Pyonephrosis.
—As a condition this is to be distinguished from ordinary abscess of the kidney, in that it implies the retention in the renal cavity or pelvis of pus with eventual destruction of kidney tissue. In other words it is an empyema rather than an abscess. It results from septic or tuberculous invasion, plus ureteral obstruction, regardless of the obstructing cause, e. g., calculus, plugs of mucus, stricture, kinking of ureter, or extrinsic tumor causing pressure. Occlusion may be so complete that no urine escapes from the affected kidney, while that from the other is clear, or the phenomenon may be intermittent. There results more or less enlargement and often great dilatation of the diseased kidney. Pus thus retained has been known to be discharged into the intestine or even into the lung. Spontaneous recovery is rare. Aspiration from the back in these cases is proper for diagnostic purposes.
Treatment.
—Pyonephrosis, like any other collection of pus, calls for incision (nephrotomy) and drainage, with removal of any possible foreign body, such as calculus. If the entire kidney be found destroyed, or so compromised as to jeopard its future, a nephrectomy may be done at once, while it may be a secondary measure in cases of permanent urinary fistula following drainage. So, too, if the kidney be found tuberculous, it is better to remove it than to temporize.
Perinephritis.
—To pus formed in a perirenal phlegmon is given the term perinephritic abscess; this is sometimes due to external or penetrating injuries; sometimes it appears as a primary condition difficult of explanation; but it usually follows inflammation of adjacent structures, such as the kidney itself (tuberculous pyelitis), the liver, the colon, and the appendix. While perinephritis usually terminates by suppuration, spontaneous recovery, with more or less absorption of exudate, is known to occur. These perinephritic collections sometimes attain enormous size, and are then sure to migrate, always along lines of least resistance, which takes them usually downward, either toward the loin or the groin. I once tapped below Poupart’s ligament a collection which exceeded a gallon. These abscesses may also, more rarely, burst into any of the adjoining cavities, and discharge either by the mouth, bowel, or bladder, or even externally.
Symptoms.
—In addition to the usual systemic indications of the presence of pus there may be tumor in the lumbar region, sometimes with distinct fluctuation, usually with rigidity of the lumbar and psoas muscles, perhaps even contractions of the thigh muscles which may simulate hip disease. These abscesses have been mistaken for peri-appendical phlegmons. If necessary to establish the presence of pus the exploring syringe may be used, but this is rarely necessary.
Treatment.
—While in the early stages the local application of guaiacol may be of use, every collection of pus thus formed here, as well as elsewhere, needs evacuation and drainage. This latter is to be provided by opening through the loin, in order that gravitation in the dorsal position may be of greatest assistance. A more or less free incision, such as is made for exploring or removing the kidney, will usually be sufficient, but may be combined with a counteropening at any point where the latter would be of advantage. Thus should pus present in the groin an opening should be made both posteriorly and at the point where it appears to be coming toward the surface.