Neurology Flashcards
What is a cerebrovascular accident?
Ischaemia or infarction of brain tissue secondary to inadequate blood supply
OR
Intracranial haemorrhage
What are the different types of cerebrovascular accidents?
Transient Ischaemic Attack(TIA)
Stroke:
Haemorrhagic
Ischaemic
What is a TIA?
Sudden onset focal neurological deficit.
Older definition:
symptoms of a stroke that resolve within 24 hours.
New definition:
transient neurological dysfunction secondary to ischaemia without infarction.
What is a crescendo TIA?
where there are two or more TIAs within a week. This carries a high risk of developing in to a stroke.
What are the risk factors for a TIA?
Increasing age
Hypertension
Smoking
Diabetes
Hypercholesterolaemia
Atrial fibrillation
HTN
VSD
Carotid stenosis
What are the causes of a TIA?
Thrombus formation or embolus (for example in patients with atrial fibrillation)
Atherosclerosis
Shock
Vasculitis
What artery is commonly the route of a TIA?
90% = ICA
10% = Vertebral
What are the symptoms of a TIA?
Depends on the site of the TIA:
ACA - weak/numb contralateral leg
MCA - weak/numb contralateral side of body, face drooping w/forehead spared, dysphasia (temporal)
PCA - Vision loss
Vertebral A - Cerebellar Syndrome
What would be the signs of a TIA in the Anterior Cerebral artery?
Weak/numb contralateral leg
What would be the signs of a TIA in the Middle Cerebral Artery?
weak/Numb contralateral side of body
Face drooping w/ forehead spared
Dysphasia
What would be the signs of a TIA in the Posterior Cerebral Artery?
Vision loss:
Contralateral homonymous hemianopia w/ macula sparing = occipital cortex affected.
What would be the signs of a TIA in the Vertebral Artery?
Cerebellar Syndrome: DANISH w/ +tve romberg test
What is Amaurosis Fugax?
a painless temporary loss of vision, usually in one eye
Due to occlusion/reduced blood flow to the retina through the ophthalmic, retinal or ciliary artery.
This is a bad sign as it often signals stroke is impending
What is the Primary investigation for a TIA?
Clinically made:
Usually TIA/Stroke is obvious
FAST campaign
ABCD^2
What is the FAST acronym?
FACE
ARMS
SPEECH
TIME
What is the ABCD^2 scoring system for TIA/Stroke?
No longer recommended by NICE
Age >60
BP >140/90
Clinical Sx
Duration 1hr +2 / <1hr
DM - Type 2
How can you distinguish between a TIA and a Stroke?
You cant until after recovery
TIA Sx resolve usually within/<24 hours
Stroke Sx last more than 24 hours
What is the management of a TIA?
Aspirin 300mg
Start secondary prevention of CVD:
Clopidogrel 75mg
Atorvastatin 80mg
What are the main complications of a TIA?
Increased risk of stroke
Increased risk of underlying CVD
What are the two types of stroke?
Ischaemic (85% of cases)
Haemorrhagic (15% of cases)
Define a stroke?
Focal neurological deficit that lasts for more than 24 hrs due to infarction
What is an Ischaemic Stroke?
Reduction in cerebral blood flow due to arterial occlusion or stenosis. Typically divided into thrombotic, embolic, and lacunar
What is a Haemorrhagic Stroke?
Ruptured blood vessel leading to reduced blood flow to the brain
What are the subtypes of haemorrhagic stroke?
Intracerebral: bleeding within the brain parenchyma
Subarachnoid: bleeding into the subarachnoid space
Intraventricular: bleeding within the ventricles; prematurity is a very strong risk factor in infants
What is the 3rd leading cause of mortality in the US and UK?
Stroke
What are the risk factors for stroke?
Hypertension - greatest RF
Increased age - 68-75 MC
Smoking
Diabetes
Hypercholesterolaemia
AF
FHx
Medication
What are the symptoms of stroke?
Focal neurological deficit based on site of the infarct.
What would be an extra finding in haemorrhagic stroke?
Increased intracranial pressure (ICP)
Causes midline shift
What is a Lacunar Stroke?
Very common type of ischaemic stroke of the lenticulostriate arteries.
These supply the deep brain structures (BG, IC, Thalamus, pons)
What are the clinical manifestations of a stroke in the anterior cerebral artery?
Contralateral hemiparesis and sensory loss with lower limbs > upper limbs
What are the clinical manifestations of a stroke in the Middle cerebral artery?
Contralateral hemiparesis and sensory loss with upper limbs > lower limbs
Homonymous hemianopia
Aphasia: if affecting the ‘dominant’ hemisphere (the left in 95% of right-handed people)
Hemineglect syndrome: if affecting the ‘non-dominant’ hemisphere
What are the clinical manifestations of a stroke in the Posterior cerebral artery?
Contralateral homonymous hemianopia with macular sparing
Visual agnosia
What are the clinical manifestations of a stroke in the Vertebrobasilar artery?
Cerebellar signs
Reduced consciousness
Quadriplegia or hemiplegia
What are the clinical manifestations of a stroke in Weber’s syndrome (midbrain infarct; branches of posterior cerebral artery)
Oculomotor palsy and contralateral hemiplegia
What are the clinical manifestations of a stroke in Lateral medullary syndrome (posterior inferior cerebellar artery occlusion)
Ipsilateral facial loss of pain and temperature
Ipsilateral Horner’s syndrome
Ipsilateral cerebellar signs
Contralateral loss of pain and temperature
What are the clinical manifestations of a stroke in the Basilar Artery?
Locked in syndrome
What are the primary investigations for a stroke?
NCCT Head:
Ischaemic - mostly normal
Haemorrhagic - Hyperdense blood
What is the management for an Ischaemic stroke?
immediate CT to exclude primary intracerebral haemorrhage
If presents within 4.5hrs:
Clot buster (thrombolysis) - IV Alteplase
Aspirin 300mg for 2 weeks
Prophylaxis - Lifelong clopidogrel (75mg)
What is the function of Alteplase?
Tissue plasminogen activator that rapidly breaks down clots and can reverse the effects of a stroke if given in time.
What is the management of a Haemorrhagic Stroke?
Neurosurgery referral
Iv mannitol for increased ICP
What type of stroke should be suspected if the patient is on oral anticoagulants?
Suspect Haemorrhagic until proven otherwise
What is the prophylactic prevention of secondary strokes?
Clopidogrel 75mg once daily (alternatively dipyridamole 200mg twice daily)
Atorvastatin 80mg should be started but not immediately
Carotid endarterectomy or stenting in patients with carotid artery disease
Treat modifiable risk factors such as hypertension and diabetes
What is a haematoma?
Describes a bleed that has mostly clotted and hardened
What is a Haemorrhage?
Describes an active ongoing bleed
Where can intracranial haemorrhages occur?
Extradural
Subdural
Subarachnoid
Intracerebral
What is an Extradural (Epidural) haemorrhage (EHD)?
Bleeding into the potential space between the skull and the dura mater.
The blood then collects in this space and is referred to as an extradural haematoma (EDH).
What are the causes of Extradural haemorrhage?
Usually Trauma (blunt trauma):
Arterial bleed - often middle meningeal artery
Venous bleed - often due to dural venous sinus
What is the most common blood vessel damaged to cause an extradural bleed?
Middle meningeal artery due to damage to the pterygoid bone
What are some rarer causes of an EDH?
Non-traumatic:
Haemorrhagic tumour
Coagulopathy
Infection
Vascular Malformation
What are the risk factors for an EDH?
Younger age (20-30)
Male
Anticoagulant usage
Why is an EDH less likely to occur in the elderly?
The Dura matter is more firmly adhered to the skull so blood is less likely to accumulate in this region.
What are the symptoms of an Extradural bleed?
Initial event / loss of consciousness
Lucid interval - “I feel fine”
Rapid Decline of neurological status due to raised ICP:
Dec GCS, Cushing Triad, N+V
Evidence of head injury:
Bleeding from ears
bruising/scalp haematoma
Death
What are the cushings triad signs of an extradural haemorrhage?
Hypertension
Bradycardia
Respiratory irregularity
Why is there an increased ICP in an EDH?
Haemorrhage - increased volume decreased pressure
old blood clots which can then take up water (osmotically active)
Will increase in volume and raise ICP
What are the primary investigations of an EDH?
NCCT head:
Lens shaped hyperdense bleed
Confined to suture lines
Midline shift
What is the management on an EDH?
Urgent Surgery
IV Mannitol to reduce ICP
What are the complications of an EDH?
Cerebral oedema
Raised intracranial pressure and herniation
Ischameia: can occur due to mass effect, herniation, hypoperfusion, vasospasm
Seizures
Infection
What is the Typical presentation of an EDH?
The typical history is a young patient with a traumatic head injury that has an ongoing headache.
They have a period of improved neurological symptoms and consciousness followed by a rapid decline over hours as the haematoma gets large enough to compress the intracranial contents.
What is a Subdural Haemorrhage?
When blood accumulates in between the dura and arachnoid matter
What are the causes of a Subdural haemorrhage?
Often due to the rupture of a bridging vein caused by trauma:
Shearing deceleration injury
Abused children (shaken baby sydrome)
What are the risk factors for a subdural haemorrhage?
Increased age
alcoholics
Trauma
Cortical atrophy (due to age/dementia)
Child abuse
What are the symptoms of a subdural haemorrhage?
Often gradual symptom onset with a latent period.
Progressive confusion and cognitive deficit
Headaches and vomiting
Focal neurological deficit, e.g. weakness or fixed dilated pupil
What are the clinical signs of a subdural haemorrhage?
Raised ICP
Cushing Triad - HTN, Bradycardia,
Resp irregularity
Fluctuating GSC
What are the primary investigations of a subdural haemorrhage?
NCCT Head:
Banana/Crescent shaped dense region.
Not confined to suture lines.
May have midline shift
If acute - Hyperdense (bright)
If Subacute - Isodense
If Chronic - Hypodense (darker than brain
What is the treatment for a subdural haemorrhage?
IV mannitol - reduce ICP
Burr hole / Craniotomy to relieve pressure
What is a subarachnoid haemorrhage (SAH)?
Subarachnoid haemorrhage involves bleeding in to the subarachnoid space, where the cerebrospinal fluid is located, between the pia mater and the arachnoid membrane.
This is usually the result of a ruptured cerebral aneurysm.
What are the possible causes of an SAH?
Trauma
Non-Trauma: (spontaneous)
Berry Aneurysm from circle of willis- MC of spontaneous SAH
AVM
Where do berry aneurysms often occur?
Usually at junctions of arteries within the circle of Willis.
Often communicating junctions
What is the most common artery affected in an SAH?
Circle of Willis:
Anterior communicating artery
ACA junction
What are the risk factors for a SAH?
What are some strong associations with SAH?
Increased age - >50yrs
HTN
PKD
Trauma
FHx
Smoking
Alcohol excess
Strong associations with Cocaine Use and Sickle Cell
What are the symptoms of a SAH?
Occipital Thunderclap Headache
Meningism (mimics meningitis)
Reduced GSC
Nerve palsies - 3rd / 6th
What are the characteristics of the headache experienced in an SAH?
Occipital Thunderclap Headache
Sudden onset
Worst headache of their life (0-10 instantly)
May have a sentinel headache preceding this
Why may you get nerve palsies in SAH?
3rd nerve palsy:
An aneurysm arising from the posterior communicating artery will press on the 3rd nerve, causing a palsy with a fixed dilated pupil
6th nerve palsy:
A non-specific sign which indicates raised intracranial pressure
What are the primary investigations in a SAH?
CT Head - diagnostic with 100% sensitivity if performed within 6 hrs.
If Negative:
Lumbar Puncture (performed after 12hrs)
will show xanthochromia / yellowish CSF due to RBC haemolysis
Angiography (CT or MRI) can be used once a subarachnoid haemorrhage is confirmed to locate the source of the bleeding.
Who do SAHs more commonly affect?
Black patients
Female patients
Age 45-70
What is the Glasgow Coma Scale (GCS)?
Tool for assessing consciousness:
Based on Eyes, verbal and motor response.
Normal - 15/15
Comatose - 8/15
Unresponsive - 3/15
Eyes:
Spontaneous = 4
Speech = 3
Pain = 2
None = 1
Verbal response:
Orientated = 5
Confused conversation = 4
Inappropriate words = 3
Incomprehensible sounds = 2
None = 1
Motor response:
Obeys commands = 6
Localises pain = 5
Normal flexion = 4
Abnormal flexion = 3
Extends = 2
None = 1
What are important differential diagnoses of SAH?
Meningitis - no thunderclap headache in this
Migraine - no meningism/thundercap headache in this
What is the treatment for an SAH?
1st line:
Neurosurgery:
1st - Endovascular coiling
2nd - Surgical clipping
Give immediate Nimodipine (CCB) 60mg - prevents vasospasm
What is an Intracerebral haemorrhage?
Intracerebral haemorrhage involves bleeding into the brain tissue. It presents similarly to an ischaemic stroke.
Often has a headache/come and signs of raised ICP
Define Meningitis?
Inflammation of the meninges
This is a notifiable condition to PHE
What are the different causes of Meningitis?
Viral:
Enterovirus (coxsackie)
HSV2
VZV
Bacterial:
N. Meningitidis
S. pneumonia
What is the most common cause of meningitis?
Viral cause
What organism is the most common cause of viral and bacterial meningitis?
Viral - Enterovirus (coxsackie)
Bacterial - S. pneumoniae
Which is a more severe form of meningitis?
Bacterial is more severe
What are the main risk factors for meningitis?
Extremes of age (Infant/elderly)
Immunocompromised
Crowded environment - barracks/uni
Non-vaccinated
What is the most common bacterial cause of meningitis in neonates (0-3 months)?
Group B Strep (S. agalactiae)
Due to the colonisation of mothers vagina which can cause infection in neonate at birth.
Also E.coli and Listeria
What is the most common bacterial cause of Meningitis in Infants?
N. meningitidis
S. pneumoniae
H. Influenzae (now rare due to vaccine)
Why is Haemophilus influenzae now a less common cause of meningitis?
Due to vaccination
What are the common bacterial causes of meningitis in adults?
S. pneumoniae
N. Meningitidis
What are the most common bacterial causes of meningitis in the elderly?
S. pneumoniae
N. meningitidis
Listeria
What are the most common bacterial causes of meningitis in the immunocompromised?
Listeria monocytogenes
M. Tuberculosis
What vaccines are available for meningitis coverage?
N. Meningitidis - Men B + Men C + Men ACWY
S. pneumoniae - PCV Vaccine
What is meningococcal Septicaemia?
N. meningitidis infection in the blood.
This causes a non-blanching purpuric rash
This is due to Disseminated intravascular coagulopathy (DIC) and subcutaneous haemorrhages
What are the symptoms of Meningitis?
Meningism:
Headache, Photophobia, Neck stiffness
Fever
Nausea + Vomiting
Seizures
What are the clinical signs of meningitis?
Kernig’s Sign:
When the hip is flexed and the knee is at 90°, extension of the knee results in pain
Brudzinski Sign:
severe neck stiffness causes the hips and knees to flex when the neck is flexed
What are the primary investigations in meningitis?
Lumbar Puncture (LP) + CSF Analysis
FBC - raised WCC
CRP - raised
Blood glucose - compared with CSF
Blood culture
What are some contraindications for a lumbar puncture?
Raised ICP
GCS <9
Focal Neurological signs
Where is a lumbar puncture usually taken from?
Between L3/L4
What would the results of an LP CSF sample analysis look like in bacterial meningitis?
CSF:
Appearance - Cloudy
WCC - High neutrophils
Protein High
Glucose - Low
Culture - bacterial organism
bacteria swimming in the CSF (cloudy) will release proteins (high) and use up the glucose (low). Immune response to bacteria is neutrophils
What would the results of an LP CSF sample analysis look like in Viral meningitis?
CSF:
Appearance - Clear
WCC - High Lymphocytes
Protein - Normal/Mildly raised
Glucose - Normal
Culture - Negative
Viruses cant be seen (clear) don’t use glucose (normal) but may release a small amount of protein (normal/mild inc). Immune response to viruses are lymphocytes
What is the treatment for viral Meningitis?
Usually milder and so Supportive Tx
If HSV/VZV infection then Acyclovir
What is the treatment for bacterial meningitis in a hospital?
Under 3 months:
Cefotaxime + Amoxicillin to cover listeria (from pregnancy)
Over 3 months: Ceftriaxone
What is the treatment for suspected meningitis w/ non-blanching rash present in the community?
Urgent/immediate IM Benzylpenicillin
Prior to immediate transfer to a hospital
What are some complications of meningitis?
Hearing loss is a key complication
Seizures and epilepsy
Cognitive impairment and learning disability
Memory loss
Cerebral palsy, with focal neurological deficits such as limb weakness or spasticity
What are some specific complications related to meningococcal meningitis?
Risk of DIC
Risk of Waterhouse Friedrichsen Syndrome
What is Waterhouse Friedrichsen Syndrome?
Adrenal insufficiency caused by intra-adrenal haemorrhage as a result of meningococcal DIC
What is the most common cause of fungal meningitis?
Cryptococcus Neoformans
Candida
Very rarely affects immune competent people
What is Encephalitis?
infection of the brain leading to inflammation of the brain parenchyma
What are the causes of Encephalitis?
Viral (most common)
Also bacterial, fungal, parasitic, paraneoplastic
What is the most common cause of encephalitis?
HSV-1
Accounts for 95% of the cases
Also CMV, EBV, HIV
What are the risk factors of encephalitis?
Immunocompromised
Extremes of age
Transfusion/Transplantation
Why can close contact with cats be a risk factor for encephalitis?
Risk of toxoplasmosis infection
What are the symptoms of encephalitis?
Fever
Headache
Focal Neurological deficit
Encephalopathy:
Behavioural changes
psychotic behaviour
mood changes
Confusion
Seizures
What are the clinical signs of encephalitis?
Pyrexia
Reduced GCS
Focal neurological deficit:
Aphasia
Hemiparesis
Cerebellar signs
What is the most common place to be affected by encephalitis?
Temporal and inferior frontal lobe
What are the primary investigations for encephalitis?
CT/MRI Head:
Shows evidence of unilateral encephalitis
CSF analysis:
Viraemia - increased lymphocytes
Consider PCR for confirmation
What is the treatment of encephalitis?
Acyclovir
What is multiple sclerosis?
Chronic progressive autoimmune, T-cell mediated inflammatory disorder
of the CNS
against the myelin basic protein of oligodendrocytes
causing demyelination of CNS neurons
What type of reaction is MS?
Type 4 Hypersensitivity Reaction:
T-Cell mediated
What are the risk factors for MS?
Females
20-40
Autoimmune disease
FHx
EBV
What is the pathophysiology of MS?
T4 Hypersensitivity Rxn
T-cells cause inflammation and damage against the myelin basic protein of oligodendrocytes.
The inflammation also damages the myelin on neurons in the CNS leading to demyelination
What are the types of MS?
Relapse - Remitting:
The most common pattern (85% of cases)
Episodic flare-ups (may last days, weeks or months), separated by periods of remission
Secondary Progressive:
Starts with relapse remitting
Gets progressively worse w/o remission
Primary Progressive:
Symptoms get progressively worse from disease onset with no periods of remission
What percentage of MS patients progress from relapse remitting to secondary progressive MS?
60-75% progress within 15 years
What are the causes of MS?
Unclear cause for demyelination but:
Multiple genes
Epstein–Barr virus (EBV)
Low vitamin D
Smoking
Obesity
combination of these have an influence
What is the presentation of MS?
Variable presentation
Sx progress over 24 hrs and can last days-weeks and then Improve
What are the symptoms of MS?
Blurred Vision
Numbness and tingling
Weakness
Fatigue
Bowel and bladder dysfunctions
Uhtoff’s Phenomenon
What is Uhtoff’s Phenomenon?
worsening of MS symptoms following a rise in temperature, such as a hot bath or shower
What are the clinical signs of MS?
Optic Neuritis - inflamed optic nerve and inability to see red (properly)
Internuclear Ophthalmoplegia - impaired 6th nerve and therefore one eye doesnt abduct in one direction but fine in other
Sensory loss - demyelination of spinothalamic and DCML pathways
Cerebellar signs - Ataxia and tremor
UMN signs - Spastic paraparesis
Lhermitte Phenomenon - Electric shock sensation on neck flexion
Charcot Neurological Triad: Dysarthria, Nystagmus, Intention tremor
What are the primary investigations for MS?
Clinical Dx (using McDonald criteria) and Sx progression/remission
MRI of Brain and spinal cord:
Used to support Dx by identification of demyelinating plaques
LP - may show oligoclonal bands in CSF
What is the McDonald Criteria?
Criteria used to diagnose MS:
Uses symptoms/signs which demonstrate dissemination in space (i.e. different parts of the CNS affected) and time.
What would the results of the McDonald Criteria be to diagnose MS?
2 or more relapses
AND EITHER
Objective clinical evidence of 2 or more lesions
OR
Objective clinical evidence of one lesion WITH a reasonable history of a previous relapse
(Objective evidence’ is defined as an abnormality on neurological exam, MRI or visual evoked potential)
Who manages MS?
MDT:
including neurologists, specialist nurses, physiotherapy, occupational therapy and others.
How can MS be treated long term?
Disease modifying treatments such as beta-interferon and monoclonal antibodies
How can acute relapses of MS be treated?
Steroids:
IV Methylprednisolone
+ Sx treatment of Complications:
Depression - SSRIs
Neuropathic pain - Gabapentin
Exercise - maintain strength
What is Guillain Barre Syndrome?
Guillain-Barré syndrome (GBS) is an autoimmune, rapidly progressive demyelinating condition of the peripheral nervous system, often triggered by infection
“Equivalent to MS for the PNS”
What are the causes of Guillain Barre Syndrome?
Usually triggered post infection (6 weeks) and strongly associated with:
Campylobacter jejuni (most common)
CMV
EBV
What is the most common cause of Guillain Barre Syndrome?
Post C. jejuni infection
Who is typically affected by Guillain Barre syndrome?
Males
Age peak (15-30 & 50-70)
Hx of recent infection (typically GI or Respiratory)
What is the most common type of Guillain Barre Syndrome?
Acute demyelinating inflammatory polyneuropathy (ADIP) in 90% of cases
What is the pathophysiology of Guillain Barre Syndrome?
Molecular Mimicry:
A pathogenic antigen (e.g. Campylobacter jejuni) resembles myelin gangliosides in the peripheral nervous system
The immune system targets the antigen of pathogen and subsequently and attacks the similar antigen of the myelin sheath of sensory and motor nerves
This autoimmune process involves the production of anti-ganglioside antibodies (anti-GMI is positive in 25% of patients)
The demyelination causes polyneuropathy
What are the symptoms of Guillain Barre syndrome?
Recent Hx of Infection (GI/URTI)
Glove/stocking numbness
Ascending symmetrical muscle weakness and paralysis
Back and leg pain
SOB - can progress to resp failure
What are the clinical signs of Guillain Barre Syndrome?
Reduced sensation in limbs
Symmetrical weakness - lower extremities first (proximal then distal)
Loss of deep tendon reflexes (hyporeflexia)
Autonomic dysfunction - Tachycardia, HTN, postural hypotension etc.
Respiratory distress - RF in 35% of patients
What are the primary investigations for Guillain Barre syndrome?
Clinical Dx of Hx of recent infection with progressive weakness and areflexia
Ix to exclude other causes:
TFTs - Hypothyroidism for cause of weakness
U&Es - Electrolytes for neuropathic issues
Spirometry - measure lung function
What investigations can aid to confirm the diagnosis of Guillain Barre?
Nerve conduction studies:
Conduction velocity reduced/blocked
LP - Raised protein + normal WCC = inflammation but no infection
What is the management of Guillain Barre syndrone?
First line:
IV Ig for 5 days
+ Plasma exchange
What is the prognosis of Guillain Barre?
Good prognosis
85% make a full recovery
When may Ig treatment for Guillain Barre be contraindicated?
If patient is IgA deficient
May cause an allergic reaction
What is Huntington’s Chorea (HD)?
Autosomal dominant genetic condition that causes progressive deterioration of the nervous system.
What is the penetrance of HD?
Full penetrance:
All genotypes of Huntington’s will express the phenotype
What are the genetics related to HD?
Huntington’s chorea is a “trinucleotide repeat disorder” that involves a genetic mutation in the HTT gene on chromosome 4.
CAG repeats affecting HTT gene
What is a common feature of tri-nucleotide repeat disorders in terms of prevalence?
They Show anticipation:
where successive generations have more repeats in the gene, resulting in:
Earlier age of onset
Increased severity of disease
When do symptoms of HD usually present?
Often ASx in patients under 30 yrs
Sx present between 30-50 yrs
People with HD will have more severe symptoms typically around 60+ yrs
What are the symptoms of HD?
Insidious progressive worsening:
Starts with cognitive, psychiatric and mood problems.
Then can progress to:
Chorea (involuntary, abnormal movements)
Eye movement disorders
dysarthria
dysphagia
How is a Diagnosis of HD made?
Clinical diagnosis with FHx HD and subsequent generations showing anticipation.
Genetic testing - >35 CAG repeats on chromosome 4
What is the treatment of HD?
No Tx to stop or progress HD
Provide Extensive counselling and support
Can provide Sx treatment for chorea:
Antipsychotics (olanzapine)
Benzodiazepines (diazepam)
Dopamine-depleting agents (tetrabenazine)
What is the prognosis of HD?
Progressive uncurable condition
Life expectancy of 15-20 years post diagnosis
High rate of suicide
What is a possible explanation of the chorea in HD?
Lack of GABA
Excessive Nigrostriatal pathway
What is Parkinson’s Disease (PD)?
A neurodegenerative disorder characterised by loss of dopaminergic neurones within the substantia nigra pars compacta (SNPC) of the basal ganglia (nigrostriatal pathway).
What is the prevalence of PD?
The second most common neurodegenerative disorder after dementia
What are the risk factors for PD?
Increased age
Male
FHx
What is the peak age of onset for PD?
55-65 yrs
What are the causes of PD?
Idiopathic condition but potentially related to genetics
There are secondary causes of parkinsonism:
Drugs
Wilsons disease
What are the genetic factors related to PD?
Mutation in Parkin Gene
Mutation in alpha-Synuclein gene
What is the pathogenesis of PD?
Progressive degeneration of dopamine neurons from SNpc that project to the Striatum (Str)
Therefore loss of Str inhibition which will subsequently increase activation of the subthalamic nucleus (STN)
This will activate the GPi/SNr which will increase inhibition on the Thalamus.
Therefore an inhibited thalamus will not signal to the MC making it harder to initiate movement resulting in parkinsonism.
What are the typical Parkinsonism Symptoms?
Bradykinesia
Resting Tremor
Rigidity
What are the symptoms of PD?
Parkinsonism
Anosmia - early sign
Constipation
Postural instability
Sleep disturbances
Cognitive/memory problems
Depression
What are the clinical signs of PD?
Signs are often Asymmetrical (unilateral)
Pin rolling tremor of thumb
Lead pipe arm (reduced arm swing)
Shuffling gait
Cogwheel movement
What makes up a diagnosis of PD?
Clinical Dx based on Sx and Examination.
Bradykinesia + 1 or more other Cardinal Sx
What is the treatment for PD?
No cure so Sx management
Levodopa (synthetic Dopamine) to increase levels
+ Benserazide or Carbidopa
(Often combined with a peripheral decarboxylase inhibitor to prevent breakdown of dopamine)
Combination therapies:
Benyldopa (Levodopa + Benserazide)
Carledopa (Levodopa + Carbidopa)
What is the issue with using levodopa to treat PD?
Initially works well but soon the Px becomes resistant to it and the effects wear off.
Therefore want to only use it when Sx are bad enough to prevent early resistance.
What is an important differential diagnosis to PD?
Lewy body dementia (often associated with parkinsonism)
Parkinson Sx then Dementia = Parkinson dementia
Dementia then Parkinson Sx = Lewy body dementia w/ Parkinsonsim.
What is dementia?
A syndrome caused by neurodegeneration of various causes resulting in progressive reduction of cognition and difficulty with ADLs
What is the commonest cause of dementia?
Alzheimer’s Disease (AD)
Accounts for 60-75% of all dementias
What is the epidemiology of AD?
Rarely affects under 65yrs
(otherwise EOAD which accounts for 3% of cases)
Affects more females than males
Prevalence significantly rises with age
What is the pathophysiology of AD?
Accumulation of Beta amyloid plaques (Ab plaques) and Tau Neurofibrillary tangles (NFT) in the cerebral cortex.
This leads to cortical scarring and brain atrophy
Additionally, damage to ACh neurons leading to poor neurotransmission
What is the APP protein?
Amyloid Precursor protein that is pathologically cleaved into Beta Amyloid plaques that accumulate in the brain (AD) and other tissues (in amyloidosis)
What are the risk factors for AD?
Increasing age
Downs Syndrome
APP gene mutation
APOE4 allele for familial AD (linked to EOAD)
What are the symptoms of AD?
Agnosia - cant recognise things
Apraxia - Cant do basic motor skills
Aphasia - Speech difficulties
What is the progression of cognitive decline like in AD?
Steady progressive decline
What is the second most common cause of dementia?
Vascular Dementia
Accounts for roughly 20% of cases
What is Vascular Dementia?
Cognitive decline that occurs in a stepwise manner due to a Hx of cerebrovascular events.
What is the pathophysiology of Vascular dementia?
Hx of cerebrovascular events leads to infarction and loss of brain cells/damaged tissue.
Neurons cannot regenerate so the neurodegeneration is permanent.
Increased risk of secondary cerebrovascular events can lead to further brain damage and cognitive decline.
What are the symptoms of vascular dementia?
Signs of vascular pathology:
Raised BP
Hx of cerebrovascular events
Focal CNS signs
General cognitive decline in a stepwise manner