About 20% of patients with subarachnoid haemorrhage have a sudden headache several weeks before the acute event
This is thought to be due to a sentinel bleed, which is a minor subarachnoid bleed before the main rupture
It is a warning sign that must be investigated
Investigations
Non-contrast CT head within 6 hours
If normal CT, consider performing an LP but discuss pros and cons with the patient
Management
Confirm the diagnosis with CT brain (CTA, CT perfusion, Non-Con CT)
A to E resuscitation
Aim to decrease the SBP to 160mmHg which can be done by managing the pain with IV morphine and an antiemetic
Consult senior or neurosurgeon for the choice of antihypertensive if this is not enough
Nimodipine
Within 4 days of SAH and usually up to 21 days
Oral dose: 60mg every 4 hours (hepatic impairment 30mg every 4 hours)
IV infusion: Co-infuse with compatabile solution (e.g. 0.9% normal saline, 5% dextrose) Give infusion via a central catheter using an infusion pump; do not use PVC giving sets because of the loss of nimodipine and contamination by plasticisers; use polyethylene sets
Adult >70kg IV 1mg/hour for first 2 hours with the infusion solution at a rate of 20 mL/hour
If well tolerated increase dosage up to 2mg/hour up to 2 mg/hour with an increase in the rate of co-infusion solution to 40 mL/hour
Adult <70kg or labile BP or hepatic impairment, IV initially 0.5mg/hour; give co-infusion solution at a rate of 10 mL/hour up to a maximum of 1 mg/hour