DIABETES (from ____, through, and _____, to pass), a disease characterized by a habitually excessive discharge of urine. Two forms of this complaint are described, viz.— Diabetes Mellitus, or Glycosuria, where the urine is not only increased in quantity, but also contains a greater or less amount of sugar, and Diabetes Insipidus, or Polyuria, where the urine is simply increased in quantity, and contains no abnormal ingredient. The former of these is the disease to which the term diabetes is most commonly applied, and is by far the more serious and important ailment.
Although sometimes classed by medical writers among diseases of the kidneys, diabetes mellitus is rather to be regarded as a constitutional disorder. Its cause is still a matter of uncertainty, but there is sufficient evidence to connect it with a defect in the process of the assimilation of food, more especially that stage in which the function of the liver is concerned. The important researches of Claude Bernard, and subsequently those of Schiff, Harley, Pavy, M'Donell, and others, have shown that this organ, besides the secretion of bile, has the additional function of forming in large quantity a substance to which the names of glycogen, dextrin, or amyloid substance have been given. This matter is capable of being converted by the action of ferments into glucose, or grape sugar, and such a change is supposed by some to take place normally in the blood where the sugar thus formed is consumed by oxidation in the course of the circulation, while by other authorities it is held that the glycogen is not directly converted into sugar, but is transformed into other compounds.
The theories of diabetes founded on these views ascribe its production either to an excessive formation of glycogen or to some defect in its transformation, the result being that grape sugar passes out of the body by the kidneys. It has long been known, both by experiment and by observa-tion in disease, that injuries to certain parts of the nervous system, particularly the floor of the fourth ventricle in the brain, and that portion of the sympathetic nerve which sends branches to the liver and regulates its blood supply, are followed by the appearance of sugar in the urine. Hence certain pathologists seek an explanation for the disease in a morbid state of the parts of the nervous system whereby these particular nerves are either irritated or paralyzed and the flow of blood through the liver tem-porarily or permanently increased.... It must, however, be remarked that, although in some instances the portions of the nervous system above mentioned are found after death to be involved in disease, this is by no means constant, and that in many cases of diabetes the post mortem appearances are entirely negative. While, therefore, considerable light has by modern research been thrown upon this disease, its pathology cannot be regarded as settled. See NUTRITION.
It ought to be mentioned that small quantities of sugar are frequently found in the urine in many diseases, and even in health after articles of food rich in sugar or starch have been eaten, as also in some forms of poisoning.
Little is known regarding the exciting causes of diabetes. Exposure to wet and cold, privation, depressing mental emotions, or mental overwork, the abuse of alcohol and of saccharine and starchy substances, have all been assigned as causes. It appears to be in some instances hereditary. It is most common among adults, and occurs much more fre-quently in males than in females.
The symptoms of diabetes are usually gradual in their onset, and the patient may suffer for a length of time before he thinks it necessary to apply for medical aid. The first symptoms which attract attention are failure of strength, and emaciation, along with great thirst and an increased amount and frequent passage of urine. From the normal quantity of from two to three pints in the twenty-four hours it may be increased to 10, 20, or 30 pints, or even more. It is usually of pale colour, and of thicker consistence than normal urine, possesses a decidedly sweet taste, and is of high specific gravity (1'03 to l'Oo). It fre-quently gives rise to considerable irritation of the urinary passages.
By simple evaporation crystals of sugar may be obtained from diabetic urine, which also yields the characteristic chemical tests of sugar, while the amount of this substance can be accurately estimated by certain analytical processes. The quantity of sugar passed may vary from a few ounces to two or more pounds per diem, and it is found to be markedly increased after saccharine or starchy food has been taken. Sugar may also be found in the blood, saliva, tears, and in almost all the excretions of persons suffering from this disease. One of the most distressing symptoms is intense thirst, which the patient is constantly seeking to allay, the quantity of liquid consumed being in general enormous, and there is usually, but not invariably, a vora-cious appetite. The mouth is always parched, and a faint, sweetish odour may be evolved from the breath. The effect of the disease upon the general health is very marked, and the patient becomes more and more emaciated. Be suffers from increasing muscular weakness, the temperature of his body is lowered, the skin is dry and harsh, the teeth are loosened or decay, while dyspeptic symptoms, constipation, and loss of sexual power are common accompaniments. There is in general great mental depression or irritability.
Diabetes as a rule advances comparatively slowly except in the case of young persons, in whom its progress is apt to be rapid. Various complications arise in the course of the disease, among which may be mentioned cataract, various cutaneous eruptions, kidney diseases, inflammatory chest affections, and especially pulmonary consumption, which is one of the most frequent modes of fatal termination in diabeter. Occasionally death occurs suddenly from exhaustion.
Diabetes is a very fatal form of disease, recovery being exceedingly rare. Nevertheless much may be done by appropriate treatment to mitigate the severity of the symptoms and to prolong life.
Cases may thus continue for years without material change to the worse, and in some rare instances it would seem that the disease is cured. The unfavourable cases are chiefly those occurring in young persons, also where serious chest or other complications arise, and especially where the disease itself is of severe character, the quanti ty of sugar passed being persistently large, and the patient losing flesh and strength rapidly.
With respect to the treatment of diabetes, the regula-tion of the diet has by all authorities been regarded as a matter of the first importance, inasmuch as it has been proved beyond question that certain kinds of food have a powerful influence in aggravating the disease, more particularly those consisting largely of saccharine and starchy matter ; and it may be stated generally that the various methods of treatment proposed aim at the elimina-tion as far as possible of these constituents from the diet. Hence it is recommended that such articles as bread, potatoes, and all farinaceous foods, turnips, carrots, parsnips, and most fruits should be avoided ; while animal food and soups, green vegetables, milk, cream, cheese, eggs, butter, and tea and coffee without sugar, may be taken with advantage. As a substitute for ordinary bread, which most persons find it difficult to do without for any length of time, bran bread, gluten bread, almond biscuits, and even well-browned toast or rusks are recommended. Alcoholic stimulants are of little or no use, but if prescribed should be in those forms containing the least saccharine matter, such as claret, Burgundy, brandy, or bitter ale.
Thirst may be mitigated by iced water, or water slightly acidulated with phosphoric acid. The employment of a diet consisting entirely of skimmed milk has been recom-mended by Dr Donkin of London, who has obtained good results from this method of treatment. The milk is administered in quantities of from 8 to 12 pints in the twenty-four hours, all other articles of diet being excluded.
The plan of treatment once proposed, of administering sugar in large quantity in diabetes, proved to be highly injurious, and is now abandoned.
Numerous medicinal substances have been employed in diabetes, but few of them are worthy of mention as possessed of any efficacy. Opium is often found of great service, its administration being followed with marked amelioration in all the symptoms, and, according to some high authorities, with cure of the disease. It is borne in diabetes in larger doses than usual, and from 5 to 12 grains or more may be taken in the twenty-four hours. In like manner codeia (one of the constituents of opium), in doses of half a grain increased to two or three grains three times a day, has been used with good effect.
In most cases, however, it is the dieting of the patient to which the physician has to look in dealing successfully with this formidable disease; and sufferers ought always to be impressed with the necessity of strictly abstaining from those articles of food which by general consent are allowed to exercise a hurtful influence in aggravating the symptoms.
In diabetes insipidus, there is constant thirst and an excessive flow of urine, which, however, is not found to contain any abnormal constituent. Its effects upon the system are often similar to those of diabetes mellitus, except that they are much less marked, the disease being in general very slow in its progress. In some cases the health appears to suffer very slightly. It is rarely a direct cause of death, but from its debilitating effects may predispose to serious and fatal complications. Little is known as to its pathology, but it is generally supposed to own a similar origin to diabetes mellitus. It is best treated by tonics and generous diet. Opium and valerian have been found beneficial. (J. O. A.)