Motor Neuron Disease Flashcards
What is motor neuron disease
An untreatable and rapidly progressive neurodegenerative condition affecting the motor nerves
Affects both the upper and lower motor neurons
What is the most common subtype of MND
Amyotrophic lateral sclerosis
ALS
What are the symptoms of MND
Muscle weakness - focal onset but will spread continuously until generalised paresis
Problems with speech, swallowing and breathing
Cognitive impairment and emotional changes
Does MND cause sensory issues
NO
Its a motor disease
What causes MND
Motor neurone degeneration or death
90% of cases are sporadic
The rest are familial cases
Some genetic aetiology but as yet unknown
At what age does sporadic MND usually present
Between 50-75
Most are in mid 60s
Which ethnic group is most affected by ALS
Caucasians
Much less common in non-Caucasian populations
What is the median survival after a diagnosis of MND
3 years
Is MND becoming more or less common
More common
How many new cases of MND are there in Scotland per year
200 (approx.)
Which sex is more affected by MND
Both sexes are affected
Slightly more common in men
What is the main way to classify MND
Classified by the part of the nerve pathway that is primarily affected
Primary lateral sclerosis – UMN disease
ALS - mixed UMN and LMN
Progressive muscular atrophies - LMN disease
How can you classify MND
UMN vs LMN
Motor disease or extramotor (frontotemporal dementia symptoms)
Region of onset
Based on genes - not usually done
Is MND a single illness
NOPE
Its an umbrella term that includes all types - ALS, PLS, PMA, PBP
All are different and have different outcomes
Which subtype of MND kills quickly
ALS
Mixed UMN and LMN signs
Particularly the bulbar subtype of ALS as heavy bulbar and respiratory involvement
Can also have Pick’s alongside it
What is progressive muscular atrophy
LMN variant of MND
Therefore present with purely the peripheral component, without the UMN issues (e.g. no spasticity, brisk reflexes etc)
Has a variable prognosis and can last for years
Patients will flail their arms and legs
Makes up 10% of cases
What is primary lateral sclerosis
UMN variant of MND
Good survival of over 5 years
Only seen in 1-3% of cases
What are the upper motor neuron signs in MND
Increased tone - spasticity Pyramidal weakness Hyperreflexia Extensor plantar response Spastic gait Exaggerated jaw jerk Slowed movements Pseudobulbar effects - speech and swallowing issue
What are the lower motor neuron signs in MND
Muscle wasting Weakness Fasciculations Absent or reduced deep tendon reflexes Muscle cramps
What are the bulbar symptoms of MND
Problems with speech and/or swallowing
Hypersalivation
Hard to compensate for
Seen in 1/3 of MND patients
What is the most common symptoms that patients present with
Limb impairment is the most common
Followed by bulbar symptoms - speech/swallowing
How can MND affect weight
It makes people lose weight
They become cachectic and wasted and can’t maintain body weight
Are upper or lower limbs more commonly affected in MND
Upper
Who is more affected by the bulbar variant of MND
Women
How does the bulbar variant of MND present
Problems with speech - will eventually struggle to communicate
Struggle with eating - swallowing difficulty
Get wasted, fasciculating tongue
Will also cause wasting of the facial muscles and the pharynx is effected (affects speech)
Has the worst prognosis
How do you manage bulbar variant MND
Early communication devices (voice banking etc)
Nutritional support - PEG tube
May get a gastrostomy
Respiratory tract care - know how to spot a chest infection and deal with choking)
Non-invasive ventialtion like BiPAP for respiratory symptoms
What type of MND is diagnosed if the patient first presents with bulbar issues
ALS
The bulbar variant of MND is a subtype of ALS
What is often the cause of death in MND
Respiratory complications such as choking or aspiration pneumonia
Disease makes them weak and malnourished so struggle to fight of chest infections
Weakness of respiratory muscles
What is split hand syndrome
A pattern of hand muscle wasting seen in ALS The thenar (thumb) muscles are wasted but the others are fine
What symptoms of MND are seen in the upper and lower limbs
Muscle wasting
Loss of tone and contractures
Can lose function - if you loose hand function you are completely dependant
How do the upper and lower limb symptoms of MND affect day to day life
Affects washing, dressing, feeding, turning in bed
Become dependent on others for these tasks
They often need mobility aids and hoists - lots of OT involvement
How can you stop contractures forming
Lots and lots of physio
In which type of MND is Pick’s/FTD common
Familial ALS
Which subtypes of MND have the most benign prognosis
Flail arm syndrome
Flail leg syndrome
Primary Lateral Sclerosis - UMN variant
What is the main investigation for MND
Neuro/Electrophysiology
EMG - looks at how well the muscle is innervated by the nerve
In MND it will show denervation of the nerve but also renervation of surrounding nerves trying to sprout out and compensate
How do you diagnose MND
It is a clinical diagnosis - most tests are to exclude mimics
Lack of evidence of other disease processes that could explain symptoms - diagnosis of exclusion
MRI to exclude structural cause
CK - mildly raised in MND but very high suggests a muscle pathology
Symptoms of LMN or UMN degeneration on examination or electrophysiology are supportive of diagnosis
Progressive spread of signs
Can you get a false positive diagnosis of MND
Yes - as its a clinical diagnosis some will get diagnosed with MND when in fact its just a mimic
False positives including multifocal motor neuropathy, Kennedys disease, myopathy (inclusion body), cervical spondylitic radiculomyelopathy
Which specialities often see patients with MND first
Stroke
ENT
Often people think it could be a neuropathy or carpal tunnel
Which drug can be used to manage MND in some patients
Riluzole - only drug available
Can prolong life by around 3 months in late stage disease
Lots of side effects - liver and renal failure, muscle issues
How is BiPAP used in MND
Given to patients who struggle to breathe when lying flat
Used overnight
Which allied health professionals are involved in MND care
Key worker assessing needs and co-ordinate care
Speech and language - speech therapy, technology etc
Dieticians - nutrition support
Respiratory support and assessment
Occupational therapy
Each patient is also allocated a consultant (neurologist) and 2 nurses to manage their case - specialist MND nurses
GP should also be involved
Is MND managed in hospital or at home
Aim to manage them at home as they will be more comfortable and aren’t going to be ‘treated’
How often are MND patients assessed
Every 4-6 weeks
What level of weight loss signals a poor prognosis
More than 10% weight loss
How can you support a MND patient nutritionally
Dietician input
Give small high energy supplements regularly
Consider feeding difficulty - may need support at mealtimes
Early insertion of gastrostomy tubes should be clinical priority - can still eat but most nutrition comes through PEG tube
Makes patients more comfortable and removes stress of eating with swallowing issues
How can you treat hypersalivation in MND
Hyoscine
Buscopan
Botox
How can you treat muscle cramps in MND
Quinine - not very good
Baclofen - don’t give too much
How can you treat muscle spasms in MND
Baclofen
Tizanidine
Gabapentin
What respiratory interventions are used in MND
Non invasive ventilation is offered to support type 2 respiratory failure
BiPAP helps symptoms - particularly overnight
Tracheostomy is next step
What are the red flag signs of respiratory failure
Breathlessness Orthopnoea Recurrent chest infection Disturbed sleep Non-refreshed sleep Nightmares Daytime sleepiness Poor concentration
How are benzodiazepines used in MND
Lorazepam can be used to help with breathlessness and anxiety
What are the emotional symptoms of MND
Inappropriate crying or laughing - due to frontal lobe effects
Patience and understanding may be poor
Apathy and disinhibition
Does MND lead to cognitive impairment
Yes in around 50% of patients
Associated with frontotemporal dementia
Will have apathy, disinhibition, poor planning/decision making
When should you refer to palliative care
Early on
Need to put in place plans for future care and needs
Helps cope with complex needs
Plan for death
What is the only licensed treatment for MND
Riluzole
It is an antioxidant
Prolongs survival by 2-3 months
Not all patients chose it as they are often quite disabled by presentation
How would ALS present on examination
It is a mixed subtype so leads to a confusing exam as both UMN and LMN signs present
Why is primary lateral sclerosis hard to diganose
- Often hard to diagnose as you don’t get the classic peripheral signs of MND
Get a lot of tests looking for purely central issue - again a diagnosis of exclusion
Those with primary lateral sclerosis often progress and develop peripheral symptoms - true of false
True
Why is primary muscular atrophy hard to diganose
Can present like other motor neuropathies so many end up on treatment for those
The diagnosis comes when they don’t respond - diagnosis of exclusion
