Motor Neurons Disease Flashcards
What is motor neuron disease?
A collection of neurodegenerative diseases causing progressive loss of neurons in the motor cortex, cranial nerve nuclei and anterior horn cells. 50% of patient die within 3 years of a diagnosis.
Are men or women more likely to develop motor neuron disease?
It affects men more than women
Describe the 4 types of motor neuron disease?
ALS amyotrophic lateral sclerosis – loss of motor neurons in the cortex and anterior horn of the cord giving combined upper and lower signs. Familial cases with gene on C21
Progressive bulbar palsy – only affects cranial nerves primarily V and IX-XII
Progressive muscular atrophy – anterior horn lesions so LMN signs only, distal muscles first
Primary lateral sclerosis – loss of betz cells in motor cortex, UMN signs only, marked spastic leg weakness and pseudobulbar palsy (rare)
How does motor neuron disease present?
Usually > 40yrs with stumbling spastic gait, foot-drop, proximal myopathy weak grip (door handle problems), weak shoulder abduction (washing hair is difficult) and aspiration pneumonia.
Frontotemporal dementia is often associated with MND
Upper and Lower motor neurons can be affected
No sensory loss, sphincter disturbance or cerebellar signs distinguishing it from MS
Eye movement are never affected distinguishing it from MG
Fasiculations, wasting of small hand muscles/tibialis anterior
How should suspected motor neuron disease be investigated?
MRI/CT to exclude other causes
LP to exclude inflammatory causes
Nerve conduction studies will be normal differentiating it from a neuropathy
Electromyography will show a reduced quantity of action potentials
How is motor neuron disease managed?
Should involve neurologist, palliative nurse, hospice, physio, OT, speech therapist, dietician and social services
Riluzole – inhibitor of glutamate release and NMDA antagonist. Can prolong life by 3months
Non invasive ventilation at night can extend life by 7 months
Excess saliva – positioning, oral care and suctioning. Trial antimuscarinic
Dysphagia – blend food
Spasticity – exercise sometimes botulin
Communication – augmentative and alternative communication equipment
End of life care
What is acute bulbar palsy
Disease of the nuclei of CN IX-XII in the medulla. It is a LMN lesions causing problems with speech, and swallowing. You will see a flaccid fasciculating tongue, normal or absent jaw jerk and quiet, hoarse or nasal speech.
What can cause bulbar palsy?
Causes MND, Guillain Barre, Polio, Myasthenia Gravis, syringobublia, brainstem tumour and central pontine myelinolysis.
What is corticobulbar palsy/pseudobulbar palsy?
UMN lesions of the cranial nerves IX-XII due to bilateral lesions above the mid pons. Presents with slow tongue movements, slow deliberate speech, increased jaw jerk, increased pharyngeal and palatal reflexes and pseudobulbar affect – weeping and mood changes which are unprovoked.
What can cause corticobulbar palsy or pseudobulbar palsy?
Causes MND, stroke and central pontine myelinolysis.
