Medical management of renal lithiasis; increasing the protective urinary colloids with hyaluronidase.

Urine is a highly saturated solution due to the presence of certain colloids. The protective action of urinary colloids is of major importance in preventing precipitation, agglomeration and conglomeration of crystalloids from a super-saturated solution. If the concentration of such protective colloids is insufficient, stone formation begins or is accelerated. In 680 human subjects, the incidence of stone was found to be almost inversely proportional to the degree of protective urinary colloids present. Urine specimens were subjected to ultramicroscopic examination, determination of electric charge carried by the colloidal particles, determination of the surface tension, and photo-ultramicrographic studies. Subcutaneous injection of hyaluronidase mixed with physiologic saline solution greatly increases the content of protective colloids in the urine. The colloids are caused to set up to a gel, thereby preventing electrolytes present from crystallizing. They act as excellent dispersing agents and prevent the formation of stone. Hyaluronidase therapy, using 150 turbidity reducing units every 24 to 72 hours, was effective in preventing calculous formation or reformation during a period of 11 to 14 months in 18 of 20 patients in whom, previously, stones formed rapidly. In a second series of ten patients in whom stones formed rapidly, larger doses of hyaluronidase, averaging 300 turbidity reducing units every 24 to 48 hours, were given. The period of observation at the time of report was from six to ten months. In this group, there was no new stone formation or enlargement of existing stones as evidenced by x-ray studies at 30- to 60-day intervals.