Tuberculosis Of The Kidney may be due to primary hematogenic infection, in which case the condition is usually unilateral, or to secondary involvement following similar disease of other portions of the genito-urinary tract. It may be a part of a general miliary tuberculosis and present numerous minute grayish white tubercles scattered throughout the renal substance, particularly in the cortex. The foci may be surrounded by a narrow zone of congestion.

When there has been an ascending infection from the ureters or a primary local tuberculosis the changes are quite characteristic. The process may begin as a miliary tubercle, which by invasion and lymphatic extension spreads through the organ. The apices of the pyramids are involved and the disease extends through them to the cortex. These areas undergo coagulation necrosis, soften, and eventually discharge their contents into the pelvis of the kidneys, leaving an irregular cavity. On section there are seen numerous large cavities communicating with the pelvis of the kidney. The discharged material infects the mucous covering of the pelvis and the disease gradually extends downward along the ureter until the entire urinary tract may be involved. This, of course, when the tuberculosis has been primary in character and not due to an ascending infection. The ureter may become obstructed, and the kidney undergo dilatation, thus forming a cold abscess of the kidney, the organ being changed into a sac with thick walls and containing tuberculous pus.

Fig. 169. - Tuberculous Pyelonephritis ( modified from Bollinger).

Syphilis is infrequent and not definite in its manifestations.

There have been found gumma giving rise to thick stellate scars.