Urinary calculi in Limbang District.

THE causes and mechanisms of urolithiasis are even nowadays not well understood. An increased concentration of crystalloids in urine as happens, for· example, in dehydration is one of the factors frequently cited. Randall (1937) drew attention to the importance of urinary tract infections as an initiating factor, and proposed that some stones started off as a plaque-like precipitate on the mucosal surface of the renal papillae. Carr (1954) further pin-pointed the lymphatics as the primary site. Boyce et al., (l955) postulated that a fall in the concentration of "calcium-binding substances" which normally keep the calcium salts in solution, will cause stones to precipitate out. Boyce and Sulkin (1955) proposed uroproteins enter into linkage with crystalloids and salts are then precipitated into this mucoprotein matrix, with calculi as the end result.