What is Keshan Disease?
Keshan disease is a cardiomyopathy that predominantly affects children and women of childbearing age. It was first identified in the Keshan County of China, hence the name. The disease is characterized by an enlargement of the heart, leading to heart failure and, in severe cases, death. The defining feature of Keshan disease is its geographical association with selenium-deficient areas.
The Role of Selenium Deficiency
Selenium is a trace element essential for the proper functioning of the human body. It plays a crucial role in the antioxidant defense system, thyroid hormone metabolism, and immune function. Keshan disease is primarily linked to
selenium deficiency, as regions with low dietary selenium intake have higher incidences of the disease. The deficiency impairs the antioxidant enzyme
glutathione peroxidase, leading to increased oxidative stress and damage to heart tissues.
Is Keshan Disease Influenced by Other Factors?
While selenium deficiency is the primary cause, other factors may exacerbate the condition. The presence of certain viral infections, particularly
Coxsackievirus, has been implicated in the progression of Keshan disease. These viruses may act synergistically with selenium deficiency to produce the pathological changes observed in the heart tissue.
How is Toxicology Related to Keshan Disease?
Toxicology plays a role in understanding how selenium and its deficiency impact human health. Studies in
environmental toxicology have shown that selenium levels in the soil can vary significantly due to geological factors, affecting the selenium content in crops and, consequently, human dietary intake. Furthermore, excessive selenium supplementation, while rare, can lead to selenium toxicity, known as selenosis, which underscores the importance of maintaining balanced selenium levels.
What Are the Symptoms of Keshan Disease?
The clinical manifestations of Keshan disease can vary, but common symptoms include fatigue, palpitations, shortness of breath, and swelling in the limbs due to heart failure. In severe cases, it can lead to sudden cardiac arrest. These symptoms are a result of the heart's reduced ability to pump blood effectively, a condition termed
cardiac myopathy.
How is Keshan Disease Diagnosed?
Diagnosis of Keshan disease involves a combination of clinical evaluation, dietary assessment, and laboratory tests to measure selenium levels in the blood. Electrocardiograms (ECGs) and echocardiograms are also used to assess heart function and detect signs of cardiomyopathy. It is crucial to differentiate Keshan disease from other forms of heart disease that might present with similar symptoms.
What Are the Treatment Options for Keshan Disease?
Treatment primarily focuses on selenium supplementation to correct the deficiency. Oral selenium supplements, such as
sodium selenite or selenomethionine, are commonly used. In addition, supportive treatments to manage heart failure symptoms, such as diuretics and beta-blockers, may be prescribed. Preventive measures include dietary diversification to ensure adequate selenium intake.
Can Keshan Disease Be Prevented?
Prevention is possible through public health interventions aimed at improving dietary selenium intake in high-risk areas. This can be achieved by fortifying foods with selenium or encouraging the consumption of selenium-rich foods such as
Brazil nuts, seafood, and organ meats. Regular monitoring of soil and food selenium levels can also help prevent outbreaks of Keshan disease.
What is the Global Impact of Keshan Disease?
Although Keshan disease is most prevalent in certain regions of China, it serves as a critical example of how micronutrient deficiencies can lead to severe health outcomes. It highlights the importance of
nutritional toxicology in understanding the relationship between diet and disease. Efforts to study and address selenium deficiency can have broader implications for global public health.
