1Hunt-Hess Scale — Complete SAH Management Guide
Published in 1968 by neurosurgeons William E. Hunt and Robert M. Hess, the Hunt-Hess scale grades aneurysmal subarachnoid haemorrhage (aSAH) based on patient clinical presentation. It directly correlates with operative risk, perioperative 30-day mortality, and guides the timing of surgical clipping versus endovascular coiling.
| Grade | Clinical Neurological Features | 30-Day Mortality | WFNS Equivalent |
|---|---|---|---|
| I | Asymptomatic or minimal headache, slight nuchal rigidity | ~5% | Grade I (GCS 15) |
| II | Moderate to severe headache, meningismus; no neurological deficit except cranial nerve palsy (e.g., CN III) | ~10% | Grade I–II (GCS 13–15) |
| III | Drowsiness, confusion, or mild focal deficit | ~25%–30% | Grade III (GCS 13–14 + deficit) |
| IV | Stupor, moderate-to-severe hemiparesis, early decerebrate rigidity, vegetative disturbances | ~45%–60% | Grade IV (GCS 7–12) |
| V | Deep coma, decerebrate posturing, moribund appearance | ~70%–80% | Grade V (GCS 3–6) |
2Aneurysm Securing: Endovascular Coiling vs. Surgical Clipping
The landmark ISAT (International Subarachnoid Aneurysm Trial) established endovascular coiling as the preferred first-line modality when both options are anatomically feasible, demonstrating reduced 1-year dependency and mortality:
- Coiling Preferred: Posterior circulation (basilar/vertebral) aneurysms, elderly patients (>65 years), Hunt-Hess Grade I–II, and narrow-neck saccular aneurysms.
- Clipping Preferred: Middle cerebral artery (MCA) bifurcations, broad-neck or fusiform aneurysms, young patients prioritizing long-term durability, and those with large parenchymal hematomas requiring operative evacuation.
- Timing Window: Secure the aneurysm within 24 to 48 hours for Hunt-Hess Grades I–III to eliminate catastrophic re-rupture risk (~4% in the first 24h). For Grades IV–V, stabilize intracranial pressure via an external ventricular drain (EVD) first; re-evaluate securing as the clinical grade improves.
3Vasospasm & Delayed Cerebral Ischaemia (DCI)
Delayed cerebral ischaemia (DCI) secondary to arterial vasospasm represents the leading cause of secondary morbidity in survivors. It arises between days 4 and 14 post-bleed (peaking between days 7 and 10):
- Nimodipine 60 mg orally every 4 hours for 21 days: The only pharmacological intervention with class 1A evidence to reduce poor neurological outcomes and secondary cerebral infarction.
- Strict Euvolaemia: Maintain normal intravascular volume with isotonic crystalloids. The classic "Triple-H therapy" has been abandoned; hypervolaemia is harmful, but induced hypertension (target MAP 100–120 mmHg) remains the first-line rescue for symptomatic DCI once the aneurysm is secured.
- Surveillance: Daily Transcranial Doppler (TCD) tracking mean flow velocities (>120 cm/s indicates moderate, >200 cm/s indicates severe vasospasm in the MCA).
4Acute Hydrocephalus & ICP Management
Acute obstructive hydrocephalus develops in approximately 20% of patients due to blood blocking arachnoid villi or intraventricular hemorrhage obstructing the Aqueduct of Sylvius. Urgent placement of an External Ventricular Drain (EVD) can dramatically reduce intracranial pressure and convert a poor presenting grade (Grade IV/V) into a favorable surgical candidate (Grade II/III).