Neurology š§ Flashcards
What is the most common cause of dementia?
Alzheimerās
What are the risk factors for Alzheimerās disease?
-age
-genetics (mutations in APP, PSEN1, PSEN2, APOE)
-cardiovascular disease
-depression
-low educational attainment
-low social engagement & support
-head trauma
-learning difficulties
What are the pathological changes seen in Alzheimerās disease?
-beta-amyloid plaques (extracellular)
-neurofibrillary tangles (intracellular)
Where in the brain are beta-amyloid plaques & neurofibrillary tangles deposited in Alzheimerās disease?
hippocampus & medial temporal lobes
What are the clinical features of Alzheimerās disease?
-cognitive impairment
-behavioural and psychological symptoms (BPSD)
-early memory impairment & difficulty learning new information
-difficulties with activities of daily living
What are the cognitive domains assessed using cognitive assessment tools?
-attention & concentration
-memory
-language
-praxis (planned motor movement)
-executive function
-visuospatial function
What are the differential diagnoses for Alzheimerās disease?
-depression (& other psychiatric disorders)
-drugs (especially anti-cholingergics)
-delirium
What are the diagnostic criteria for Alzheimerās disease?
-functional ability
-cognitive remains (impairment involving 2+ cognitive domains)
-exclusion of differentials
What is mild cognitive impairment?
When there is a deficit in a single domain (of the dementia diagnosis areas) and it is mild.
What are the investigations for Alzheimerās disease?
-full bloods to exclude other diagnoses
-ECG, syphilis testing, CXR
-neuroimaging (typically MRI)
What is the non-pharmacological management of Alzheimerās disease?
-assess capacity & advanced care planning
-inform DVLA
programmes to improve/maintain cognitive function
-managing BPSD
-care plans
-end-of-life care
What is the pharmacological management of Alzheimerās disease?
mild-to-moderate AD: acetylcholinesterase inhibitors (donepezil, rivastigmine)
moderate-to-severe: memantine
What is Bellās palsy?
idiopathic unilateral facial nerve palsy causing unilateral facial weakness
What are the functions of the facial nerve?
-supplies stapedius muscle within ear
-muscles of facial expression
-parasympathetic supply to lacrimal & salivary glands
-provides taste to anterior 2/3 of tongue
What is the most common cause of facial nerve palsy?
Bellās palsy
What are the clinical features of Bellās palsy?
-rapid onset unilateral facial weakness (<72h)
-post-auricular/ear pain
-difficulty chewing
-incomplete eye closure
-drooling
-tingling
-hyperacusis (heightened sensitivity to sound)
-loss of nasolabialfold
-drooping of eyebrow
-drooping corner of mouth
-asymmetrical smile
-Bellās sign (upward movement of the eye maintained on attempt to close the eye)
How do you differentiate between Bellās palsy & stroke?
strokes are forehead sparing, Bellās palsy causes forehead paralysis
What does the House-Brackmann system assess?
degree of facial nerve damage/paralysis following surgery or Bellās palsy
How is Bellās palsy diagnosed?
-clinical diagnosis based on unilateral facial weakness, rapid onset, no forehead sparing
-blood test, neuroimaging, HIV test to exclude other causes (incl. Ramsay-Hunt)
What is the management of Bellās palsy?
-largely supportive
-prednisolone if presenting within 72h of onset (50mg for 10 days)
What is the prognosis of Bellās palsy?
most patients will fully recover within 4 months
What is a cluster headache?
-severe primary recurrent unilateral headaches around the eye or temporal region
-last 15min to 3h
What are the diagnostic criteria for cluster headaches?
-at least 5 attacks
-severe, unilateral orbital/temporal pain lasting 15-180 mins
-associated with one of the following on the ipsilateral side; conjunctival infection, nasal congestion, eyelid oedema, forehead sparing, facial sweating, mitosis/ptosis
-restlessness/agitation
-occurring every 2 days up to 8 per day
What are the 2 subtypes of cluster headaches?
-episodic: pain-free intervals of at least 3 months between clusters
-chronic: do not have a period of remission lasting longer than 3 months
What are the red flag characteristics in headaches?
-severe sudden onset
-progressive or persistent, acute change
-worse on standing
-worse on lying
What are the investigations for cluster headaches?
-neurology review
-MRI and CT to exclude other causes
What is the management of cluster headaches?
-sumatriptan
-trigger avoidance
-traditional analgesia
-short burst oxygen therapy
-verapamil as preventative
What is delirium?
an acute confusional state that causes disturbed consciousness, attention, cognition & perception
What are the characteristic features of delirium?
-acute onset
-symptoms fluctuate throughout the day
-altered awareness & attention
-disturbed cognition
-evidence of organic cause
What are the 3 subtypes of delirium?
-hyperactive: agitation, restlessness, hallucinations
-hypoactive: lethargic, withdrawn, drowsy
-mixed delirium
What are the risk factors for delirium?
-age
-multiple comorbidities
-frailty
-malnutrition
-visual/hearing impairment
-functional impairment
-alcohol excess
-major injury e.g. hip fracture
-cognitive impairment
What is the diagnostic criteria for delirium?
-disturbance in awareness & attention
-acute onset, acute change from baseline & fluctuant
-disturbance in cognition
-not better explained by another neurocognitive disorder
-evidence of an organic cause
What is the management of delirium?
-address underlying cause
-mental capacity assessment
-rapid tranquillisation may be required (benzodiazepines, anti-psychotics)
What are the options for rapid tranquillisation in delirium?
-benzodiazepines: lorazepam
-anti-psychotics: haloperidol, olanzepine
What are the 2 stages of assessing capacity?
- does the person have an impairment of the mind or brain, as a result of illness or external factors (drugs/alcohol)?
- does the impairment mean the person is unable to make a specific decision when they need to?
What are the main causes of dementia?
-Alzheimerās disease (50-70%)
-vascular dementia (20%)
-Lewy-body dementia (15-20%)
-frontotemporal dementia (2%)
-rarer causes: Parkinsonās, Huntingtonās
What are the behavioural and psychological symptoms of dementia (BPSD)?
-agitation & emotional lability
-depression & anxiety
-sleep cycle disturbance
-disinhibition
-withdrawal/apathy
-motor disturbance
-psychosis
What are the main features of vascular dementia?
-stepwise decline in function
-predominant gait, attention & personality changes
-may have focal neurological signs (previous stroke)
What are the main features of Lewi-body dementia?
-Parkinsonism
-falls, syncope
-hallucinations
What are the main features of frontotemporal dementia?
-marked personality change
-behavioural disturbances
-memory and perception relatively preserved
How is the severity of dementia assessed?
-MMSE
-MoCA
-clinical dementia rating (CDR)
How is the severity of dementia categorised?
Mild: MMSE 21-26, MoCA 18-25, CDR 1
Moderate: MMSE 10-20, MoCA 10-17, CDR 2
Severe: MMSE <10, MoCA <10, CDR 3
What is the pharmacological management of dementia?
-acetylcholinesterase inhibitors (donepizil, rivastigmine)
-memantine
What is encephalitis?
inflammation of the brain parenchyma, which characteristically presents with abnormal brain function
What is the most severe cause of encephalitis?
herpes simplex virus encephalitis - usually fatal without treatment
What are the possible causes of encephalitis?
infectious: can be viral, bacterial, fungal, parasitic
non-infectious: paraneoplastic, post-infectious, autoimmune
What are the features of HSV encephalitis?
-HSV1: rapid onset fever, headache, altered mental status, seizures, neurological deficits
-can cause CNS infection by invasion following oropharyngeal infection, or reactivation of dormant virus
-damage is typically within the temporal lobes
What are the features of post-infective encephalitis?
-immune mediated disorder usually seen in children
-demyelinating condition
-development of encephalopathy 4-13 days following an infection or vaccination
-due to development of antibodies against components of myelin
What are the features of autoimmune encephalitis?
-immune-mediated inflammatory disorders of the brain tissue
-antibody develops against an antigen within the CNS
-this initiates an immune response which leads to encephalitis
-e.g. NMDA encephalitis: antibody targets the NMDA receptor
What are the features of paraneoplastic encephalitis?
-due to the immune system reacting to antigens expressed on the tumour and the nervous system
specific cancers have been linked to specific autoantibodies:
-limbic encephalitis
-brainstem encephalitis
-antibody related syndrome
What are the clinical features of encephalitis?
-fever
-headache
-altered mental status
-focal neurological deficits
-seizures
What investigations are important in encephalitis?
-neuroimaging
-EEG
-CSF analysis: protein, viral PCR, MC&S, glucose, serology
-serological testing
What is the management of encephalitis?
-infective causes: antimicrobials
HSV encephalitis: IV aciclovir
-paraneoplastic, autoimmune & post-infective causes: immunosuppressive e.g. steroids
What is a seizure?
transient neurological change due to synchronous, hyper excited neuronal activity in the brain
What is the aetiology of epilepsy?
-genetic
-structural abnormalities
-metabolic disorders
-immune disorders
-chronic infections
-unknown
What is the pathophysiology of epilepsy?
-imbalance between inhibitory & excitatory signals
-gabanergic = inhibitory
-glutametergic = excitatory
What are the risk factors for epilepsy?
-cerebrovascular disease
-head trauma
-cerebral infections
-family history
-premature birth
-congenital malformations of the brain
-genetic conditions associated with epilepsy
What are the different types of seizures?
-area of onset: focal, general, focal to bilateral tonic-clonic
-awareness: aware, impaired awareness
-motor: tonic, clonic, myoclonic, atonic, spasms
-non-motor: absence, sensory, emotional, autonomic or behavioural changes
What are the different types of epilepsy?
-focal epilepsy
-generalised epilepsy
-generalised & focal epilepsy: combination of both
-unknown epilepsy: insufficient evidence to conclude whether focal, generalised, or both
What are the 4 stages of a seizure?
-prodrome: feeling or sensation occurring before the onset of a seizure
-early ictal: characterised by an aura, suggestive of focal epilepsy
-ictal phase: depends on seizure type, tonic-clonic movements, urinary incontinence, tongue biting
-post ictal: recover period once the seizure has finished
What are the diagnostic criteria for epilepsy?
any of the following:
-2+ unprovoked seizures occurring more than 24h apart
-1 unprovoked seizure with a probability of further seizures felt to be at a similar recurrence risk to patients with 2+ unprovoked seizures over the next 10 years
-a diagnosed epilepsy syndrome
What are the differential diagnoses for epilepsy?
-syncope & anoxic seizures
-behavioural, psychological & psychiatric
-sleep-related conditions
-paroxysmal movement disorders
-migraine associated disorders
What are the investigations for epilepsy?
-EEG: supports a diagnosis of epilepsy & determines seizure type
-MRI/CT: structural abnormalities
What are the key aspects of epilepsy management?
-education & safety
-treating acute seizures
-long term treatment with anti epileptics
What are the safety precautions in epilepsy?
-driving: depends on type of license & type of seizure
-water safety: showers instead of baths
-fire safety: caution with heat/flames
-environmental safety: home/work environment
-other: heights, contraception, high risk activities
What are the common anti epileptic drugs?
-sodium valproate
-carbamazepine
-lamotrigine
-levetiracetam
-phenytoin
What are the key points about sodium valproate?
-unclear mechanism
-teratogenic
-SEs: liver injury, pancreatitis, increased suicide risk
What are the key points about carbamazepine?
-sodium channel antagonist
-increased teratogenic risk
-SEs: agranulocytosis, SIADH
What are the key points about lamotrigine?
-sodium channel antagonist
-SEs: severe skin reactions
What are the key points about levetiracetam?
-unclear mechanism
-SEs: CNS disturbances (somnolence, decreased energy, headache), neurophsychiatric disturbance
What are the key points about phenytoin?
-sodium channel antagonist
-teratogenic
-SEs: arrhythmia with parenteral use, gum hypertrophy, cerebellar atrophy
What is the pharmacological management of focal seizures?
1st line - Lamotrigine (if childbearing potential), alternative carbamazepine (if no childbearing potential)
2nd line - Levetiracetam, oxcarbazepine or sodium valproate
What is the pharmacological management of generalised tonic-clonic seizures?
1st line - sodium valproate* or lamotrigine.
2nd line - clobazam, lamotrigine, levetiracetam or topiramate
What is the pharmacological management of absence seizures?
1st line - ethosuximide or sodium valproate*.
2nd line - lamotrigine
What is the pharmacological management of myoclonic seizures?
1st line - sodium valproate.
2nd line - levetiracetam or topiramate
What is the pharmacological management of juvenile myoclonic epilepsy?
1st line - sodium valproate*.
2nd line - lamotrigine , levetiracetam or topiramate
What is an essential tremor?
a tremor during voluntary muscle contratction, is brought out by anti-gravity positions (e.g. outstretched hands)
What is the cause of essential tremor?
-associated with strong family history
-suspected to be autosomal dominant
-exact mechanism not understood
What are the clinical features of an essential tremor?
-usually bilateral
-occurs on movement/outstretching of the arms
-most commonly affects the hands & arms
-typically high frequency with low amplitude
-improves slightly with alcohol
-usually no other neurological signs
How is a diagnosis of essential tremor made?
clinical diagnosis based on:
-isolated upper limb action tremor
-with/without tremor in other sites (e.g. head)
-duration >3 years
-no other neurological features
What is the pharmacological management of essential tremor?
propranolol (beta blocker) or primidone (anti-epileptic)
What are the non-pharmacological management options for essential tremor?
-neuromodulation
-botox injections
-deep brain stimulation
What is frontotemporal dementia?
-focal degeneration of frontal & temporal lobes
-disturbances is social behaviour, personality & language
-typically affects patients at a younger age (average 58)
What are the 3 subtypes of frontotemporal dementia?
-behavioural variant: most common, personality & behaviour change
-non-fluent primary progressive aphasia: articulatory difficulty
-semantic primary progressive aphasia: impaired single-word comprehension
What is the aetiology of frontotemporal dementia?
strong genetic predisposition: MAPT, GRN, C90RF72 gene
What is the pathophysiology of frontotemporal dementia?
-degeneration of frontal/temporal lobes
-deposition of abnormal proteins e.g. tau proteins, Pick bodies
What are the clinical features of FTD (behavioural variant)?
-disinhibition
-loss of empathy
-apathy
-hyperorality (e.g. dietary changes, consuming non-edible products)
-compulsive behaviour
What are the clinical features of FTD (primary progressive aphasia variant)?
-effortful speech
-halting speech
-speech-sound errors
-speech apraxia
-difficulty finding words
-surface dyslexia or dysgraphia (mispronouncing difficult words)
What are the motor syndromes associated with FTD?
-FTD with motor neurone disease
-corticobasal syndrome: rare neurogenerative disorder
-progressive supranuclear palsy
What are the pharmacological management options for FTD?
medications to manage behavioural/cognitive dysfunction e.g.:
-SSRIs
-atypical antipsychotics
What is the prognosis of frontotemporal dementia
overall survival is 8-10 years from symptom onset
What is Guillain-BarrƩ syndrome?
-acute, inflammatory polyneuropathy
-progressive ascending weakness of the lower limbs
-majority of patients have a preceding illness (gastroenteritis or flu)
What are the common triggers of Guillain-BarrƩ syndrome?
-campylobacter (25-50%)
-other infection: CMV, EBV, hepatitis E, mycoplasma pneumoniae
What is the pathogenesis of Guillain-BarrƩ syndrome?
-immune-mediated damage to peripheral nerves
-demyelination
What are the key investigations for suspected Guillain-BarrƩ syndrome?
-electromyography
-nerve conduction studies
-lumbar puncture: high protein, normal WCC
-spirometry: to measure involvement of respiratory muscles
What is the management of Guillain-BarrƩ syndrome?
-plasma exchange or IV immunoglobulin quickens recovery
-supportive care: analgesia, respiratory support, DVT prophylaxis
What is the Hughes disability score used for?
functional assessment of patients with Guillain-barre syndrome
What are the factors associated with poorer prognosis in Guillain-barre syndrome?
-old age
-preceding campylobacter infection
-rapid onset and severe presenting symptoms
-need for mechanical ventilation
What is the triad of features in Hornerās syndrome?
unilateral:
-miosis (pupil constriction)
-ptosis
-anhidrosis
What is the pathophysiology of Hornerās syndrome?
lesion along the oculosympathetic pathway, which is a sympathetic pathway responsible for:
-pupil dilatation
-sweating
-eyelid elevation
What are possible causes of Hornerās syndrome?
-stroke
-space occupying lesion
-multiple sclerosis
-syringomyelia (fluid-filled spinal cord cyst)
-trauma
-pancoast tumour
-thoracic outlet syndrome
-thoracic aneurysm
-carotid artery dissection
-cavernous sinus pathology
-neck mass
What are the neurological features associated with Hornerās syndrome?
-brainstem signs: diplopia, vertigo, ataxia, focal weakness
-spinal cord signs: weakness, sensory level, bowel & bladder impairment
-axillary or lung apex involvement: arm pain, hand weakness
-isolated Hornerās: concerning for carotid dissection
What are the investigations in Hornerās syndrome?
-CT angiography to exclude carotid artery dissection
-MRI for suspected spinal cord lesions
-CT chest for suspected pan coast tumour
How is Hornerās syndrome diagnosed?
-cocaine drops: fails to cause pupil dilatation
-apraclonidine drops: causes exaggerated pupil constriction
What is Huntingtonās disease?
-autosomal dominant neurodegenerative condition
-characterised by chorea, dystonic & cognitive changes
-onset around 30-50 years
-caused by CAG triplet repeats
What are the motor features of Huntingtonās disease?
-chorea: abnormal, abrupt, involuntary movements
-dysphagia & speech difficulties
-dystonia: muscle spasms & contractions
-parkinsonian features: bradykinesia, rigidity
What are the psychiatric features of Huntingtonās disease?
-mood changes: often precede motor symptoms
-depression & increased suicide risk
-paranoia, delusions, irritability, agitation, sleep disturbance
What are the cognitive features of Huntingtonās disease?
-affects ability make complex decisions & multitask
-memory loss & dementia may develop
How is Huntingtonās disease diagnosed?
PCR analysis/gel electrophoresis to identify the number of CAG repeats
What is the pharmacological management of Huntingtonās disease?
-dopamine depleting agents (e.g. tetrabenazine): helps with chorea, but may result in Parkinsonism
-antipsychotics (e.g. risperidone)
-benzodiazepines (e.g. clonazepam)
What is the prognosis of Huntingtonās disease?
normally fatal 15-20 years after symptom onset
What are the risk factors for IIH (idiopathic intracranial hypertension)?
-increased weight
-female
-reproductive age
What are the medications/conditions associated with IIH?
-medications: GH, tetracyclines, retinoids
-excess vitamin A
-systemic illness: sleep apnoea, hyper coagulable disorders, PCOD, SLE, Behcetās syndrome, endocrine disorders
What are the potential mechanisms behind IIH?
-venous sinus narrowing/stenosis
-central obesity
-altered sodium & water retention
-impaired CSF reabsorption
What are the clinical features of IIH?
-headache: worse lying down/bending over
-papilloedema
-visual changes: diplopia, flashes, transient visual loss, 6th nerve palsy
How is IIH diagnosed?
-exclude structural causes of raised ICP with neuroimaging
-raised pressures on lumbar puncture
Dandy criteria:
-typical symptoms
-absence of additional neurological features
-raised ICP with normal CSF composition
-absence of other causes of intracranial HTN
What are the differential diagnoses of IIH?
-space occupying lesion
-venous outflow obstruction
-obstructive hydrocephalus
-decreased CSF reabsorption
-increased CSF production (choroid plexus papilloma)
What are the different causes of optic disc swelling?
-papilloedema (raised ICP)
-optic nerve pathologies (optic neuritis)
-retinal artery or vein occlusion
-uveitis
What is the management of IIH?
-weight loss
-carbonic anhydrase inhibitors (e.g. acetazolamide)
-surgical treatment: optic nerve sheath fenestration, shunting
What is the main complication of IIH?
permanent visual loss
What the pathophysiology of Lewy body dementia?
presence of Lewy bodies in the cerebral cortex & brainstem
Which genetic mutations are associated with Lewy body dementia?
SNCA, PSEN1/PSEN2, APOE, APP
What are the characteristic features of Lewy body dementia?
-fluctuating cognition
-visual hallucinations
-Parkinsonism (bradykinesia, rest tremor, rigidity)
-REM sleep disorders: may precede cognitive decline
What are the clinical features that support a diagnosis of Lewy body dementia?
-severe sensitivity to antipsychotic agents
-postural instability & repeated falls
-syncope
-severe autonomic dysfunction (constipation, orthostatic hypotension, incontinence)
-excessive daytime sleepiness
-decreased sense of smell
What is the specialist neuroimaging that supports a diagnosis of Lewy body dementia?
-SPECT: looks at dopamine uptake
-polysomnography: assesses for REM sleep disorders
-EEG, MRI
What are the pharmacological interventions for Lewy body dementia?
-cholinesterase inhibitors (rivastigmine, donepezil)
-memantine
-antipsychotics (e.g. quetiapine)
-melatonin (for REM sleep disorders)
-levodopa
What is the prognosis of Lewy body dementia?
-mean survival is 6.1 years
-features with worse prognosis: cognitive fluctuations, early hallucinations, gait abnormalities
What is the difference between chronic migraine & episodic migraine?
-chronic: headache on more than 15 days each month, 8 of which have features of migraine
-episodic: less frequent than above
What are the typical features of migraines?
-attacks last 4-72 hours
-unilateral
-pulsating
-moderate/severe intensity
-aggravated by physical activity
-associated with nausea/photophobia/phonophobia
-may be associated with aura (neurological symptoms preceding headache)
What are red flags when differentiating between migraine and TIA/stroke?
-motor weakness
-diplopia
-visual symptoms affecting only one eye
-poor balance
-decreased level of consciousness
What is the acute management of migraines?
-simple analgesia (paracetamol, ibuprofen, aspirin)
-triptans
-antiemetics
What are the preventative options in migraine?
-propranolol
-topiramate (contraindicated in pregnancy)
-amitriptyline
-galcenezumab
What is the pharmacological management for menstrual-related migraine?
-frovatriptan
-zolmitriptan
What are the complications associated with migraines?
-status migraine: persists for over 72 hours
-persistent aura without infarction: lasting over 1 week
-migrainous infarction: cerebral infarction occurs during aura
-migraine aura-triggered seizure
-ischaemic stroke
What is a mononeuropathy?
-damage/dysfunction of a single peripheral nerve
-leads to motor and/or sensory dysfunction
-commonly due to entrapment or compression
What are the functions of visceral fibres in the PNS?
-visceral sensory fibres: carry signals from thoracic & abdominal compartments
-visceral motor fibres:form the autonomic nervous system (sympathetic & parasympathetic)
What are the functions of somatic fibres in the PNS?
-sensory input from skin, muscles, bones & joints
-motor output to glands & muscles
What are the 3 broad groups of mononeuropathies?
-cranial
-upper limb
-lower limb
What are the main nerves of the upper limb?
-median
-ulnar
-radial
-axillary
-other: musculocutaneous, long thoracic, suprascapular, spinal accessory
What are the main nerves of the lower limb?
-common peroneal
-tibial
-femoral
-sciatic
-other: sural, obturator, lateral cutaneous nerve of the thigh
What are the 12 cranial nerves?
-CN I: olfactory
-CN II: optic
-CN III: oculomotor
-CN IV: trochlear
-CN V: trigeminal
-CN VI: abducens
-CN VII: facial
-CN VIII: vestibulocochlear
-CN IX: glossopharyngeal
-CN X: vagus
-CN XI: accessory
-CN XII: hypoglossal
What are the possible causes of peripheral nerve injury?
-compression (e.g. compartment syndrome, carpal tunnel)
-transection (usually due to trauma)
-inflammation
-ischaemia (due to vasculitis, atherosclerosis, DM)
-radiation
What is the path of the median nerve?
-derived from brachial plexus (C5-T1)
-travels alongside the brachial artery into the cubital fossa
-travels along forearm, through carpal tunnel
Which nerve is affected in carpal tunnel syndrome?
median
What is the sensory function of the median nerve?
sensory innervation to the palmar & distal dorsal aspects of the lateral 3 1/2 digits & central palm
What are the motor functions of the median nerve?
-in the forearm: pronator trees, FCR, PL, FDS, pronator quadrates, FPL, part of FDP
-in the hand: thenar eminence & 2 lateral lumbricals
What are the causes/risk factors for carpal tunnel syndrome?
-risk factors: DM, pregnancy, RA, obesity, thyroid disease
-other causes: haematoma, trauma, tumour, vasculitis
What are the clinical features of carpal tunnel syndrome?
-sensory loss/parasthesia over palmar & distal dorsal aspects of the lateral 3 1/2 digits
-weakness/clumsiness using the hand
-weakness of thumb abduction
-thenar eminence wasting
-hand pain: typically worse at night
What are the special tests for carpal tunnel syndrome?
-Phalenās test: hyperflexing hands & holding dorsal surfaces together for 1 minute reproduces symptoms
-Tinel test: percussion over median nerve proximal to the carpal tunnel reproduces symptoms
What is the path of the ulnar nerve?
-originates from brachial plexus
-medial to brachial artery in the upper arm
-passes between medial epicondyle & olecranon
-runs through the cubital tunnel (at the elbow) and Guyonās canal (at the wrist)
What is the sensory function of the ulnar nerve?
-little finger & medial side of ring finger
-medial side of the dorsum of the hand
What is the motor function of the ulnar nerve?
-in the forearm: flexor carpi ulnaris, flexor digitorum profundus
-intrinsic muscles of the hand & hypothenar muscles
What are possible causes of cubital tunnel syndrome?
-trauma (e.g. distal humerus fracture)
-prolonged elbow flexion
-leaning on the elbow
-osteophyte formation due to arthritis
-mass lesions
What are the clinical features of ulnar nerve neuropathy?
-sensory loss/parasthesia over little finger and ring finger
-grip weakness
-wasting of the hypothenar eminence/interossei muscles
-claw hand deformity in severe cases
What is the path of the radial nerve?
-branches off the brachial plexus
-runs along the radial groove of the humerus
-wraps around humerus & passes anteriorly to the lateral epicondyle & through the cubital fossa
-gives off superficial sensory branch & deep motor branch
What is the sensory function of the radial nerve?
sensory innervation to the dorsal aspect of the radial 3 1/2 digits
What is the motor function of the radial nerve?
-triceps
-extensor muscles of the forearm
What are the typical causes of radial nerve palsy?
-mid-humeral fracture
-Saturday night palsy (arm placed over chair etc for an extended period)
-posterior interosseous syndrome (due to compression of the posterior interosseous branch)
What are the clinical features of radial nerve palsy?
-wrist drop
-weakness of finger extension
-sensory loss/parasthesia over dorsum of hand
What is the path of the common peroneal nerve?
-terminal branch of the sciatic nerve (L4-S2)
-also known as common fibular
-passes through the popliteal fossa, then around the head of the fibula
-divides into superficial & deep peroneal nerves
What are the functions of the superficial peroneal nerve?
-sensory: skin over anterolateral skin & top of foot
-motor: muscles in lateral compartment of lower leg
What are the functions of the deep peroneal nerve?
-sensory: space between big toes & 2nd toe
-motor: muscles in the anterior compartment of the lower leg
What are the possible causes of peroneal nerve palsy?
-trauma/injury to the knee
-external compression from tight splint, leg crossing etc.
What are the clinical features of peroneal neuropathy?
-foot drop
-tripping over when walking
-sensory loss over the dorsum of foot & lateral shin
What are the diagnostic tests for mononeuropathies?
-electrodiagnostic tests (EMG, NCS) to confirm the neuropathy
-imaging to identify the cause of the compression
-specific blood tests depending on the suspected cause (e.g. thyroid function & DM in carpal tunnel)
What is multiple sclerosis?
-chronic, immune-mediated demyelinating neuroinflammatory condition
-demyelination can lead to scarring & secondary neuronal loss
-usually has relapsing-remitting course
What is the mean age of onset of MS?
20-40 years
What are the causes/risk factors for developing MS?
-genetic predisposition
-viral infections (EBV/glandular fever)
-low sunlight exposure & vitamin D
-others: obesity, smoking, female
What is the pathophysiology of MS?
-destruction of oligodendrocytes (which are important in myelin sheath formation)
-possible autoimmune cause
-formation of MS plaques
-inflammation, scarring, axonal injury
Which sites in the brain are typically affected in MS?
-optic nerves
-spinal cord
-brainstem (may present with ophthalmoplegia)
-cerebellum (ataxia & gait disturbance)
-juxtacortical white matter
-periventricular white matter
What are the classifications of MS?
-relapsing-remitting (85-90%): episodes of exacerbation followed by periods of recovery
-primary progressive (10-15%): sustained progression of severity from onset of disease
-secondary progressive: disease course switches from relapsing-remitting to progressive
What are the visual manifestations of MS?
-optic neuritis: visual loss, pain, scotoma, poor colour differentiation, RAPF, optic nerve swelling
-eye movement disorders: intranuclear ophthalmoplegia (INO) & abducens palsy
What are the motor manifestations of MS?
-weakness & ataxia
-UMN signs: spasticity, reduced power, hyper-reflexia)
-transverse myelitis: inflammation in the SC causing parasthesia & weakness below the level
-cerebellar syndrome: ataxia, slurred speech, tremor, nystagmus, vertigo, clumsiness
What are the sensory/autonomic manifestations of MS?
-parasthesia
-pain
-heat sensitivity
-sexual dysfunction
-bladder & bowel dysfunction
What are the cognitive.psychological manifestations of MS?
-cognitive impairment (memory, attention, concentration)
-fatigue
-depression
How is a diagnosis of MS made?
-clinical diagnosis, supported by the use of MRI
-based on MS attack supported by objective clinical evidence (e.g. MRI)
-McDonald criteria
What are oligoclonal bands?
-bands of immunoglobulins found in the CSF of 95% of patients with MS
-can be used as markers of dissemination
What are the general principles of management of MS?
-bladder dysfunction: anticholinergics, botox injections, self-catheterisation
-bowel dysfunction: dietary changes, laxatives, enemas
-depression: SSRIs
-fatigue: non-pharmacological interventions, modafinil (CNS stimulant)
-pain: amitriptyline, gabapentin, pregabalin
-spasticity: physiotherapy, baclofen (muscle relaxant), botox injections
What is the management of an acute relapse of MS?
-steroids: oral or IV
-gastroprotection: PPI
What factors are linked to prognosis in MS?
-disease type: relapsing-remitting has better prognosis than primary progressive
-incomplete recovery after first attack = worse prognosis
-clinical manifestations at onset: pyramidal, brainstem, and cerebellar symptoms (poor prognosis). Sensory symptoms, optic neuritis (favourable prognosis)
-pregnancy: protective during pregnancy. Increased risk of relapse in postpartum period.
-imaging: lesion load and cerebral atrophy linked to prognosis (higher burden and increased atrophy have worse prognosis)
What is myasthenia gravis?
-autoimmune disorder
-formation of antibodies by B lymphocytes that bind to the ACh receptors at the NMJ
-this prevents binding of ACh, leading to increasing muscle weakness with repeated use
What are the peak age incidences of myasthenia gravis?
20-30 years (most females) and 60-70 years (mostly males)
What is the link between myasthenia gravis and the thymus gland?
-thymus gland is involved in +ve and -ve selection of T lymphocytes
-10-15% of patients with MG have a thymoma (benign thymus gland tumour)
-85% have thymic hyperplasia
-disease may improve with removal of the thymus gland
What is the pathophysiology of myasthenia gravis?
-AChR-Abs bind to ACh-R on skeletal muscle (type II hypersensitivity reaction)
this has several effects on the NMJ:
-blocks ACh binding
-causes cross-linking and destruction of ACh-R
-complement-mediated destruction of the post-synaptic membrane
How are the different subtypes of myasthenia gravis classified?
-clinical subtypes: ocular, generalised
-antibody subtypes: ACh-R, anti-MuSK, anti-LRP4, seronegative
-thymic abnormalities: normal, thymoma, hyperplasia, atrophy
-age of onset: neonatal, juvenile, early-onset (<50), late-onset
What are the clinical features of ocular myasthenia gravis?
-diplopia
-ptosis
-weak eye movements
-pupillary sparing
-symptoms worse at the end of the day
What are the clinical features of generalised myasthenia gravis?
-bulbar symptoms: fatiguable chewing, dysarthria, dysphagia
-weakness of facial muscles
-weakness of neck muscles
-proximal muscle weakness, arms more affected than legs
-weakness of respiratory muscles
What is the ice pack test in myasthenia gravis?
ptosis improves are application of ice to the eyelid for 1 minute (neuromuscular transmission is better at lower temp)
How is a diagnosis of myasthenia gravis made?
-based on clinical features and serological testing
-ice pack test, serum antibodies, electromyography (EMG), CT/MRI of thymus gland
What is the management of myasthenia gravis?
-acetylchoniesterase inhibitors (pyridostigmine)
-corticosteroids (prednisolone)
-immunosuppressants (azathioprine)
-thymectomy
What is myasthenic crisis?
-life-threatening condition
-worsening of weakness that requires respiratory support
-requires ITU admission
What is the management of myasthenic crisis?
-FVC to monitor respiratory function
-IV immunoglobulines
-plasma exchange
-corticosteroids
What are the precipitating factors of myasthenic crisis?
-warm weather
-surgery
-stress
-infections/illness
-co-morbidities
-pregnancy
-medications: Abx, antihypertensives, anti-arrhythmics etc.
What are the primary features of Parkinsonism?
-bradykinesia
-resting tremor
-rigidity
-postural instability
What is the peak age of onset of Parkinsonās disease?
55-65 years
What is the pathophysiology of Parkinsonās disease?
-loss of 50-80% of neurones within the substantia nigra
-this affects the modulation of pyramidal motor output, causing problems with initiating movement
What are some of the associated symptoms of Parkinsonās disease?
-expressionless face
-small writing
-soft voice
-drooling
-shuffling gait
-positive Glabellar tap
-depression
-bowel & bladder symptoms
-sleep disorder
-sexual dysfunction
How is Parkinsonās disease diagnosed?
-identification of features of Parkinsonian syndrome
-exclusion of differential diagnoses (e.g. stroke, trauma, tumour, hydrocephalus, negative response to levodopa etc.)
-identification of supportive features of Parkinsonās disease
What are the investigations for Parkinsonās disease?
-neuroimaging (CT/MRI)
-PET scanning with fluorodopa
What are the pharmacological management options for Parkinsonās disease?
-levodopa (given in combination with DOPA decarboxylase inhibitor)
-dopamine agonists
-MAO-B inhibitors
-COMT inhibitors
What are the different types of peripheral neuropathies?
-radiculopathies (involves spinal nerve root)
-polyneuropathies (dysfunction of multiple nerves in the PNS)
-mononeuropathies (dysfunction of a single peripheral nerve)
What are the commonest causes of peripheral neuropathies?
-diabetes mellitus
-carcinomatous neuropathy
-B vitamin deficiency (B12/thiamine/folate)
-drugs (Abx, amiodarone, statins, hydralazine, phenytoin)
What are the different mechanisms of peripheral nerve damage?
-axonal degeneration
-Wallerian degeneration (compression or lesion)
-demyelination
What is the typical distribution of polyneuropathies?
āglove and stockingā distribution, as more distal nerves are affected first
What is the typical distribution of radiculopathies?
dermatomal/myotomal, as radiculopathies affect spinal nerve roots
What is mononeuritis multiplex?
simultaneous peripheral neuropathy of 2+ separate nerves (e.g. common peroneal neuropathy + ulnar neuropathy)
What are the investigations for peripheral neuropathy?
-electromyography (evaluates muscle units)
-nerve conduction studies (evaluates peripheral nerves)
-investigations to determine the cause (FBC, TF, autoimmune tests, serology, imaging)
What is the management of peripheral neuropathy?
-treatment of underlying cause
-neuropathic analgesia (gabapentin, duloxetine)
