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Neuroradiology
Demonstration data

Hunt and Hess Grade

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.
  • Rosen DS, Macdonald RL. Subarachnoid hemorrhage grading scales: a systematic review. Neurocrit Care. 2005;2(2):110-118.

⚕️ For clinical decision support only. Always verify calculations and apply clinical judgment.