Stroke / TIA / SAH

Question 1

What is stroke?

Answer 1

Sudden onset loss of CNS function >24 hours due to vascular cause - 85% ischaemic, 15% haemorrhagic

Question 2

What is TIA?

Answer 2

Brief episode of neurologic dysfunction caused by focal brain or retinal ischaemia with clinical symptoms typically lasting <1 hour, without evidence of acute infarction on imaging

Question 3

Causes of intracranial haemorrhage?

Answer 3

Intracerebral: HTN, amyloid angiopathy, trauma, bleeding disorders, amphetamines, cocaine, vascular malformations - rarely may require neurosurgical intervention

SAH
SDH
EDH

Question 4

Risk factors for stroke / TIA?

Answer 4

Major: age, HTN, smoking, cholesterol, DM, previous CVA, MI, peripheral vascular disease, AF, valvular heart disease, illicit drugs

Minor: OCP, HRT, migraine, alcohol, family history

Question 5

Causes of ischaemic stroke?

Answer 5

1. ATHEROTHROMBOSIS (50%): large vessel atheroma - local narrowing and distal thromboembolism - most common sources are aortic arch, carotid bifurcation, vertebral artery origins and other major branch points of intra/extracranial large vessels
2. SMALL VESSEL DISEASE (20-25%): lipohyalinosis and fibrinoid degeneration of small IC vessels - age HTN and diabetes are risk factors. Causes small LACUNAR infarcts
3. CARDIOEMBOLIC (20-25%): thrombus in heart 2ndary to arrhythmias (most commonly AF), valvular heart disease (replacements, vegetations etc), poor LV function, post MI - embolises left heart > cranial vessels. If septal defect present (e.g. PFO) - emboli may also cross from right side > peripheral venous circulation e.g. DVTs
   4) Less common causes (<5% but greater in young):

Question 6

What are the less common causes of ischaemic strong (<5% but greater in young)?

Answer 6

Arterial dissection (carotid/vertebral arteries): often with neck pain / Horner’s if carotid, or Hx of trauma to neck eg. RTA.

Hypotension e.g. cardiac arrest leading to watershed infarction.

Secondary to CNS infection e.g. syphilis, HIV, TB, cerebral abscess or infective endocarditis.

Illicit drugs - cocaine, IV use

Venous sinus thrombosis

Vasculitis e.g. giant cell, Takayasu’s

Hypercoagulability e.g. antiphosphoipid syndrome, systemic malignancy

Rare genetic disorders - CADASIL, mitochondrial, Fabry’s, homocysteinuria, connective tissue disorders, sickle cell disease

Question 7

What is an anterior circulation stroke?

Answer 7

Carotid territory most commonly MCA

1. Contralateral hemiparesis and/or hemisensory loss (relatively leg sparing)
2. Contralateral homonymous hemianopia
3. Dysphasia (NOT dysarthria) usually dominant hemisphere affected or sensory neglect and apraxia, usually non-dominant hemisphere affected

All 3 = TACS, 2 = PACS

Question 8

What is a lacunar stroke?

Answer 8

Complete contralateral hemiparesis / hemisensory loss

Question 9

What is a POCS?

Answer 9

Vertebrobasilar terrotory

Ipsilateral cerebellar signs (cerebral stroke)
Contralateral homonymous hemianopia in occipital lobe stroke
Brainstem strokes: diplopia, hemi or quadriparesis, cerebellar features (pons), crossed sensory symptoms (medulla), Horner’s syndrome

Question 10

What is amaurosis fugax?

Answer 10

Transient monocular blindness due to transient retinal artery occlusion (branch of carotid) - affect eye on SAME side as affected carotid artery

Question 11

Management of acute stroke?

Answer 11

CT within 1 hour or immediately if deteriorating, on an anticoagulant, candidate for IV rTPA or high suspicion of haemorrhage

Ix: bloods, glucose, ECG, CXR

Admit all to dedicated acute stroke unit (better outcomes)

Supportive: oxygen, hydration, nutrition, glucose and electrolyte monitoring

IV rTPA within 4.5 hours for certain inpatients