21. Pathology of the Central Nervous System Part Two Flashcards Preview

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1

CEREBROVASCULAR DISEASE (1)

Leading cause of mortality and morbidity
Incorporates strokes, TIAs, intracerebral haemorrhage

2 main pathological processes
Hypoxia, ischaemia and infarction due to impaired blood supply/oxygenation
Haemorrhage from CNS vessels

2

CEREBROVASCULAR DISEASE (2)

Brain requires constant supply of glucose and oxygen
Brain accounts for 1-2% body weight but receives 15% resting cardiac output and accounts for 20% blood oxygen consumption
Cerebral blood flow is autoregulated to maintain adequate perfusion over a wide range of blood pressure and ICP

3

CEREBROVASCULAR DISEASE (3)

Blood flow reduced to a portion of the brain, tissue survival depends on :
Collateral circulation
Duration of ischaemia
Magnitude and rapidity of flow reduction

Blood flow reduced to the whole brain ie. Global hypoperfusion (eg hypotension, cardiac arrest) can result in generalised neuronal dysfunction

4

Stroke (1)

130,000 patients per year have a stroke in UK

Major neurological disorder

5

F A S T

Face- facial drooping
Arms- person may not be able to raise both arms and keep them raised due to weakness or numbness
Speech- slurred speech
Time- is of the essence ring for ambulance urgently

6

Stroke or Transient Ischaemic Attack

TIAs are characterised by temporary loss of function that resolves itself within 24 hours

Sometimes called “mini-strokes”

Symptoms are similar to that of a full stroke but recovery is rapid

7

Treatment of TIAs

1 in 10 chance of having a full stroke within 4 weeks if left untreated

Anti-platelet therapy: aspirin or clopidogrel

Control blood pressure

Lower cholesterol

8

stroke (2)

Loss of function lasting greater than 24 hours

2 main pathological types:

Ischaemic

Haemorrhagic

9

STROKE – Risk Factors

Hypertension
Diabetes mellitus
Heart disease – ischaemic, atrial fibrillation
Previous transient ischaemic attacks
Hyperlipidaemia

10

STROKE - Causes

Hypoxia of brain
Blockage of blood vessel by atheroma
Blockage of blood vessel by embolus

Bleed into the brain
Hypertension related
Berry aneurysm

11

MANAGEMENT

NICE guidance
Thrombolysis
Aspirin/Clopidogrel
Physiotherapy
Occupational therapy
SALT
Supportive treatment

12

Causes of Haemorrhagic Events

Hypertension
Vascular malformation
Berry aneurysm
Neoplasia
Trauma
Drug abuse
Iatrogenic

13

INTRACEREBRAL HAEMORRHAGE

‘Haemorrhagic stroke’
Presents as headache, with rapid or gradual decrease in conscious level – localizes depending on site of bleed
Usually arterial in origin
Show mass effect
In 80% of cases with hypertension bleed is ‘capsular haemorrhage’
Few survive

14

Subarachnoid Haemorrhage

Spontaneous
Often catastrophic
80% rupture of saccular aneurysms

‘Thunderclap headache’
‘Meningitis like’ signs
Requires neurosurgical input

15

SUBDURAL HAEMORRHAGE

Fluctuant conscious level
Often on anticoagulants
Bleeding from bridging veins between cortex and venous sinuses
Blood between dura and arachnoid
Often minor trauma in the elderly

16

EXTRADURAL HAEMORRHAGE

Post head injury, slowly falling conscious level, possibly with lucid period
Often with fractured temporal or parietal bone
Typically the middle meningeal artery

17

Dementia (1)

Progressive and largely irreversible clinical syndrome with widespread impairment of mental function.

Complex needs and high levels of dependency and morbidity

People should have chance to make decisions about their care in conjunction with the medical teams

18

Dementia (2)

80,000 people in the UK
> 65 years old increased risk
Memory loss
Speed of thought
Language
Understanding/Judgement
People can become disinterested in usual activities
Have difficulties in controlling emotions

19

Dementia (3)

About 70% is Alzheimer’s Disease
Remaining 15% is Vascular dementia (recurrent small strokes)
15% Dementia with Lewy bodies
Along with some very rare causes!
Eg syphilis

20

Dementia (4)

Can be mimicked by depression or delirium

Long standing history or slow decline with possible personality change

Increasing prevalence with increasing age

21

Brain area: Frontal

Dysfunction:
Disorders of behavior
Mood
Motivation
Judgment
Planning
Reasoning
Appetite and continence
Disinhibition

22

Brain area: Temporal

Dysfunction: Memory dysfunction

23

Brain area: Parietal

Dysfunction: Dysphasia and dyspraxia

24

Brain area: Subcortical

Dysfunction: Slowness of thought processes

25

Assessment

Can include
TSH – ensure thyroid function is normal
CT scan (Not all cases) to check for intracranial pathology
Vitamin B12, thiamine – alcoholism

26

Alzheimer’s Disease

Due to an accumulation of Aβ amyloid, Tau – neurofibrillary tangles and plaques, and loss of neurones and synapses

Leads to defects of visual-spatial skill (gets lost), memory loss, decreasing cognition, ansognosia (lack of awareness)

27

Treatment

Needs multidisciplinary team approach

New treatments include cholinesterase inhibitors eg rivastigmine

Their use is closely controlled by NICE

28

Epilepsy

‘A recurrent tendency to spontaneous, intermittent, abnormal electrical activity in part of the brain, manifest as seizures’
Seizures can take many forms
Focal twitching, trance-like, convulsions
Usually no identified cause
For example, can be due to
Space occupying lesions
Stroke
Alcohol withdrawal

29

Epilepsy - diagnosis

Good history taking
Exclude structural abnormality
EEG
Any triggers? Eg TV

30

Epilepsy - management

Compliance is very important
Depending on seizure type
Have serious side effects, eg teratogenic
Examples
Sodium valproate – epilim
Carbamazepine
Phenytoin
Lamotragine