[Typical annual course of urolithiasis in relation to the chemical structure of the concrements (author's transl)].

Urolithiasis is seen in our region throughout the year as a periodic appearing disease with peaks not only in summer, but also--somewhat lower--in January, April and October. This appearance is especially caused by the calcium oxalate stones. Uric acid calculi show a rise between May and October. The magnesium ammonium phosphate stones appear almost completely irregular.