Is It Air or Fat? Chyluria as the Lesser Known Cause of Dark Fluid Levels within the Urinary System

Chyluria is caused by the development of the reno-lymphatic fistula leading to reflux of chyle in urine. The most common cause of chyluria is a parasitic infection, especially lymphatic filariasis; however, rarely chronic renal infections like tuberculosis can also cause chyluria. The presence of fat fluid level in the pelvicalyceal system, perinephric, retroperitoneal collections and in the urinary bladder on CT scan in a case of chronic pyelonephritis is an important indicator of the presence of the reno-lymphatic fistula. We describe clinical picture and CT images of a patient with chyluria showing fat fluid in abdominal collections.