Contents
This is the common name of a genetic disease that causes dysplasia (poor shape) of the right ventricle. This defect is the cause of arrhythmogenic right ventricular cardiomyopathy. Patients also have a characteristic keratinization of the skin on the hands and feet and strangely twisted, as if braided hair. They are called woolly hair.
The disease was first introduced in 1986 by a Greek scientist who described cases of the disease that had a family history among many inhabitants of the island of Naxos. The symptoms of the disease mentioned above appear gradually. Children have woolly hair from birth. Changes in the skin of the feet and hands, i.e. keratoderma, appear in infancy. Cardiomyopathy, on the other hand, appears in adolescence.
Usually, patients seek help due to fainting occurring during even slight physical exertion or bothersome (sometimes even fatal) cardiac arrhythmias.
Naxos disease – causes
Since arrhythmogenic right ventricular cardiomyopathy runs in families (about 30-50% of cases), it is said to be the genetic basis of the disease. So far, 6 genes that may be responsible for the development of the disease have been identified.
However, there are many other hypotheses to explain the development of ailments. The evidence presented is not convincing enough to conclude that we know the cause of the disease.
Some researchers believe that the disease is a consequence of myocarditis caused by enteroviruses and adenoviruses. However, skeptics say that simply detecting viruses in the heart muscle is not sufficient evidence. As a counter-argument they cite the fact that a weakened heart muscle may be more susceptible to viral attack.
Another view is that the cause of the disease is the natural death of heart cells, or apoptosis. Another hypothesis is that heart cells reprogram themselves and turn into fat cells.
Hornet of hands and feet
The disease is the result of a mutation in the gene responsible for the production of creatine. In addition to skin changes, excessive sweating of the feet and hands is also observed. Skin eruptions are usually located symmetrically on both parts of the limbs. The skin affected by the disease is clearly different from the rest of the body. The thickenings of the skin mainly include the superficial layers of the epidermis. The skin is hard, it has a yellow wax tint, it is separated by deep furrows. The nails also become keratinized. Their plate is clearly thickened, which makes it rise. This is because mainly the subungual layer undergoes keratinization.
There is no XNUMX% effective drug that can be used to treat keratosis. Usually, drugs of general and local action are used. Patients take oral retinoids, preparations that have no side effects and – unfortunately – do not give a permanent remission of the disease.
Topical ointments with salicylic acid are used to facilitate exfoliation of excess keratinized epidermis.
Arrhythmogenic right ventricular cardiomyopathy
It is an extremely dangerous symptom of heart muscle disease. A characteristic feature of the disease is the progressive loss of heart muscle cells, i.e. cardiomyocytes. In the course of the disease, they are replaced by adipose and fibrous tissue. The consequence of this are disturbances in the electrical work of the heart, and thus life-threatening ventricular arrhythmias. Chest pain and reduced exercise capacity may also be symptoms of this condition. But it happens that the disease does not give any symptoms. Sometimes its only symptom is sudden cardiac death.
This form of heart disease is a common cause of sudden cardiac death among athletes and young people who are generally considered healthy. According to medical statistics, the disease is responsible for approx. 25 percent. sudden cardiac deaths among people between 20 and 40 years of age. Arrhythmogenic right ventricular cardiomyopathy occurs almost three times more often in men than in women and usually appears before the age of 40
The basic examination that allows to diagnose the disease is echocardiography. It is sometimes performed through the esophagus. Cardiac echo results are usually confirmed by magnetic resonance imaging, ultrafast computed tomography or isotope scanning. The recommended test is venticulography, which allows you to perform a cardiac biopsy. The test is invasive, and due to ionizing radiation it is performed in special cases.
Most patients undergo magnetic resonance imaging, because this non-invasive and completely safe examination allows to accurately assess the anatomical and morphological structure of the heart. Thanks to the obtained images, it is possible to distinguish adipose and fibrous tissue from healthy cells of the heart muscle. Some patients are given contrast before the test, which makes it easier to assess the degree of cardiac fibrosis.
Naxos disease – treatment
Specialists still cannot determine the best and most effective therapy for this disease. This is because there is little clinical experience in treating this ailment.
Most often, however, patients are given drugs that prevent ventricular tachycardia. If antiarrhythmic treatment does not bring the expected results or if it is not tolerated by the patient, the doctor considers electrocution ablation, i.e. moderate the heart rate with appropriate electrical impulses. But it is also known that ablation is not as effective in this case as in the case of other heart conditions. The progressive nature of arrhythmogenic cardiomyopathy contributes to this.
Since the disease carries a high risk of sudden cardiac death, patients in cardiac arrest are implanted with a cardioverter-defibrillator.
As the disease progresses, the consequence of arrhythmogenic right ventricular cardiomyopathy may spread to the left ventricle. Then we are dealing with biventricular heart failure. The patient must then take medications that will support the work of the heart, including angitensin-converting enzyme inhibitors, beta-blockers or diuretics, i.e. diuretics.
In extreme cases of heart failure, it is necessary to consider transplantation. However, you should be aware that the waiting time for a heart transplant can be 12 to 18 months. The condition of transplantation is also good efficiency of other organs, e.g. liver and kidneys.
Tekst: Anna Jarosz