Struvite stones in cats

Struvite stones, which are made up of magnesium-ammonium-phosphate, often lead to illness in cats.

A range of different reasons must be considered to determine the cause of struvite stones. One factor is very long intervals between urinating. Many cats urinate only once per day, for example, as they were originally desert animals and therefore their bodies are able to produce extremely concentrated urine. A further point is that the mineral content of the food is of decisive importance as it influences the pH-value of the cat’s urine. Values above 7.0 provide favourable conditions for stone formation. The often-cited magnesium content of food, or rather in the urine, is not the only cause for the formation of struvite stones.

Struvite stones can be dissolved by means of a special diet which lowers the urine pH to values of 6.2 - 6.5. In addition, the volume of urine must be raised through an increase in water consumption. If the cat does not eat the special diet, acidification of the urine can also be achieved through methionine and ammonium chloride although the urine pH must be consistently monitored. If struvite stones are already too big, however, removal by means of an operation is advisable.