Beriberi is a disease resulting from faulty metabolism and is directly caused by the deficiency of vitamin B1 or thiamin and by other deficiencies in the diet. Among Orientals this deficiency is usually produced by the too exclusive use of decorticated or polished rice, but it may be equally caused by the too exclusive use of white wheat flour and other carbohydrate staples. Clinically, beriberi is characterized by degenerative changes in the nervous system including a multiple peripheral neuritis, which may exist alone but is often combined with generalized edema and serous effusions, and by a tendency to the development of cardiac hypertrophy, which frequently results in cardiac failure and sudden death.
The pathology and symptomatology of beriberi may therefore be discussed under three heads: Cardiac pathology, anasarca, and degenerative changes in the nervous system.
1. THE HEART Since all the deaths are caused by heart failure, in Oriental beriberi at necropsy the heart is always considerably enlarged, particularly on the right side.