Clinical grading of aneurysmal subarachnoid haemorrhage severity, correlating with surgical risk and mortality.
The Hunt and Hess scale grades the clinical severity of aneurysmal subarachnoid haemorrhage from I to V based on symptoms and level of consciousness, and is used to estimate operative risk and prognosis.
🧮 Interactive Calculator
📐 Formula
Grade I–V from the clinical presentation
🎯 When to Use
Bedside clinical grading at presentation of aneurysmal SAH.
Estimating surgical risk and communicating severity between teams.
Prognostic counselling alongside imaging grades.
⚙️ How It Works
Grade I — asymptomatic or mild headache and slight nuchal rigidity.
Grade II — moderate-to-severe headache, nuchal rigidity, no deficit other than cranial nerve palsy.
Grade III — drowsiness, confusion or mild focal deficit.
Grade IV — stupor, moderate-to-severe hemiparesis.
Grade V — deep coma, decerebrate posturing, moribund appearance.
📊 Interpreting the Result
Approximate mortality: grade I ~1–5%, II ~5–10%, III ~10–20%, IV ~30–40%, V ~50–80%.
Higher grades correlate with worse surgical outcome and are sometimes managed with delayed intervention.
Serious systemic disease or severe vasospasm adds one grade in the original scheme.
⚠️ Limitations & Pitfalls
Subjective and with only moderate inter-observer agreement.
Does not incorporate imaging findings; combine with modified Fisher for vasospasm risk.
The WFNS scale (GCS-based) is often preferred for reproducibility.
📚 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.