Neuro pathology part 2

Question 1

Ischaemic stroke causes

Answer 1

Sudden cessation of adequate blood flow to region of brain- occlusion of artery supply
Blood vessel disease - Large artery stenosis, small vessel disease
Thrombosis of blood vessel
Embolism e.g. Cardio-embolism
Hypoperfusion e.g. post MI

Question 2

Ischaemic stroke risk factors

Answer 2

same as those for atherosclerosis: hypertension, diabetes, age, obesity, smoking, hypercholesterolaemia, genetic/ethnic factors

Question 3

ischaemic stroke development of infarction

Answer 3

Infarction due to disrupted blood flow
Hypoxia > Neurons irreversibly damaged after 5-7 minutes
Cells swell up – cytotoxic oedema
Necrosis (infarct core) with surrounding ischemic area (penumbra)
If blood supply restored, penumbra can recover
Eventually necrotic area becomes a fluid-filled cavity (“pseudocyst”)

Question 4

Acute stroke imaging NICE guidelines 2019

Answer 4

indications for thrombolysis (breaking down of clot) or (removal of clot) thrombectomy
on anticoagulant treatment
a known bleeding tendency
a depressed level of consciousness (GCS below 13)
unexplained progressive or fluctuating symptoms
Papilloedema (raised intracranial pressure), neck stiffness or fever
severe headache at onset of stroke symptoms.
CT scan within 24 hours otherwise
If thrombectomy (removal of thrombus) indicated, a CT angiogram (CTA) and CT perfusion imaging are added

Question 5

Ischaemic stroke: stroke and prognosis

Answer 5

Dedicated stroke care unit
Neurosurgical interventions
Reperfusion therapy

Question 6

Dedicated stroke care unit

Answer 6

Dedicated stroke care unit – aim to prevent complications of neurological impairment (e.g. aspiration, pneumonia, pressure ulcers)

Question 7

Neurosurgical interventions examples

Answer 7

decompressive craniotomy- reducing intracranial pressure

Question 8

Reperfusion therapy

Answer 8

Intravenous or intra-arterial thrombolysis

Mechanical thrombectomy

Question 9

How does imaging help with treatment and prognosis

Answer 9

Exclude intracranial haemorrhage as this precludes thrombolysis
Demonstrate early signs of ischaemia
Exclude stroke mimics –e.g. tumour

Question 10

Ischaemic stroke on non contrast CT early signs

Answer 10

Early signs are subtle – hyperdense vessel, or loss of grey/white matter differentiation

Question 11

Ischaemic stroke on non contrast CT later signs

Answer 11

seen as a low-density area corresponding to vascular territory affected (e.g. wedge-shaped MCA as shown here) and mass effect

Question 12

Ischaemic stroke on non contrast CT- low density is due to

Answer 12

Low density is due to cytotoxic oedema (swollen cells)

Later, as swelling reduces, and area is replaced by glial cells, a low-density area will remain

Question 13

Diffusion weighted imaging (DWI)

Answer 13

Used in MRI and can be used to see ischaemic stroke earlier- however, is not used routinely

Question 14

consequences depend on the affected vessel

Question 15

Transient Ischaemic attack (TIA)

Answer 15

a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction.

Question 16

Transient Ischaemic attack (TIA) localised symptoms

Answer 16

similar to stroke (FAST criteria) usually no more than 1-2 hours. Usually, conscious

Question 17

Transient Ischaemic attack (TIA) causes

Answer 17

Temporary localised reduction in blood flow to the brain.
Stenosis of the artery (e.g. internal carotid artery or intracranial arteries)
Small embolus
bifurcation of the carotid artery is the most common site

Question 18

Transient Ischaemic attack (TIA) risk factors

Answer 18

same as for ischaemic stroke

Question 19

Imaging in TIA and non disabling stroke following rapid assessment in TIA clinic (2019 NICE guidelines) brain imaging

Answer 19

diffusion-weighted imaging

blood sensitive sequences….

Question 20

Types of Brain bleeds

Answer 20

Intra-axial – within the brain parenchyma

Extra-axial – outside of the brain but within the skull

Question 21

Intra-axial bleed:Intracerebral Haemorrhage (ICH) causes

Answer 21

hypertension; occasionally due to aneurysm or arteriovenous malformation
usually basal ganglia, pontine, or cerebellar

Question 22

Intra-axial bleed: Intracerebral Haemorrhage (ICH) symptoms

Answer 22

same as for ischemic stroke, but frequently more severe. Headaches and coma are more commonly associated. Raised Intracranial pressure +++

Question 23

Intra-axial bleed: Intracerebral Haemorrhage (ICH) treatment

Answer 23

medical – reduce hypertension and aim to prevent secondary cerebral injury. Surgical if large

Question 24

imaging of ICH

Answer 24

CT is very sensitive for fresh blood
Well circumscribed hematoma seen within the brain parenchyma
High density indicating fresh blood
Often surrounded by oedema (low density - vasogenic rather than cytotoxic)

trauma may show fractures too

Question 25

Head injury

Answer 25

GCS less than 13 on initial assessment in the emergency department. GCS less than 15 at 2 hours after the injury on assessment in the emergency department. Suspected open or depressed skull fracture. Any sign of basal skull fracture ('panda' eyes, cerebrospinal fluid leakage from the ear or nose, Battle's sign). Post-traumatic seizure. Focal neurological deficit. More than 1 episode of vomiting.

Question 26

Extra-axial bleeds

Answer 26

extradural subdural subrachnoid

Question 27

extradural haematoma

Answer 27

Collection of blood between inner surface of skull and outer layer of dura Usually associated with hx of trauma (RTC/sports)> gradual LOC Commonly caused by rupture of the middle meningeal artery, often associated with skull fracture Coma > Invariably lethal if unrecognized Prompt blood clot extraction (if large enough)>best prognosis

Question 28

extradural haematoma CT appearances

Answer 28

Acute hemorrhage has high density (HU 50-100) Lentiform (bi-convex) in shape Can cause mass effect and herniation Bone windows may identify underlying fracture

Question 29

Subdural haematoma

Answer 29

Collection of blood in subdural space – between dura and arachnoid mater > Caused by tearing of bridging veins Occur in any age group: Infants (SPA)- suspected physical abuse Young adults (RTC) Elderly (falls) Typically present with depressed conscious state; focal deficits develop In elderly > confusion>pseudodementia following minor trauma

Question 30

subdural haematoma CT appearances

Answer 30

Crescent-shaped collection - blood tracking between dura and the arachnoid mater High density if acute, low density if chronic; often mixed

Question 31

Subarachnoid Haemorrhage

Answer 31

Bleeding between arachnoid and pia mater Type of stroke (3-5% of all strokes). High mortality Typical older middle age patients <60 usually spontaneous Rupture of berry aneurysms 70%, Arteriovenous malformations (AVM) (10%) Other e.g. bleeding disorders, tumours, trauma

Question 32

Subarachnoid Haemorrhage

Answer 32

Symptoms: Thunderclap headache, neck stiffness (irritation of meninges); acute confusion, neurological signs and reduced consciousness.

Question 33

Subarachnoid Haemorrhage treatment

Answer 33

– bed rest, and reduce hypertension; if berry aneurysm – endovascular coil may be indicated

Question 34

Subarachnoid Haemorrhage CT appearances

Answer 34

``` High density (fresh blood) within basal cisterns, cerebral fissures and sulci (indicating that it is within the subarachnoid space) Most commonly around COW (circle of willis) which is where most berry aneurysms occur ```