Motor Neuron Disease Flashcards
What are other names for motor neuron disease?
Lou Gehrig’s Disease and Amyotropic Lateral Sclerosis )(ALS)
What is motor neuron disease?
Progressive neurodegenerative disease in which neurons of the cerebellum, brainstem and spinal cord become damage. Leads to muscle weakness, paralysis and respiratory failure
What neurons are affected?
cerebellum, brainstem and cerebral hemispheres
What pathways are impacted by neuron degeneration?
corticospinal, lower motor neuron and corticobulbar
What is the corticospinal pathway?
axons of upper motor neurons go from primary motor cortex and descend into the brainstem and spinal cord and directly synapse with lower motor neurons that control skeletal muscle
What is the corticobulbar pathway?
axons synapse with lower motor neurons in the motor nuclei of cranial nerves supplying eyes, jaw, face and some muscles of the neck and pharynx
How many people die and are diagnosed with/from motor neuron disease in Australia each day?
2 for each
What is the average life expectancy?
27 months
What is the prevalence in Australia?
1,900 (approx)
What is the incidence rate of motor neuron disease as according to the AIHW?
Increasing over last decade - 592 people died in 2001 compared with 787 in 2013
How many people have ALS worldwide?
4 - 7 out of every 100,000
What gender is more effected by ALS?
Males (20% more for males)
How many cases of ALS are sporadic compared to familial?
90% sporadic, 5-10% familial
How many people in the USA have ALS?
30,000
What are the general symptoms of ALS?
muscle aches, cramps and twitching; clumsiness and stumbling; weakness or changes in hands, arms, legs and voice; slurred speech, difficulty swallowing or chewing; fatigue; muscle wasting; weight loss; emotional liability; cognitive change and respiratory changes
What pattern are symptoms usually displayed?
distal to proximal
What are the three areas symptoms can be attributed to?
lower motor neuron, corticospinal and corticobulbar
What are some lower motor neuron symptoms?
focal and multifocal weakness, atrophy, cramps and muscle twitching
What are the corticospinal symptoms?
spasticity and hyperresponsive reflexes
What are the corticobulbar symptoms?
dysphagia and dysarthria
What is sialorrhea?
excess drooling
What is fasciculation?
muscle twitching
What are the early symptoms of ALS?
stumbling, loss of dexterity, weakness of hand muscles, slurring of speech, difficulty swallowing, cramps and muscle twitching, hyperactive reflexes
What are the late symptoms of ALS?
paralysis, breathing difficulties, fatigue, insomnia, cognitive skills (mild), behavioural change, fronto-temporal cognitive changes in some cases, excess laughing or crying, pain and discomfort
What is unnaffected by ALS?
senses of sight, hearing, smell, taste and touch as well as bowel, bladder and sexual dysfunction
What is the aetiology of ALS?
viruses, toxins, chemicals by which nerve cells are controlled and communicate, genetic factors, immune mediated damage, nerve growth factors and growth, repair and ageing of motor neurons
What are sporadic cases of ALS hypothesized to be caused by?
o No known cause for sporadic ALS.
Viral, retroviral or environmental causes are hypothesized. May also be due to occupational exposure to chemicals or electromagnetic fields, lead exposure, cigarette smoking and dietary consumption of increased fat and glutamate intake associates with risk and fibre has reduced risk
What is the life expectancy after diagnosis?
1 - 5 years
How many people live for longer than 10 years after diagnosis?
10%
How do symptoms present in younger people?
milder symptoms at diagnosis and usually a longer course
What is resistance to ALS?
may demonstrate improvement and live longer than ten years
How does death usually occur?
respiratory failure
What is the cure for ALS?
no known cure
How is ALS diagnosed?
blood tests, nerve conduction studies, electromyography and MRI scans
What is the medication demonstrating the best efficacy and is the most commonly used?
Riluzole -extends survival 2-3 monthsand may help to remain in milder stage of disease for longer
What type of medication is riluzole?
anti-glutamatergic
What medications are used to treat symptoms?
antispasmodic medications, nonsteroidal anti-inflammatories and antibiotics
What benefits does a multidisciplinary team have on ALS?
longer lives, better quality of life
What two procedures are shown to increase quality and (possibly) length of life?
gastrostomy and noninvasive positive-pressure ventilation
