HYDATID OF THE KIDNEY.
Cysts of this kind connected with the kidney are of comparatively rare occurrence, and are more frequently met with in other parts of the body. As Thomas" observes, "it is generally found to exist with greater or less frequency wherever man and his faithful friend and companion, the dog, are associated. It has been met with in Europe, Asia, Africa, worth and South America, and in all the col onies of Australasia; while chilly Iceland and sunny Australia vie with each other in offering this unwelcome immigrant a congenial home." As to its prevalence in America Dr. William Osler," of Bal timore, observes : " In this section of the country it is rarely met with, and in the inspection of over 800 bodies only three instances have been found." So far as the kidney is concerned, in a recent article by Dr. William Gardner," of Melbourne, it is stated: "In Davaine's collection of 566 cases of echinococcus disease, observed in man, 30, or 5.3 per cent, occurred in the kidney. The left kidney is found to be much more frequently the seat of the disease than the right, and men are twice as often attacked as women. Out of 68 cases collected by Berand 48 opened into the pelvis of the kidney, with the develop ment in some cases of pyelitis." The frequency with which kidney hydatids communicate with some part of the urinary passages, and are thus voided, is a matter of general observation. In this way a spontaneous cure is sometimes brought about and the precise nature of the disorder may pass unno ticed. This may to some extent explain the supposed rarity of renal infection. In a case I have elsewhere referred to, which came under my notice, it was for some time supposed that the woman was suffer ing from renal calculus until the urine was examined by the micro scope and the parasite detected.
When small, hydatids of the kidney may occasion no symptoms, these being for the most part due either to the rupture of the cyst and the discharge of its contents into the pelvis of the viscus, or to the pressure exercised on the organ by the increasing dimensions of the growth. This increase has sometimes become so considerable as to interfere with the function of the part, thus leading to a compensa tory hypertrophy in the opposite organ. Again it has been noticed
that an hydatid of the kidney has led to a mobility of the organ for which an operation has become necessary, and thus the parasite has been accidentally discovered. An hydatid involving the kidney can sometimes be distinguished, on manipulation, by a characteristic fremitus or kind of friction-feel. This is not always recognizable, and its absence has therefore but little significance.
The most trustworthy method of diagnosis is that obtained by the exploring trocar, which permits of the withdrawal of some of the fluid contents and the recognition of the characteristic hooklets by the microscope. By the detection of these distinguishing products in the forces I was able, in a case referred to under the section on hydro nephrosis, to diagnose a pelvic hydatid of considerable standing. It must, however, he remembered that the introduction of a very fine trocar and cannula into an hydatid cannot invariably be done with impunity, and when this method of diagnosis has necessarily to be adopted the surgeon should be prepared with all the appliances for at once proceeding with whatever radical measure may be selected. Gardner '° observes : "Simple puncture, although generally devoid of risk, has been known to cause sudden death, sometimes apparently from shock. The objection to puncture as the mode of treatment for internal hydatids, however, lies less in the occasional perils of the operation than in its frequent inefficacy." It has been stated that these symptoms are due to the poisonous nature of the contents of these cysts and their absorption, but I do not think there is sufficient proof of this.
Hydatid cysts sometimes assume a considerable size. In one case operated upon by Spiegelberg," a woman, aged forty-two, had a retro peritoneal echinococcus cyst connected with the omentum, the large and small intestines, and the right kidney, which was mistaken for an ovarian cyst; the fibrous capsule and a portion of the right kidney were removed. The patient died twenty-six hours after the opera tion.