Neurology/neurosurgery - Subarachnoid haemorrhage (Core clinical problems - unconscious patient/sudden onset headache)

Question 1

What are the symptoms of SAH?

Answer 1

Sudden onset
Short lasting (seconds to minutes) headache
Photophobia
Nausea, vomiting , stiff neck and Kernig’s sign may be present

Question 2

What is Kernigs sign?

Answer 2

When hip flexed at right angle, pain on extending the knee.

Question 3

Why do you get meningism in a SAH (photophobia/stiff neck/kernig’s sign?)

Answer 3

Blood irritates the meninges.

Question 4

Why might an SAH cause reduced or deteriorating consciousness? What else might this manifest as?

Answer 4

ICP rising

May manifest as papilloedema and retinal haemorrhage

Question 5

Why might we see focal deficit in SAH?

Answer 5

• False localising effect of increasing ICP
• Co-existent intracerebral haemorrhage
• vasospasm due to blood irritation and therefore ischaemia

Question 6

Systemic features of SAH might include Cushing Reflex - what is this?

Answer 6

Hypertension
Bradycardia
Abnormal breathing

Question 7

What causes the Cushing Reflex

Answer 7

• Hypertension: CPP = MAP - ICP. Therefore Raised ICP will cause MAP to rise to maintain CCP
• Bradycardia: High MAP will cause baroceptor stretch leading to decreased heart rate in attempt to reduce BP
• Irregular breathing: ?due to damage to respiratory centres in brainstem

Question 8

What are the most common causes/sites for an SAH?

Answer 8

1) Aneurysm rupture - commonly occurring at junctions in the Circle of Willis
2) AVMs - anomalous malformed vessels, congenital, enlarge during life to present in adult hood
3) Vessels weaken by infection (rarely)
4) Coagulopathy (rarely)
5) Trauma (rarely)

Question 9

What is the one investigation you want to do if you can only do one?

Answer 9

CT Brain - non-contrast

Question 10

What percentage of SAH will appear on CT scan?

Answer 10

95%

Question 11

How does fresh blood appear on CT?

Answer 11

Bright white

Older blood less bright/grey

Question 12

SAH will be confined to the suture lines true/false?

Answer 12

False: Extra-dural will be confined to suture lines

Question 13

If no bleed on a CTB - what might you do next? In an SAH, what would you expect to see?

Answer 13

LP at about 12 hours 
See xanthochromia (straw pink or yellow CSF)

Question 14

What is a contraindication to an LP?

Answer 14

Any signs on CTB of lesion that would obstruct CSF outflow in the brain

Question 15

When should angiography be done? Why is it done?

Answer 15

If patient is awake and only mildly drowsy - to find the source to the bleed

Question 16

How would a bleeding aneurysm be treated?

Answer 16

Either by endovascular coiling or surgical clipping; the former is most common today

Question 17

If the patient has impaired consciousness or severe bleed, what should be done in regard to angiography and treatment?

Answer 17

This is a specialist decision. These patients have a lower tolerance for treatment and have higher mortality/lower prognosis.

Question 18

What is the mortality in the first few days of aneurysmal SAH?

Answer 18

30-40%

Question 19

What is the biggest risk in the first 6weeks post SAH?

Answer 19

Rebleeding

Question 20

What are the early complications of an SAH?

Answer 20

• CSF obstruction due to formation of blood clot, leading to hydrocephalus
• Rebleeding

Question 21

What are the late complications of an SAH?

Answer 21

• Blood reabsorption into the arachnoid granulations, blocking CSF reuptake and causing a communicating hydrocephalus

Question 22

What other things should be considered as the cause of a SAH?

Answer 22

Trauma - usually less worrying

Berry aneurysm - related to polycystic kidney disease