity
The Hunt & Hess grade is determined by assessing the patient's clinical neurological status at presentation. Grade 1 requires asymptomatic or minimal headache with slight nuchal rigidity. Grade 2 includes moderate to severe headache with nuchal rigidity and possible cranial nerve palsy but no other neurological deficit. Grade 3 indicates drowsiness, confusion, or mild focal neurological deficit. Grade 4 is stupor with moderate to severe hemiparesis and possible early decerebrate rigidity. Grade 5 is deep coma with decerebrate rigidity and a moribund appearance. Higher grades correlate with increased mortality: Grade 1 (5-10%), Grade 2 (10-15%), Grade 3 (35-40%), Grade 4 (60-70%), Grade 5 (70-90%). The grade should be assessed before sedation or surgical intervention and reassessed after any clinical deterioration.
Score Interpretation
The Hunt & Hess Scale is one of the most widely used clinical grading systems for subarachnoid hemorrhage, recognized by the American Heart Association/American Stroke Association (AHA/ASA) guidelines for SAH management. The scale provides critical prognostic information — mortality increases stepwise from 5-10% in Grade 1 to 70-90% in Grade 5 — and directly influences treatment decisions, including the timing of aneurysm securing, the need for external ventricular drainage, and the intensity of vasospasm monitoring. Grade 1-2 patients are considered "good-grade" SAH with favorable outcomes in 70-80% of cases, while Grade 4-5 patients are "poor-grade" with high rates of morbidity and mortality. The scale also correlates with the risk of vasospasm, delayed cerebral ischemia, and overall functional outcome at discharge and follow-up. Despite the WFNS scale being more recent, Hunt & Hess remains widely used in clinical practice and research. It should be performed at initial presentation and reassessed after any clinical deterioration and before surgical or endovascular intervention.
Grade 1 — Mild SAH — 1–1
Asymptomatic or minimal headache, slight nuchal rigidity. Mortality: 5-10%.
Management: Admit to ICU or step-down unit. Early aneurysm securing (coiling/clipping) within 24-48 hours. Start nimodipine 60 mg q4h PO/NG for 21 days. Close neurological monitoring.
Grade 2 — Moderate SAH — 2–2
Moderate to severe headache, nuchal rigidity, no neurological deficit except cranial nerve palsy. Mortality: 10-15%.
Management: ICU admission. Early angiography and aneurysm treatment. Nimodipine prophylaxis. Monitor for vasospasm with daily TCD. Maintain euvolemia and avoid hypotension.
Grade 3 — Severe SAH — 3–3
Drowsiness, confusion, mild focal neurological deficit. Mortality: 35-40%.
Management: ICU admission with invasive monitoring (ICP, arterial line). CT angiogram or DSA for aneurysm localization. Discuss with neurosurgery for aneurysm securing. Consider EVD for hydrocephalus. Nimodipine therapy.
Grade 4 — Severe SAH with Stupor — 4–4
Stupor, moderate to severe hemiparesis, early decerebrate rigidity. Mortality: 60-70%.
Management: ICU admission with ICP monitoring. EVD for hydrocephalus. Ventilation support if needed. Discuss with neurosurgery for aneurysm securing. Blood pressure optimization — maintain SBP <160 mmHg before aneurysm treatment. Consider vasospasm prophylaxis and monitoring.
Grade 5 — Critical SAH / Coma — 5–5
Deep coma, decerebrate rigidity, moribund appearance. Mortality: 70-90%.
Management: ICU admission with full intensive monitoring and support. EVD for hydrocephalus. Discuss prognosis with family. Consider angiogram and aneurysm treatment if clinical improvement. Multidisciplinary approach — neurosurgery, critical care, neuro-intervention.
Reference Ranges
| Population | Normal Range | Notes |
|---|---|---|
| Patients with aneurysmal SAH | Grade 1-5 | Higher grade = higher mortality. Grade 1: 5-10%, Grade 2: 10-15%, Grade 3: 35-40%, Grade 4: 60-70%, Grade 5: 70-90% |
Dr. Mahmoud El-Sayed, MD, Neurology Specialist
Dr. Mahmoud El-Sayed is a neurology consultant with expertise in cerebrovascular disease and TIA management.
View medical review board & editorial policy →Example Calculation
A 55-year-old woman with a history of hypertension and cigarette smoking presents to the emergency department with the worst headache of her life — a sudden-onset, severe thunderclap headache that began while she was having breakfast. She reports nausea, vomiting, and photophobia. On arrival, she is awake but drowsy, confused about the date and situation, and requires prompting to answer questions. She has mild left-sided arm drift on motor examination (focal neurological deficit). There is significant nuchal rigidity on neck flexion. CT head without contrast reveals diffuse subarachnoid hemorrhage with blood in the basilar cisterns and both sylvian fissures. Hunt & Hess Grade: The patient has drowsiness, confusion, and a mild focal deficit (left arm drift) without stupor or coma. This corresponds to Grade 3. Predicted mortality: 35-40%. Management: The patient is admitted to the neurological ICU. An external ventricular drain is placed for ICP monitoring and CSF drainage given early hydrocephalus. CT angiography reveals a 7 mm anterior communicating artery aneurysm. Nimodipine 60 mg is started via NG tube. The patient undergoes endovascular coiling of the aneurysm on hospital day 1. She develops angiographic vasospasm on day 5 treated with induced hypertension and intra-arterial vasodilators. She is discharged to rehabilitation on day 21 with mild cognitive impairment but no motor deficits.
Related Conditions
Related Medications
Common Mistakes
Confusing Hunt & Hess with WFNS SAH grading scale
The Hunt & Hess scale is based on clinical symptoms and signs (headache, nuchal rigidity, level of consciousness, neurological deficit), while the WFNS scale is based specifically on the Glasgow Coma Scale (GCS) and the presence or absence of focal neurological deficit. WFNS Grade 1 = GCS 15 without deficit, Grade 2 = GCS 13-14 without deficit, Grade 3 = GCS 13-14 with deficit, Grade 4 = GCS 7-12, Grade 5 = GCS 3-6. The Hunt & Hess scale offers more detailed clinical descriptors, while WFNS provides more objective and reproducible grading. Both are commonly used in clinical practice and research.
Not reassessing Hunt & Hess grade after clinical changes
The Hunt & Hess grade is dynamic and should be reassessed after clinical deterioration, before aneurysm treatment, and after any major intervention. A patient's grade may improve after ventricular drainage or deteriorate due to rebleeding or vasospasm. The grade at the time of treatment (not just admission) is most predictive of surgical and overall outcomes.
Frequently Asked Questions
What is subarachnoid hemorrhage (SAH)?
What is cerebral vasospasm and why is it important?
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. PubMed
- Teasdale GM, Drake CG, Hunt W, et al. A universal subarachnoid hemorrhage scale: report of a committee of the World Federation of Neurosurgical Societies. J Neurol Neurosurg Psychiatry. 1988;51(11):1457. PubMed
- Connolly ES, Rabinstein AA, Carhuapoma JR, et al. Guidelines for the management of aneurysmal subarachnoid hemorrhage: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke. 2012;43(6):1711-1737. PubMed