Subarachnoid haemorrhage

Question 1

Definition

Answer 1

Bleeding within the subarachnoid space where the CSF fluid is most commonly due to cerebral aneurysm. Other possible causes include trauma or AV malformation

Question 2

Symptoms

Answer 2

Thunderclap headache
Vomiting
Photophobia
Neck stiffness
Neurological symptoms e.g. CN palsies, particularly CN3, 4, 6, dysphasia, vision changes, unconsciousness, hemiparesis/hemiplegia, seizures

Question 3

Investigations

Answer 3

1. Non-contrast CT head (<6 hours after SAH). If negative, perform LP
2. Lumbar puncture (>12 hrs after SAH) to detect xanthochromia and increased RBC
3. CT angiography to check where bleed from

Question 4

CT features

Answer 4

Bright hyperdense blood most commonly within the basal cisterna. Sometimes in the sulci and if severe within the ventricles

Question 5

Treatment

Answer 5

Coiling or clipping
Nimodipine and 125ml/hr saline to prevent vasospasm (risk 7-14 days after SAH)

Question 6

Complications

Answer 6

Re-bleeding (within 12 hours common)
Vasospasm
Hydrocephalus - give drain/VP shunt or LP
ECG changes, increased troponin, ST elevation (mimics MI)
Electrolyte abnormalities - hyponatraemia due to SIADH
Seizures
Pulmonary oedema, pneumonia

Question 7

Screening

Answer 7

Only if 2 or more first degree relatives with intracranial aneurysms

Question 8

Risk factors

Answer 8

Female
Black
45-70
Smoking
Hypertension
Alcohol
AD PKD
Cocaine use
CT disorders
Neurofibromatosis
SCA
FHx