Subarachnoid Haemorrhage

Question 1

Define Subarachnoid Haemorrhage

Answer 1

Arterial bleeding into the subarachnoid space (between arachnoid and pia mater)

Question 2

Aetiology of Subarachnoid Haemorrhage

Answer 2

Rupture of intracranial cerebral aneurysm, usually at the circle of Willis
85% rupture of saccular aneurysm
10% Perimesencephalic haemorrhage
5% Arteriovenous malformations |bleeding diatheses |vertebral or carotid artery dissection with intracranial extension | mycotic aneurysms | cocaine and amphetamine abuse

Question 3

Risk factors for Subarachnoid Haemorrhage

Answer 3

POLYCYSTIC KIDNEY DISEASE
Female, >50
Hypertension
Smoking
Excess alcohol 
Saccular aneurysms: PKD, Marfan's, Ehlers-Danlos syndrome

Question 4

Symptoms of Subarachnoid Haemorrhage

Answer 4

Headache (Sudden onset | "thunderclap" headache | feels like "hit on the head with a baseball bat" | occipital area | 10/10
Nausea and vomiting
Neck stiffness
Photophobia
Reduced consciousness level

Question 5

Signs of Subarachnoid Haemorrhage on examination

Answer 5

Meningism: Neck stiffness, Kernig’s sign, pyrexia
Focal neuro signs (usually on the second day): ophthalmoplegia
Reduced GCS
Raised ICP: papilloedema, IV or III cranial nerve palsy, Cushing’s reflex
Subhyaloid haemorrhage on fundoscopy

Question 6

Investigations for Subarachnoid Haemorrhage

Answer 6

1. Urgent CT head (non-contrast)
2. If CT is negative, do a LP at 12 hours after onset

CT: hyperdense area in the basal region of the skull
LP: xanthochromia, raised opening pressure, raised RBC, reduced WCC

ECG: identify cardiac abnormalities

FBC: leucocytosis
U+Es: mild-severe hyponatraemia 
Clotting studies: elevated INR, prolonged PTT
Troponin: elevated within 24h 
Glucose: may be elevated 

Angiography (CTA, MRA): detect the source of bleeding)