Charcot-Marie-Tooth disease is a hereditary neuromuscular disorder. It causes progressive paralysis of the extremities with subsequent muscle wasting. There is no known causative cure.
What is Charcot-Marie-Tooth disease?
Charcot-Marie-Tooth disease is the name given to an inherited neuromuscular disease. In this type of disease, muscle breakdown occurs due to nerves. The disease is named after its first descriptors Jean-Martin Charcot, Pierre Marie and Howard Tooth. The technical name of the disease is Hereditary Motor-Sensitive Neuropathy Type 1, abbreviated HMSN 1. The word “hereditary” describes the hereditary nature of the syndrome. Motor-sensitive means that both mobility and sensation are impaired. Neuropathy generally refers to a disease of the nerves. Charcot-Marie-Tooth disease is also called neural muscular atrophy. This term emphasizes the nerve-related muscle loss that results from the disease. Charcot-Marie-Tooth syndrome is one of the most common inherited nerve disorders. The prevalence is 1 in 2500.
Causes
Charcot-Marie-Tooth disease is an inherited disorder. It is usually passed on via the autosomal dominant mode of inheritance. A mutation is present on chromosome 17. The peripheral myelin protein gene (PMP) is duplicated. This mutation initially leads to a thickening of the myelin sheath. It is assumed that this results in an undersupply of nutrients. As a result, damage to the nerve cell process or the myelin sheath itself occurs. The myelin sheath surrounds the nerves like a sheath and is responsible for the correct transmission of nerve impulses from the brain to the muscle. If the myelin sheath is damaged, the nerve impulses cannot reach the muscle. Conversion of the commands from the brain in the muscle is then no longer possible. The result is weakness and degeneration of the affected muscles. Since the disease is inherited in an autosomal dominant manner, both sexes are equally affected. The offspring of a person with the disease is also a carrier of the trait with a probability of 50 percent. If both parents are heterozygous, there is a 75 percent probability that the child will develop the disease. If one parent is homozygous, the disease is passed on with a probability of 100 percent.
Symptoms, complaints, and signs
In most cases, the first symptoms appear in childhood. Occasionally, the disease does not manifest until between the ages of 20 and 30. Initially, weakness of the hands or feet is noticeable and progresses as the disease progresses. It spreads to the arms and legs. The muscles of the affected extremities regress. As a result, certain parts of the body may become deformed because the normal balance between different muscles is no longer maintained. For example, a hollow foot may develop. Deformations of fingers and toes also occur. Sensory disturbances can occur concomitantly. Early signs of Charcot-Marie-Tooth disease are changes in the gait pattern. The foot elevator muscle (Musculus tibialis anterior) is often the first to be affected. The result is a stepper gait. The foot can no longer be lifted. Since it hangs down when walking, the whole leg must be lifted. The planting of the foot cannot be controlled. The gait becomes unsteady. Falls may occur. Pain in the affected body parts may occur.
Diagnosis and course of the disease
To establish the diagnosis, the initial focus is on the patient’s medical history and a thorough physical examination. The presence of the disease in the parents provides a crucial clue. Physical examination reveals decreased strength in the hands and feet, and possibly in the arms and legs. Fist closure may be incomplete. Extension of the fingers is no longer completely possible. The foot cannot be lifted against resistance. Toe stance is not possible. Abduction and adduction of the arms and legs may be limited and strength reduced. The affected muscles are degenerated. Reflexes, especially the Achilles tendon reflex, are weakened or cannot be triggered. Measurement of nerve conduction velocity reveals slowed conduction. Depending on the findings, a nerve biopsy may be necessary. If the findings are unclear, the diagnosis can be supplemented by imaging techniques. Imaging reveals no evidence of Charcot-Marie-Tooth syndrome.It is used to exclude differential diagnoses. In case of unclear family history, genetic diagnosis is possible. The disease progresses at different rates. Some patients remain only slightly limited throughout their lives. In others, the disease progresses to its full expression. This manifests as extensive paralysis of the arms and legs.
Complications
Unfortunately, this disease cannot be treated causally, resulting in extreme limitations and discomfort for the patient in everyday life. The affected person primarily suffers from weakness, which mainly occurs in the patient’s hands and feet. Furthermore, there are severe paralyses and other sensory disturbances caused by Charcot-Marie-Tooth disease. Movement restrictions also occur and the everyday life of the affected person is made considerably more difficult and restricted by the disease. In many cases, disorders of coordination and concentration also occur. Patients suffer from an unsteady gait and not infrequently need help from other people in their daily lives. Stimuli are also passed on only slowly. Various activities that are performed with the hands may no longer be possible, resulting in restrictions in the exercise of the profession. Physiotherapy measures can limit and treat some of the symptoms of Charcot-Marie-Tooth disease. However, complete recovery does not occur. Not infrequently, care by a psychologist is also necessary if the disease causes psychological complaints and depression. In this case, there are usually no complications and the patient’s life expectancy is also not affected by the disease.
When should one go to the doctor?
In the past, this disease was called Charcot-Marie-Tooth disease. Today, it is more commonly referred to as neural muscular dystrophy or hereditary motor-sensitive neuropathy type I (HMSN I). Because this hereditary condition is more common in some families, the first visits to the doctor are usually during pregnancy. Whether abortion can be justified and is actually considered in the presence of Charcot-Marie-Tooth disease is a matter of counseling. The onset of symptoms of Charcot-Marie-Tooth syndrome prompts another visit to the physician, usually in infancy. In other cases, consultations with the family physician or an orthopedic surgeon occur later in life. The reason is that in some cases the symptoms of Charcot-Marie-Tooth syndrome may not appear until between the ages of twenty and thirty. The signs that suggest a visit to the doctor are increasing feelings of weakness in the extremities. Charcot-Marie-Tooth disease, which is genetically determined, develops in affected individuals with symptoms of varying severity. It usually remains relatively constant in its degree of exacerbation. The progressive weakening and paralysis of the arms and legs can therefore last for several decades. Physicians can only alleviate the symptoms of neuropathies, deformities or muscle shortening, but cannot stop the progression of the disease. Those affected by Charcot-Marie-Tooth disease must sooner or later be provided with assistive devices such as crutches or wheelchairs.
Treatment and therapy
There is no known causative treatment for Charcot-Marie-Tooth disease. Therapy is limited to symptomatic measures. Preservation of mobility is the primary goal. Early physiotherapeutic measures to train the compensatory musculature and fall prevention can improve the quality of life. The provision of orthopedic aids such as walking aids or splints, which correct weakness of the foot lifter, for example, plays an important role. If the clinical picture is fully developed, the use of a wheelchair is unavoidable. Rehabilitation stays are recommended to enable intensive and comprehensive therapy to maintain mobility and quality of life. Possible pain can be treated with analgesics. In the case of impairing deformities, especially of the feet, surgical correction can bring relief. [[Psychotherapy|psychological care] is useful in individual cases.
Outlook and prognosis
Charcot-Marie-Tooth disease is not curable. The disease progresses progressively, but life expectancy is not reduced. The protracted course is associated with increasing signs of failure of the arms and legs.The disease causes chronic pain and movement restrictions and represents a considerable physical and mental burden for those affected. The prognosis depends on the individual symptoms of the patient. An effective therapy does not yet exist. Treatment is limited to a change in diet and physiotherapy. There is no prospect of an improvement in the condition. Instead, the above-mentioned measures are used in an attempt to delay the progression of the disease. For the patients, the ongoing therapy represents a considerable burden. The prognosis of hereditary motor-sensitive neuropathy type I is accordingly poor. Patients need to maintain close contact with a team of physicians including general practitioners, orthopedic surgeons, and neurologists to optimize therapy. In addition, the prognosis can be improved by the support of family members or friends who act as a support in everyday life. The prognosis of Charcot-Marie-Tooth disease is determined by the specialist in charge, taking into account the patient’s constitution and the stage of neuropathy.
Prevention
Preventive measures to avoid Charcot-Marie-Tooth disease are not known because the cause of the disease is hereditary. Outbreak of the syndrome cannot be prevented in gene carriers. Likewise, there are no known ways to stop the progression of the disease. Quality of life can be improved by timely physiotherapeutic measures.
Follow-up
Because Charcot-Marie-Tooth disease is not curable, follow-up cannot be sharply distinguished from therapy. The goal is to slow the progression of the disease. Care with close contact between the patient and physicians is recommended. A team of general practitioners, orthopedists and neurologists optimizes the design of lifelong treatments. The basis of the aftercare examinations is the clinical examination. At the beginning, there is a discussion about the current complaints. Then the body is examined in general and at specific points. In particular, regions affected by neural muscular atrophy are tested for performance and the loss of muscle circumference is documented. The neurological examination focuses on the function of the nerves and muscles. To begin, the neurologist asks about current symptoms. This is followed by tests to assess gait, posture, balance, and movement limitations. In addition, reflexes and the sensation of pain and touch are tested. In some circumstances, the physician may also order equipment-based analysis procedures. These include electromyography to measure muscle activity and nerve conduction velocity measurement. Other examination methods include a nerve ultrasound, computer tomography or magnetic resonance imaging. After the examination, the orthopedist regularly checks the fit of orthopedic devices. According to the progress of the disease, these are health or therapeutic shoes, insoles and walking aids. As follow-up treatments after surgery on the feet, special physiotherapeutic measures are usually necessary.
What you can do yourself
Charcot-Marie-Tooth disease is a chronic condition. So those affected must learn to cope with the symptoms over a long period of time. The first point of contact for dealing with the disease in everyday life is the physiotherapist. The compensatory musculature should be trained as well as possible. In addition, exercises for fall prevention provide a significant increase in the quality of life. Those affected are often dependent on the help of relatives. They, too, can consult the physiotherapist to learn how they can better help the affected person. In principle, the aim is to maintain maximum independence for the sufferer. Light exercise such as water gymnastics can also help. Depending on the severity of the disease, orthopedic aids such as walking aids can make the affected person’s everyday life noticeably easier. The choice of footwear is also important. An orthopedist should be consulted in this regard. Sufferers should generally try to lead a healthy lifestyle. Since psychological problems often occur as well, it may be advisable to consult a psychologist. It is advisable to adapt the home furnishings to the physical limitations of the affected person. In some cases, it is worth moving to a smaller apartment.More detailed information and advice on how to deal with everyday life is also available to those affected and their relatives in self-help groups.
