Modified Fisher Scale for SAH
Predicts risk of symptomatic cerebral vasospasm after subarachnoid haemorrhage (SAH) based on CT appearance of blood distribution. Guides monitoring intensity.
Score interpretation
No SAH or IVH on CT. Vasospasm risk negligible.
→ If clinical suspicion remains: LP for xanthochromia. CT angiography to exclude aneurysm.
Minimal SAH, no bilateral IVH. ~24% risk of symptomatic vasospasm.
→ Neurosurgery / neurology admission. Nimodipine 60mg PO/NG every 4h for 21 days. Adequate hydration. TCD monitoring. Repeat CT + CTA/DSA for aneurysm.
Minimal SAH with bilateral IVH. ~33% vasospasm risk.
→ ICU/HDU care. Nimodipine. EVD if hydrocephalus. Intensive TCD monitoring. BP management. Aneurysm securing (coiling/clipping) urgently.
Thick SAH, no bilateral IVH. ~33% vasospasm risk.
→ ICU care. Nimodipine. Hypervolaemia prophylaxis. TCD daily. Early aneurysm securing. Repeat neuroimaging if neurological deterioration.
Thick SAH with bilateral IVH. ~40% vasospasm risk.
→ ICU. Nimodipine. EVD for raised ICP/hydrocephalus. Intensive TCD monitoring. Vasospasm treatment: HHH therapy (hypertension, hypervolaemia, haemodilution) or intra-arterial vasodilators if refractory.
Interpretation bands for the Modified Fisher. Apply clinical judgement and local guidance.
References
- Claassen J, et al. Effect of cisternal and ventricular blood on risk of delayed cerebral ischemia after subarachnoid hemorrhage: the Fisher scale revisited. Stroke. 2001;32(9):2012–2020.
Related
Curated clinical cross-links plus same-class fallbacks.
- Hydrocortisone (Oral Replacement) · Glucocorticoid Replacement
- Cetuximab · Anti-EGFR Monoclonal Antibody — Head and Neck Cancer
- Cisplatin · Platinum Chemotherapy — Head and Neck Cancer
- Methotrexate · Chemotherapy / Immunosuppressant — Head and Neck / Granulomatosis
- Pembrolizumab (Head and Neck SCC) · PD-1 Inhibitor
- Nivolumab (Head and Neck SCC) · PD-1 Inhibitor
- Acute Stroke / TIA Assessment · NICE NG128; RCP Stroke Guidelines 2023
- Status Epilepticus (Adults) · NICE CG137; ESEM guidelines; RCP Neurology Guidelines
- Suspected Subarachnoid Haemorrhage · NICE NG228; RCEM 2023; AHA/ASA 2023
- Adult Head Injury · NICE NG232 (2023)
- Bell's Palsy / Facial Nerve Palsy · ENT UK 2017; AAN
- Vertigo Workup · ENT UK; NICE CKS
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.