CAUSATION OF CYSTINURIA.
The causation of cystinuria is still conjectural. From the fact that cystine contains sulphur and that it is very similar in its com position to taurin (Roberts), it has been considered that the symptom is a sign of hepatic derangement, and Prout, remarking "the peculiar tallowy and waxy character of the complexion," so frequently noticed in these cases, and finding fatty matter in the urine, suggested it was the outcome of fatty liver. Clinically it has been found often to coexist with disorders of the hepatic functions. Thus it has been found in the Ever of typhoid patients, and is sometimes associated with jaundice and other symptoms of hepatic derangement. Virchow and Scherer have detected cystine iu diseased livers.
Dr. Dickinson mentions the case of a doctor, who had habitually passed cystine crystals in the urine. The patient, when Dr. Dickinson saw him, had extreme ascites with evidence of obstruction of the portal vein, which his eventual recovery indicated as thrombotic. He had frequent bilious attacks. A second attack apparently of portal thrombosis, more severe than the first and attended with hiematemesis profuse enough to endanger life, occurred twenty-four years after the commencement of cystinuria. During convalescence the cystine was observed to be unusually abundant. It was noted that bile was almost absent from the stools, the previous inactivity of the liver having been aggravated apparently by the sea air. No hereditary proclivity had been traced in this case.
Dr. Ralfe took the following view in 1885: " eystine is formed directly from taurin, iu a manner perhaps analogous to the forma tion of indigo from indol. The observations of Naunyn and Dragen dorff have shown that normal urine contains traces of bile acids, of which glycocholic acid is the chief, so that it is probable that some portion of the taurocholic acid is oxidized, and furnishes the partially oxidized sulphur product, which in minute quantities is always in normal urine. Moreover, Dr. Oliver has recently shown, by means
of his peptone test, that the bile acids are often enormously increased in the urine in many morbid conditions, especially those connected with functional derangements of the liver and ancemia (Lancet, April and May, 1885). It may be, therefore, that under certain conditions the quantity of taurin eliminated by the kidney is increased, or its excretion checked, while the transformation into unoxidized sulphur is incompletely carried out, so the intermediate product cystine is the result." Up to within a short time these various theories were accepted, but the recent researches into the intestinal ptomaines have thrown an unexpected and startling light upon the production of cystinuria, and although at present the views put forward cannot be accepted in their entirety, sufficient evidence is forthcoming to establish some casual relation between cystinuria and a form of intestinal mycosis of an infecting type.
Thus the researches of Stadthagen and Brieger, v. Udransky, and Baumann have shown that cystinuric urines contain diamines, and in particular putrescin, cadaverin, and a diamine which is isomeric with the latter (perhaps neuridin or saprin). These bodies occur at the same time in the feces of such patients, while both urine and faeces of healthy persons are free from them. It is pos sible, therefore, that they originate in a special form of intestinal infection, and are absorbed from the alimentary canal and eliminated together with cystine in the urine.