克山病Keshan Disease

歴史的,病因論的考察

抄録

Objective: Keshan disease is an endemic cardiomyopathy found in Keshan, north-east China. The first patient was identified in 1935. This disease is characterized by a blood circulation disorder, endocardium abnormality and myocardium necrosis. Selenium (Se) deficiency is thought to be a major factor by Chinese scientists. However, the exact etiology has not been clarified up to now. The government decided to apply sodium selenite to growing crops, and the incidence of the disease decreased dramatically. However, a few cases still occur as chronic or latent types. This paper reviews Keshan disease from a historical aspect and also the present situation.
Methods: We made a reference survey and summarised the etiology, pathological changes, clinical manifestation, and other views of Keshan disease.
Result: So far, epidemiological surveys have shown that Keshan disease occurs in large areas in 14 provinces in China, mainly in the countryside. It has been confirmed by clinical and pathological studies that Keshan disease is an independent endemic myocardial disease caused by biological and geological factors. The largest prevalence age rates are boys under 15 years old and women of childbearing age. There are several hypotheses; acute carbon monoxide poisoning, virus infection, malnutrition, or selenium deficiency. The first is not currently believed to be the cause. The following was pointed out; studies on the relationship between diet and the endemic areas of Keshan disease in 1961, where the food custom of the local residents was relatively simple and a so-called “one-sided diet” (eating a limited variety of food) might be related to the incidence of Keshan disease. In 1973, large-scale investigations on the natural environments were performed in the endemic areas of Keshan disease in the whole country. As a result, it was reported that there was a relationship between the incidence of Keshan disease and the special natural environment in the endemic areas and the cause of Keshan disease was strongly supported by nutritional, biological, geological and chemical (selenium deficiency) factors. In 1981, on the other hand, it was found that the levels of antibodies against Coxsackie virus were higher in the serum of Keshan disease patients than of normal subjects. This fact supposed that the cause of Keshan disease was related to a virus infection. However, it is difficult to explain why the clinical and pathological manifestations of Keshan disease are similar to those of other diseases, e. g. idiopathic dilatational myocardial disease. Further research should be performed on Keshan disease to clarify the etiology.