Keshan disease is a rare disease of the heart muscle that is mainly attributed to selenium deficiency. The disease was named after a town in northeast China‘s Manchuria. In selenium deficiency, the body cannot sufficiently synthesize the enzyme glutathione peroxidase, which is essential in neutralizing oxidative stress and requires the selenium-containing amino acid L-selenocysteine to build it.
What is Keshan disease?
Keshan disease takes its name from a city in Manchuria, a northeastern province of China, and embodies a heart muscle disease called cardiomyopathy. The particular cardiomyopathy is essentially attributed to a deficiency of the trace element selenium. The region is known for its selenium deficiency and for a comparatively more frequent, almost endemic occurrence of Keshan disease than in regions of the world whose soils provide sufficient selenium. Selenium is taken up by plants and is then available throughout the food chain. Keshan disease results from a deficiency of the enzyme glutathione peroxidase, which requires the selenium-containing amino acid selenocysteine to build up. Keshan disease is not easily distinguished symptomatically from other cardiomyopathies. The courses of the disease vary between acute, chronic, and latent forms. Symptomatic complaints include heart failure, cardiac rhythm problems, and, in the chronic course, hypertrophy of the myocardium with all the other problems that may result.
Causes
Selenium deficiency, which is considered the main cause of Keshan disease, is responsible for the body’s inability to synthesize sufficient amounts of the amino acid selenocysteine. Selenocysteine is very similar to cysteine. The only difference is that the sulfur atom of cysteine is substituted by a selenium atom. Selenocysteine is a necessary building block of the enzyme glutathione peroxidase (GPx) and other selenoproteins whose main function is to break down peroxides and oxidative stress. The enzyme reduces hydrogen peroxide and simultaneously oxidizes the tripeptide glutathione to glutathione disulfide. In the reaction, selenium acts as a coenzyme. Glutathione peroxidase is a necessary component of red blood cells (erythrocytes), for which hydrogen peroxide is highly toxic. Glutathione peroxidases thus exert an important protective effect on the cardiovascular system against damage caused by peroxides. A deficiency of the enzyme in erythrocytes can therefore cause hemolytic anemia, a form of anemia caused by premature and increased dissolution of red blood cells. The development of Keshan disease can indeed be explained by selenium deficiency via the causative cascade selenium deficiency, selenocysteine deficiency and consequent deficiency of glutathione peroxidase. Nevertheless, the underlying mechanism for the occurrence of the disease is not (yet) fully understood. In expert circles, the simultaneous involvement of a virus from the human coxsackievirus family is discussed as the cause of Keshan disease, in addition to selenium deficiency.
Symptoms, complaints, and signs
Keshan disease manifests itself through various symptoms and complaints In addition to cardiac arrhythmias, which may be the first symptoms to appear, there is a gradual change in the myocardium. Muscle cells are replaced by connective tissue-like cells, resulting in an interspersion of the myocardium with connective tissue. This is also accompanied by hypertrophy of the heart muscle, typical signs of cardiomyopathy. As the disease progresses, increasing heart failure is observed, accompanied by corresponding loss of performance. In rare cases, Keshan disease can also be the cause of immediately life-threatening cardiogenic shock.
Diagnosis and course of the disease
The symptoms of Keshan disease are usually abundantly nonspecific; because hypertrophy of the myocardium, cardiac arrhythmias, and heart failure of varying severity may be due to other causes, careful diagnosis is indicated. In addition to the ECG, important diagnostic tools include imaging techniques such as coronary angiography, echocardiography, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear cardiology procedures. The diagnostic procedures are well suited to depict the respective actual condition.However, the findings do not yet provide a clear statement as to what causes the pathological changes. The suspicion of Keshan disease can only be substantiated if a laboratory analysis of the blood plasma confirms a selenium deficiency. The course of Keshan disease ranges from mild to chronic to severe.
Complications
Various symptoms or complications occur due to Keshan disease. However, this disease affects most people differently, so a general course of the disease cannot usually be predicted. However, there are often symptoms of the heart, so that in the worst case the affected person can die of cardiac death. Likewise, there is muscle atrophy and pain in the muscles. The patient’s resilience and performance drop enormously and a general feeling of illness appears. The quality of life and everyday life of the affected person are considerably restricted by Keshan’s disease. Furthermore, a so-called cardiogenic shock can occur. If this is not treated, the affected person can die in the worst case. Treatment is causal and symptomatic and in most cases leads to a rapid improvement of the symptoms. No particular complications occur. However, the person affected must find out what is causing the selenium deficiency. Furthermore, infusions or medication can be used to limit the symptoms of Keshan disease. If treated, the patient’s life expectancy will not be reduced.
When should you see a doctor?
Irregularities of heart activity and disturbances of heart rhythm should always be intensively examined by a doctor. If there are interruptions in the heartbeat, palpitations, an abnormality in blood pressure, disturbances in blood flow or a sensation of pain in the chest, a doctor should be consulted immediately. A decrease in the usual physical performance, an inner restlessness or an increased need for sleep indicate existing discrepancies of the organism, which should be clarified by a doctor. In Keshan disease, the symptoms develop slowly and gradually over a long period of time. With this steady progressive course of the disease, it is often difficult to objectively assess the health development. It is therefore recommended to participate in regular check-ups and stress tests. In addition, a physician should be consulted as soon as the affected person suffers from general weakness, fatigue or sleep disturbances over a longer period of time. A visit to the doctor is required in the event of a feeling of oxygen deficiency, general dysfunction or changes in respiratory activity. Irritability, abnormalities in behavior, dissatisfaction or mood swings may indicate existing health problems. If the complaints increase or become more widespread, a doctor should be consulted. If there are rapid signs of fatigue, if accustomed job requirements can no longer be met, and if a decline in cognitive performance is noticed, a doctor must be consulted.
Treatment and therapy
If laboratory tests confirm a selenium deficiency, one of the most important measures is to correct the deficiency. However, it should be clarified beforehand which causes mainly caused the selenium deficiency and thus Keshan disease. If there is no selenium deficiency due to an unbalanced diet with a reported low selenium content, the absorption capacity for the trace element may be reduced due to inflammatory diseases in the digestive tract or due to diarrheal diseases, so that a temporarily higher selenium intake should be considered. With a sufficient selenium concentration in the blood plasma, which should be above 80 µg/l. With sufficient selenium concentration in blood plasma and blood serum, the causes of Keshan disease will be addressed. If the myocardium is already irreversibly damaged, other therapeutic measures may also be considered to directly treat specific symptoms. After reaching a concentration of about 80 to 160 µg/l in the blood plasma, selenium administration can be reduced to avoid selenium poisoning (selenosis). The daily intake of selenium as a maintenance requirement for a healthy adult is between 30 and 70 micrograms.
Outlook and prognosis
With early diagnosis as well as medical treatment, complete recovery of the patient is possible. The deficiency of selenium is gradually compensated by the administration of special medications. This leads to an alleviation of the symptoms that have occurred and, in the course of the coming weeks or months, to freedom from symptoms. The levels of selenium in the organism continue to be monitored regularly so that an optimal supply can take place. In addition, the cause of the deficiency is analyzed. If the causes of the Keshan disease can be clarified and permanently corrected, a lasting cure is possible. If left untreated, selenium deficiency can lead to the premature death of the affected person in the event of a severe course of the disease. The affected person is at risk of cardiac death if the selenium deficiency is acute and prolonged. There is also a risk of death if the disease is already far advanced or if there are additional diseases of the heart. Due to the severe course of the disease, early treatment is particularly important. If there is a new outbreak of the disease in the course of life, it should also be reacted to as quickly as possible and medical care should be sought. In some cases, the organism of the affected person is already weakened to such an extent that the symptoms are stronger when the disease breaks out again and complications as well as impairments occur earlier.
Prevention
Preventive measures to avoid Keshan disease in the form of additional selenium supplements to the daily diet are only advisable in regions with extreme selenium deficiency in the arable and garden soils. The food produced there also has very low selenium content, as does the meat of the animals that feed on the plants. Selenium deficiency permeates the entire food chain in the regions concerned. Decreased absorption capacity of trace elements in the intestine over a long period of time may also necessitate the intake of additional selenium beyond the normal diet if the selenium concentration in the blood has dropped below about 80 µg/l.
Follow-up
In general, follow-up measures for Keshan disease are very limited. In this regard, first and foremost, a rapid and, above all, early diagnosis of the disease is very important so that no further complications or other complaints occur. Keshan’s disease cannot heal on its own, so the affected person should consult a doctor at the first symptoms and signs of the disease. In most cases, the disease itself can be relatively well alleviated by taking various medications. However, the affected person should always ensure that the medication is taken regularly and in the correct dosage, as Keshan’s disease cannot heal itself. Regular checks and examinations by a doctor are also necessary in order to correctly determine the concentration in the blood. In children, especially parents must pay attention to the symptoms of the disease and consult a doctor if necessary. In many cases, a proper diet can also relieve the symptoms of Keshan disease permanently and above all properly, and the disease rarely reduces the life expectancy of the affected person.
This is what you can do yourself
Depending on the cause, Keshan disease can be treated by sufferers themselves. If the disease is based on a selenium deficiency, a change in diet is already sufficient. A balanced and healthy diet supplies the body with the necessary trace elements and thus also reduces the symptoms. Recommended are mainly fruits and vegetables, especially light foods and foods that do not put excessive strain on the heart, as well as lean meat and plenty of fluids. Drinks such as alcohol, coffee and cigarettes should be avoided. If irreversible damage has already occurred, further therapeutic measures are indicated, such as targeted cardiac muscle training or wearing a pacemaker. In the event of serious complications such as cardiogenic shock, the emergency physician must be called immediately. First aid must be given and resuscitation measures may also be indicated. In the case of such a severe course, a longer hospital stay is necessary in any case. The affected person can best support the healing process by refraining from physical exertion and adhering to the prescribed diet.Advanced Keshan disease also needs to be monitored regularly so that any complications can be detected and treated early.
