PYONEPHROSIS.
Suppuration involving the pelvis of the kidney, however produced, may, by obstruction of the ureter incidental to such a condition, lead to the dilatation of the kidney and its conversion into a pus-contain ing sac. As with hydronephrosis, a bag of fluid bounded by the capsule and its septa may be thus substituted for the natural organ.
A hyclronephrosis may become a pyonephrosis by the intercurrence of suppuration, and the causes of the former are among those of the latter. One or both kidneys may be involved in varying degrees, as we see in cases such as those of enlarged prostate with cystitis, and in the more advanced forms of urethral stricture. Of all the causes of pyonephrosis the presence of a calculus within the kidney is by far the most common, so much so that some have thought the term calculous pyelitis would be generally applicable. This, however, is not the case, as numerous examples of very extensive pyelitis and distention are the direct result of tubercular disease either in the kidney or its duct.
Instances occur where there can be no doubt the obstruction in the ureters and the pyelitis were directly due to the general invasion of the urinary organs with the gonorrhoeal bacteria. These represent some of the most acute forms of the disorder, and death not unfre quently happens from urmia.
The pent-up pus and urine in a pyouephrotic kidney will often escape intermittently along the ureter. Here the secretion in the first instance generally presents an acid reaction and is charged with pus which gradually falls to the bottom of the glass on standing for some time. When the matter cannot escape freely in this way, ulcera tion of the capsule may occur and the contents of the sac find their way in various directions, as through the loin, along the psoas muscle into the iliac fossa, under Poupart's ligament, or even into the cavity of the peritoneum. In some instances it has penetrated the diaphragm and escaped through the bronchi, while in others some part of the intestines has been opened into. Such are the numerous directions in which a vent may be found for an abscess of this nature when left to itself.
Ammoniacal decomposition of urine within the kidney may lead to the interior of this organ being largely encrusted by a soft, phos phatic, mortar-like substance which shows a tendency to adhere wherever the surface is rendered rough or uneven. Sir William
Roberts states that fibrous septa within the kidney are sometimes calcified, and he refers to an instance where in examining a specimen of this kind it was necessary to cut the kidney across with a saw. Microscopical examination of a portion showed the characters of true bone, though in a rudimentary state.
The early symptoms of this affection are those of pyelitis. Refer ence has already been made to the surgical conditions under which it most frequently occurs. From this point of view we are chiefly in terested, with the knowledge before us of what is likely to occur, in preventing obstructive disorders leading to such a state of disor ganization. Urethral strictures and prostatic enlargement furnish examples of causes most likely to produce these effects unless dealt with in good time by suitable measures. In some instances of this kind renal tumefaction can be discovered, and when in conjunction with this we have rigors and Variations in temperature the retention of pus is rendered probable. Some of these cases terminate in complete suppression of urine extending over three or four days before death occurs.
The most acute forms of suppurative pyelitis may be seen in con nection with the cystitis arising out of urethral obstruction, and require prompt treatment by perineal cystotomy with drainage, as referred to in the section relating to cystitis.
Where the case is of a less acute character and there is such an amount of renal tumefaction as to render dilatation with pus and urine likely, an exploration should he made. This is best done in the first instance with the aspirator needle from the loin, the surgeon being prepared, if evidence of pyonephrosis is afforded, to proceed to open the kidney for the purpose of digital exploration and drain age. In a certain proportion of cases where the disorder is not far advanced, though palpable enlargement of the organ has occurred, and the obstruction is removable either by the withdrawal of a calculus from the pelvis of the kidney or its spontaneous escape along the ureter, recovery after opening and drainage may occur. If, however, the kidney is completely disorganized, its removal should be pro ceeded with at once.