A ureteral obstruction is a blockage in one or both of the tubes (ureters) that carry urine from your kidneys to your bladder. Ureteral obstruction can be curable. However, if it's not treated, symptoms can quickly move from mild — pain, fever and infection — to severe — loss of kidney function, sepsis and death.
Ureteral obstruction is fairly common. Because it's treatable, severe complications are rare.
Ureteral obstruction care at Mayo Clinic