What is Amyotrophic Lateral Sclerosis (ALS), the disease Stephen Hawking has?
On December 21, a medical conference was held in Tel-Aviv, to find ways to promote research of this incurable disease.
Stephen Hawking, the scientist, is the best known person suffering from the rare and incurable muscular dystrophic disease ALS. His visit to Israel provides an opportunity to draw the public's attention to the 600 people in Israel who suffer from this serious disease. Below is an article about ALS, written by Dr. Boaz Weller, Head of the Department of Neurology at the Bnei-Zion Medical Center in Haifa, and details from the meeting held 12 December that dealt with finding ways to promote research on this disease.
The muscular dystrophic disease, ALS, is the worst in a group of degenerative diseases afflicting motor neurons. It is a rare and incurable disease. ALS is also known as Lou Gehrig's Disease, after the famous American baseball player who contracted this disease while in his thirties. In England it is known as Motor Neurone Disease (MND) and in France as Maladie de Charcot.
ALS affects the peripheral motor neuron system by which the brain controls most of the voluntary muscles of the body. As these neurons are destroyed they can no longer stimulate the muscles. This weakens the muscles until they become completely paralyzed. As ALS gradually progresses, the muscles that control the limbs, swallowing, speech and breathing become impaired, in no particular order. ALS strikes 1–2 out of every 100,000 people every year; about 10% of these cases involve a dominant inherited disease. The prevalent age for appearance of ALS is 45–65 years; cases have been reported in older and even younger individuals, but such cases are rare.
The first signs of ALS are usually mild and non-specific, often leading to delayed detection of the disease. These signs may appear as muscle weakness in the upper and lower limbs accompanied by difficulty performing certain movements: difficulty writing and picking up objects. Climbing stairs and prolonged walking can become difficult, or falling may occur while walking. Muscle cramping may occur, the voice may change and pronouncing words and/or swallowing may become difficult. Head drop due to neck muscle weakness may also be apparent at the onset of ALS.
The most important diagnostic test is electromyography – EMG, which can reveal dysfunction in motor neurons while sensory neurons function normally.
Manifestation and progression of ALS differs from one patient to the next, so it is very difficult to forecast its rate of advancement in individual patients. The typical course is progressive limb muscle weakness until the arms and legs become completely paralyzed, with weakening of the muscles responsible for swallowing, chewing and speaking and, finally, impairment of the respiratory muscles, which is the cause of death for most of the patients. Most ALS sufferers survive for 2 to 5 years; about 20% survive for 5 to 10 years, while 10% survive beyond 10 years.
The cause of the disease is unknown, hence the difficulty in finding effective medication. Several possible mechanisms have been suggested for the disease: toxic environmental factors – neurons poisoned by metals, chemicals or foods; high glutamate activity – glutamate is a chemical substance that stimulates neurons. Excessive amounts of glutamate elevates neuron activity to the point of fatally damaging muscle cells.
Lack of substances responsible for growth and maintenance of neurons along with abnormal buildup of cell components and immune system damage have all been proposed as further causes. Heredity – for some of the genetic patients the lack of genes means hindered production of the protein responsible for neutralizing the activity of toxic substances called free radicals. These substances can cause the neurons to die.
None of the factors mentioned above have been absolutely proven to cause ALS, other than the genetic cause and excess glutamate. Perhaps a combination of several factors is the basis of the disease. Many medications have been tried on ALS with no appreciable success. The only medication to slow the rate of progress of ALS has been Riluzole. Sadly, it prolonged life expectancy by only two months. Auxiliary treatments include relieving stiffness, speech impairment, cramping and swallowing difficulties. An important part of the treatment involves supporting the patients and their families. Such support includes providing patients with physiotherapy, supplementary medical equipment, communication therapists, nutritional support, respiratory support and mental support.
Since this is a severe and terminal disease and because patients understand their own situation, it is acceptable at early stages of the disease to discuss their wishes with them concerning artificial respiration.
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