Struvite and Staghorn Stones:  Urinary infections associated with kidney stones can be a difficult and important problem to treat.  Certain types of infections cause the development of kidney stones.  These infections produce an enzyme called urease.  This enzyme causes the urine pH to increase favoring the formation of magnesium ammonium phosphate (struvite) crystals.  Some calcium crystals can also form.  Frequently large, difficult to treat staghorn stones develop.  The infections are impossible to eradicate with antibiotics alone.  Some of the bacteria can live deep in the stone, where antibiotics cannot penetrate.  Therefore, the stone(s) often need surgical removal with concomitant antibiotic treatment.  The key to eradicating the infection is surgical removal of the entire stone with few if any fragments left behind.  Lithotripsy alone is often ineffective.

Although men have more kidney stones,  women are more likely to develop urinary infections and struvite stones.  Certain bladder disorders are associated with chronic bladder infections and struvite stones.  Also, people who have had bladder removal and ureteral diversion are more likely to develop urinary infections.

Urinary Infections Complicating Kidney Stones: Although some chronic urinary infections can cause stones, the opposite is also true.  Stones can lead to chronic urinary infections.  If someone with a stone develops a kidney infection, the stone can become secondarily infected.  The bacteria can reach deep pockets within the stone that make eradication difficult or impossible.  Sometimes long term antibiotic therapy is necessary.  Any patient with pre-existing kidney stones who develops a urinary infection must be effectively treated.