Neurology Flashcards
Signs of Parkinson’s Disease on Examination
Inspection
- Asymmetrical resting tremor: 5Hz (exacerbated by counting backwards)
- Hypomimia (decreased facial expression)
- Extrapyramidal posture
Arms
- Demonstrate bradykinesia
- Tone: cogwheel rigidity
- Enahnced by synkinesis (nvoluntary muscular movements accompanying voluntary movements)
- Normal power and reflexes
- Coordination may be abnormal in multiple system atrophy
Eyes
- Movements:
- nystagmis if multiple system atrophy
- Vertical gaze palsy if progressive supranuclear palsy
- Saccades: slow initiation and movement
Extras
- Glabellar tap (primitive reflex where the eyes shut if an individual is tapped lightly between the eyebrows
- Persistent = myerson’s sign of parkinson’s
- Gait
- Slow initiation
- Shuffling
- Hurrying: festination
- Absent arm swing
- Write sentence, draw spiral
- BP lying and standing (autonomic dysfunction)
Causes of Parkinsonism
Idiopathic Parkinson’s Disease
Parkinson plus syndromes:
- Progressive supranuclear palsy
- Multiple system atrophy
- Lewy body dementia
- Corticobasilar degeneration
Multiple infarcts in the substantia nigra
Wilson’s disease
Drugs: neuroleptics and metoclopramide
Investigations for Parkinsons
Bloods
decreaseed Ceruloplasmisn (Wilson’s Disease)
Imaging
- MRI brain
- Functional neuroimaging (dopamine transporter imaging such as FP-CIT or beta-CIT SPECT, or fluorodopa PET)
Other
- olfactory testing
- genetic testing
Management of Parkinson’s
For first-line treatment:
if the motor symptoms are affecting the patient’s quality of life: levodopa
if the motor symptoms are not affecting the patient’s quality of life: dopamine agonist (non-ergot derived), levodopa or monoamine oxidase B (MAO‑B) inhibitor
1st Line Dopamingeric:
- MAO-B inhibitor
- Dopaminergic agent
2nd-Line dopamingergic
- Amantadine
- Trihexyphenidyl
e. g. rasagiline: 1 mg orally once daily
e. g. carbidopa/levodopa: 50 mg orally (immediate-release) three times daily initially
Physical ativity: resistance training improves motor symptoms
If moderate Parkinson’s OR refractory tremor
Add amantadine, trihexyphenidyl or deep brain stimulation
Add in COMT inhibitor if on cabridopa/levodopa and effects dimishinging e.g. entacapone: 200 mg orally with each dose of carbidopa/levodopa
Drugs to Treat Parkinson’s
Levodopa
- usually combined with a decarboxylase inhibitor (e.g. carbidopa or benserazide) to prevent peripheral metabolism of levodopa to dopamine
- reduced effectiveness with time (usually by 2 years)
- unwanted effects: dyskinesia (involuntary writhing movements), ‘on-off’ effect, dry mouth, anorexia, palpitations, postural hypotension, psychosis, drowsiness
- no use in neuroleptic induced parkinsonism
Dopamine receptor agonists
- e.g. Bromocriptine, ropinirole, cabergoline, apomorphine
- ergot-derived dopamine receptor agonists (bromocriptine, cabergoline) have been associated with pulmonary, retroperitoneal and cardiac fibrosis.
- The Committee on Safety of Medicines advice that an echocardiogram, ESR, creatinine and chest x-ray should be obtained prior to treatment and patients should be closely monitored
- patients should be warned about the potential for dopamine receptor agonists to cause impulse control disorders and excessive daytime somnolence
- more likely than levodopa to cause hallucinations in older patients. Nasal congestion and postural hypotension are also seen in some patients
MAO-B (Monoamine Oxidase-B) inhibitors
- e.g. Selegiline
- inhibits the breakdown of dopamine secreted by the dopaminergic neurons
Amantadine
- mechanism is not fully understood, probably increases dopamine release and inhibits its uptake at dopaminergic synapses
- side-effects include ataxia, slurred speech, confusion, dizziness and livedo reticularis
COMT (Catechol-O-Methyl Transferase) inhibitors
- e.g. Entacapone, tolcapone
- COMT is an enzyme involved in the breakdown of dopamine, and hence may be used as an adjunct to levodopa therapy
- used in conjunction with levodopa in patients with established PD
Antimuscarinics
- block cholinergic receptors
- now used more to treat drug-induced parkinsonism rather than idiopathic Parkinson’s disease
- help tremor and rigidity
- e.g. procyclidine, benzotropine, trihexyphenidyl (benzhexol
Path of Parkinson’s
Destruction of dopaminergic neurons in pars compacta of the substantia nigra
The nerve cell bodies of the pars compacta are coloured black by the pigment neuromelanin - this is lost in Parkinson’s
beta-amyloid plaques
Neurofibriliary tangles: hyperphosphorylated tau
Features of Parkinson’s
TRAPPS PD
Tremor: increased by stress, decreased by sleep
Rigidity: lead-pipe, cog-wheel
Akinesia: slow initiation, difficulty with repetitive movement, micrographia, monotonous voice, mask-like face
Postural instability: stooped gait with festination
Postural hypotension and other autonomic dysfunction
Sleep disturbance
Pyschosis
Depression, Dementia
Sleep disorders in Parkinson’s
Insomnia and frequent waking –> excessive daytime sleepiness
Inability to turn, restless legs, early mornign dystonia (medication wearing off), nocturia, obstructive sleep apnoea
REM behavioural sleep disorder
Loss of muscle atonia during REM sleep –> violent enactment of dreams
Autonomic dysfunction in Parkinson’s
Drugs + neurodegeneration
Postural hypotension
Constipation
Hypersalivation –> dribbling
Urgency, frequency and nocturia
Erectile dysfunction
Hyperhidrosis
L-DOPA side effects
DOPAMINE
Dyskinesia
On-Off phenomena = motor fluctuations
Psychosis
Arterial BP decrease
Mouth dryness
Insomnia
Nausea and vomiting
Excessive daytime sleepiness
Multisystem Atrophy
Papp-Lantos bodies: alpha-synuclein inclusions of glial cells
Autonomic dysfunction: postural hypotension, impotence, loss of sweating, dry mouth and urinary retention and incontinence
AND
Parkinsonism
AND
Cerebellar ataxia
If autonomic features predominate, may be referred to as Shy-Drager syndrome
Progressive Supranuclear Palsy
Tauopathy
Cardinal Features
- Supranuclear ophthalmoplegia
- Neck dystonia
- Parkinsonism
- Pseudobulbar palsy
- Behavioral and cognitive impairment
- Imbalance and walking difficulty
- Frequent falls
Postural instability –> falls
Vertical gaze palsy
Oculocephalic reflex –> involuntary eye movements better
convergence insufficiency
Pseudobulbar palsy: speech and swallowing problems
Parkinsonism: Symmetrical onset, tremor unusual
Corticobasilar Dementia
Neurodegenerative condition affecting the cerebral cortex and basal ganglia
Cardinal features
- Parkinsonism
- Alien hand syndrome
- Apraxia (ideomotor apraxia and limb-kinetic apraxia)
- Aphasia
Unilateral Parkinsonism
Rigidity in particular
Aphasia
Astereognosis: inability to identify an object by active touch of the hands without other sensory input
Due cortical sensory loss —> alien limb phenomenon and automous arm movements
Lewy Body Dementia
Alpha-synuclein and ubitquitin Lewy Bodies in the brainstem and neocortex
Features
Fluctuating cognition
Visual hallucinations
Parkinsonism
Causes of Tremor
Resting:
Parkinsons
Intention:
cerebellar disease
Postural: worse with arms otustretched
- Benign essential tremor
- Endocrine: hyperthyroidism
- Alcohol withdrawal
- Beta-agonists
- Anxiety
Benign Essential Tremor
Autosomal dominant
Occurs with movement and worse with anxiety/ caffeine
Doesn’t occur with sleep
Better with alcohol
Signs of Cerebellar Syndrome on Examination
DANISH
Dydiadochokinesia: hands and feet
Ataxia
Nystagmus + rapid saccades
Intention tremor and dysmetria (lack of coordination of movement typified by the undershoot or overshoot of intended position with the hand, arm, leg)
Slurred speech
Hypotonia/Heel-shin test
Causes of Cerebellar Syndrome
DAISES
Demyelination
Alcohol
Infract: brainstem stroke
SOL e.g. shwannoma + other cerebellopontine angle tumours
Inherited: Wilson’s disease, Friedrich’s ataxia, Ataxia-telangiectasia, Von Hippel Lindau syndrome
Epilepsy
System atrophy, multiple
Vestibular and Cerebellar Nystagmus
Cerebellar cause
Fast phase towards lesion
Maximal looking towards lesion
Vestibular cause
Fast phase looking away from lesion
Maximal looking away from lesion
Lateral Medullary Syndrome / Wallenberg’s
Occlusion of vertebral artery or PICA (posterior inferior cerebellar artery)
—> ischaemia to lateral part of medulla oblongata in the brainstem
Sensory deficits that affect the trunk and extremities contralaterally (opposite to the lesion),
AND
Sensory deficits of the face and cranial nerves ipsilaterally (same side as the lesion)
DANVAH
Dysphagia: damage to nucleus ambiguus –> motor to CN IX and X
Ataxia: damage to inferior cerebellar peduncle
Nystagmus: damage to inferior cerebellar peduncle
Vertigo: damage to vestibular nucleys
Anaesthesia (contralateral): damage to spinothalamic tract
Anaesthesia (ipsilateral): damage to spinal trigeminal nucleus
Horner’s syndrome: damage to sympathetic fibres
Vestibular Schwannoma
Benign slow growing tumout of superior vestibular nerve
SOL —> Cerebellopotine angle syndrome
Assoc with NF type II
Unilateral SNHL
Tinnitus
Vertigo
Increase ICP –> headache
Ipsilateral CN V, VI, VII and VII palsies
Cerebellar signs
Signs:
Facial anaesthesia
Absent corneal reflex
LMN facial nerve palsy
Lateral rectuis palsy
SNHL
DANISH
Cerebellopontine Angle Tumours
Vestibular schwannoma (80%)
Meningioma
Cerebellar astrocytoma
Metastases
Von Hippel-Lindau
Renal cysts
Bilateral renal cell carcinoma
Haemangioblastomas often in cerebellum –> cerebellar signs
Phaeochromocytoma
Islet cell tumours
Friedrich’s Ataxia
Autosomal recessive mitochondrial disorder
Progressive degeneration of the:
Dorsal column
Spinocerebellar tracts and cerebellar cells
Corticosinal tracts
Onset in teenage years
Associated with HOCM and mild dementia
Main features:
Pes cavus
Bilateral cerebellar ataxia
Leg wasting + areflexia but extensor plantars
Loss of vibration and proprioception
Additional Features
High-arched palate
Optic atrophy and retinitis pigmentosa
HOCM: ESM and 4th heart sound
DM
Ataxia Telangiectasia
Autosomal recessive neurodegenerative disease
Defect in DNA repair
Onset in childhood / adolescents
Features
Progressive ataxia
Telangiectasia: conjunctivae, eyes, nose, skin creases
Immunocompromised: defective cell-mediated immunity
Lymphoproliferative disease
Wilson’s disease
Autosomal recessive of ATP7B gene on chromosome 13
CLANK:
Cornea: Keiser-Fleischer rings
Liver: CLD
Arthritis
Neuro: Parkinsonism, Ataxia, Psychiatric problems
Kidney: Fanconi Syndrome
Signs of an Upper Motor Neuron Lesion on Examination
Inspection: walking aids, disuse atrophy, contractures
Limb posiiton
- Leg: extended, internally rotated with root plantar flexed
- Arm: flexed, internally rotated, supinated
Gait
- Unilateral lesion —> circumducting
- Bilateral lesion –> scissoring
UMN signs
- Increased tone
- Pyramidal distrubution of weakness
- Leg: extensors stronger than flexors
- Arm: flexors stronger than extensors
- Hyper-reflexia
- Extensor plantars
Sensation
Sensory level = cord lesion
Completion: CN (evidence of MS), Cerebellum (evidence of MS)
Pyramidal distribution
Extensor in lower limbs
Flexors in upper limbs
Spastic paraparesis
Bilateral
Common causes:
Multiple sclerosis
Cord compression
COrd trauma
Cerebral palsy
Other causes:
Familial spastic paraparesis
Vascular: aortic dissection –> Beck’s syndrome
Infection: HTLV-1
Tumour: ependymoma
Syringomyelia
Mixed UMN and LMN = MAST
Motor neuron disease
Ataxia, Friedrich’s
Subacute degeneration of cord (B12 def)
Taboparesis (tertairy syphilis)
Spastic Hemipararesis
Hemisphere
Stroke
Multiple sclerosis
Space-occupying lesion
Cerebral palsy
Hemicord (can be monoparesis)
Multiple sclerosis
Cord compression
Cord Compression
Presentation
- Pain
- Local, deep
- Radicular pain
- Weakness
- LMN at the level of compression –> nerve roots affected
- UMN below the level of compression –> cord affected
- Sensory level
- Spinchter disturbance
Causes
- Trauma, vertebral #s
- Infection: epidural abscess, TB
- Malignancy: breast, thyroid, bronchus, kidney, prostate mets
- Disc prolapse: L1/L2
Invx: MRI
Mx
Neurosurgical emergency
Malignancy: dexamethasome IV, radioterpay
Abscess: surgical debridement and IV antibiotics
Cauda Equina Lesion
Presentation
Pain: back pain and radicular pain down legs
Weakness: bilateral and flaccid
Sensation: saddle anaesthesia
Spincters: incontinence / retention / poor anal tone
Causes
Trauma
Malignancy
Abscess
Disc prolapse
Beck’s Syndrome
Anterior Spinal Artery Syndrome
Infraction of spinal cord in distribution of anterior spinal artery
Ventral 2/3 of cord
Causes: aortic dissection
Para/ quadri-paresis
Impaired pain and temperature sensation
Preserved touch and propioception
Syringomyelia
Syrinx: tubular cavity in central canal of the cord
Commonly located in the cervical cord
Syrinx expands ventrally affecting:
- Decussating spinothalamic neurons
- Anterior horn cells
- Corticospinal tracts
Can have static background symptoms, worsening on coughing, sneezing
Causes:
- Blocked CSF circulation with decreased flow from posterior fossa
- Arnold-Chiari malformation (cerebellum herniates through foramen magnum)
- Masses
- Spina bifida
- Secondary to cord trauma, myelitis, cord tumours and AVMs
Main Features
Dissociated sensory loss
- Loss of pain and temperature
- Preserved touch , proprioception and vibration
- Cape distribution
Wasting/ weakness of hands + claw hand
Loss of reflexes in upper limb
Charcot joints: shoulder and elbow
Other Signs
Horner’s syndrome
UMN weakness in lower limbs with extensor plantars
Syringobulbia: cerebellar and lower CN signs
Kyphoscoliosis
Invx: MRI
Mx
Surgical decompression at foramen magnum for Chiari malformation
Human T-lymphotropic Virus-1
Retrovirus, prevalent in Japan and Caribbean
Adult T cell leukaemoa / lymphoma
Tropical spastic paraplegia / HTLV myelopathy
Slowly progressive spastic paraplegia
Sensory loss and paraesthesia
Bladder dysfunction
Definition of Acute Stroke
Rapid onset focal neurological deficit of vascular origin lasting >24 hours
Path of Acute Stroke
80% ischaemic
Atheroma: large or small vessel
Embolism: cardiac (AF or endocarditis) or atherothromboembolism
20% haemorrhagic
Raised BP, trauma, aneurysm rupture, anticoagulation, thrombolysis
Bamford Classification
Bamford classification of stroke (based on clinical features)
Total anterior circulation stroke (TACS) = carotid/ MCA or ACA
- Unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
- Homonymous hemianopia
- Higher cognitive dysfunction e.g. dysphasia, neglect, apraxia
Partial anterior circulation stroke (PACS)
- Involves smaller arteries of anterior circulation e.g. upper or lower division of middle cerebral artery
- 2 of the above criteria are present
Posterior circulation infarcts (POCI, c. 25%)
- Involves vertebrobasilar arteries
- Presents with 1 of the following:
- cerebellar or brainstem syndromes
- loss of consciousness
- isolated homonymous hemianopia
Lacunar infarcts (LACI, c. 25%)
- Involves perforating arteries around the internal capsule, thalamus and basal ganglia
- Presents with 1 of the following:
- unilateral weakness (and/or sensory deficit) of face and arm, arm and leg or all three.
- pure sensory stroke.
- ataxic hemiparesis
Definition of Multiple Sclerosis
Chronic inflammatory condition of the CNS characterised by multiple plaques of demyelination separated by time and space
Pathology of Multiple Sclerosis
CD4 cell mediates destruction of oligodendrocytes
—> demyelination and eventual neuronal death
Initial viral inflammation primes humoral antibody response
Plaques of demyelination are hallmark finding
Classification of Multiple Sclerosis
Relapsing-remitting = 80%
Secondary progressive
Primary progressive = 10%
Progressive relapsing
Signs and Symptoms of Multiple Sclerosis
Presentation
TEAM
Tingling
Eye: optic neuritis (decrease central vision and eye pain on eye movement)
Ataxia + other cerebellar signs
Motor: spastic paraparesis
Clinical Features
Sensory: dys/paraesthesia, decreased vibration sense, trigeminal neuralgia
Motor: spastic paraparesis, transverse myelitis
Eye: diplopia, bilateral intranuclear opthalmoplegia, optic neuritis
Cerebellum: trunk and limb ataxiamscanning dysarthria, falls
GI: swallowing
Lhermitte’s sign
Electric shoch sensation in trunk and limbs after flexion of the neck
Internuclear opthalmoplegia
Can abduct on convergence but not on lateral gaze
Uhthoff’s sign
Decrease in visual acuity with heat e.g. hot bath
Sign of optic neuritis
Optic Neuritis
Pain on eye movement
Rapid decrease in central vision
Uhthoff’s
Decreased acuity
Decreased colour vision
White disc
Central sarcoma
RAPD
Intranuclear opthalmoplegia
Also known as ataxic nystagmus / conjugate gaze palsy
Disruption of MLF connect CN VI to CN III
Weak adduction of affacted eye
Nystagmus in contralateral eye upon gaze
Convergence preserved
Diagnosing Multiple Sclerosis
Bloods
FBC
comprehensive metabolic panel
thyroid-stimulating hormone (TSH
vitamin B12: rule out sub-acute degernation of the cord
MRI brain and spine
Gd-enhanced - image active inflammation
Typically in periventricular white matter
Lumbar puncture
Glucose, protein, and cell count should be normal
Oligoclonal bands and elevated CSF immunoglobulin G (IgG) and IgG synthesis rates are present in 80% of MS cases
Antibodies
Anti-NMO (anti-aquaporin 4 [AQP4]) antibody testing is recommended to rule out neuromyelitis optica (Devic syndrome)
Anti-MBP
Visual evoked potential
Visual evoked potentials are most commonly abnormal, with somatosensory and auditory evoked potentials less so.
DDx
CNS sarcoidosis
SLE
Devic’s syndrome: neuromyelitis optica: MS variant with transverse myelitis and optic neuritis (NMO +ve) +MRI Brain NORMAL
McDonald Criteria
McDonald Criteria for diagnosing MS
Classification of Motor Neuron Disease
Amyotrophic Lateral Sclerosis: 50%
Corticospinal tracts —> UMN and LMN signs + fasciculations
Progressive Bulbar Palsy: 10%
Only affects CN IX - XII —> bulbar palsy
Progressive Muscular Atrophy: 10%
Anterior horn cell lesion –> LMN signs only
Distal to proximal
Better prognosis compared with ALS
Primary Lateral Sclerosis
Loss of Betz cells in motor cortex –> mainly UMN signs
Marked spastic leg weakness and pseudobular palsy
No cognitive decline
Amyotrophic Lateral Sclerosis
Typically LMN signs in arms and UMN signs in legs
Both the upper motor neurons and the lower motor neurons degenerate
Familial cases: chromosome 21 (superoxide dismutase gene)
Presentation
- Fasciculations (muscle twitches) in the arm, leg, shoulder, or tongue
- Muscle cramps
- Tight and stiff muscles (spasticity)
- Muscle weakness affecting an arm, a leg, neck or diaphragm.
- Slurred and nasal speech
- Difficulty chewing or swallowing
When symptoms begin in the arms or legs, it is referred to as “limb onset” ALS. Other individuals first notice speech or swallowing problems, termed “bulbar onset” ALS
Individuals with ALS usually have difficulty swallowing and chewing food, which makes it hard to eat normally and increases the risk of choking. They also burn calories at a faster rate than most people without ALS. Due to these factors, people with ALS tend to lose weight rapidly and can become malnourished.
individuals may experience problems with language or decision-making, and there is growing evidence that some may even develop a form of dementia over time.
Mx
Medical: Riluzole
Drooling: Amitriptyline
Dysphagia: NG tube
Pain: Analgesic ladder
Spasticity: baclofen, botulinum
Breathing support: NIV prolongs life by 7 months
Conservative:
Physical therapy
Speech therapy
Nutritional support
Progressive Bulbar Palsy
Normal Production of Sound
Phonation: layrnx and vocal cord
Articulation: Tongue and mouth
Larynx - produces vowels and some consonants.
Lips - produce m, b and p.
Lingula - l and t.
Throat and soft palate (guttural) - nk and ng.
Bulbar palsy is the result of diseases affecting the lower cranial nerves (VII-XII)
A speech deficit occurs due to paralysis or weakness of the muscles of articulation which are supplied by these cranial nerves.
Importantly, these lesions do not affect speech in isolation. The bulbar nerves also innervate muscles involved in swallowing and facial muscles.
Presentation
Lips - tremulous.
Tongue - weak and wasted and sits in the mouth with fasciculations.
Drooling - as saliva collects in the mouth and the patient is unable to swallow (dysphagia).
Absent palatal movements.
Dysphonia - a rasping tone due to vocal cord paralysis; a nasal tone if bilateral palatal paralysis.
Articulation - difficulty pronouncing r; unable to pronounce consonants as dysarthria progresses.
Mx
Drooling: Amitriptyline
Dysphagia: NG tube
Pain: Analgesic ladder
Spasticity: baclofen, botulinum
Conservative:
Physical therapy
Speech therapy
Nutritional support
Progressive Muscular Atrophy
Affects LMN
Presentation
- weakness and wasting of muscles in the legs, arms, hands and body
- fatigue
- muscle cramps and pain
- fasciculations
- clumsiness
- breathing difficulties
- weight loss
Unilateral LMN to single limb with sensation intact
Old Polio
Differential for Peripheral Neuropathy
Mainly Sensory
Diabetes Meltius
Alcohol
B12 deficiency
Chronic renal failure and cancer (paraneoplastic)
Vasculitis
Drugs: isoniazid, vincristine
Mainly Motor
HMSN / CMT
Paraneoplastic: Lung cancer, Renal cell carcinoma
Lead poisoning
Acite: GBS and Botulism
Notes on isoniazid: Isoniazid binds with active form of
pyridoxine called pyridoxoal-5-phosphate to form isoniazid-pyridoxal
hydrazone which is excreted in the urine causing pyridoxine deficiency.
Dose of 10 mg of pyridoxine for each 100 mg dose of isoniazid prevents
pyridoxine deficiency
Usually occurs after 6 months of therapy - usually reverses on stopping drug
Signs of Diabetic Neuropathy on Examination
Inspection: fingers pricks from DM monitoring
Peripheral vascular disease
Charcot joints
Motor
Bilateral loss of ankle jerks (2º to sensory neuropathy)
Mononeuritis multiplex –> foot drop
Sensory
Distal sensory loss in stocking distribution
Completion: fundi, upper limbs and cranial nerves, urine dip
Sensory neuropathy
Mononeuritis multiplex
CNIII
CNVI
Ulnar nerve
Signs of Charcot-Marie-Tooth Syndrome on Examination
Also known as Peroneal Muscular Atrophy
Also known as Hereditary Motor and Sensory Neuropathy
Inspection
Pes cavus (high arch, fixed plantar flexion)
Symmetrical distal muscle wasting
–> claw hand
–> champagne bottle legs
Thickended nerves esp. common peroneal nerve around fibula
Motor
High-stepping gait: foot drop
Weak foot and toe dorsiflexion
Absent ankle jerks
Sensory
Variable loss of sensation in a stocking distribution
Classification of Charcot-Marie-Tooth
HMSN 1
Commonest form
Demyelinating
AD mutation in the peripheral myelin protein 22 gene
HMSN 2
Second commonest form
Axonal degeneration
Autosomal dominant
Nerve conduction studies can discrimate between the two:
Decreased velocity = demyelination = Type I
Decreased amplitude = axonal degeneration = Type II
Signs of Myasthenia Gravis on Examination
Inspection: thymectomy scar
Eyes
Bilateral ptosis: worse on sustained upward gaze
Complex opthalmopegia
Facial movements
Myasthenic snarl on smiling
Voice
Becomes nasal
Deterioration: ask patient to count to 50
Limbs
Fatigueability: repeatedly flap arm
Completion: Assess FVC / respiratory function
Management of Myasthenia Gravis
Invx
Anti-AChR, Anti-MuSK
EMG: decreased response to titanic train of impulses
Tensolin test: imrpovement with edrophonium chloride (no longed used)
TFTs: Graves in 5%
<50 female: check for autoimmune disease: DM, RA, GRaves, SLE
>50 male: check for thymoma
Mx
Acute
Plasmapheresis or IVIG
Monitor FVC - ventilation may be required
Chronic
Pyridostigmine
Immunosupression: corticostreoids and azathioprine
Surgical: thymectomy (removes molecular mimicry)
Lambert-Eaton myasthenic syndrome
Antibodies against voltage-gate calcium channels –> reduces acetyl choline release from nerve terminal
Paraneoplastic e.g. SCLC
Lower limb girdle weakness - difficulty climbing stairs and rising from chair
Areflexia
Weakness improves on repetitive testing
Differential for bilateral ptosis
Myasthenia gravis
Myotinic dystrophy
Congenital
Senile
Bilateral horner’ (rare)
Guillain Barre Syndrome
Classification
AIDP: Acute inflammatory demyelinating polyneuropathy
Miller-Fisher: opthalmoplegia + ataxia + areflexia
Molecular mimicry: antibodies cross-react with ganglioside
Bacteria: Campylobacter jejuni, Mycoplasma
Viruses: CMV, EBV
Presentation
Symmetrical ascending flaccid paralysis
Sensory disturbance: paraesthesia (tingling)
Autoimmune neuropathy: labile BP
Invx
Stool MC+S
Anti-gangliosde antibodies
LP: Increased CSF protein
Nerve conduction studies: demyelination (reduced velocity)
Mx
Supportive: 4 As
Airway: ventilation if FVC <1.5L
Analgesia: NSAIDs, Gabapentin
Autonomic: vasopressors, catheter
Antithrombotis: TEDs, LMWH
Immunosupression: IVIG, plasma exchange
Physiotherapy: prevent flexion contractures
Prognosis: 85% complete recovery, 10% unable to walk at 1 year, 5% mortality
Signs of Facial Nerve (CN VII) Palsy on Examination
Inspection
Unliateral facial droop
Absent nasolabial fold
+/- absent forehead creases
?scar on parotid mass
Rash around external meatus
Weakness
Raising eyebrows: frontalis
Screwing up eyes: orbicularis oculi
Bell’s sign: papebral oculogyric reflex, eyeball rolls back on closure of eyelid
(this is normal response 75% but you can’t normally see this as eye lids closes –> becomes noticeable only when the orbicularis oculi muscle becomes weak)
Smiling: orbicularis oris
UMN: sparing of frontalis and orbicularis oculi
Due ot bilateral cortical representation
Millard-Gubler Syndrome
Also kown as ventral pontine syndorme
One of teh crossed paralysis syndromes
Pons
CN VI (abducens) nucleus —> ipsilateral lateral rectus palsy
CN VII (facial) ncuelus —> ipsilateral LMN facial palsy
Corticospinal tracts —> contralteral hemiparesis
Causes vary by age
Young
- tumour
- demyelination (e.g. MS)
- viral infection (e.g. rhombencephalitis)
Older
- vascular (basillar artery occlusion /stroke)
Cerebellopontine Angle Syndrome
Distinct neurological syndrome of deficits that can arise due to the closeness of the cerebellopontine angle to specific cranial nerves
CN V: Trigeminal nerve
CN VI: Abducens nerve
CN VII: Facial nerve
CN VIII: Vestibulocochlear nerve
AND
Cerebellar Signs
Signs
Facial anaesthesia + absent corneal reflex
Lateral rectus palsy
LMN facial nerve palsy
Sensorineural hearing loss
DANISH
5, 6, 7, 8 and cerebellum
Features of Ramsay Hunt Syndrome
Reactivation of VZV in geniculate ganglion of CN VII
Preceding ear pain or stiff neck
Vesicular rash in auditory canal +/- TM, pinna, tongue, hard palate
No rash = zoster sine herpete
Ipsilateral facial weakness, hyperacusis and ageusia
May affect CN VIII –> vertigo, tinnitus and SNHL
Cholesteatoma
Locally destructive expansion of stratified squamous epithelium within the middle ear
Usually secondary to attic performation of TM in chronic suppurative otitis media
Presentation
Foul smelling white discharge
Vertigo, deafness, headache, pain
Facial paralysis
Complications
Deafness: ossicle destruction
Meningitis
Cerebral abscess
Mx
Surgery
Lyme Disease
Borellia burgdoferi
Early: local erythema migrans
Systemic malaise
Late Disseminated:
CN palsy e.g. Facial nerve palsy
Polyneuropathy
Meningoencephalitis
Arthritis
Myocarditis
Heart block
Afferent and efferent arms of the Corneal Reflex
The reflex is mediated by:
Nasociliary branch of the ophthalmic branch (V1) of the 5th cranial nerve (trigeminal nerve) sensing the stimulus on the cornea only (afferent fiber).
Temporal and zygomatic branches of the 7th cranial nerve (Facial nerve) initiating the motor response (efferent fiber).
Signs of Horner’s Syndrome on Examination
Face: PEAS
Ptosis: partial (superior tarsal muscle)
Enopthalmos
Anhydrosis
Small pupil
No opthalmoplegia
Ptosis, Myosis, Anhydrosis
Neck scars: central lines, carotid endarterectomy
Hands: complete claw hand and intrinsic hand muscle weakness
Decrease or absent sensation in T1 dermatome
Differential for Horner’s Syndrome
Central
Multiple sclerosis
Wallenberg’s syndrome / Lateral Medullary Syndrome
Pre-ganglionic (neck)
Pancoast tumour: T1 nerve root lesion
Trauma: carotid endarterectomy or central line
Post-ganglionic
Cavernous sinus thrombosis: Usually secondary to spreading facial infection through opthalmic veins –> CN 2, 4, 5, 6, palsies
Anatomy of Horner’s Syndrome
1st-order neuron
Arnold-Chiari malformation
CVA/intrapontine haemorrhage
Basal meningitis (syphilis)
Intrinsic tumour - glioma
Syringobulbia/ syringomyelia
2nd-order neuron
Pancoast tumour
Occlusion/dissection
Tumour
Trauma – surgical,birth
Thyroid malignancy
3rd-order neuron
Tumour
Granuloma
Herpes zoster
NPC
Signs of Third nerve palsy / Oculomotor Nerve Palsy on Examination
Features
Complete ptosis: Levator Palpebrae Superioris
Eye points down and out: unopposed supeior oblique and lateral rectus
+/- Dilated pupil (does not react to light)
Medical CN III palsy: Pupil NOT dilated (normal and reactive)
Surgical CN III palsy: Pupul DILATATED
- Parasympathetic fibres originate in the Edinger Westphal nuceal and run on periphery of oculomotor nerve
- Recieve rich blood supply from external pial vessels: affected late in medical causes
Superior cerebellar artery aneurysm
Weber’s Syndrome
Ipsilateral CN III palsy
Contralateral hemiaplegia
Holmes-Adie Pupil
Holmes-Adie (Myotonic) Pupil
Dilated pupil that has no response to light
Sluggish response to accomodation
Therefore light-near dissociation
Decreased or absent ankle and knee jerks
Benign condition, more common in young females
Triad:
Dilated pupil (mydriasis) which does not constrict in response to light
Loss of deep tendon reflexes
Abnormalities of sweating
Argyll Robertson Pupil
Previously known as “prostitutes pupil”
Features
Small, irregular pupils
Accomodate but doesn’t react to light
Atrophied and depigmented iris
May have sensory ataxiaa -> Tabes dorsalis
Do fasting glucose / random glucose
Causes
Quaternary syphilis
Diabetes melitus
Accomodate but do not react
Light-near dissociation
Marcus Gunn Pupil
More commonly known as a relative afferent pupillary defect (RAPD)
Suggests optic nerve pathology
Optic nerve is afferent fibre of light-reflex
Affected eye constricts from consenual response but dilates as light is shinning directly into eye - swinging light reflex
Features of Optic Atrophy
Decreased visual acuity
Decreased colour vision esp. red desaturation
Central scrotoma
Pale optic disc
RAFP (Marcus Gunn pupil)
The Visual Pathway
Retina
–>
Optic nerve
–>
Optic chiasm (decussation of nasal fibres /temporal fields)
–>
Optic tract
–>
Lateral geniculate nucleus of thalamus
–>
Optic radiation
Superior field: temporal
Inferior field: parietal
–>
Visual cortex
Homonymous Hemianopia
Retrochiasmic
Greater defect = closer to chiasm OR larger lesion
Contralateral
Examine for ipsilateral hemiparesis
Examine for cerebellar signs
Right: test for neglect
Left: test for aphasia
Bitemporal Hemianopia
Chiasmatic lesion
Pituitary tumour: compresses from below = descending visual loss
Prolactinoma
Acromegaly
Cushing’s
Craniopharyngioma: compresses from above = ascending visual loss
Supraseller tumour (calcified)
