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30 Sep 2011 00:00
It is a tragedy that it takes a sporting hero to be struck down by a life-threatening disease to create public awareness of the condition. Such is the case of former Springbok legend Joost van der Westhuizen, who was diagnosed with motor neurone disease (MND) a few months back.
MND is a range of progressive neurodegenerative diseases of the nerve cells in the brain and the spinal cord that control voluntary muscle movement.
The most common form of MND is amyotrophic lateral sclerosis (ALS).
Progressive bulbar palsy affects two out of 10 MND sufferers. In this case, the muscles affected are those used for talking, chewing and swallowing. Other types of MND such as progressive muscular atrophy and primary lateral sclerosis, although rare, are equally devastating.
The nerve cells—or the motor neurons—waste away and die so they can no longer send messages to the muscles. This leads to muscle weakness, twitching and, eventually, paralysis of the arms, legs and other parts of the body. Often it’s the chest or neck muscles that are the first to be affected, which causes difficulties in swallowing and breathing. Most sufferers die of respiratory failure.
As to its prevalence, on average between two and five people out of 100 000 develop MND. And twice as many men than women will succumb to the disease, the majority of whom will be over the age of 50.
About 10% of MND is known to be inherited, but in as many as 90% of cases, the cause is unknown. There are several theories: MND is the result of bodily trauma or cancer; a latent virus that somehow becomes evident; caused by environmental toxins or toxic drugs; or genetic defects that affect the nerve cells.
Tragically, the prognosis is not good. Life expectancy after the onset of MND varies between one and five years. Although it can sometimes be longer, it’s dependent on the activity of the disease and the muscle groups affected. Ten percent of sufferers can live more than 10 years.
There is no test for ALS. Patients with suspected ALS are normally sent to a specialist neurologist for assessment. In the early days, minor symptoms make it difficult to confirm the diagnosis.
Various tests are performed to exclude other causes of the symptoms: electromyography, in which small needles are used to record the nerve impulses in the affected muscles; nerve conduction studies, which measure the speed at which nerves carry electrical signals; a test that measures the nerve activity running between the brain and spinal cord called a transcranial magnetic stimulation; as well as other tests such as magnetic resonance imaging scans.
Treatment is restricted to the symptoms, not the cause, although there are drugs that are effective in slowing down the progress of MND. A multidisciplinary approach is required to deal with common symptoms, which may include cramps, difficulty swallowing, urinary symptoms and depression.
Although it’s generally agreed that it is in its infancy, stem-cell research holds promise. Stem cells are biological cells that have not yet become specialised to perform tasks. As they have the ability to renew themselves, they have the potential to replenish human tissue, including neurons and nervous system support cells.
But stem-cell research must not be confused with stem-cell treatment. At the moment, the greatest potential for stem-cell research may be in creating a living human laboratory model of the disease that scientists can study.
Gaining a better understanding of the development and spread of MND could pave the way for the development of new drugs.
Stem-cell treatment is purely experimental at this stage. The consensus is that we have a long way to go.
Motor neurone disease will be the topic of Bonitas House Call on October 8 at 9am on SABC2
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