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
Name two clinical features of each type of haemorrhage: extradural, subdural and subarachnoid.
extradural- seizures, CSF rhinorrhoea
subdural- headache, N&V
subarachnoid- thunderclap headache, altered consciousness
Define an epileptic seizure.
An epileptic seizure is a paroxysmal event in which change is behaviour, sensation and cognitive processes are caused by excessive hypersynchronous neuronal discharges in the brain.
Name 4 causes of epilepsy.
idiopathic
head injury
CNS infection
CNS neoplasm
Name 5 characteristic features of an epileptic seizure.
tongue biting incontinence transient paraesthesia deja vu involuntary jerky movements of limbs
Name four characteristic features of non-epileptic attacks that distinguish them from epileptic seizures.
- last longer- upto 20 minutes
- associated with psychosocial distress
- dramatic motor phenomena or prolonged atonia
- ictal crying and speaking
Name two types of syncope and describe the characteristic features of each.
orthostatic hypotension
vasovagal syncope
Define syncope.
Syncope is a transient loss of consciousness caused by transient global cerebral hypoperfusion characterised by rapid onset, short duration and spontaneous complete recovery.
Name the three cardinal features of Parkinson’s Disease and the symptoms for each.
- Bradykinesia- problems with doing up buttons, microphagia, shuffling gait
- tremor- at rest, may be unilateral
- rigidity- pain, problems with turning in bed
Name 3 common co-morbidities in Parkinson’s Disease.
- Depression and other psychiatric problems
- Dementia
- Autonomic dysfunction
Describe the three pharmacological strategies for the management of Parkinson’s disease.
dopamine agonists- levodopa
monoamine oxidase B inhibitor- selegiline
cathechol-O-methyltransferase inhibitor
Describe the characteristic features of essential tremor.
- uncontrolled shaking movements with no other symptoms
- mostly in arms and legs
- no known cause
- increasing incidence with age
- tends to occur in families
What are the three clinical features of normal pressure hydrocephalus?
gait abnormality
urinary incontinence
dementia
Define dystonia.
Dystonia is a movement disorder that causes involuntary contractions of your muscles. These contractions result in twisting and repetitive movements. a state of abnormal muscle tone resulting in muscular spasm and abnormal posture
Describe the clinical features of Huntington’s disease.
chorea behavioural disturbances psychosis cognitive impairment personality change with increasing aggression depression bradykinesia spasticity clonus
Describe the clinical features of cerebellar dysfunction.
staccato speech unsteadiness dysphagia blurred vision nystagmus ataxia action tremor dysdiadochokinesia
Name 2 causes of acquired ataxia.
paraneoplastic cerebellar dysfunction
multisystem atrophy
Name 2 forms of inherited ataxia.
Friedreich’s ataxia
spinocerebellar ataxia 6
You are called by the paramedics to inform you that they have been called to see a 65 year old right handed man who presents with a right sided weakness, dysarthria, loss of vision and difficulty speaking. The paramedics inform you that the symptoms came on suddenly at 13:30. It is now 15:00.
What is the likely diagnosis?
What do you do next?
middle cerebral artery stroke
they are eligible for thrombolysis as it’s only been an 1.5 hr since onset of symptoms, MCA means can do decompressive craniectomy is increased ICP and clot retrieval - multiple options available
What are the risk management strategies for stroke?
dual antiplatelet therapy
statins
antihypertensives
warfarin or NOACs for AF
What is amaurosis fugax?
An attack of transient and painless loss of vision in one eye that is indicative of transient retinal ischaemia usually associated with stenosis of ipsilateral carotid artery.
What are the first and second line medications for dementia?
1st line: acetylcholine esterase inhibitor- rivastigmine
2nd line; NDMA antagonist (anti-glutamate)- memantine
Which of the following is a likely consequence of a skull fracture?
subarachnoid haemorrhage subdural haematoma extradural haematoma subarachnoid haematoma cerebellar haemorrhage
extradural haematoma
What are the red flag symptoms for suspecting a brain tumour?
new headache with hx of cancer papilloedema cluster headache seizure significantly altered consciousness, memory, confusion, coordination
What are the predictive features of a positive temporal artery biopsy for giant cell arteritis?
jaw claudication diplopia abnormalities on palpation (absent pulse, beaded, enlarged) raised ESR anaemia scalp tenderness temporal headache
What are the mechanisms of action of antiepileptic drugs?
- reduce pre-synaptic excitability by inhibiting voltage-gated sodium and potassium channels
- reduce neurotransmitter release by inhibiting voltage-gated calcium channels (pregabalin)
- target GABA receptor, transaminase and transporter.
What are the two pathological features of Parkinson’s?
loss of dopaminergic neurones in the substantia nigra
presence of intracellular lewy bodies in neurones
What gait disturbances would you expect to see in someone with Parkinson’s?
shuffling, festination, unsteadiness on turning, difficulty initiating walking
What is bradykinesia?
slowness of initiation of voluntary movement wit progressive reduction in speed or amplitude or repetitive actions
What are the motor complications of late-stage PD?
- wearing off of medication
- on-dyskinesia: hyperkinetic when drugs work
- off-dyskinesia: painful dystonic posturing when drugs don’t work
- freezing: unpredictable loss of mobility
Give three side effects of dopamine agonists.
tiredness
gambling
hypersexuality
What are the 3 preparations of L-dopa?
dispersible (morning) standard release (day time) slow release (night time)
What is normal pressure hydrocephalus?
It describes the condition of ventricular dilatation in the absence of increased CSF pressure on lumbar puncture, characterised by a triad of gait abnormality, urinary incontinence and dementia.
Where do brain metastases tend to originate from?
lung breast stomach prostate thyroid kidney
What is 3rd nerve lesion/palsy?
compression of the oculomotor nerve against the petroclinoid ligament when the temporal lobe uncus herniates caudally. It leads to compression of the parasympathetic fibres causing the ipsilateral pupil to be fixed and dilated.
What is the Brown-Sequard syndrome?
It is damage to one half of the spinal cord (cord hemisection) resulting in ipsilateral paralysis and loss of proprioception (as these are carried by the dorsal column and corticospinal tracts which decussate in the medullary pyramids) and contralateral loss of pain and temperature (as these are carried by the spinothalamic tract which decussates immediately on entering the spinal cord at one or two segments above point of entry)
How do midline cerebellar lesions present?
truncal and gait ataxia, nystagmus, vertigo, vomiting, obstructive hydrocephalus
How do lesions of the cerebellar hemispheres present?
ipsilateral limb ataxia with intention tremor, past point and mild hypotonia.
What is ataxia?
It is a neurological sign consisting of a lack of muscle coordination during voluntary movements.
What is the main function of the cerebellum?
Coordination and precision of movements on ipsilateral side of body.
How does Wernicke’s encephalopathy manifest?
acute confusion
ataxia
ophthalmoplegia
What causes Wernicke’s encephalopathy?
thiamine deficiency
What are the 3 ways by which CNS infections can occur?
- direct inoculation from trauma, surgery
- contiguous focus or haematogenous spread to choroid plexus
- invasion via nerves (herpes simplex)
Name 3 contraindications to performing a lumbar puncture.
- abnormal clotting
- petechial back rash
- raised ICP (check for papilloedema)
Where in the brain will you find dopaminergic neurones?
Substantia nigra
