Stroke

Question 1

What is a stroke?

Answer 1

a clinical diagnosis that refers to a sudden onset focal neurological deficit of presumed vascular origin

Question 2

There are both ischaemic and haemorrhagic causes of stroke. Differentiate between the two.

Answer 2

Ischaemic: embolic e.g. AF, thrombotic, thrombus formation secondary to plaque rupture in ICA
Haemorrhagic bleeding

Question 3

What is a focal neurological deficit?

Answer 3

a set of symptoms or signs in which causation can be localised to an anatomic site in the CNS typically deduced through the history and exam

Question 4

List some focal neurological deficits.

Answer 4

Movement changes e.g. loss of power, paralysis, change in tone
Sensation changes e.g. altered or less of sensation
Loss of coordination or fine motor control
Speech or language difficulties e.g. dysphasia, dysarthria
Difficulty swallowing
Visual problems e.g. visual field defects, visual loss, diplopia

Question 5

What is the earliest sign of stroke in a CT scan?

Answer 5

hyperdense vessel sign - due to thrombus in the vessel

usually middle cerebral artery

Question 6

What is the second earliest CT sign of a stroke?

Answer 6

Loss of the insular ribbon - loss of grey-white matter differentiation of the insular cortex
Occurs because this part of the brain (MCA territory) has the least potential for collateral supply

Question 7

Within 24 hours of a stroke, what are the clinical signs seen in a CT head?

Answer 7

hypoattentuation of brain tissue
loss of grey white matter differentiation
cortical hypodensity (looks darker on CT)
sulcal effacement
swelling

Question 8

24 hours after a stroke occurs, if thrombolysis is not successful, swelling can occur and ‘malignant MCA syndrome’ can develop. What is this?

Answer 8

rapid neurological deterioration (e.g. headache, vomiting, decreased GCS) due to space-occupying effects of cerebral oedema +/- haemorrhagic transformation
Poor prognosis and risk of death

Question 9

What are some of the chronic appearances post-stroke on CT?

Answer 9

swelling subsides
encephalomalacia (liquidified necrosis of brain tissue)
appears low density

Question 10

In stroke, what is the difference between core and penumbra? What imaging can be used to detect it?

Answer 10

Core: area which will not recover even if reperfused
Penumbra: area which is ischaemic but is potentially salvageable if reperfusion occurs
CT perfusion