Motor neuron disease Flashcards
Define motor neurone disease
A cluster of neurodegenerative diseases
Characterized by selective neuron loss in motor cortex, cranial nerve nuclei and anterior horn cells
Upper and lower motor neurons can be affected
How is MND distinguished from myasthenia gravis?
MND does not affect eye movements
How is MND distinguished from MS and polyneuropathies?
In MND there is no sensory loss or sphincter disturbance
Name the 4 clinical patterns of MND
ALS/amyotrophic lateral sclerosis
Progressive bulbar palsy
Progressive muscular atrophy
Primary lateral sclerosis
Describe amyotrophic lateral sclerosis
Most common type of MND
Loss of motor neurons in the motor cortex and anterior horn of the cord
What signs are present in amyotrophic lateral sclerosis
Combined UMN and LMN signs
Describe factors causing a worse prognosis of amyotrophic lateral sclerosis
Bulbar onset
Increased age at diagnosis
Decreased FVC
What does progressive bulbar palsy affect?
Cranial nerve nuclei 9-12 in the medulla
Where is the lesion in progressive muscular atrophy
Anterior horn cell lesion
What signs are present in progressive muscular atrophy
LMN signs only
Which muscles are most affected in progressive muscular atrophy
Distal muscles
Describe the prognosis of progressive muscular atrophy in comparison to ALS
Progressive muscular atrophy has the better prognosis compared to ALS
Describe progressive lateral sclerosis
Loss of betz cells in the motor cortex
What signs are present in progressive lateral sclerosis?
UMN
Marked spastic leg weakness
Pseudobulbar palsy
No cognitive decline
When should you consider a diagnosis of MND?
Patient aged >40 yo (median age of onset = 60yo)
Stumbling, spastic gait, foot drop, proximal myopathy, weak grip and shoulder abduction
Aspiration pneumonia
What signs may be present in someone with MND?
UMN - spasticity, brisk reflexes, upgoing plantars
LMN - wasting, fasciculations of tongue, abdomen, back and thigh
Which dementia is associated with MND (ALS)?
Frontotemporal dementia
Which gene is thought to be linked to MND and frontotemporal dementia?
C0orf72
Which diagnostic criteria is used for ALS?
El Escorial
What is Brain/cord MRI useful for?
Excluding structural pathology
What is LP useful for?
Excluding inflammatory causes
What is neurophysiology useful for?
Detecting subclinical denervation and help exclude mimicking motor neuropathies
Describe the prognosis of MND
Poor - 3 years post onset in half of patients
Describe the management of MND
MDT approach
Riluzole can help improve survival - inhibitor of glutamate release and NMDA receptor antagonist
Excess saliva - positioning, oral care, suctioning, antimuscarinic (propantheline or Glycopyrronium bromide), botulinum toxin A
Dysphagia - blend food, gastrostomy
Spasticity - exercise, orthotics
Communication - augmentative and alternative communication equipment
End of life care - involve palliative care services from diagnosis
Breathlessness - opioids and NIV
What are the signs of bulbar palsy
LMN lesion of the tongue and muscles of talking and swallowing
Flaccid, fasciculating tongue
Jaw jerk normal or absent
Speech is quiet, hoarse or nasal
What can cause a bulbar palsy?
MND, Guillain-Barre, polio, myasthenia gravis, Syringobulbia, brainstem tumours, central pontine myelinolysis
Describe corticobulbar palsy
UMN lesion of muscles of swallowing and talking due to bilateral lesions above the mid-pons
Commoner than bulbar palsy
What are the signs of corticobulbar palsy
Slow tongue movements with slow deliberate speech
Increased jaw jerk
Increased pharyngeal and palatal reflexes
Pseudobulbar affect- weeping unprovoked by sorrow or mood incongruent giggling
Which conditions also present with emotional incontinence without mood change?
MS Wilsons Parkinson's Dementia Nitrous oxide use Head injury
