Background
- Neurodegenerative condition characterised by loss of upper and lower motor neurons throughout the nervous system.
- Incidence ~2/100,000 and prevalence ~7/100,000; average age of onset ~65, although around 10% can present <45 years; males>females
- Most cases are sporadic but 5-10% are familial
- Genes associated include SOD1 gene (20% of familial cases)
- Several different forms of MND, most common of which is amyotrophic lateral sclerosis (ALS) (other types e.g. primary lateral sclerosis, are really very rare)
Clinical features
- It is often said that 1/3 will present with bulbar symptoms; 1/3 with arm symptoms; 1/3 with leg symptoms
- Weakness, wasting, cramps, fasciculations (lower motor neuron); combined with brisk reflexes (upper motor neuron)
- Disturbed speech/swallowing (dysarthria/dysphagia)
- No sensory involvement
- Cognitive impairment and dementia is not uncommon
Investigations
- Blood tests are usually normal (may have raised CK)
- Imaging is also usually normal (should be performed if symptoms are localised to exclude other cause of neuropathy)
- Electromyography can reveal diagnostic features of denervation and reinnervation
Management/Prognosis
- MND progresses often rapidly and, as pathology spreads/worsens, subsequent respiratory depression is eventually fatal
- usually 18-30 months after diagnosis
- Riluzole can be used to extend life expectancy BUT patients are often disabled at this stage and many patients opt not to take this
- A multidisciplinary team involving physio, OT, SALT is important in managing patients with ALS/MND
- Later on in the disease, non-invasive ventilation and percutaneous gastrostomy feeding may improve quality of life
- Palliative care should be discussed
Notes on Medicine/Surgery 