What are Motor Neurone Diseases?
Motor Neurone Diseases is a group of progressive degenerative diseases affecting motor neurones with varying corticospinal involvement.
The diseases destroy cells that control important muscle activity such as speaking, walking, breathing, and swallowing. The damaged nerve cells are unable to send signals to the muscles to do their activity resulting in weakness, wasting and tremors of the muscles.
The Motor Neurone Diseases includes conditions such as Amyotrophic Lateral Sclerosis (ALS), progressive bulbar palsy, primary lateral sclerosis, and progressive muscular atrophy.
What causes Motor Neurone Diseases?
The cause is unknown but environmental, toxic, viral, or genetic factors have found to play a part in its formation.
1.In all Motor Neurone Diseases, there is loss of nerve cells in the anterior horn of spinal cord and motor nuclei of brain stem.
2.In Primary Lateral Sclerosis there is corticospinal tract degeneration most evident in the lower spinal cord but traceable to internal capsule and corona radiata.
Who is at risk of Motor Neurone Diseases?
Motor Neurone Diseases occurs in middle age 40-60 years old and are more common in males.
It occurs as endemic in Guam where there is high familial incidence in association with Parkinson dementia complex.
What are the symptoms of Motor Neurone Disease?
The typical course of Motor Neurone Diseases except for primary lateral sclerosis is 2 to 6 years resulting in death.
1.acute onset of asymmetrical muscle tremors, weakness and wasting in both lower limbs with ascending progression of the weakness upwards to the arms and face .
2.the lower cranial nerves can also be affected leading to bulbar weakness, (dysphagia or difficulty with swallowing), facial weakness and respiratory difficulties. If this happens , hospitalization is a must.
3.spasticity of the muscles
5.mental function is usually not affected
How is the diagnosis of Motor Neurone Disease made?
The diagnosis of Motor Neurone Disease involve
1.History of a rapid onset and progression of motor weakness, wasting, tremors, hyperreflexia and the absence of fever.
2.physical and neurological examinations for peripheral neurological deficit.
What are the complications for Motor Neurone Disease ?
1.Progression of nerve involvement to whole body
2.Paralysis of respiratory muscles and swallowing can be life threatening
What is the treatment for Motor Neurone Disease?
Treatment for Motor Neurone Disease may be urgent especially in cases of respiratory distress:
1.Hospitalization and early intubation with a respirator on standby in case of difficulty in respiration
2.treatment of the condition is supportive only as there is no cure for the disease
a.physiotherapy to strengthen muscles
b.Speech therapy for speech and swallowing
3.The drug riluzole approved to treat ALS, prolongs life by 2-3 months but does not relieve symptoms.
4.Symptoms such as spasticity can be treated with muscle relaxants.
Anticonvulsants and pain killers can help to relieve pain.
5.A healthy and balanced diet is necessary to maintain strength in the muscles and mind
What is the prognosis of Motor Neurone Disease?
Most Motor Neurone Diseases except for primary lateral sclerosis (which is usually not fatal) are relentless diseases with progression to death.