[Horseshoe kidney: not a simple fusion anomaly]

The horseshoe kidney is a congenital anatomical defect of the kidney that occurs in 0,25% of the population and is generally characterized by the fusion of the lower poles of the two kidneys through an isthmus and to which may be associated with urogenital and renal vascular anomalies. Asymptomatic in 1/3 of the cases and, most of time, accidentally discovered during a radiological examination, promotes nephrolithiasis, ureteropelvic junction obstruction, hydronephrosis, vesicoureteral reflux and pyelonephritis. We report two cases of patients with kidney horseshoe, characterized by the abrupt onset of a septic state with oligo-anuric acute renal failure, electrolyte and acid-base abnormalities, rapid decay of the general conditions, with detection of nephrolithiasis, hydronephrosis and acute pyelonephritis and whose clinical management resulted in a significant and synergistic nefro-urology involvment. The kidney horseshoe not represent so only a simple fusion anomaly but rather an important anatomical condition that, once diagnosed, it would be worthy of a careful clinical, radiological and laboratory surveillance, in order to prevent the potential complications that may be also particularly severe.