Motor Neurone Disease Flashcards
What is motor neurone disease (MND)?
It refers to a group of neurodegenerative diseases, in which there is progressive degeneration of both upper and lower motor neurones
The sensory neurones are spared
What are the four classifications of motor neurone disease?
Amyotrophic Lateral Sclerosis (ALS)
Progressive Bulbar Palsy (PBP)
Progressive Muscular Atrophy (PMA)
Primary Lateral Sclerosis (PLS)
What is the most common classification of motor neurone disease?
ALS
What is ALS?
It is a condition in which there is degeneration of the of the motor cortex neuronal cells, resulting in upper motor lesion features, and anterior horn cells, resulting in lower motor lesion features
What are the five clinical features associated with ALS?
Muscle wasting
Muscle weakness
Muscle stiffness
Muscle cramps
Rippling of the muscles
What is the characteristic features of ALS?
The presentation of lower motor neurone features in the arms and upper motor neurone features in the legs
In familial cases of ALS, which chromosome does the gene mutation lie on? What does this gene code for?
Chromosome 21
Superoxide dismutase
What is the second most common classification of motor neurone disease?
PBP
What is PBP?
It is a condition in which there is degeneration of both upper and lower motor neurones in the bulbar area of the brainstem
What is the function of motor neurones in the bulbar area of the brainstem?
They innervate the tongue muscles, pharynx and larynx
What are the three clinical features associated with PBP?
Tongue palsy
Speech slurring
Swallowing difficulties
What motor neurone disease classification carries the worst prognosis?
PBP
What is PMA?
It is characterised by lower motor neurone degeneration only
What clinical feature is associated with PMA?
Muscle weakness, which tends to affect distal muscles before proximal
What motor neurone disease classification carries the best prognosis?
PMA
What is PLS?
It is characterised by upper motor neurone degeneration only
What are the three clinical features of PLS?
Lower limb weakness
Lower limb stiffness
Hyperreflexia
What are the six risk factors of motor neurone disease?
Older Age > 60
Male Gender
Family History
Smoking
Heavy Metals Exposure
Pesticide Exposure
Describe the typical presentation of motor neurone disease
It results in an insidious, progressive weakness of the muscles throughout the body affecting the limbs, trunk, face and speech
What are the four common presentations of motor neurone disease?
Clumsiness
Tripping over
Object dropping
Dysphasia
What are the four lower motor neurone features of motor neurone disease?
Muscle Wasting
Muscle Tone Reduction
Fasciculations
Hyporeflexia
What is the key lower motor neurone feature of motor neurone disease?
Fasciculations
In motor neurone disease, which muscles tend to experience wasting first?
Upper limb muscles
What two muscles most commonly experience muscle wasting in motor neurone disease?
Small hand muscles
Tibilias anterior
What are the three upper motor neurone features of motor neurone disease?
Muscle Spasticity
Hyperreflexia
Extensor Plantar Reflex
What two clinical features don’t indicate motor neurone disease?
External ocular muscle wasting
Cerebellar features
In most cases, how is motor neurone diagnosed?
Clinically
What is a clinical diagnosis of motor neurone disease based on?
There is evidence of lower and upper motor neurone features in at least three regions of the body, with no associated sensory clinical features
What three investigations can be used to confirm a diagnosis of motor neurone disease?
Electromyography (EMG)
Nerve Conduction Studies
MRI Scan
What is electromyography (EMG)?
It measures muscle response or electrical activity in response to a nerve’s stimulation of the muscle
What are three features of motor neurone disease on EMG?
Reduced Number of Action Potentials
Increased Action Potential Amplitude
Widespread Denervation
What EMG feature is required to confirm diagnosis of motor neurone disease?
The features should be demonstrated in all four limbs, the muscles above the neck and the tongue
What are nerve conduction studies?
They measure how fast an electrical impulse is transmitted through the nerve
How are nerve conduction studies used to diagnose motor neurone disease?
Motor neurone disease results in normal motor conduction, and is therefore used to exclude a neuropathy
How are MRI scans used to diagnose motor neurone disease?
Motor neurone disease results in normal results, and is therefore used to exclude cervical cord compression and myelopathy
What pharmacological management option is used in motor neurone disease?
Benzothiazoles
What benzothiazole is used to manage motor neurone disease?
Riluzole
What is the function of Riluzole?
It is an NDMA antagonist which inhibits the release of glutamate
How does Riluzole treat motor neurone disease?
It can be administered to slow down the progression of the disease and extend survival by a few months, in ALS
What are the five supportive management options for motor neurone disease?
Non-Invasive Ventilation (NIV)
PEG Feeding
Physiotherapy Input
Occupational Therapy Input
Speech & Language Therapy Input
What is a complication associated with motor neurone disease?
Frontotemporal Dementia
What are the two common death causes of motor neurone disease?
Respiratory failure
Pneumonia
