Definition:—Suppuration within the connective tissue which envelops the kidney.
Etiology:—The formation of a pus sac around the kidney may be due to consecutive inflammation of these tissues from nephritis, from pyelonephritis, or from suppurative inflammation of the appendix or other intestinal inflammation; from spinal caries, from hypatic or splenic abscess, from pelvic cellulitis, and in women from abscess of the tubes or ovaries. It may occur from contiguous, malignant or tubercular disease, or as a result of septic infection, or from severe protracted infectious fevers. Only occasionally does it occur as a result of local injury, from falls, severe muscular strain, blows or contusions. In some cases a definite cause is not discoverable.
Symptomatology:—A dull, throbbing pain, increased by motion or jarring, will be located over the diseased area. There may be some bulging and fluctuation, or occasionally the symptoms may resemble those of psoas abscess. At other times the pain may be extreme, of a darting or shooting character, and may extend down the inside of the thigh, or the skin may become numb and somewhat anesthetic. Pressure between the crest of the ilium and the ribs will induce tenderness and increased pain, and at times the skin over the diseased part may be tender, swollen and red. The legs are flexed with the patient lying upon the back to reduce muscular tension. The presence of fever depends upon the degree of absorption. Usually there are rigors, with irregular temperature. In pronounced cases the pus becomes icorous or exceedingly fetid, resulting in hectic fever. Accidental rupture will induce septic inflammation of the parts into which the pus escapes.
Diagnosis:—Local tenderness and swelling or bulging, with the inflammation of the skin, occurring without the extreme pain of obstruction of the ureters, the urine being free from pus, will suggest the local character of the difficulty, especially if constitutional symptoms of pus infection are present. If the fluctuation is comparatively superficial, an exploring needle may be introduced.
Prognosis:—This depends upon the depth of the abscess and upon the constitution of the patient. If superficial, it may be readily evacuated and irrigated. If deep, severe constitutional symptoms may result before a perfect diagnosis is made, or it may burrow or rupture and escape into other parts and produce septic inflammation, under which circumstances the prognosis is unfavorable.
Treatment:—The constitutional symptoms must be promptly met as indicated. These must not be neglected for the surgical measures. As early as possible the abscess should be opened and the cavity evacuated and irrigated and free drainage instituted. Those agents recommended elsewhere to antagonize the development of pus and to antidote within the blood the influence of septic absorption must be administered freely and persistently. Iron tonics and other stimulating restoratives must be freely given.