Severe renal hemorrhage caused by pyelonephritis in 7 horses: Clinical andultrasonographic evaluation

Case records of 7 horses diagnosed with pyelonephritis were reviewed to det ermine common features that might aid in diagnosis, treatment, and prognosi s of this disease. All 7 horses had been admitted for evaluation of hematur ia. During cystoscopy of 5 horses, hemorrhage was observed from one or both ureters. Renal biopsy of 1 horse, laboratory analysis of ureteral discharg e of 2 horses, and renal ultrasonography of all horses indicated that pyelo nephritis was the cause of hemorrhage. Sonographic renal changes included d ecreased length, increased echogenicity, abnormal outline, loss of corticom edullary distinction, pyelectasia, and focal hypoechoic or hyperechoic cort ical defects. Renal hemorrhage in all horses eventually resolved but recurr ed in 4 of 5 horses that were followed long-term.