Neurology Flashcards
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
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 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 Lewy body dementia?
- 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?
ACA - 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.
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
What disease causes a rapidly progressive decline and what other features would you see?
Creutzfeldt-Jacob disease
prion infection causing spongiform encephaopathy
causes rapidly fata demetia - death within 1 year
myoclonic jerks and extra-pyramidal signs
causes - sporadic, infected hosipital infection, familial, blood transfusions in 1995
What is Huntington’s disease?
autosomal dominant disease with 100% peetrance - trinucleotide expansion repeat of CAG.
symptoms - cognitive decline –> progresses to subcortical dementia, personality change, choreinform involuntary movements, dysarthria, psychiatric disturbance.
genetic test - children must wait until old enough to decide
What is the pathophysilogy of HD?
reduced GABA (reduced inhibition) causing dopamine hypersensitvity and increase in dopamine transmission
increased stimualtion at thalamus and cortex –> involuntary movements
Name 2 medical conditions that can cause psychiatric symptoms?
neurosyphilis - grandiosity, euphoria, mania, personality change
Wilson’s disease - copper excess leading to both neuro and psych changes, liver disease and kayser-fleischer rings
Name a potentially reversible cause of dementia?
Normal pressure hydrocephalus
triad of - ataxia, dementia and urinary incontinence
causes - idiopathic, SAH, head trauma, meningitis
tx with ventriculoperitoneal shunt
What are the features of an ataxc gait?
wide-based
falls
cannot walk heel-to-toe
often worse in the dark or with eyes closed
What are the 2 main causes of an ataxic gait?
- cerebellar problem
2. issue with proprioception
What are the cerebellar causes of an ataxic gait?
MS
posterior fossa tumour
alcohol
phenytoin toxicity
deficits are ipsilateral to cerebellar lesion
What are the features of cerebellar syndrome?
ataxia + nystagmus
What are the proprioceptive causes of an ataxic gait?
sensory neuropathies - low B12
inner ear problems affecting the vestibular system
How do you distinguish between a cerebellar and proprioceptive cause of ataxic gait?
walk normally with eyes open, problems start when eyes closed –> proprioceptive
problems exists all the time –> cerebellar
What are the features and causes of a circumduction (spastic) gait?
features - stiff gait, circumduction of the legs +/- scuffing of the toe of the shoes
cause - stroke (hemiplegia)
What are the features and causes of a shuffling (extra-pyramidal) gait?
features - flexed posture, shuffling feet, postural instability, slow to start
cause - Parkinson’s diease, PD+ syndromes, other causes of Parkinsonism such as antipsychotic medications
What are the causes of an antalgic gait?
AKA limping
MSK cause - painful limb
What are the features and causes of high stepping gait?
features - trip over often, struggle with dorsiflexion of the foot, lift ffeet high whilst walking to avoid tripping over
cause - foot srop (common peroneal nerve pasly)
What are the features and causes of Trendelenberg gait?
Features - unstable hip, sound side sags on Tredelenberg test
Causes - congenital hip dislocation, DDH, gluteus medius muscle weakness, superior gluteal nerve damage
What are the features and causes of an apraxic gait?
features - glued to the floor when attempting to walk, wide based unsteady gait with a tendency to fall (novice on ice)
causes - normal pressure hydrocephalus, multi-infarct states, Alzheimer’s disease
How does the onset of an episode of weakness help you assess the cause of it?
Sudden onset - likely to be a vascular event
medium onset - likely to be related to demyelination
insidious onset - slow-growing tumours etc
What are the patterns and distributions of muscle weakness?
- proximal weakness - muscle problem - hair, chair, stairs - struggle to do things close to their trunk
- distal weakness - nerve problem - nueropathy starts distally and works its way up - glove and stocking distribution
- symmetrical - genetic or metabolic cause eg. diabetes, muscular dystrophy
- asymmetrical - vasculitis or inflammatory
- mononeuropathy - entrapment
- polyneuropathy - systemic like diabetes
What are the features of peripheral neuropathy?
chronic and slowly progressive
length-dependent
sensnory, motor or both
glove and stocking distribution
How does mononeuritis multiplex present and what are some causes?
individually erves picked off randomly - wrist drop, leg numbness, foot drop
subacute presentation (months) inflammatory/immune-mediated
causes - inflammation of the vasa nervorum can block off the blood supply to the nerve causing sudden deficit
vasculitis (Wegner’s, PAN, RA), sarcoidosis
Give some examples of entrapment mononeuropathies.
Median nerve at wrist = carpal tunnel syndrome
ulnar nerve at elbow
radial nerve at axilla
common peroneal nerve in leg
What causes a myasthenic crisis?
infection
natural part of the disease
under or overdosing of medication
How should a myasthenic crisis be treated?
urgent neuro review
monitor breathing - serial FVC measurements
anaesthetic review
How does muscular dystrophy present and what clinical test can be done to demonstrate it?
presents in childhood with proximal muscle weakness
can have bulky muscles at first = pseudohypertrophy
then muscle wasting occurs
scoliosis is prominent later on
Gower test = positive
How is myopathy investigated?
creatinine kinase
EMG
ESR, CRP
+/- genetic (DMD, Becker)
+/- biopsy
What is the definition of coma/brain death?
unarousable unresponsiveness
What are the 3 domains used in assessing the Glasgow Coma Scale (GCS)?
- best eye opening response
- best verbal response
- best pain response
What are the 4 levels of best eye opening response?
- spontaenously
- to speech
- to pain
- None