Silicate renal calculi in Kenyan dogs

Renal calculi were detected in 124 (53%) of 241 native Kenyan dogs during a necropsy survey for Spirocerca lupi infection. Affected kidneys were grossly normal but histologically pyelitis was present in 33% of the dogs. Over 50% of the stones were bilateral. Most were small and yellowish, the largest one was 2.5 cm. One native dog had a cystic calculus that obstructed its bladder.
Chemical analysis of the calculi revealed only traces of magnesium and phosphate. Emission spectrum studies identified the calculi as magnesium calcium aluminum silicate.
Decreased water intake or increased insensitive water loss do not seem to be important causative factors. Silica levels in water and maize should be determined.