Bilateral Staghorn Calculi

A roentgenogram of the kidneys, ureter, and bladder of a 58-year-old man shows bilateral stones in the renal pelvis and the renal calyces. The patient had a history of recurrent urinary tract infections caused by Proteus mirabilis. A ureteral catheter (pigtail) had been placed in the pelvis of the left kidney to facilitate drainage.

Drs Demetrios Papaioannides, Aphrodite Vlachopanou, Demetrios Cyrochristos, and Christos Tatsis of Arta, Greece, write that the calculi were triple-phosphate stones-composed of calcium, ammonium, and magnesium phosphate. These stones are caused by the action of bacteria; the culprit may be Proteus, Klebsiella, Enterobacter, or Pseudomonas species. The infective organism produces the enzyme urease, which splits urea to form ammonium ions, thus rendering the urine alkaline. The bacteria are found within the interstices of the stone crystals; therefore, the infection is very difficult to eradicate, and the rate of recurrence is high.

In this setting, recurrent pyelonephritis is common. The patient usually does not complain of pain, but loin ache may be present. The stones grow rapidly and fill in, or make an internal cast of, the renal collecting system. Injury to the kidneys is caused by obstruction, local infection, and infection of the renal parenchyma.

A nephrectomy is indicated for the patient with a unilateral stone whose renogram shows very poor function. Avoid nephrectomy in patients with bilateral disease. Open surgical removal is the best option for treatment of complete staghorn calculi.