Introduction
Even after being a widespread disorder, CMT still does not have an apparent recognition in India. This is basically due to unawareness and lack of proper diagnosis. Ignorance of the facets of CMT deprives a person from living a deserved quality life. Hence it has become inevitable to develop and spread the knowledge of this disorder among the patients & medical practitioners in order to fight and refrain it.
An Overview of Charcot-Marie-Tooth Disorder
Charcot-Marie-Tooth, or CMT, is the most commonly inherited neurological disorder, affecting approximately 1 in 2,500 adults. CMT is found world-wide in all races and ethnic groups. It was discovered in 1886 by three physicians, Jean-Martin-Charcot, Pierre Marie, and Howard Henry Tooth.
CMT patients slowly lose normal use of their feet/legs and hands/arms as nerves to the extremities degenerate and the muscles in the extremities become weakened because of the loss of stimulation by the affected nerves. Many patients also have some loss of sensory nerve function. CMT is one of the 40 diseases covered by the MDA, but unlike muscular dystrophy, in which the defect is in the muscles, CMT is a disorder in which the defect is in the nerves that control the muscles.CMT usually isn’t life-threatening and almost never affects brain function. It is not contagious, but it is hereditary and can be passed down from one generation to the next. CMT...
...is also known as peroneal muscular atrophy (PMA) and hereditary motor sensory neuropathy (HMSN).
...is slowly progressive, causing deterioration of peripheral nerves which control sensory information and muscle function of the foot/lower leg and hand/forearm.
...causes degeneration of peroneal muscles (located on the front of the leg below the knees).
...causes foot-drop walking gait, foot bone abnormalities, high arches and hammer toes, problems with balance, problems with hand function, occasional lower leg and forearm muscle cramping, loss of some normal reflexes, scoliosis (curvature of the spine) and sometimes, breathing difficulties.
...does not affect life expectancy, but can, in rare instances, cause severe disability.
...has no cure, although physical therapy, occupational therapy and moderate physical activity are beneficial.
...is sometimes surgically treated.
...is usually inherited in an autosomal dominant pattern, which means if one parent has CMT there is a 50/50 chance of each child inheriting the disorder.
...may become worse if certain neurotoxic drugs are taken.
...can vary greatly in severity, even within the same family. ...can now be diagnosed by a blood test (CMT types: 1A, 1B, 1C, 1D, 1E, 1F, 1X, 2A, 2E, 2I, 2J, 2K, 4A, 4E, 4F, HNPP, CHN, and DSN).
Diagnosis of CMT
CMT is usually first noticed when someone develops lower leg weakness and foot deformities such as foot drop, hammer toes and high arches, but that alone will not lead to diagnosis. Sensory loss is often identified when the doctor tests for deep tendon reflexes, such as the knee jerk, which are reduced or absent in CMT patients.Since CMT is strongly hereditary, it is important to tell the doctor about any other family members with CMT-like symptoms. Lack of family history does not rule out CMT, but it will cause the doctor to look further to rule out other causes of neuropathy such as diabetes or exposure to certain chemicals or drugs.Further testing may be electrodiagnostic, genetic, or both. Electrodiagnostic testing used to diagnose CMT usually includes a nerve conduction velocity test (NCV), which measures the strength and speed of electrical signals moving down the peripheral nerves. Delayed responses are a sign of demyelination (type 1) and small responses are a sign of axonopathy (type 2). An electromyogram (EMG) is also used to measure the electrical signal’s strength in the muscles of the arms or legs. Genetic tests, done by drawing blood, are available to test for many, but not all, of the common chromosomal defects causing CMT. A positive genetic test can provide definitive diagnosis and provide useful information for family planning. However, a negative result does not rule out CMT since some forms cannot yet be tested by DNA sampling. Currently, 18 types can be identified by DNA testing: 1A, 1B, 1C, 1D, 1E, 1F, 1X, 2A, 2E, 2I, 2J, 2K, 4A, 4E, 4F, HNPP, CHN, and DSN.
Types and Causes of CMT
The nervous system consists of motor neurons and sensory neurons. One set of nerves carries messages from the brain outward to the rest of the body and one brings messages from the extremities back to the brain. Messages that travel from the brain down the spinal cord, through the lower motor neurons (such as the sciatic nerve of the leg) to the muscles of the body are part of the motor neuron circuitry. Messages that travel upward from the sensory input to the spinal cord and finally the brain are sent by sensory neurons.The peripheral nervous system is also comprised of motor and sensory nerve fibers, and since CMT affects the peripheral nerves, it results in both motor symptoms (weakness and muscle wasting) and sensory symptoms (numbness). The peripheral nerves are often described as being like electrical wires with an inner core (the axon), which is wrapped in insulation (a sheath called myelin). When the myelin is damaged (Type 1 CMT), the nerve impulses are conducted more slowly than normal. If the axon itself is damaged (Type 2), the speed of nerve conduction is almost normal, but the strength of the signal is reduced. All forms of CMT are either demyelinating or axonal in nature. Since CMT is a multi-gene disorder, there are many different defective genes, which cause the disorder. Since 1991, more than 30 different genes causing CMT have been identified and the loci are known for at least another ten causes.
Treatment and Management of CMT
Treatment of CMT is done in conjunction with medical professionals of various specialties. After diagnosis by a neurologist, CMT patients are usually directed to either a podiatrist for care of their foot problems, an orthotist for the manufacture and fitting of braces, an orthopaedic surgeon for surgeries to straighten toes, lengthen heel cords or lower arches, or a physical therapist or occupational therapist to design exercise programs to strengthen muscles or learn energy conservation.Although there is no cure for CMT at the present time, there are many therapies that can greatly improve life and function for CMT patients. The general advice for patients seeking assistance is to look first for the least invasive way to correct their problems. In general, it is important for people with CMT to maintain what movement, muscle strength and flexibility they have. Hence, physical therapy and moderate activity are recommended. Overexertion, however, should be avoided. Swimming or water therapy is an excellent form of exercise since it does not put undue stress on the joints. A physical therapist can design an exercise program that fits a patient’s personal strengths and flexibility. It is impossible to build up muscles already atrophied by CMT, so the best program works on strengthening unaffected muscles that can help do the work of those that have atrophied because of CMT.Bracing is another non-invasive form of correcting problems caused by CMT. Often gait abnormalities can be corrected by the use of either articulated (hinged) or unarticulated, molded braces called AFOs (ankle-foot orthoses). These braces help control foot drop and ankle instability and often provide a better sense of balance for patients. There are many new forms of bracing available for CMT patients, depending, of course, on the severity of their foot deformities and muscle weaknesses.Appropriate footwear is important for people with CMT. Because of lack of good sensory reception in the feet, CMT patients may also need to see a podiatrist for help in trimming nails or removing calluses that develop on the pads of the feet. It is important to consult a medical professional so that the patient does not injure himself/herself doing these procedures.The final decision a patient might make in caring for his/her foot or leg deformities is to have surgery. Many patients choose to stabilize their feet or correct progressive problems. These procedures include straightening and pinning the toes, lowering the arch, and sometimes, fusing the ankle joint to provide stability. Recovery from these surgeries can be long and sometimes difficult. Before considering surgery, a patient should always ask what the benefits may reasonably be considered to be and that must be weighed against the problems that might be incurred.An additional problem related to CMT that needs to be addressed by a medical professional is the pain that some patients experience. Pain might be sharp and sudden or the gnawing, continuous ache of chronic pain. Some pain is associated with dysfunctional nerves that fire off sporadically and some can be attributed to weakened and poorly functioning muscles. Joints and ligaments in the feet and ankles are often painful because of the extra strain put on them by other muscles that have been rendered useless by CMT. Because the causes of pain vary, so will the treatments. No one, however, should be told that there is no pain associated with CMT, since pain is experienced in a very personal and individual way. Although medical professionals are involved in many stages and forms of treatment, the patients themselves are responsible for much of the management of their CMT. Basically, people with CMT are healthy individuals and they must work to maintain that health. Because circulation is a problem in individuals with CMT, people must take care to keep their hands and feet as warm as possible. They also should take extra care to avoid falling because fractures take longer to heal in someone with an underlying disease process. Additionally, the resulting inactivity may cause the CMT to worsen. Falls can generally be avoided by watching where one walks and by wearing appropriate footwear.There is no magic nutritional diet to treat CMT, but it is important for CMT patients to control their weight. Not only does extra weight make physical activity more difficult, but it also increases the stress on already compromised joints and muscles.It is also important for patients to maintain as much strength and flexibility as possible. Generally, patients should consult a physical therapist or physician before beginning an exercise program, and avoid strenuous activity and overwork. Moderate activity and physical exercise can be beneficial, but patients must be conscious of their physical limitations. Patients must learn to say no to tasks that overwhelm them and to delegate tasks to other members of their family when possible.Finally, stress management is important in maintaining a healthy body. Any disabling condition can affect the way people think and feel about themselves, but having a chronic illness like CMT, which is often unseen, places stress on individuals and often causes depression. People with CMT can suffer from low self-esteem and relationships with others can be affected. Even when a person has learned to live with CMT, the progressive nature of the disorder may bring about more loss and the grieving process can begin again.Some patients cope successfully on their own or with the support of family and friends; others find it therapeutic to talk to a professional counselor or to participate in a support group
References :
www.lindacrabtree.com
www.cmt.org.uk
www.hnf-cure.org
www.charcot-marie-tooth.org
