Blood Supply and Stroke

Question 1

Describe features of the vertebral artery

Answer 1

• First branch of the first part of the subclavian artery which ascends in the foramina in transverse processes of the upper 6 cervical vertebrae and enters the skull through foramen magnum and pierces the meninges to enter subarachnoid space.

Question 2

Describe features of the basilar artery

Answer 2

It is formed by the union of both vertebral arteries at the pontomedullary junction. It then ascends to anterior pons and terminates as bifurcation into posterior cerebral arteries.

Question 3

What are the branches of the basilar artery? what do they supply?

Answer 3

• Anterior inferior cerebellar artery, labrinthine artery, pontine arteries and superior cerebellar artery. These arteries wrap posteriorly to supply the cerebellum

Question 4

Describe features of the internal carotid artery

Answer 4

• Passes into the skull via carotid canal in the temporal bone, passes through the cavernous sinus and perforates dura mater at the anterior clinoid process and enters the subarachnoid space. It divides into anterior and middle cerebral arteries and gives off posterior communicating artery.

Question 5

What are the different segments of the internal carotid artery?

Answer 5

C1 - Cervical segment.
C2 - Petrous segment.
C3 - Lacerum segment (it doesn’t ravel through but travels above).
C4 - Cavernous segment (when its passing through the cavernous sinus)
C5 - Clinoid segment (peirces dura mater)
C6 - Ophthalmic segment.
- Communicating segment (origin of posterior communicating artery

Question 6

What is the anterior and posterior supply of the circle of willis?

Answer 6

Anterior supply - Internal carotids become the middle cerebral artery and the anterior cerebral artery.
Posterior supply - Vertebral arteries become the basilar artery which bifurcates as the posterior cerebral artery. Add uncovered pic

Question 7

What is the function of the posterior/anterior communicating arteries

Answer 7

Posterior - connects anterior and posterior supply of the circle of willis.
Anterior - Connects the anterior cerebral arteries.

Question 8

What can occur if there is an aneurism of the PCA?

Answer 8

It can compress the 3rd cranial nerve which can lead to a palsy

Question 9

What arteries supply the areas of the brain?

Answer 9

Question 10

What cause a rise in intracranial pressure?

Answer 10

Increased CO2 (this leads to vasodilation which will increase pressure), Hypoxia and increased temperature.

Question 11

Define what a stroke is

Answer 11

A clinical syndrome characterised by sudden onset of rapidly developing focal/global neurological disturbance which least more than 24hours or leads to death.

Question 12

What is a transient ischaemic attack?

Answer 12

Neurological dysfunction caused by focal brain/spinal cord or retina ischaemia without evidence of acute infarction

Question 13

What are some of the causes of ischaemic strokes?

Answer 13

Thrombosis, embolism or hypoperfusion (hypoperfusion leads to watershed areas which are between main supply areas which will be affected by hypoperfusion first)

Question 14

What is the penumbra

Answer 14

Area of ischaemia which is not yet infarcted but will if not perfused quickly

Question 15

What is a total anterior circulation stroke (TACS)? and what is needed for a diagnosis?

Answer 15

Large cortical stroke affecting areas supplied by middle and anterior cerebral arteries. All three os the following must be present; Unilateral weakness (and/or sensory deficit) of the face arm and leg. Homonymous hemianopia (defect of half of visual field) and higher cerebral dysfunction

Question 16

What is a partial anterior circulation stroke (PACS)? And what is needed for diagnosis?

Answer 16

Less severe TACS, where only part of the anterior circulation has been compromised. Two of the following must be present; Unilateral weakness (and/or sensory deficit) of the face arm and leg. Homonymous hemianopia (defect of half of visual field) and higher cerebral dysfunction.

Question 17

What is a posterior circulation syndrome (POCS) and what is needed for a diagnosis?

Answer 17

It is damage to area of the brain supplied by posterior circulation (brainstem or cerebellum.) On of the following must be present; Cranial nerve palsy and contralateral motor/sensory deficit. Bilateral motor/sensory deficit. Conjugate eye movement disorder (inability to move both eyes together). Cerebellar dysfunction or isolated homonymous hemianopia

Question 18

What is a lacunar stroke and what is needed for a diagnosis?

Answer 18

This is subcortical stroke, there is no loss of higher cerebral functions. One of the following must be present; Pure sensory stroke or pure motor stroke, sensori-motor stroke or ataxic hemiparesis

Question 19

What occurs in an anterior cerebral artery ischaemic stroke?

Answer 19

There will be contralateral leg weakness and/or sensory loss. Insert pic

Question 20

How will a middle cerebral artery stroke present?

Answer 20

• Contralateral hemiplegia (arm>leg),
• Cdontralateral hemisensory loss,
• Conjugate eye deviation (looking towards side of lesion)
• Contralateral hemianopia.
• There can be language deficit if on dominant hemisphere (wernikes aphasia or broca’s aphasia),
• can have Hemineglect

Question 21

What is hemianopia?

Answer 21

Where half of your visual field is lost

Question 22

How will a posterior cerebral artery stroke present?

Answer 22

• Hemianopia,
• If in dominant hemisphere then can have alexia without agraphia (write but cannot read) and visual agnosia (difficulty naming objects)
• If in non-dominant hemisphere then prosopagnosia (difficulty recognising faces)
• Bilateral cortical blindness

Question 23

How can a basilar artery occlusion present?

Answer 23

Very rare but can present with quadriplegia, diplopia and bulbar symptoms (facial weakness, dysphagia, dysarthria or dysphonia) Can have locked-in state

Question 24

What are the stroke mimics?

Answer 24

The 5 ‘S’s;

• Seizures,
• Sepsis,
• Syncope,
• Space occupying lesions,
• Somatisation (phycological)

Question 25

Describe the appearance of a stroke on ADC-MRI at acute, subacute and chronic stages

Answer 25

Acute - Hypointense,
Subacute - Return to near baseline then hyperintense
Chronic - Hyperintense

Question 26

Describe the appearance of a stroke on DWI at acute, subacute and chronic stages

Answer 26

Acute - Marked hyperintense,
Subacute - Hyperintense,
Chronic - Hypointense

Question 27

What is the treatment of an acute stroke?

Answer 27

• Use non-enhanced CT immediately to rule out intracranial haemorrhage.
• Give oxygen therapy and blood sugar control (4-11mmol/L) (also do blood tests so FBC, U+Es and coag screen),
• If ischaemic stroke then can do thrombolysis (Alteplase), thrombectomy (best treatment), theraputic hypothermia, BP control, Aspirin, Antiplatelet/anticoag treatment if complex presentation

Question 28

What is the secondary prevention for strokes?

Answer 28

• Anti-thrombotics (clopidogrel or aspirin and dipyridamole),
• If in AF then warfarin or DOACs,
• Control BP, want to make sure systolic is <130mmHg. Use CCB, or diuretics or ACE inhibitors
• Control cholesterol with statins if total cholesterol is above 4mmol/L

Question 29

What is the typical presentation of a subarachnoid haemorrhage

Answer 29

It tends to be described as being hit on the back of the head/worst headaches of life there can also be sudden LOC or almost immediate death. Poor prognosis. They are most often caused by aneurysm