INFRARED SPECTROMETRIC ANALYSIS OF ENDEMIC BLADDER STONES IN NIGER

The composition of 42 bladder stones from young children in Niger has been determined by infrared spectrometry. Nucleus and subsequent layer s were analyzed separately. The major constituents of the stones were ammonium acid urate (AAU) and calcium oxalate monohydrate (COM). The n ucleus consisted of nearly pure AAU in 17 stones (40%) and it was foun d to be the major constituent of the nucleus in 8 other stones (19%). Furthermore, it was present as a minor constituent of the center in an other 9 stones (21%). In only 3 calculi (7%) the nucleus consisted of pure COM. This study suggests that (a) AAU is the initiating material for nucleation in this stone type in Niger, and (b) the incidence of e ndemic bladder stone disease is higher in Africa than previously repor ted.