Subarachnoid Haemorrhage

Question 1

What is a SAH?

Answer 1

Intracranial haemorrhage defined as blood in subarachnoid space. Most common cause is traumatic SAH. However can be sponatenous.

Question 2

What are the causes of spontaneus SAH?

Answer 2

1. Intracranial aneurysm. Conditions associated with these are hypertension, APCKD, Ehlers-Danlos syndrome and coarctation of the aorta.
2. Arteriovenous malformation,
3. Pituitary apoplexy,
4. Mycotic (infective) aneurysms

Question 3

What are the presenting features of a SAH?

Answer 3

1. Thunderclap headache,
2. Nausea and vomiting,
3. Meningism
4. Coma,
5. Seizures,
6. ECG changes: ST elevation

Question 4

What are the investigations for a SAH?

Answer 4

Non-contrast head CT is first line.
1. If CT done within 6 hours and is normal then do not do LP and instead consider alternative diagnosis.
2. If CT done after 6h and is normal then do LP

Question 5

Describe features of a LP in the context of suspected SAH

Answer 5

Should be done if head CT is normal but done 6 hours after onset of symptoms.
LP should be performed at least 12 hours after onset of symptoms to allow development of xanthochromia (RBC breakdown)
Xanthochromia allows for distinguishing from blood which occurs during LP.

Question 6

What are the investigations following confirmation of a SAH?

Answer 6

CT incracranial angiogram +/- digital subtraction angiogram.
This is to identify aneurysms or AV malformation

Question 7

What is the management of a SAH?

Answer 7

1. Supportive: bed rest, analgesia, VTE prophylaxis and discontnue antithombotics.
2. Nimodipine (prevents vasospasm)
3. Neuroradiologist/surgeon intervention. Most coiled but few may require craniotomy and clipping

Question 8

What are the complications of a SAH?

Answer 8

1. Re-bleeding (presents with worsening neuro symptoms)
2. Hydrocephalus (do LP orinsert external ventricular drain)
3. Vasospasm (delayed cerebral ischaemia)
4. Hyponatraemia due to SIADH (give hypertonic saline and fludrocortisone)
5. Seizures
6. DVT, UTI, lower respiratory tract infection

Question 9

What are the cardiopulmonary complications following a subarachnoid haemorrhage?

Answer 9

Sympathetic stimulation and catecholamine release can lead to myocardial injury (stunned myocardium)
lower RTI
Tako tsubo cardiomyopathy

Question 10

What are the important predictive factors in SAH?

Answer 10

1. Conscious level on admission,
2. Age,
3. Amount of blood visible on CT

Question 11

Describe features of an extradural haematoma

Answer 11

1. Blow to head or rapid deceleration. Most occur in the temporal region where a skull fracture ruptures the middle meningeal artery.
2. Presents with features if raised ICP. Some pateints may have lucid interval.

Question 12

Describe features of a subdural haematoma?

Answer 12

1. Most occur in frontal and parietal lobes. Risk factors are old age, alcoholism and anticoagulation.
2. Slower onset of symptoms than in extradural. May have fluctuating confusion/consciousness

Question 13

What is coning?

Answer 13

Occurs due to raised ICP which compresses the brian - cranial nerve palsies and compression of the brainstem which can cause bradycardia.

Question 14

What are the different types of hydrocephalus?

Answer 14

1. Obstructive (non-communicating) - tumouts, haemorrhage, developmental abnormalities
2. Non-obstructive (communicating) - INcrease in CSF production or failure of reabsorption by arachnoice granules which can occur post haemorrhage.

Question 15

What is the triad of symptoms of normal pressure hydrocephalus?

Answer 15

1. Dementia,
2. Incontinence,
3. Disturbed gait