Links:
- Non-contrast CT scan head
- if negative but suspicion high -> LUMBAR PUNCTURE for xanthochromia if headache is >12 hours old.
- Assess severity of SAH
- Hunt and Hess Scale based on symptoms/exam and WFNS scale highly predictive of complications and survival
- Fisher Score on non contrast head CT predicts risk of vasospasm.
- Hunt Hess and Fisher must be documented on arrival.
HUNT HESS
| Grade | Criteria | Index of Perioperative Mortality (%) |
| 0 | Aneurysm is not ruptured | 0-5 |
| I | Asymptomatic or with minimal headache and slight nuchal rigidity | 0-5 |
| II | Moderate to severe headache, nuchal rigidity, but no neurologic deficit other than cranial nerve palsy | 2-10 |
| III | Somnolence, confusion, medium focal deficits | 10-15 |
| IV | Stupor, hemiparesis, medium or severe, possible early decerebrate rigidity, vegetative disturbances | 60-70 |
| V | Deep coma, decerebrate rigidity, moribund appearance | 70-100 |
FISHER
| Group | Blood on CT |
| 1 | No SAH detected |
| 2 | Diffuse or vertical layer of subarachnoid blood <1mm thick |
| 3 | Localized clot and/or vertical layer within the subarachnoid space >1mm thick |
| 4 | ICH or IVH with diffuse or no SAH |
MODIFIED FISHER
| Group | No SAH | Thin SAH | Thick SAH | IVH | |
| 1 | No SAH; no IVH | + | – | – | – |
| 2 | Thin diffuse or focal SAH, no IVH | – | + | – | – |
| 3 | Thin diffuse or local SAH, with IVH | – | + | – | + |
| 4 | Thick focal or diffuse SAH, no IVH | – | – | + | – |
| 5 | Thick local or diffuse SAH with IVH | – | – | + | + |
Blood Pressure in SAH
- Severe HTN associated with increased risk of aneurysm bleed
- Maintain SBP < 140 if aneurysmal bleed until definite aneurysmal treatment (permissive HTN to facilitate cerebral perfusion is desired after aneurysm is secured)
- Use short acting anti-HTN such as labetalol, nicardipine
- Short acting is key as these patients are prone to vasospasm (see below)
- Cerebral Angiography once stable, guidelines require within 48 hoours
- Once bleed stabilized start nimodipine 60 mg q4 hour x 21 days. Improves neurologic outcomes because it decreases delayed cerebral ischemia. Vasospasm is what increases morbidity and mortality in the post-SAH period
Complications
- Hydrocephalus – occurs in ½ of patients, blood obstructs CSF outflow
- Any decline, or evidence of hydrocephalus ► place external ventricular drain (EVD) to measure intracranial pressure (ICP elevated > 20 mmHg) (see ICP management below)
- Rebleeding –first 24-48 hours if unsecured,
- Presents w. new AMS, focal neuro deficits
- Repeat Head CT
- If new bleed ► early neurosurgical intervention and blood pressure control
- Vasospasm and Delayed Cerebral Ischemia –peaks 7-10 days
- Presents with new focal neuro deficits, AMS. High suspicion in patients with SAH Fisher grade > 3 on presenting CT scan helps risk stratify patient
- Order: transcranial dopplers: increased flow velocities.
- Seizures – common, controversial whether to start prophylactic anti-epileptics
- Sodium abnormalities -> SIADH, cerebral salt wasting
- Cardiopulmonary dysfunction—Intracranial hemorrhage ► catecholamine surge ► systolic dysfunction, troponinemia with ST changes, pulmonary edema. Usually self-limited