Modified Fisher Scale for SAH
Predicts risk of symptomatic cerebral vasospasm after subarachnoid haemorrhage (SAH) based on CT appearance of cisternal and intraventricular blood (Frontera 2006). Any intraventricular haemorrhage (IVH) counts; the scale did not define a thickness threshold. 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.
Thin SAH, no IVH. ~24% risk of symptomatic vasospasm (Frontera 2006).
→ Neurosurgery / neurology admission. Adults: nimodipine 60mg PO/NG every 4h for 21 days. Children: use a children's formulary. Adequate hydration. TCD monitoring. Repeat CT + CTA/DSA for aneurysm.
Thin SAH with IVH. ~33% vasospasm risk.
→ ICU/HDU care. Nimodipine. EVD if hydrocephalus. Intensive TCD monitoring. BP management. Aneurysm securing (coiling/clipping) urgently.
Thick SAH, no IVH. ~33% vasospasm risk.
→ ICU care. Nimodipine. Maintain euvolaemia (prophylactic hypervolaemia is not recommended). TCD daily. Early aneurysm securing. Repeat neuroimaging if neurological deterioration.
Thick SAH with IVH. ~40% vasospasm risk.
→ ICU. Nimodipine. EVD for raised ICP/hydrocephalus. Intensive TCD monitoring. Maintain euvolaemia. Delayed cerebral ischaemia: induced hypertension; intra-arterial vasodilators or angioplasty if refractory (triple-H therapy is no longer recommended).
Interpretation bands for the Modified Fisher. Apply clinical judgement and local guidance.
References
- Frontera JA, Claassen J, Schmidt JM, et al. Prediction of symptomatic vasospasm after subarachnoid hemorrhage: the modified Fisher scale. Neurosurgery. 2006;59(1):21–27.
- Hoh BL, Ko NU, Amin-Hanjani S, et al. 2023 Guideline for the management of patients with aneurysmal subarachnoid hemorrhage: a guideline from the American Heart Association/American Stroke Association. Stroke. 2023;54(7):e314–e370.
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.