Urothelial microvascular response to chronic renal inflammatory disease

Renal pelvocaliceal mucosal opacification has been observed clinically in patients with inflammatory disease. We studied the microvascular changes that might be responsible for this finding using barium injection and microradiographic studies of 20 human kidneys excised due to infection. There were six patients with staghorn calculi and chronic pyelonephritis, four with pyohydronephrosis, eight with acute and chronic pyelonephritis, and two with xanthogranulomatous pyelonephritis. The microangiograms correlated with severity of inflammation. In mild cases, slight vessel hypertrophy involved the terminal arterioles and arteries supplying the urothelium. In severe cases, there was marked neovascularity with feeding vessel hypertrophy and mucosal thickening. Our studies demonstrate that abnormal pelvocaliceal vascularity is responsible for the findings seen on urography and angiography of inflammatory disease.