Nature Of The Disease

Diabetes mellitus is a disease characterised by the passage of a large quantity of urine containing grape sugar or glucose and usually of high specific gravity - 1.035 or more - excessive thirst, and sometimes exaggerated or perverted appetite; progressive emaciation; muscular weakness and langour. The disease runs a chronic course, and the majority of cases terminate fatally in from two to four years. Death may result from inanition or from "diabetic coma" or other causes. The knowledge of the disease has been very largely obtained from experimentation upon the lower animals, in which diabetes can be artificially produced. The treatment is almost entirely dietetic and hygienic, for as yet no medicinal remedy has been found which is curative, and very few have been discovered which are even palliative in any number of cases. Diabetes is therefore essentially a dietetic disease, for although not usually caused by errors in diet it may be exceptionally so produced, and most cases are more or less benefited by dietetic treatment, while some may undoubtedly be cured by it.

Diabetes was described more than a century ago; and Rollo inaugurated the dietetic treatment by withholding vegetable food. In 1838 Gmelin and Tiedemann established the existence of the relation between the digestion of carbohydrates and the formation of sugar. In 1848 the eminent physiologist Claude Bernard began elaborate researches which first threw definite light upon the relations of the liver to the consumption of sugar and the formation of glycogen, and since that day a number of physiologists and clinicians in many countries have contributed extensively to the knowledge of the disease. Notwithstanding this fact, however, the true cause of this affection is still obscure, and aside from dietetic treatment but little advance can be claimed in regard to the controlling influence of medicine. The method of production and elimination of the sugar and the influence of the disease upon general nutrition is understood, but its real exciting cause and the fundamental reason for the interesting departure from the normal metabolism of starchy foods which is its basis is still unknown.

Frequency

Diabetes is not a very rare disease, and a few cases occur from time to time in the experience of almost every general practitioner. It is reputed to be of more common occurrence today than it was fifty years ago, but this fact is possibly due to the much more careful and frequent urinary analyses which are made as a matter of routine by all physicians, that often reveal a latent diabetic condition which might otherwise have been overlooked. In regard to those cases which are of neurotic origin, the general increase in the proportion of diseases of the nervous system which has been observed in the United States must be taken into consideration. Diabetes may occur alone or in association with a variety of diseases, particularly those of the liver, pancreas, lungs, and nervous system.

Causation

The influence of heredity can be traced as a factor in about one third of all cases. The disease may occur in any climate and in any age with either sex, but it is commonest in males in the proportion of three to one. In females it occurs oftenest between twenty and forty years; in males, between thirty and forty-five years. It is somewhat more common among the wealthy than the poor because of sedentary habits combined with overindulgence in eating. The obese, particularly those who have much omental fat, are more liable to diabetes than are thin persons who are more active.

Cantani has observed the unusual prevalence of diabetes in southern Italy, where carbohydrates are so extensively used, and he believes that the liver is exhausted by metabolising such food, while at the same time it is weakened by failure to receive proteids. This view will hardly withstand the criticism that in many other countries the natives have lived for generations upon carbohydrates without developing diabetes.

Among the various determining causes of the disease have been reported blows and shocks affecting particularly the nervous system, injuries to the back of the head and blows over the liver, as well as general concussion, such as that produced in railway accidents; exposure to cold, wet, and fatigue; convalescence from fevers; emotional strain, worry, mental fatigue, and anxiety. Tumours and haemorrhage at the base of the brain and circumscribed lesions of the floor of the fourth ventricle have been known to occasion the disease. A number of cases have been associated with disease of the pancreas, as stated below (p. 672).