Neuro Flashcards
Pathology of the nervous system
What age-related changes occur in the CNS?
- Decrease in brain weight.
- Cerebral cortical atrophy.
- Secondary loss of white matter due to axonal degeneration.
- Structural changes in surviving cortical neurones like neurofibrillary tangles (AD) and reduced size, numbers and dendritic branches,
- Alterations in quantity and distribution of NTs.
- Increase in astrocytes.
- Thickening of the leptomeninges.
- Arteriosclerosis and amyloid angiopathy.
- Compensatory enlargement of lateral ventricles.
- Large and numerous granulations on the brain.
- gyri = narrow; sulci = broad
What are neurodegenerative disorders?
NDD is an umbrella term for disorders characterised by progressive neuronal cell loss with distinct patterns in different disorders.
Define dementia.
Dementia can be defined as an acquired global impairment of intellect, memory and personality without impairment of consciousness.
What are the various causes of dementia?
Traumatic: dementia pugilistica
Vitamin: deficiency of B1 (thiamine- WK syndrome), B2, B12
Autoimmune: vasculitis
Neoplasms: & other intracranial lesions (subdural haematoma, hydrocephalus)
Infections: HIV, neurosyphilis, Whipple’s, TB
Substance abuse: drugs and toxins (alcohol, barbiturates, heavy metals)
Hormones: hypothyroidism, hypoparathyroidism (endocrine)
Electrolyte disturbances: liver failure, uraemia (metabolic)
D: depression and degenerative (AD, Huntington’s, Lewy body, Prion, Parkinson’s, frontotemporal lobar)
What are the features of dementia?
Acquired loss of higher mental function affecting episodic memory, language function, frontal executive function, visuospatial function and apraxia.
severe enough to cause social & occupational impairment
being chronic and stable
What are the key areas to test whilst taking a history for dementia?
- Memory
- Functional ability
- Personality and frontal lobe function
- Language
- Visuospatial ability
- Psychiatric features
- Tempo of progression
- Family history of dementia
- Alcohol and drug abuse
- Medication
- Other neurological problems
What investigations would you conduct to identify treatable causes of dementia?
- Blood tests (CBC, ESR, vitamin B12, urea, electrolytes, glucose, liver function, serum calcium, thyroid, HIV serology)
- Brain imaging- MRI & CT
- Detailed neuropsychometric assessment
- CSF measurement
- Genetic tests
- EEG
- Brain biopsy
What is the state between normal cognition and dementia called?
Mild cognitive impairment
What are the key clinical features of Alzheimer’s Disease?
- Episodic memory impairment
- Language impairment: difficulty finding words
- Apraxia
- Agnosia
- Frontal executive function affected
- Parietal presentation: visuospatial difficulties
- Posterior Cortical Atrophy: visual disorientation
- Personality remains intact
- Anosognosia: deficit of self-awareness
- Tempo: insidious onset; gradual progression.
- Late non-cognitive features: myoclonus, seizures, sleep cycle reversal, incontinence, impaired swallowing leading to terminal aspiration pneumonia.
What genes are involved in the inheritance of AD?
Amyloid precursor protein gene on Chr.21
Presenilin 1 on Chr.14
Presenilin 2 on Chr.9
Genotype e4e4 on the ApoE gene on Chr.19.
What pattern of inheritance is seen in AD?
Autosomal dominant
What environmental risk factors are associated with AD?
Increasing age, trauma and vascular risk factors.
Anti-inflammatory drugs are thought to reduce the risk of AD.
What are the 4 main histological hallmarks of AD?
- Loss of neurones and synapses (temporal and cerebral atrophy- brain weight reduced to 1100g)
- Extracellular senile plaques
- Intracellular neurofibrillary tangles
- Amyloid angiopathy
What are the characteristics of DLB?
- visual hallucinations
- fluctuating cognition (variation in attention and alertness)
- REM sleep behaviour disorder (RBD)
- dysautonomia
- parkinsonism
What can be used to temporarily improve cognitive function in DLB?
Cholinesterase inhibitors
What are the main causes of vascular dementia?
- multi-infarct dementia (usually in middle cerebral arterial distribution)
- cerebral small-vessel disease
- post-stroke dementia
What are the common signs of vascular dementia?
Apraxic gait disorder
Pyramidal signs
urinary incontinence
How can vascular dementia be distinguished from AD?
Imaging and clinical features
history of TIAs
follows succession of cerebrovascular events
stepwise course
What is the most frequent cause of stroke?
hemiplegia due to a vascular lesion of the internal capsule
What are the 3 arteries that supply blood to the internal capsule?
anterior choroidal (from ICA) medial striate (from anterior cerebral) lenticulostriate (from middle cerebral)
What are the functions of each cortical lobe?
Frontal- higher functioning, personality, motor control, speech production
Temporal- hearing, language comprehension, emotional control, memory
Parietal- sensation- pain, touch, pressure, temperature
Occipital- vision and visual perception
Name 4 components of CSF that be measured on doing a lumbar puncture.
protein serology, cytology and culture glucose WCC (appearance)
What are the cortical territories of the anterior, posterior and middle cerebral arteries?
The ACA supplies the medial part of the frontal and the parietal lobe and the anterior portion of the corpus callosum, basal ganglia and internal capsule.
MCA- majority and lateral surface of hemisphere
PCA- midbrain, thalamus, inferomedial part of the temporal lobe, occipital pole, visual cortex, and splenium of the corpus callosum.
Describe the difference between a TIA and a stroke.
They are both results of compromised vascular supply causing focal or global neurological deficits. However, a TIA resolves entirely within 24 hours where as stroke lasts over 24 hours or leads to death.
Name 5 risk factors for TIA/stroke.
hypertention diabetes mellitus smoking cardiac disease clotting disorders oral contraceptive pill previous TIA (for stroke)
Name 3 clinical features of a stroke in each of the cerebral artery territories.
ACA- lower limb paresis, drowsiness, akinetic mutism
MCA- Aphasia, facial droop, contralateral limb weakness and sensory loss
PCA- contralateral homonymous hemianopia, visual agnosia, cortical blindness
Name 4 clinical features of posterior circulation strokes.
hemi/tetra/facial paresis dysarthria vertigo nausea and vomiting visual disturbance
What is the eligibility criteria for a patient to receive thrombolysis in stroke management?
alteplase - also known as tissue plasminogen activator (tPA) - should be administered to all patients presenting with stroke, providing:
Haemorrhagic stroke has been excluded.
The patient presents within four and a half hours of having the event.
Access to specialised services is available.
Name one cause of each type of haemorrhage: extradural, subdural and subarachnoid.
extradural- head injury/trauma near pterion region between temporal and parietal bones
subdural- blunt trauma causing rapid acceleration-deceleration of the head
subarachnoid- ruptured berry aneurysm