Subarachnoid haemorrhage (SAH) is bleed into the subarachnoid space and non-traumatic cases are usually due to rupture of an intracranial aneurysm.

Symptoms and signs

• Severe headache of sudden onset implies SAH until proved otherwise
• headache becomes severe within seconds, peaking in 1–5 min
• may be associated with vomiting and loss of consciousness
• may be subsequent photophobia and neck stiffness
• Symptoms sometimes resolve within a few hours but still investigate with CT scan of head
• 30% of patients with SAH may have ‘minor’ leaks hours or days before the major haemorrhage, which are often misdiagnosed as simple headaches or migraine
• Unexplained coma or seizures with subsequent persistent severe headache can indicate acute SAH
• Examination may be normal
• Signs include neck stiffness, photophobia, intraocular haemorrhages (on fundoscopy), dilated pupils, focal findings (unilateral weakness, loss of visual fields and dysphasia)

Investigations

Baseline investigations

• FBC and clotting profile
• UEC and serum glucose
• ECG

CT scan of head

• Within 6 hr of onset of symptoms, but no longer than 24 hr of admission

Lumbar Puncture

• If initial CT normal (especially if performed more than 24-72 hr after initial headache onset) and clinical suspicion for SAH high, perform lumbar puncture at least 12 hr after symptom onset
• exclude SAH completely by analysis of CSF
• see Lumbar puncture guideline

Analysis of CSF

• Opening pressure
• Send sample to clinical biochemistry immediately for centrifugation to allow CSF spectrophotometry for xanthochromia
• if tap was traumatic, this is especially important
• record time from headache onset in hours/days on CSF xanthochromia request card to allow best assessment
• protect sample from light and warn clinical biochemistry before you send sample
• do not use air tube to transport sample
• MC&S, glucose and protein
• send blood for glucose, protein and bilirubin with CSF sample

Differential diagnosis

• Meningitis
• Encephalitis
• Cerebral venous sinus thrombosis (with raised opening pressure)

• If consciousness impaired, check airway and maintain it
• Codeine phosphate 60 mg oral (or IM) 4-hrly as required up to maximum 240 mg in 24 hr
• Observe respiratory effort and monitor ECG
• If SAH confirmed, bleep on-call neurosurgical SpR, and request transfer to neurosciences

• First discuss with neurosciences team

Medication

• Nimodipine 60 mg oral 4-hrly including throughout night
  • commence within 4 hr of SAH or as soon as diagnosis confirmed
  • if unconscious, crush tablets and give immediately via nasogastric tube
• Manage blood pressure - see Acute stroke guideline - Immediate treatment, Blood pressure

Supportive therapy

• If no contraindication, give maintenance IV fluids – see maintenance IV fluid guideline
• Arrange for nursing staff to measure patient's legs and fit TED stockings

If improving and stable

• In confirmed SAH, consider CT angiography at earliest opportunity with a view to operative therapy - discuss with interventional neuroradiology and neurosurgery to determine best mode of intervention

If not improving or deteriorating

• Think about:
• metabolic cause (diabetes insipidus, hyponatraemia, hypoxia)
• hydrocephalus
• acute rebleed
• Consider further CT scan of head

• Until headache has subsided and patient stable, monitor 4-hrly:
• Glasgow coma score
• neurological observations
• pulse
• BP
• temperature
• When stable, monitor BP at least twice daily in patients taking nimodipine

• If no operative intervention planned, continue oral nimodipine for a total of 21 days
• Discharge after 2-4 weeks and review in out-patient clinic
• If patient hypertensive, treat BP according to national guidelines e.g. British Hypertension Society