DIABETES INSIPIDUS The concentration of the urine is relatively less than the quantity; the specific gravity often registers 1.005 and lower and the color is abnormally light. The great loss of water through the kidneys increases the thirst (polydipsia.) and diminishes the excre tion of water by the skin, which as a rule is dry and roughened.
The disease is rare—rarer than diabetes mellitus although rela tively more frequent in childhood. Ten to fifteen per cent. of the total number affected occur in the first decade but the majority of these in the second half of this decade.
constant pathologic-anatomical basis for diabetes insipidus has not been discovered. Diseases of the cerebellum and especially of the medulla may show evidence of diabetes insipidus but it is doubtful if these cases are identical in their pathogenesis with those in which no anatomical lesion of the brain whatever is found. Cerebral concussion also plays an undoubted role. Polyuria often de velops towards the end of an acute infectious disease, increases to a dis tressing degree, continues many weeks beyond the primary disorder and then gradually returns to normal. This condition should not be classified as true diabetes insipidus but at most as a symptomatic form of the disease. The etiology and pathogenesis are generally unknown.
insipidus, if it is not a postinfee tious polyuria, is practically always a serious disease in childhood whether it develops in the train of a cerebral disease or appears spon taneously. Children suffer much from the distressing thirst, take no pleasure in their play or work, become irritable and quickly exhausted. A gradual emaciation almost always occurs, due to the difficulty of administering sufficient nourishment because of the large quantity of fluids which they drink. Considerable loss of heat results from rais ing this large quantity of fluid, usually drunk cold, to the temperature of the body. I estimated in one patient, a boy ten years of age, that this loss of heat increased the calorimetric needs of the body about 13 per cent. more than normal. These children usually are for their age mark edly deficient in growth and especially in the development of muscle and bone. No other change in metabolism has yet been discovered. Although the secretion of urine may reach three to four quarts in moder ately severe cases, and seven to eight quarts and more in severe cases even in children, the constituents of the urine (urea, uric acid, mineral salts) are present in normal amount. The urine often but not always contains inosit, the significance of which however is still in doubt.
Other symptoms and retrograde changes arc lessened perspiration, often some reduction in the temperature of the body, marked concen tration of the blood serum, trophic changes in the nails, defective growth of hair, rarely forms of neuritis, especially optic neuritis.
The diagnosis is easily made from the symptoms. It is only necessary to decide whether it is a true diabetes insipidus or a symp tomatic polyuria.
The prognosis and course cannot be predicted with certainty. It is dependent in diseases of the brain much more upon the primary condition than upon the diabetes insipidus. When the disease occurs spontaneously and becomes fully developed, it usually goes on to a fatal termination by gradual exhaustion or by some intercurrent dis ease (tuberculosis) for which it furnishes the soil. The prognosis however is not nearly as serious as in diabetes mellitus since complete recoveries and in other cases improvements have occurred. A well defined polyuria and polydipsia may continue through life and be regarded as an inconvenience rather than a disease.
Treatment is not entirely without effect.. Systematic, careful and graded restriction of fluids may produce beneficial and permanent results. I have seen several of these favorable cases among children. Hospital treatment is often more effective than that at home. Ex clusive diets, as meat, milk or vegetable, have been strongly recom mended but cannot be enforced. The care and nourishment should be directed to strengthening the body as much as possible. The question has recently arisen if it would not be possible to reduce the exchange of fluids in the body by a salt free diet and thus induce a gradual return to normal conditions. This deserves further investigation. Recently a child suffering with diabetes insipidus recovered under this treatment in my hospital service. Everything which stimulates the peripheral circulation is to be recommended. A constant out-of-door life has often a marked effect upon the polyuria and polydipsia. Favorable results have been reported from the use of the sulphur baths at Kreuznach and Nagheim and recently air and sun baths have been extolled.
Almost every drug has been tried and especially opium, bella donna, strychnine, ergotin, pilocarpin, antipyrin and the salicylates, recently adrenalin. On account of the great uncertainty in their action only the temporary use of such powerful drugs has seemed justified in children.