Thirst is a very marked symptom, which, in certain exceptional cases classed under the head of polydipsia, is the original syinptom. This point will be again referred to under the head of DIAGNOSIS.
The digestive function is impaired in polyuric patients. This is readily under stood, the digestion being disturbed by the ingestion of a large quantity of water, which dilutes the gastric juice. Constipation usually exists.
A phenomenon of some interest, theo retically spealdng, has been noticed in some quite exceptional cases, namely: an abnormal flow of saliva. Kiilz ob served this condition for a time in a young hysterical subject, and was able to collect, in one day, more than one pint of saliva.
It is known that physiologists have, during their experiments, sometimes ob served salivation in dogs and rabbits, after certain lesions of the medulla oblongata, etc. In some cases the pulse is slow, and there is also a certain rela tion between this slowness of the pulse and the increase of the polyuria.
The blood is sometimes more concen trated than in the normal state, but this is by no means a constant symptom; when it exists it would seem to indicate an exaggerated permeability of the kid neys, and the inability to retain the water of the economy.
The bladder is larger than in the nor mal state; the kidneys may also be rela tively larger, but they do not present any structural alterations.
Although in some cases polyuria un accompanied with glyeosuria is a com paratively harmless affection, yet in others the condition may be a serious one, attended with grave alterations in the general health, and leading in a few years to death. These serious cases of polyuria are believed to depend upon dis ease of the pancreas. Cases of polyuria run EL much more rapid course, and are much more fatal, in children than in people. Mongour and Gentes (La Presse Med., Dee. 20, '99).
Diagnosis.—This usually presents very little difficulty. The absence of abnor mal principles in the urine indicates by exclusion the existence of simple poly uria. It may happen, however, that the diagnosis between this condition and that of interstitial nephritis gives some little trouble. In certain cases of the
last-named affection albuminuria may not exist during a certain period. On the other hand, there are cases of poly uria in which, without any actual ne phritis, traces of albumin may be found in the urine.
However, when interstitial nephritis exists, certain urmmic symptoms, hyper trophy of the heart or some one of the symptoms of Bright's disease, are always present. Besides searching for the symp toms of urmmia (cephalalg,ia, dyspncea, etc.), it should also be remembered that a patient suffering from Bright's disease eliminates less nitrogen in his urine than polyuric patients, and that the urine fre quently contains casts. In view of these characteristics, it is generally easy to es tablish a diagnosis.
Polyuria presents several varieties: primary polyuria and primary polydipsia. How are these to be distinguished? In polydipsia thirst is unquestionably the first symptom; it is not preceded by frequent micturition. Polyuric patients do not perspire; in polydipsia perspira tion is likely to occur. In the latter affection the quantity of urine does not amount to the quantity of liquid in gested; so that, if the patient refrain from drinking during several hours, there will be, during this time, a diminu tion or even an arrest of the excretion of the urine.
Finally, in the polydipsic patient the blood is more rich in water, while in the polyuric it is more concentrated.
Polyuria, frequently- spoken of as dia betes insipidus, should, in many cases, be referred, not to its connection with the renal function, but to polydipsia, to which it is, of necessity, a secondary phenomenon. Tbe diagnosis of these cases of primary polydipsia rest largely upon the following points: The exist ence of perspiration in spite of the poiyuria, the disappearance of the poly uria after enforced abstinence from water, the fact that the amount of urine voided does not represent the en tire amount of water ingested, and the fact that micturition is apparently de pendent in time upon the drinking of water. Westphal (Berliner klin. Woch., Sept. 2, '89).