Motor Neurone Diseases

What are Motor Neurone Diseases?

The motor neurone diseases (MND) are a group of progressive neurological disorders that destroy motor neurons, the cells that control voluntary muscle activity such as speaking, walking, breathing, and swallowing.  Characteristic symptoms of MND include gradual weakening, wasting away, and uncontrollable twitching of the muscles; spasticity or stiffness in the arms and legs; and overactive tendon reflexes. Sensation, intellect, memory, and personality are not affected in MND.  In some types of MND, such as amyotrophic lateral sclerosis (ALS, commonly called Lou Gehrig’s disease) muscle weakness is progressive and eventually leads to death when the muscles that control breathing no longer work.  Other types of MND progress slowly and last over a lifetime.  MND occur in adults and children, and are more common in men than in women.  In adults, symptoms usually appear after age 40, and may be similar to those of other diseases, making diagnosis difficult.  In children, particularly in inherited forms of the disease, symptoms are present from birth.  Inherited forms of MND are caused by genetic mutations or deletions that cause degeneration of motor neurons.  Hereditary MND include a group of childhood disorders known as the spinal muscular atrophies.  Nonhereditary (also called sporadic) MND are caused by unknown factors, although scientists think environmental toxins or viruses could act as disease triggers.  Nonhereditary MND include ALS, progressive bulbar palsy, pseudobulbar palsy, primary lateral sclerosis, progressive muscular atrophy, and post-polio syndrome. There are no specific tests to diagnose the MND.

Is there any treatment?

There is no cure or standard treatment for the MND.  Physical therapy, occupational therapy, and rehabilitation improve posture, prevent joint immobility, and slow muscle weakness and wasting.  Stretching and strengthening exercises reduce spasticity, increase range of motion, and keep circulation flowing.  Additional therapy for speech, chewing, and swallowing difficulties may be required.  Riluzole is the only prescribed drug approved by the U.S. Food and Drug Administration to treat ALS.  Riluzole prolongs life by 2-3 months but does not relieve symptoms.  Other medicines include muscle relaxants such as baclofen, tizanidine, and the benzodiazepines to reduce spasticity; glycopyrrolate and atropine to reduce the flow of saliva; and quinine or phenytoin to decrease muscle cramps.  Anti-convulsants and nonsteroidal anti-inflammatory drugs may help with pain, and other drugs may be prescribed to treat depression.  Some individuals will require stronger medicines such as morphine to cope with musculoskeletal abnormalities or pain in later stages of the disorders.

What is the prognosis?

Prognosis varies depending on the type of MND and the age of onset.  Some MND are not fatal and progress slowly.  Individuals with the spinal muscular atrophy disorders may appear to be stable for long periods, although they will never improve.  ALS is eventually fatal.
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