In this condition there is added to the infective pyelitis and pyelone phritis an obstruction of the ureter more or less complete which prevents the discharge of the pus into the bladder. Though complete obstruction existed, the purulent contents of the sac or renal tumour have been known to dry up, and become inspissated and shrivelled so as to form a harmless membranous bag. It is nevertheless unwise to count upon such a possibility owing to the risks of general sepsis or of the rupture of the sac, and operative interference should not be delayed.
A free incision having been made in the loin (as for nephrolithotomy) from the outer edge of the erector spin extending downwards and forwards to the anterior superior iliac spine, the kidney is freely exposed and incised so as to permit free evacuation of the collected pus. The finger is thrust into the renal pelvis and the entire organ carefully palpated for calculi, which, if present, should be removed through the incised wound in the organ. A sound is passed down the entrance to the ureter, and
if a stone is found there it may be displaced upwards by manipulation and removed through the renal pelvis. The suppurating cavity in the interior of the kidney is next freely irrigated by hot Boric Solution, dusted with Iodoform and thoroughly drained. Should the kidney be found extensively destroyed by the pressure of the purulent secretion, nephrectomy is certainly preferable to nephrotomy, and when the sac fails to shrivel and the pus continues to be secreted after the operation of nephrotomy, the major operation should be resorted to and the diseased sac entirely removed, provided the opposite kidney is able to function sufficiently. In some cases it may be necessary to perform a double nephrotomy and drain both kidneys from the loin. Under Hydronephrosis the treatment of non-purulent collections of fluid in the kidney caused by obstruction of the ureter is detailed.