Hunt-Hess Scale — Complete SAH Management Guide
The Hunt-Hess scale was published by William E. Hunt and Robert M. Hess in 1968 as a simple clinical grading system for aneurysmal subarachnoid haemorrhage (SAH). It classifies patients into five grades based on presenting neurological status, from asymptomatic aneurysm detection (Grade 0, sometimes added) through coma with decerebrate posturing (Grade V). The scale predicts surgical risk and 30-day mortality and guides the timing of aneurysm surgery or endovascular coiling.
| Grade | Clinical Features | 30-Day Mortality | WFNS Equivalent |
|---|---|---|---|
| I | Asymptomatic or mild headache, slight neck stiffness | ~5% | I |
| II | Moderate-severe headache, meningismus, no neurological deficit except CN palsy | ~10% | I–II |
| III | Drowsiness, confusion, or mild focal deficit | ~25–30% | II–III |
| IV | Stupor, moderate-severe hemiparesis, early decerebrate | ~45–60% | IV |
| V | Deep coma, decerebrate posturing, moribund | ~70–80% | V |
Aneurysm Securing — Surgery vs Endovascular Coiling
Following the ISAT trial (2002) and ISUIA data, endovascular coiling (endovascular embolisation) has largely replaced open surgical clipping as the first-line treatment for ruptured berry aneurysms where both are technically feasible. Key principles:
- Coiling preferred: Posterior circulation aneurysms, elderly patients, Hunt-Hess Grade I–II, aneurysms with favourable dome-to-neck ratio
- Clipping preferred: Middle cerebral artery (MCA) aneurysms, broad-neck aneurysms not amenable to coiling, patients with significant intraparenchymal haematoma requiring evacuation, young patients
- Timing: Early treatment (within 24–48 hours) strongly recommended for Grades I–III to prevent re-bleeding (highest risk in first 24 hours — ~4% per day). For Grades IV–V, treatment may be deferred until clinical improvement
Vasospasm — Critical Complication of SAH
Delayed cerebral ischaemia (DCI) from vasospasm is the leading cause of death and disability in patients surviving the initial bleed. Vasospasm typically occurs between day 4 and day 14 (peak day 7–10), affecting the proximal cerebral arteries in response to subarachnoid blood products. Key management:
- Nimodipine 60 mg every 4 hours orally for 21 days: Only proven pharmacological treatment to reduce DCI — reduces mortality and neurological deficit without reducing angiographic vasospasm
- Euvolaemia: Maintain adequate hydration — avoid hypovolaemia. Isotonic fluid preferred. Previous "triple H therapy" (hypertension, hypervolaemia, haemodilution) is no longer routinely recommended but induced hypertension is used for symptomatic vasospasm
- Monitoring: Daily transcranial Doppler (TCD) for mean flow velocities (>120 cm/s = moderate, >200 cm/s = severe vasospasm in MCA). Serial neurological examination
- Rescue therapy for symptomatic vasospasm: Induced hypertension (noradrenaline to MAP 100–120 mmHg), intra-arterial verapamil or nicardipine, angioplasty for refractory cases
Hydrocephalus in SAH
Acute obstructive hydrocephalus occurs in 15–20% of SAH patients due to blood blocking CSF drainage pathways at the arachnoid granulations. It typically presents within 24–72 hours. Management: emergency external ventricular drain (EVD) if symptomatic (decreased LOC, upward gaze palsy). Chronic communicating hydrocephalus may develop weeks later, requiring ventriculoperitoneal shunting.