Progressive degeneration of the nerves in the brain and spinal cord that control muscular activity
- More common over the age of 40
- More common in males
- Sometimes runs in familiesv
- Lifestyle is not a significant factor
Motor neuron disease is rare, with about 2 people in every 100,000 developing the disease each year in the UK. In the disease, also known as amyotrophic lateral sclerosis, degeneration of the nerves involved in muscular activity results in progressive wasting of the muscles and weakness. There are several types of motor neuron disease. Some affect mainly the spinal nerves, while other types also affect the brain. The condition is not painful, does not affect bowel or bladder function, and does not usually affect the intellect or the senses, such as sight.
The cause of motor neuron disease is unknown in the vast majority of cases. In about 1 in 20 cases, genetic factors are involved and the disease runs in the family. Motor neuron disease is more common in men than in women and usually develops after the age of 40.
What are the symptoms?
Initially, weakness and wasting develop over a few months and usually affect the muscles of the hands, arms, or legs. Other early symptoms may include:
Twitching movements in the muscles.
Stiffness and muscle cramps.
Sometimes, slurred speech, hoarseness, and difficulty swallowing.
As the disease progresses, other symptoms may include:
Dragging one foot or a tendency to stumble when walking.
Difficulty in climbing stairs or getting up from low chairs.
An affected person may have mood swings and may become anxious and depressed. If the muscles involved in breathing and swallowing are affected, small particles of food may enter the lungs and cause recurrent chest infections and possibly pneumonia. The head may fall forwards because the muscles in the neck are too weak to support it. Eventually, weakness of the muscles that control respiration may cause difficulty in breathing. Very rarely dementia may develop in the later stages of the disease.
How is it diagnosed?
There is no specific test to diagnose motor neuron disease. However, electromyography (see Nerve and muscle electrical tests) may be carried out to detect a change in electrical activity in the muscles. To exclude other possible causes of the symptoms, such as a tumour or cervical spondylosis, additional tests may be carried out, such as a lumbar puncture and MRI or CT scanning of the brain and neck.
What is the treatment?
At present, no treatment can significantly slow down the progression of motor neuron disease, although a drug called riluzole may have a small effect. Treatment for symptoms may include antidepressants to relieve depression and antibiotics to treat chest infections. If the person is having difficulty in swallowing, a gastrostomy may be created surgically. Known as a PEG or percutaneous gastrostomy, this is an opening through which a permanent feeding tube is inserted directly into the stomach.
Usually, a team of specialists provide support and care for an affected person and members of the family. Counselling may be offered to both. The person affected by the disease may have physiotherapy to keep joints and muscles supple and may be given aids to help with activities such as eating and walking (see Occupational therapy). A speech therapist (see Speech therapy) can supply communication aids to help with speech difficulties and advise on swallowing problems. Joining a self-help group is often helpful to the person with motor neuron disease and his or her family.
The outlook for motor neuron disease is variable, with approximately 2 in 10 affected people alive 5 years after diagnosis. About 1 in 10 affected people survives more than 10 years.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
The subjects, conditions and treatments covered in this encyclopaedia are for information only and may not be covered by your insurance product should you make a claim.