21. Pathology of the Central Nervous System Part Two Flashcards
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
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
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
Stroke (1)
130,000 patients per year have a stroke in UK
Major neurological disorder
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
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
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
stroke (2)
Loss of function lasting greater than 24 hours
2 main pathological types:
Ischaemic
Haemorrhagic
STROKE – Risk Factors
Hypertension Diabetes mellitus Heart disease – ischaemic, atrial fibrillation Previous transient ischaemic attacks Hyperlipidaemia
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
MANAGEMENT
NICE guidance Thrombolysis Aspirin/Clopidogrel Physiotherapy Occupational therapy SALT Supportive treatment
Causes of Haemorrhagic Events
Hypertension Vascular malformation Berry aneurysm Neoplasia Trauma Drug abuse Iatrogenic
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
Subarachnoid Haemorrhage
Spontaneous
Often catastrophic
80% rupture of saccular aneurysms
‘Thunderclap headache’
‘Meningitis like’ signs
Requires neurosurgical input
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
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
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
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
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
Dementia (4)
Can be mimicked by depression or delirium
Long standing history or slow decline with possible personality change
Increasing prevalence with increasing age
Brain area: Frontal
Dysfunction: Disorders of behavior Mood Motivation Judgment Planning Reasoning Appetite and continence Disinhibition
Brain area: Temporal
Dysfunction: Memory dysfunction
Brain area: Parietal
Dysfunction: Dysphasia and dyspraxia
Brain area: Subcortical
Dysfunction: Slowness of thought processes
Assessment
Can include
TSH – ensure thyroid function is normal
CT scan (Not all cases) to check for intracranial pathology
Vitamin B12, thiamine – alcoholism
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)
Treatment
Needs multidisciplinary team approach
New treatments include cholinesterase inhibitors eg rivastigmine
Their use is closely controlled by NICE
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
Epilepsy - diagnosis
Good history taking
Exclude structural abnormality
EEG
Any triggers? Eg TV
Epilepsy - management
Compliance is very important Depending on seizure type Have serious side effects, eg teratogenic Examples Sodium valproate – epilim Carbamazepine Phenytoin Lamotragine
Infection
Diffuse infection
Eg. Meningitis
Focal infection
Eg. Abscess
Meningitis
Bacterial Neisseria meningitidis Pneumococcus Meningococcus Viral Fungal
Presentation
Early
Headache
Cold hands and feet
Pyrexial
Late Neck stiffness Photophobia Kernig’s sign Non-blanching rash Seizures
Brain Abscess
Focal infection
Can lead to focal brain damage or mass effect
Can present with headaches, seizures, temperature
Radiologically a ‘ring enhancing lesion’ – differential diagnosis is a glioblastoma
Can spread via blood, eg.
Embolus from bacterial endocarditis
IV drug users at risk
Or direct, eg.
From an infected inner ear
Parkinson’s Disease
Movement disorder
Sporadic or familial
Occurs 1 in 1000, usually over 50 years
Can be drug induced!
Parkinson’s Clinically
rigidity
bradykinesis
resting tremor
postural instability
Parkinson’s Treatment
MDT approach
L-dopa eg Madopar
Anticholinergic drugs eg orphenadrine
Drug induced Parkinson’s (eg Haloperidol) can be helped by procyclidine
Surgery?
TUMOURS/SPACE OCCUYPING LESIONS
Benign or Malignant?
Benign tumours can cause problems depending on location and mass effects
Can affect the skull, the meninges or the brain itself
Presentation
Headaches Seizures Cognitive or behavioral change Vomiting Altered conciousness
Metastasis
Cancers elsewhere in the body can metastasize the brain
Must be included when tumours are found on CT and MRI scans
These include:
Breast
Small cell lung cancer
Meningiomas
Benign tumours
Generally well circumscribed, slow growing
Derived from meningothelial cells
Enlarge slowly, don’t often infiltrate the brain, and can be often be removed surgically
Can be found incidentally on brain imaging scans
Astrocytomas
Range from WHO Grade I-IV
Grade I generally good outcome, grade 4 usually fatal
Pituitary Tumours
Cause compression symptoms For example of the optic nerve These can be hormonally active Classified based on the hormone produced For example a prolactinoma Surgically removed transphenoidally
