Urine retention can lead to chronic infection and, if left unresolved, predispose the patient to renal calculi (urolithiasis or nephrolithiasis), pyelonephritis, and sepsis. Acute or chronic renal failure may develop secondary to renal obstruction (refer to chapter 27). If hydronephrosis has occurred due to large volumes of retained urine, renal insufficiency may develop and progress to renal failure