Haemorrhagic Stroke: Subarachnoid

Question 1

Definition

Answer 1

Spontaneous bleeding into the subarachnoid space - between the arachnoid layers of the meninges and the pia mater
- can often be catastrophic

Question 2

Epidemiology

Answer 2

50+ years

Question 3

Risk factors

Answer 3

Hypertension
Smoking
Family history
Polycystic kidney disease (PKD): 5 times more common in autosomal dominant PKD
Alcohol excess: there is a significantly increased risk with current alcohol abuse

Question 4

Aetiology

Answer 4

Berry aneurysm: saccular aneurysms; the most common cause of spontaneous SAH (MC)
- Arise at points of arterial bifurcation within the Circle of Willis; the junction between the anterior communicating and anterior cerebral arteries is the most common location
Arteriovenous malformation (AVM)
Perimesencephalic: venous bleeding with normal CT and excellent prognosis
Mycotic aneurysm: due to bacterial infection, for example, secondary to emboli from infective endocarditis
Vertebral artery dissection
Pituitary apoplexy: bleeding into the pituitary gland, often associated with a tumour

Question 5

Pathophysiology

Answer 5

Tissue ischaemia
- less blood can reach tissue due to bleeding
- less O2 + nutrients reach tissue, causing cell death
Raised ICP
- fast flowing arterial blood pumped into cranial space
Space - occupying lesions
- puts pressure on the brain
Blood irritates meninges
- can obstruct CSF outflow = hydrocephalus = build up of CSF fluid in brain
Vasospasm
- bleeding irritates other vessels
- ischaemic injury

Question 6

Signs

Answer 6

3rd nerve palsy = PCA artery will press on the 3rd nerve, causing a palsy with a fixed dilated pupil
6th nerve palsy = Non-specific sign which indicates raised ICP
Reduced GCS
Meningism
- Kernig’s sign (unable to extend patients leg at the knee when the thigh is flexed)
- Brudzinski sign (when patients neck is flexed by doctor, patient will flex their hips + knees
Retinal, subhyloid, and uterus bleeds =
- worse prognosis
- with/without also papilledema
Focal, neurological signs
- e.g. 3rd nerve palsy
Increased BP

Question 7

Symptoms

Answer 7

Occipital thunderclap headache, sudden onset
- may have sentinel headache preceding this
- worst headache of your life
- 0-10 severity instantly
Meningism
- photophobia + neck stiffness
Nausea and vomiting
Confusion, coma, and seizures

Question 8

Dx

Answer 8

GOLD STANDARD = Head CT
- detects >90% of SAH within 1st 48hours
- seen as a ‘star shaped lesion’ due to blood filling in gyro patients around the brain + ventricles
Acute (new/fresh) bleed appears hydro dense on CT (i.e. bright white)
Blood seen in fissures + cisterns +/- ventricles
ABG: -> to exclude hypoxia
CT angiography if aneurysm confirmed to see extent
Lumbar puncture:
- If CT is normal but SAH still suspected
- CSF in SAH is uniformly bloody early on + becomes xanthochromic (yellow) after several hours due to breakdown products of Hb (bilirubin)
- XANTHACHROMIA presence confirms SAH

Question 9

Tx

Answer 9

FIRST LINE = If angiography shows aneurysm = ENDOVASCULAR COILING
- preferred to surgical clipping since has lower complication rate where possible
- promotes thrombosis + ablation of aneurysm
Also give NIMODIPINE (CCB, Decreased vasopressin, and decrease BP)

Question 10

Scoring scale

Answer 10

Glasgow score scale
- out of 15
- Eyes =4
- Vertebral = 5
- Motor = 6