4 - Common Neurological Disorders 1 Flashcards
What is the definition of epilepsy?
Recurrent tendency to seizures. A seizure is an episode of transient abnormal electrical activity in the brain
Synchronus hyperexcited neuronal activity
Need 2 or more unprovoked seizures for diagnosis
What are some features in a history that might suggest a black out was a seizure?
- Prodrome: change in behaviour/mood days or hours before
- Aura: such as deja vu, strange smells
- Post ictal confusion: may also have headache, confusion
- Tongue biting
- Loss of continence
- Todd’s Palsy: temporary paralysis after
- Dysphasia
What are some of the causes of epilepsy? (6 main categories)
- Idiopathic
- Genetic predisposition
- Structural: cortical scarring from trauma, SOL, congenital cortical dysgenesis
- Metabolic:
- Immune: SLE, sarcoidosis
- Infectious: chronic infection predisposing to seizures (e.g. HIV). Different to seizures associated with an acute infection (e.g. meningitis)
What is the pathophysiology of epilepsy?
- Acquired or inherited imbalance between inhibitory (i.e. gabanergic) and excitatory (i.e. glutamatergic) signals
- High frequency bursts of excitatory action potentials leads to synchronous, hyperexcitable activity
- Transformation within neural networks that promote excitability and development of epilepsy
What are some factors that increase a persons risk of developing epilepsy?
- Cerebrovascular disease
- Head trauma
- Cerebral infections
- Family history: epilepsy or neurological illness
- Premature birth
- Congenital malformations of the brain
What are the three different ways of classifying epilsepy?
- Seizure type
- Epilepsy type (see image)
- Epilepsy syndrome
How do you classify a seizure type using the International League against epilepsy classification?
1. Focal, Generalised or Focal to Bilateral Tonic Clonic (a.k.a Secondary Generalised)
2. Impaired awareness or Normal Awareness (Complex or Partial)
3. Motor or Non Motor: absence, tonic-clonic, myoclonic, atonic, spasms
What is the difference between a focal and generalised seizure?
Focal: Starts in one hemisphere of the brain, can then spread and lead to secondary generalised. Not all leads on the EEG will start at the same time
Generalised: Affects both hemispheres of the brain at the same time, always impaired awareness. All leads on the EEG start at the same time. Preferred neural pathways
What are some examples of epilepsy syndromes and how are they diagnosed?
Diagnosed based on age of onset, seizure types, EEG features, additional clinical or radiological features. Need to know to help guide treatment
- Idiopathic generalised epilepsy: myoclonus, generalised tonic-clonic, absence
- West syndrome: infantile spasms aged 3-12 months, hypsarrhythmia on EEG
- Lennox Gastaut syndrome: tonic and absence seizures usually around 6-7 years old, slow development, treatment resistant
- Juvenile Myoclonic Epilepsy: in teens myoclonic or tonic clonic seizures often on waking, no developmental issues, genetic
What are some triggers of seizures in juvenile myoclonic epilepsy?
- Lack of sleep
- Alcohol
- Flashing lights (photosensitive)
What are the four stages of a seizure?
- Prodromal: change in mood or sensation e.g confusion, irritability, mood disturbances
- Early ictal: Aura, will only get in focal epilepsy, happens few seconds before and could a smell or a vision
- Ictal: depends on type of seizure e.g could be period of stiffness then rhythmic jerking
- Post-Ictal: confusion, drowsiness, memory loss, malaise that can take hours or days to recover from
What criteria needs to be met in order to have a diagnosis of epilepsy and what are some differential diagnoses for epilepsy?
- Syncope and anoxic seizures: LOC to impaired cerebral blood flow
- Pseudoseizures
- Sleep-related conditions
- Paroxysmal movement disorders
- Migraine associated disorders
These seizures appear the same as epileptic seizures but there is no investigational evidence for them e.g no trace on EEG, no raised lactate or prolactin after seizure
How can you tell the difference between a pseudoseizure (non-epileptic attack disorder) and an epileptic seizure?
- No clinical evidence for a pseudoseizure e.g normal CT, MRI and EEG
- Pseduoseizures may close eyes, periods of motionless unresponsiveness, rapid breathing, abrupt termination, lack of post-ictal phase, head side to side
What investigations are done following a first seizure to help aid the clinical diagnosis of epilepsy?
First seizure needs urgent referral to first fit clinic within 2 weeks.
Investigations done to rule out any precipitating cause of seizure
- EEG: see if focal cause, cannot be used to exclude epilepsy
- MRI: structural lesions that could be causing epilepsy, do CT if MRI not available
- ECG
- Bloods: FBC, U&E, LFT, Glucose, Bone profile
- Drug screen
- LP: if suspect infection
What are the aspects of management in epilepsy?
- Education and safetynetting
- Acute control of seizures
- Long term prevention of seizures (aiming for no seizures and no/few side effects)
What counselling do you need to give a patient after any fit?
- Need to stop driving and inform DVLA (if first seizure no driving for 6/12, if epilepsy need to be seizure free for a year)
- Watersafety: take showers not baths, buddy system, leave door unlocked, avoid swimming
- Environment: avoid heights, avoid flames, avoid dangerous activities
What happens at a first fit clinic?
- History, Exam, MRI, EEG
- All done to decide whether seizure is likely to represent epilepsy
- Patient education and advice
- If 2 or more seizures or 1 seizure and high risk of another, AEDs started
What are the features of the following seizures and what AEDs are used to treat them?
- Focal
- Generalised tonic clonic
- Absence
- Myoclonic
- Tonic
- Atonic
- Juvenile myoclonic epilepsy:
Focal:
1st line - Levetiracetam or lamotrigine
2nd line - Carbamazepine
Generalised tonic clonic:
1st line - sodium valproate or lamotrigine
2nd line - clobazam, lamotrigine, levetiracetam or topiramate
Absence
1st line - ethosuximide or sodium valproate
2nd line - lamotrigine
Myoclonic
1st line - sodium valoproate
2nd line - levetiracetam or topiramate
Tonic
Sodium valproate or Lamotrigine
Atonic
Sodium valproate or Lamotrigine
Juvenile myoclonic epilepsy
1st line - sodium valproate
2nd line - lamotrigine , levetiracetam or topiramate
What antiepileptics are safest to use in pregnancy?
- Lamotrigine
- Levetiracetam
What are the complications of epilepsy?
- Trauma, drowning, RTAs from actual seizure
- Status epilepticus
- Sudden unexpected death in epilepsy (SUDEP)
How are AEDs started, stopped and switched?
Start: treat with one drug and one doctor only and slowly build up until seizures controlled or maximum dose reached
Switch: Titrate new drug up and titrate old drug down
Stop: Can trial under specialist supeervision if seizure free >2 years after weighing up risks and benefits. Must decreased dose over at least 2-3 months
What advice do you need to give a woman with epilepsy on pregnancy?
- Advise all women of child-bearing age to take folic acid daily
- Avoid sodium valproate and polytherapy completely
- Most AEDs in breast milk apart from carbamazepine, valproate. Lamotrigine is in milk but not harmful
- Enzyme inducing AEDs make POP unreliable. Oestrogen containing contraceptives lower lamotrigine levels
Apart from AEDs, what other interventions can be used in epilepsy?
Psychological: relaxation, CBT may benefit some
Surgical:
- Neurosurgical resection: if single epileptogenic focus e.g tumour but risk of neurological deficits
- Vagal nerve stimulation
- Deep brain stimulation
How can you localise a focal seizure?
Temporal Lobe
- Automatisms (lip smacking, chewing, fiddling, grabbing)
- Dysphasia
- Deja-vu
- Emotional disturbance
- Hallucinations of smell, taste, sound
Frontal Lobe
- Motor features like Jacksonian March
- Subtle behavioural disturbances
- Speech arrest
Parietal Lobe
- Sensory disturbances e.g numbness, pain
Occipital Lobe
- Visual phenomena like spots, lines, flashes
What is the mechanism of action of the following AEDs and what are some side effects are each of them?
- Sodium Valproate
- Carbamazepine
- Lamotrigine
- Levetiracetam
- Phenytoin
- Phenobarbitone
- Topiramate
NEED TO MONITOR FOR DEPRESSION AND SUICIDAL THOUGHTS ON ALL AEDs
What are some symptoms of phenytoin toxicity?
- Nystagmus
- Diplopia
- Tremor
- Dysarthria
- Ataxia
What is Idiopathic Parkinson’s disease?
Chronic progressive neurodegenerative disease that occurs due to a loss of dopaminergic neurones in the substantia nigra
Most common cause of Parkinsonism (see image)
Starts unilateral then as it progresses becomes bilateral. Has non-motor symptoms too e.g depression, sleep disturbance, autonomic dysfunction
What is Parkinsonism?
Bradykinesia plus of one:
- Resting tremor
- Postural instability
- Rigidity
What is the pathophysiology of Idiopathic Parkinson’s disease?
Loss of dopaminergic neurones in the substantia nigra so less dopamine in the direct and indirect pathway.
Basal ganglia functions:
- Inhibition of muscle tone
- Coordinated, slow, sustained movement
- Suppression of useless patterns of movement
- Initiation of movement
What are the clinical features of IPD?
- Bradykinesia (slowing of voluntary movements, loss of arm swing)
- Resting ‘pill-rolling’ tremor of 4-6Hz
- Cog Wheel rigidity
- Shuffling gait
- Micrographia
- Parkinsonian mask
- Non motor: sleep disorder, bowel/bladder symptoms, sexual dysfunction, glabellar tap, depression, psychotic symptoms, anosmia
How is a diagnosis of IPD made?
UK Parkinson’s Disease Society (PDS) Brain Bank Clinical Diagnosis Criteria
Step 1
Bradykinesia plus one of: resting tremor, postural instability, muscle rigidity
Step 2
Exclusion of other causes of Parkinsonism e.g review drug chart
Step 3
3 or more supportive criteria:
- Unilateral onset
- Rest tremor present
- Progressive
- Persistent asymmetry
- Excellent response to levodopa
- Levodopa induce chorea
- Levodopa response for 5 years or more
- Clinical course of 10 years or more
What are some exclusion criteria for IPD?
- Repeated strokes and stepwise progression
- History of head trauma
- > 1 relative affected
- Sustained remission
- Unilateral features after 3 years
- Antipsychotic or dopamine-depleting drugs
- Negative response to levodopa
- Oculogyric crisis
- Exposure to neurotoxin
- Cerebral tumour or hydrocephalus
What is the MDS (movement disorder society) criteria for diagnosing IPD?
- Confirmation of Parkinsonism: bradykinesia + tremor or rigidity
- No absolute exclusion criteria present
- ≥2 supportive criteria
- Absence of red flags: rapid development gait impairment, early bulbar dysfunction, non-progressive motor symptoms ≥ 5 years while not on treatment, respiratory dysfunction, early severe autonomic dysfunction
What are some causes of Parkinsonism?
- IPD
- Multisystem Atrophy
- Progressive Supranuclear Palsy
- Dementia with Lewy Body
- Corticobasal degeneration
- Vascular
- Drug induced
- Post encephalitis
- Neurosyphillis
How do the following Parkinson’s plus syndromes present?
- MSA
- PSP
- DLB
- CBD
MSA
- Adult-onset rapidly progressive disease with profound autonomic dysfunction leading to severe postural hypotension, urogenital dysfunction, cerebellar and corticospinal features
- Poor response to treatment
PSP
- Begins at age 50-60 years with vertical gaze dysfunction, dysarthria and cognitive decline
- Tremor is rare
DLB
- Early onset dementia (< 1 year) with features of parkinsonism
- Dementia prior to motor symptoms and has visual hallucination and fluctuating consciousness
- REM sleep disorder
CBD
- Progressive dementia, parkinsonism and limb apraxia
- Alien limb syndrome
What are some drugs that can induce Parkinsonism?
- Neuroleptics e.g Risperidone, Olanzapine, Clozapine
- Metoclopramide
- Prochlorperazine
- Manganese
What investigations can be done when a patient has Parkinsonism to find if it is IPD or there is an underlying cause?
- CT/ MRI: can look for secondary cause
- PET with Fluorodopa: to localise dopamine deficiency in basal ganglia
- DaTscan: differentiate Parkinsonism from essential tremor
- Always review drug chart
How can you distinguish between a Parkinson’s tremor and a Benign Essential tremor?
How can you make a resting tremor more visible in IPD?
Unilateral so distract their other hand by asking them to mime painting a fence or something
What are the principles of management in Parkinson’s disease?
- Initial Therapy
- Adjuvant Therapy
- Surgery
- Non motor symptoms: e.g laxatives for constipation, catheter for bladder dysfunction, modafinil for excessive tiredness
Why should you not withdraw medication suddenly in Parkinson’s disease?
Risk of:
- Akinesia
- Neuroleptic malignant syndrome
Why do you not give a young patient with PD Levodopa initially?
- Side effects gets worse the longer it is used e.g dyskinesia
- Larger and more frequent dosing needed the more you use it
- Unpredictable freezing and end-of-dose reduced response the more it is used
- Try to delay use of Levodopa by using MAO-B Inhibitors and DA
How do you treat drug-induced dyskinesia in IPD?
- Alter dose of levodopa to extended release
- Give Amantadine (Dopamine agonist)
What are the main medications used to initially treat Parkinson’s disease and what are the side effects of these treatments?
Levodopa:
- Given as Co-careldopa or Co-beneldopa (Dopa De-carboxylase inhibitors)
- SE: Psychosis, Visual hallucinations, Dyskinesia, Dystonia, Vomiting (give domperidone)
Dopamine Agonists (younger patients as less SE):
- Ropinorole and Pramipezole transdermal
- SE: drowsiness, hallucinations, impulse control disorders (gambling, hypersexualitity)
- Ergot derived agonists e.g bromocriptine, not favoured as risk of PULMONARY FIBROSIS
MAO-B Inhibitors
- MAO-B involved in breaking down dopamine
- Rasagiline and Selegiline
- SE: postural hypotension, AF
What is some adjuvant therapy used in PD?
COMT Inhibitors
- Entacapone
- Stop the breakdown of levodopa in peripheries so more gets into BBB
- Adjuvant to levodopa and help with end-of-dose response
Amantadine
- Dopamine agonist that can help with dyskinesia
Apomorphine
- Non selective dopamine agonist
- Used SC for freezing episodes or for end-of-dose effects
- Postural hypotension
What surgical managament options are available for IPD?
- Thalamic or Subthalamic surgery
- Deep brain stimulation: Electrodes placed in basal ganglia. Can reverse akinesia, tremor and rigidity but can cause confused and intracerebral haemorraghes
What are some complications with Parkinson’s disease?
Motor and Non-Motor
Levodopa can cause dyskinesias. What is the meaning of the following dykinesias:
- Chorea
- Dystonia
- Athetosis
Dystonia: excessive muscle contraction leads to abnormal postures or exaggerated movements.
Chorea: These are abnormal involuntary movements that can be jerking and random.
Athetosis: Involuntary twisting or writhing movements usually in the fingers, hands or feet.
How can IPD be staged?
Hoehn and Yahr scale
or
Unified Parkinson’s Disease Rating Scale
Response to treatment gets worse as stages go on. Only treat with Levodopa when seriously affecting their life. Could start with dopamine agonists
What is vascular parkinsonism and how does it present?
Symmetrical lower-body parkinsonism with gait unsteadiness and absence of tremors and is usually associated with pyramidal signs
Patient may be diabetic or hypertensive
Treat by controlling stroke risk
What is Motor Neurone Disease and how can it be distinguished from MS, Polyneuropathies and MG?
Group of neurodegenerative diseases characterised by loss of motor neurones in motor cortex, cranial nerve nuclei and anterior horn cells.
Mixed UMN and LMN signs
No sensory loss or sphincter disturbance like in MS and polyneuropathies.
Never affects eye movements but does in MG
What are the four patterns of MND?
NEVER SENSORY SIGNS!
Amylotrophic Lateral Sclerosis (ALS - 80%)
- Loss of motor neurones in motor cortex and anterior horn of cord so mixed UMN/LMN signs
- Worse prognosis if bulbar onset, increased age, decreased FVC
Progressive Bulbar Palsy (10%)
- Only loss of cranial nerves IX-XII
- Bulbar and Corticobulbar (Pseudobulbar) palsy
Progressive Muscular Atrophy
- Anterior horn cell lesion so LMN signs only
- Affects distal to proximal muscle groups
- Better prognosis than ALS
Primary Lateral Sclerosis
- Loss of Betz cells in motor cortex so usually UMN sgns
- Spastic leg weakness and pseudobulbar palsy
- No cognitive decline
What presentation would make you consider MND?
- >40 with stumbling spastic gait
- Foot drop
- Proximal myopathy
- Weak grip and shoulder abduction
- Aspiration pneumonia
- LMN signs: wasting, fasiculation
- UMN signs: spasticity, brisk reflexes, babinski
- Bulbar signs: speech or swallowing
What is the aetiology and epidemiology of ALS?
- Usually men 50-60 years old
- Sporadic (90%)
- Familial (10%):
- C9orf72 expansion. Excess of the hexanucleotide repeat, GGGGC >30.
- Men > Women in genetic cases
- Autosomal dominant
What is the average survival with MND?
3-5 years after onset
Starts as asymmetrical limb weakness, eventually leads to respiratory muscles being affected so respiratory failure
Respiatory failure or Aspiration Pneumonia is leading cause of death!
How does ALS typically present?
First symptoms:
- Asymmetrical limb onset: hand weakness and loss of dexterity or foot drop and loss of balance running
- Bulbar symptoms: dysarthria, dysphagia/choking/aspiration
Other symptoms:
- Frontotemporal dementia
- LMN and UMN signs
What investigations are done if you suspect MND?
Clinical diagnosis but Ix can rule out other things
- Electromyograph (EMG): look for chronic/acute dennervation and fasiculations
- NCS: motor conduction altered, sensory conduction fine
- Genetic testing: C9orf72 and SOD1
- Bloods: blood borne viruses, vit B12, folate, CK
- Antibodies (rule out others): AchRA, VGCC, Anti-GM-1
- T2 Weighted MRI: will see enhancment of corticospinal tracts in MND
- LP: look for infective causes
How is MND diagnosed?
Revised El Escorial diagnostic criteria for ALS
How is ALS managed?
MDT (neurologist, palliative nurse, physio, OT, speech therapist, dietician)
Medical: Riluzole (inhibitor of glutamate release) is the only drug that can slightly improve survival by few months
Dietician: Blend food, Gastrotomy to prevent aspiration
Ventilation: Discuss NIV at night and eventual mechanical ventilation
End of Life Planning: discuss early, see if can get an advanced care direction or LPA
Help with communication needs
What is bulbar palsy and what are the signs and casues of this?
LMN lesion of the nuclei of CN IX-XII in the medulla.
- Flaccid fasiculating tongue
- Jaw jerk normal or absent
- Quiet, hoarse or nasal speech
Causes: MND, GBS, MG, syringobulbia, brainstem tumours, central pontine myelinolysis
What is corticobulbar palsy and what are the signs and causes of this?
UMN lesion due to bilateral lesions above the mid-pons
- Slow tongue movements
- Slow speech
- Increased jaw jerk
- Increased pharyngeal and palatal reflexes
- Pseudobulbar affect: crying or laughing unprovoked
Causes: MS, MND, Stroke, Central pontine myelinolysis
What are the differences between bulbar and pseudobulbar palsy?
What is Guillain-Barre Syndrome?
Acute inflammatory demyelinating polyneuropathy that usually is symmetrically ascending.
Ascending muscle weakness from lower limbs and reduced reflexes
Usually preceded by illness e.g gastroenteritis or flu
What are some triggers for GBS?
- Campylobacter jejuni (Gram -ve rod)
- Mycoplasma
- CMV
- HIV
- EBV
- Vaccinations
- UNKNOWN
What is the pathophysiology of GBS?
Trigger causes formation of antibodies which cross react and attack myelin sheath (AIDP) or axons (AMAN,AMSAN)
Variants:
- Acute inflammatory demyelinating polyneuropathy (AIDP) (90%)
- Acute motor axonal neuropathy (AMAN)
- Acute motor and sensory axonal neuropathy (AMSAN)
- Miller Fisher Syndrome (MFS)
How does AIDP, most common form of GBS, present?
PRODROME OF ILLNESS 4 WEEKS BEFORE:
- Symmetrical ascending weakness (starting at the feet)
- Reduced reflexes
- May be peripheral loss of sensation or neuropathic pain
- May progress to the cranial nerves and cause facial nerve weakness
- Autonomic neuropathy: increased BP, sweating
What is the timeline of symptoms in GBS?
- Symptoms within 4 weeks of preceding infection
- Symptoms peak after 2-4 weeks (can lead to paralysis)
- Recovery period starts 2 weeks after symptom peak
What investigations should you do if you suspect GBS and what will they show?
Brighton Criteria
- NCS and EMG: reduced signal through the nerves
- Lumbar puncture for CSF: raised protein (>5.5) with a normal WCC and glucose
- Spirometry (FVC): monitor disease progression and respiratory muscle involvement
- Antibodies: Anti-GQ1b, specific for Miller Fisher syndrome
- May also do CXR (BHL for sarcoidosis) and MRI spine to rule out other pathologies
How is GBS managed?
Definitive
- IV Immunoglobulin for 5 days
- Plasma Exchange
Supportive
- Intubation if resp failure
- Cardiovascular monitoring as may have labile BP or arrhythmias due to autonomic dysfunction. Telemetry
- DVT prophylaxis with stockings and LMWH
- Analgesia like gabapentin for neuropathic pain
How do you monitor for respiratory involvement in GBS and how do you act on this if there is involvement?
- Do FVC every 4 hours
- Transfer to ITU if respiratory involvement
- Ventilate if FVC<1.5L, PaO2<10kPa, PaCO2>6kPa
How do you score someones functional level after GBS?
Hughes Disability Score
What is the prognosis with GBS?
- Complete paralysis can have complete recovery. After 6 months 80% of patients can walk unaided
- 10% relapse
- Poor prognosis: old age, receding campylobacter jejuni infection, rapid, need for mechanical ventilation
What are some causes of death in GBS?
- Respiratory failure
- Infection
- PE (MOST COMMON)
- Cardiovascular dysfunction
What does Miller Fisher syndrome present with?
What symptoms make you doubt a diagnosis of GBS?
What is myasthenia gravis and the pathophysiology of this?
Autoimmune neuromuscular disorder characterised by weakness and fatiguability
Acetylcholine receptor antibodies block AChR
What is the epidemiology and aetiology of MG?
Epidemiology:
- Females 20-30
- Males 60-70
Aetiology:
- Other autoimmune conditions e.g RA, SLE
- Thymoma (10%)
- Thymic hyperplasia (85%)
- Genetic HLA-B8, DRw3, and DQw2
What cells in the thymus contribute to the development of MG?
What are the different subtypes of MG?
- Clinical subtypes: ocular or generalised
- Antibody subtypes: AChR-Ab, Anti-MuSK, Anti-LRP4, Seronegative MG
- Thymic abnormalities: Normal, Thymoma, Thymic Hyperplasia, Atrophy
- Age: Neonatal, Juvenile, Early Onset (<50), Late onset (>50)
What autoantibodies are associated with MG?
- AChR
- MuSK
- LRP4
How may MG present?
Fluctuating skeletal muscle weakness with fatiguability
(symptoms often worse at end of day)
Occular (often progresses to generalised in 2 years):
- Ptosis, diplopia, pupil sparing
Generalised
Bulbar: fatiguable chewing, dysarthria, dysphagia
Facial muscles: expressionless face, myasthenic sneer
Neck muscles: extensor and flexor muscles can be affected. May get ‘dropped-head syndrome’ towards end of day.
Limb muscles: proximal muscle weakness. Arms affected more than legs
Respiratory muscles: Can lead to respiratory failure, which is life-threatening
What are some precipitants of MG that can cause a crisis?
- Pregnancy
- Infection
- Surgery
- Drugs e.g opioids, tetracyclines, B blockers
- Exercise
- Emotions
What are some investigations you should do if you suspect MG?
- CT/MRI!!!!!!! - Exclude thymoma as 5 yr survival
- Ice Pack test: improve ptosis
- Autoantibodies: Anti-AChR. If this is negative try for MuSK and LRP4
- Repetitive nerve stimulation (RNS) and electromyography (EMG): progressive decline in amplitude showing fatiguability
- TFTs, Rheumatological screen
How is MG managed?
Pyridostigmine
- AChE inhibitor so cholinergic
- Slowly uptitrate
- SE: salivation, lacrimation, sweats, vomiting, miosis
Immunosuppressants
- Prednisolone: if above not working, give with bone protection, alternate day strategy and dose increased until symptomatic improvement. Different dose if ocular or generalised
- Azathioprine: check TPMT levels to see if risk of bone marrow suppression
Thymectomy
- If thymoma OR
- without thymoma, < 45 years old and have AChR antibodies
What are some differentials for MG?
- Polymyositis
- Myopathies
- SLE
- Botulism
- Takayasu’s arteritis
How can you exhibit muscle fatiguability in MG?
- Repeated blinking will exacerbate ptosis
- Prolonged upward gazing will exacerbate diplopia on further eye movement testing
- Repeated abduction of one arm 20 times will result in unilateral weakness when comparing both sides
ALWAYS CHECK FVC!!!!
What is a myasthenic crisis and who are at risk of these crises?
Life threatening weakness of respiratory muscles during a relapse of MG that requires respiratory support
What is the key investigation if you suspect myasthenic crisis and what values tell you this is crisis?
FVC!
How is a myasthenic crisis managed?
- Urgent IVIG
- Plasma exchange if poor response to above
- Consider ventilation
- NG prednisolone
AVOID PYRIDOSTIGMINE AS EXCESS SECRETIONS SO RISK OF ASPIRATION
What are the three main stages of MG?
Stage one (active): Fluctuating muscle weakness with most severe clinical features. Majority of crises occur in this phase.
Stage two (stable): Persistent, but stable symptoms. Serious exacerbations may develop due to infection, medications, or altering treatment.
Stage three (remission): A minority of patients may develop complete remission without need for treatment.
What is a myopathy and what symptoms favour a myopathy?
Primary disorder of muscle with gradual onset symmetrical weakness
- Gradual onset symmetrical proximal weakness (difficulty combing hair, climbing stairs)
- Specific muscle groups affected
- Preserved tendon reflexes
- No paraesthesia or bladder issues
- No fasiculation
If there is gradual progressive symmetrical weakness and the following symptom, what myopathy would you consider:
- Rapid onset
- Spontaneous pain at rest
- Pain on exercise
- Oddly firm muscles
- Rapid onset: Toxic, drug or metabolic myopathy
- Spontaneous pain at rest: Inflammatory myopathy
- Pain on exercise: Ischaemia or metabolic (e.g McArdle’s)
- Oddly firm muscles: Pseudohypertrophic muscular dystrophies (fat or CT infiltrations) e.g Duchennes
What are some different classifications of myopathies?
- Muscular dystrophies
- Myotonic disorders
- Inflammatory myopathies
- Metabolic myopathies
- Acquired myopathies
- Drug induced
ALWAYS CONSIDER GENETIC COUNSELLING IF INHERITED
What investigations should you do if you suspect a myopathy and what will they show?
- ESR, CK, AST and LDH: raised
- EMG
- Muscle biopsy
- Genetic testing
What is a muscular dystrophie and what are some examples of this?
Group of genetic diseases with progressive degeneration and weakness of specific muscle groups. Abnormality often in muscle membrane
Muscles can be unusually firm due to infiltration of fat or connective tissue
What are the presentations of the following muscular dystrophies:
- DMD
- Becker’s
- Facioscapulohumeral muscular dystrophy
DMD
- Presents around 4 years with clumsy walking, difficulty in standing and then respiratory failure
- Pseudohypertrophy
- CK raised 40 fold
Becker’s
- Similar to above but milder symptoms, later age, better prognosis
Facioscapulohumeral (FSHD)
- Onset 12-14 years with inability to puff out cheeks and raise hands above head
- Weakness of face, shoulders, upper arms, foot drop, scapular winging, scoliosis, anterior axillary folds, horizontal clavicles
What is a myotonic disorder and an example of this?
Tonic muscle spasms due to long chains of central nuclei within muscle fibres
Myotonic Dystrophy
DM1: 20-40 years with distal weakness (hand/foot drop), weak SCM, myotonia, testis atrophy, cardiomyopathy
DM2
What are some examples of inflammatory myopathies?
May have pain at rest and local tenderness on palpation
- Inclusion body myositis
- Polymyositis
- Dermatomyositis
What is polymyositis and how is it managed?
Important revision from rheumatology
What are some examples of the following myopathies:
- Metabolic
- Acquired of late onset
- Drug induced
Metabolic: McArdle’s disease pain and weakness after exercise due to defective glycogen storage
Acquired: part of systemic disease e.g hyperthyroidism, malignancy, Cushing
Drug: alcohol, statin, steroids, chloroquine, cocaine
