Etiologies

• Trauma
• Aneurysm (most common non-traumatic cause)
• AVM
• Arterial dissection
• Cerebral venous thrombosis
• Cocaine use
• Anticoagulation
• Reversible cerebral vasoconstriction syndrome

Clinical presentation

• Thunderclap headache (worst headache of my life) = 97% of patients
• Seizures = 10% of patients
• Sudden death = 10-15% of patient
• AMS (ranges from drowsiness to being obtunded) and nausea/vomiting due to elevated ICP

Diagnosis

• CT non-contrast
  • Picks up 92% of SAH in the first 24 hours but the sensitivity is highest in the first 6-12 hours (drops to 60% by day 5)
• If CT head is negative, do an LP
  • LP may be negative early on – best at about 12 hours
  • Look for elevated OP, RBCs that don’t clear (unlike traumatic tap), and/or xanthochromia

Treatment

• If aneurysm – surgical clipping or endovascular coiling
• Nimodipine to prevent vasospasm
• BP control to goal < 140/80