Myotonia congenita Becker belongs to the general group of so-called myopathies (muscle diseases). It is characterized by the delayed establishment of the resting membrane potential after muscle contraction. This means that the muscle tone decreases only slowly.
What is myotonia congenita Becker?
Myotonia congenita Becker is a muscle disease (myopathy) that belongs to the special group of myotonia. Myotonia is characterized by prolonged increased muscle tone. The muscle relaxes only slowly after a muscle contraction. Myotonia is a defect in the sodium ion channel. See sciencedict for Introduction to Latex Allergy.
The resting potential between the potassium ions inside the cell and the sodium ions outside the cell is restored only slowly when excited. In terms of muscle tension (muscle tone), this means that a certain change caused by muscle strength is maintained for longer. For example, if the patient clenches his fist, it takes a while before he can open his fist again. Myotonia is usually genetic.
This leads to defects in the enzymes responsible for the transport of chloride ions in the sodium channel. Myotonia congenita Becker is also characterized by identical symptoms to myotonia congenita Thomsen, since both diseases affect chloride ion transport. With a prevalence of 1 in 25,000, Becker’s myotonia congenita is a very rare muscle disease. However, the prognosis is very good. A reduction in life expectancy is not observed.
Causes
A genetic defect in the CLCN1 gene on chromosome 7 has been described as the cause of myotonia congenita Becker. This gene is responsible for the production of an enzyme that regulates the transport of chloride ions through the sodium channel. As a result of this enzyme defect, the chloride ions can no longer be transported so well, and the resting potential of the cell membrane only sets in slowly.
The resting membrane potential is an actively generated cell potential that develops between the interior of the cell and the intercellular space. The so-called sodium-potassium ion pump constantly pumps potassium ions into the cell and sodium ions out of the cell. Thus, the potassium ion concentration is increased inside the cell and decreased outside. Conversely, this naturally also applies to the sodium ions.
The resulting potential is actively maintained in order to be able to transmit electrical impulses via potential changes. Normally, when the potential is reversed by this impulse, the initial state is quickly restored. However, this process is delayed in Myotonia congenita Becker due to the disturbed transport of chloride ions.
The same also applies to myotonia congenita Thomsen. Both diseases are caused by defects in the same gene. However, there are different mutations here. Myotonia congenita Thomsen is inherited in an autosomal dominant manner, while myotonia congenita Becker is inherited in an autosomal recessive manner.
Symptoms, Ailments & Signs
The main symptom of myotonia congenita Becker is a long-lasting muscle tension (muscle tone). The muscle does not relax immediately, as is usual for a normal muscle response, but with a delay. Posture triggered by voluntary muscle contraction is maintained longer. The delayed opening of the fist when the patient clenches his fist has already been mentioned.
Furthermore, after a long period of physical rest, getting up and walking is initially only possible with difficulty. After a so-called warm-up phase, the movements normalize again. Muscle stiffness is particularly pronounced when the outside temperature is cold or when you are in cold water. When the skeletal muscles are tapped, a tonic contraction occurs, which is also known as percussion myotonia.
Patients fall more often and appear clumsy when grasping objects. However, muscle development is normal. Even an athletic physique is possible because the myotonia is not associated with muscle weakness. However, prolonged physical rest can lead to muscle weakness.
Diagnosis & course of disease
When diagnosing myotonia congenita Becker, an anamnesis of the medical history is first carried out. Physical examinations such as tapping the skeletal muscles to produce percussion myotonia and electromyography follow. Electromyography shows a series of discharges that suggest myotonia. Now the differential diagnosis for myotonia congenita Thomsen is made.
Both diseases are very difficult to tell apart. The inheritance of the myotonia can be explored in the anamnesis. If an autosomal recessive inheritance is indicated, a myotonia congenita Becker can be concluded. However, only a genetic test can provide precise information.
Complications
Myotonia congenita Becker causes considerable limitations and complications in the patient, which mainly occur in everyday life. In most cases, the muscles cannot relax immediately, meaning that certain activities cannot be carried out by the patient. Likewise, standing up can become a problem if the person concerned has rested beforehand and the muscles have not been active.
Myotonia congenita Becker significantly reduces the quality of life. Those affected also suffer from severe muscle stiffness, which also has a negative effect on the patient’s posture. It is not uncommon for those affected to appear clumsy and, for example, cannot grip or lift objects properly.
This leads to severe limitations in everyday life and in children to an extreme developmental delay. Muscle weakness can also occur, so that the patient’s resilience decreases significantly. Direct treatment of myotonia congenita Becker is not possible.
However, those affected are dependent on various therapies that can significantly alleviate the symptoms. Usually there are no complications. In some cases, however, the heart muscle is also affected, so patients may need medication to prevent heart problems.
When should you go to the doctor?
If the muscle tension cannot be released despite deliberately initiated relaxation, a doctor is needed. Delayed muscle response is considered unusual and should be seen by a doctor. A stiff posture, problems with the gripping function and disturbances in the general movement sequences should be discussed with a doctor. If the symptoms lead to frequent falls or accidents, medical clarification of the cause is required. A treatment plan must be drawn up so that relief of the symptoms can be initiated.
In the case of a general heaviness after a rest phase, restrictions in movement after a break or unsteady gait, the person concerned needs help and support. A doctor is needed to determine the present disorders. A decrease in physical capacity, difficulty in fulfilling daily obligations, and an inability to engage in usual sports activities must be discussed with a doctor. There is a medical condition that needs to be treated.
If the symptoms persist for several days or if the disturbances worsen, a doctor should be consulted. If the affected person seems clumsy in everyday life, if he shows behavioral problems or if there are emotional problems, a doctor should be consulted. The physical impairments increase the risk of a mental illness.
Treatment & Therapy
In most cases, patients with myotonia congenita Becker do not require any treatment. With some training, they can learn to perfect their movements to compensate for the symptoms. In severe cases, however, drug treatment is sometimes necessary. Mexiletine, which is known as an antiarrhythmic for cardiac arrhythmias, is given.
This drug blocks the sodium channel. Acetazolamide, carbamazepine or diazepam can also be used. However, drug treatment should only be used for a short time, as it can have various side effects. However, drug treatment can be useful, especially if the muscles have stiffened as a result of exposure to cold.
Outlook & Forecast
Myotonia congenita Becker brings with it a differentiated prognosis. A cure is impossible because it is a hereditary disease. Doctors can only relieve the symptoms. Often no lengthy treatment is necessary because the symptoms are minimal. In such a course, patients receive information on how to compensate for the signs in everyday life.
Training sessions are usually led by physiotherapists. These measures are sufficient to prevent restrictions in the quality of life. If the course is severe, medication is indicated. The available active ingredients provide temporary relief from the condition. However, there are sometimes side effects while taking it. Stiff muscles are very common in everyday life. Awkwardness and an awkward posture are also characteristic. The resilience in professional and private life is significantly reduced. Myotonia congenita Becker does not shorten life expectancy.
According to statistical surveys, the disease occurs in one patient out of 25,000 people. Many sufferers receive Myotonia congenita Becker through inheritance from their parents. The complaint status usually remains at a similar level. Changes are very rare and take place gradually.
Prevention
Myotonia congenita Becker is a genetic disease, so there is no possibility of prophylaxis. However, the onset of symptoms can be prevented. It is particularly important to avoid the cold. This also applies to bathing in cold water. This is because the muscles stiffen very quickly.
Furthermore, continuous movement is necessary to counteract muscle stiffness. Movement training also makes it possible to compensate for the symptoms of myotonia congenita Becker.
Aftercare
In most cases, those affected by myotonia congenita Becker have only a few and only limited follow-up measures available. For this reason, those affected should consult a doctor at an early stage to prevent the occurrence of other complications or symptoms. It cannot heal on its own, so the patients are dependent on the help of a doctor.
Aftercare often includes physiotherapy or physical therapy to permanently and properly relieve the symptoms. Many of the exercises from such therapies can also be repeated at home to speed up healing. Help and care from one’s own family is often very important in the case of myotonia congenita Becker.
When taking medication, it is important to ensure that the dosage is correct and that it is taken regularly in order to counteract the symptoms. Those affected should always consult a doctor first if they are unclear or have any questions. Myotonia congenita Becker usually does not reduce the life expectancy of the patient. Contact with other people affected is often very useful, as this can lead to an exchange of information.
You can do that yourself
Myotonia congenita Becker can be treated by the patients themselves with a few self-help measures and various household and natural remedies.
Various exercises from physiotherapy make it easier to get up and walk in the morning. By repeating the movement, the so-called “warm-up phenomenon” can be achieved, in which the movements can be carried out increasingly easily and with less pain. When the outside temperature is cold, the patient should wear warm clothing, as muscle stiffness is particularly pronounced under these conditions. If medication has been prescribed for the condition, the use of alternative remedies should be discussed with the doctor beforehand. The doctor can give tips for an adapted diet, which can often reduce the typical muscle problems.
Since there is an increased risk of accidents with myotonia congenita Becker, the patient should not be left alone. In the event of a fall, call an ambulance and provide first aid to the victim. If accidents happen repeatedly, adjustments have to be made in the household, such as support handles or handrails. In the advanced stage, the patient is dependent on a wheelchair.
