DISTRIBUTION OF THE DISEASE.—By far the largest majority of instances of the disease originate in tropical and subtropical climates. Thus, India, China, and South America—and in South America, Brazil, and Guiana—are countries in which it is common. It is said to be rarer on the coast of South America than in the interior; yet it is especially partial to insular countries, and most of the cases observed in this country originate in the West Indies—in Barbadoes and Cuba, in Bermuda and the island of Trinidad. Many cases occur in Bahia, Guadeloupe, Madagascar, the Isle of Bourbon, and Mauritius. Indeed, the first important study of the subject was based on cases observed in the latter island by Chapotin.2 In Africa both Egypt and the Cape of Good Hope are favorite localities, and in Australia, Brisbane has furnished many cases.
2 Thèse, Topographie médicale de l'Ile de France, 1812.
At the same time, cases do originate in temperate climates, and although the disease is rare in Europe and North America, Dickinson has collected five cases from his own practice or that of others, which undoubtedly originated in England. I know of but one case of certain North American origin, that of a woman reported by McConnell to the Medico-Chirurgical Society of Montreal, April 27, 1883. She was thirty-three years old, a native of the province of Ontario, and had had the disease eleven years. At the time of her death, which appears to have been from tubercular phthisis, there were cavities in the apices of both lungs.
SUBJECT'S ATTACKED.—There seems no election as to nativity, natives and foreigners being indiscriminately attacked in the countries in which it occurs. There is some difference of opinion as to whether the disease is more frequent in males or females; which is a reason for believing that it occurs with nearly equal frequency in both.
It is more common in middle life, but Prout reports an instance in a child eighteen months old, and Rayer one in a woman at seventy-eight years. She had had it, however, since she was twenty-five, or about fifty-three years. Dickinson was consulted with regard to a boy of five, and mentions a case fatal at twelve. Roberts says: "Chylous urine prevails mostly in youth and middle age."3 Of 30 cases collected by him, 3 were under twenty; 7 between twenty and thirty; 11 between thirty and forty; 6 between forty and fifty; and 3 over fifty.
3 Urinary and Renal Diseases, 4th ed., Philada., 1885, p. 344.
The subjects of the disease are apt to be pale and relaxed as to their tissues, but while this may be a possible result of the disease, it can hardly be regarded as a predisposing cause.
PATHOLOGY AND ETIOLOGY.—The precise mode in which chyluria is brought about is unknown. It is to be inferred, in view of our existing knowledge, that there has been produced, in some way, in each instance a communication between the urinary and chyliferous systems, although exactly where such communication is has as yet only been guessed at. It may be in the kidney itself, or its pelvis, or the ureter, or in the bladder. Cases originating in the tropics have been found associated with elephantiasis, but this is not very frequent. Dilatation of cutaneous lymphatics, producing cutaneous papules and vesicles and a discharge of lymph from them, has also been noted coincident with chyluria.
Prout,4 among the earlier writers on this subject, and more recently Bence Jones,5 Waters, Bouchardat, Robin, Bernard, and Egel, did not consider a positive lesion necessary, but ascribed the condition to a vice of nutrition and blood-making, accompanied by a slight consequent textural alteration in the blood-vessels of the kidney, through which the elements of the chyle transuded. Waters6 says that "the main pathological feature of the complaint is a relaxed condition of the capillaries of the kidney," which permits the transudation.