The ureter is the long muscular tube that serves as passageway for urine. It allows the urine to flow from the kidneys to the bladder.

Occlusion of the ureter means the ureter is blocked. This prevents the urine from flowing out of the body. Instead, it builds up behind the blockage. This can cause the kidneys to swell. It also increases the risk of permanent kidney damage.

The ureter has thick walls. Its diameter is more or less the same from top to bottom. However, it has areas that are more prone to blockage. These include the part where it crosses the inlet of the pelvic brim and where it enters the urinary bladder.

The condition is very common. It is treated by removing or bypassing the blocked part of the ureter to restore the normal flow of urine. Because the condition can be easily treated, severe complications are very rare.

Causes of Condition

The ureter can become blocked for a number of reasons. The problem can start inside the ureter. The ureter can also become narrowed when compressed by organs around it.

Some of the most common causes of the condition are:

  • Kidney stones and blood clots - Depending on their size, these can partially or totally block the flow of urine inside the ureter.

  • Certain medical procedures - These include a kidney transplant and cancer treatment to surrounding areas.

  • Congenital disorders - A person can be born with two ureters in the same kidney. In many cases, the first ureter works just fine while the other is only partially developed. The problem occurs if both ureters are not fully developed.

Other causes include:

  • Tumours - Abnormal growths in surrounding areas can compress the ureter. The same effect can be caused by pregnancy and when abdominal organs are inflamed.

  • Endometriosis - A condition in which the tissue that is often found in the uterus grows on the bladder. This can cause scar tissue to form around the ureter.

  • Severe constipation - In very rare cases, the condition is attributed to chronic severe constipation.

  • Swelling of the ureter wall - This is often caused by chronic diseases and infections.

Key Symptoms

The first signs of the condition are pain and the patient’s inability to completely empty his or her bladder. This often leads to chronic urinary tract infections (UTIs). There may also be blood in the urine. The severity of symptoms depends on the degree of blockage. It also depends on whether just one or both the ureters are affected. Unless the patient seeks treatment right away, the condition may progress and cause kidney damage.

Who to See and Types of Treatments Available

Diagnosing occlusion of the ureter starts with urine and blood tests. These can detect infection and if the kidneys are not working well. The flow of the urine from the kidneys to the bladder is also checked. Abnormal tests results are confirmed with imaging tests. Computed tomography (CT), magnetic resonance imaging (MRI), and renal nuclear scans are used to get clear images of the internal organs. These images can show if the ureter is blocked. They can also show the exact location of the blockage.

Surgeons have two goals when treating this condition. First is to remove the blockage to restore normal flow of urine. Second is to repair damage to the kidneys, if possible. Treatment starts by draining the fluid that has built up behind the blockage. This can be done by inserting a tube through the patient’s back. The doctor may also connect the bladder to an external drainage bag by inserting a tube through the urethra.

The next step is to treat the blockage through surgery. The procedure can be carried out by making an incision in the abdomen. This allows the surgeon to access the ureter and make the necessary repairs. However, these days, many surgeons prefer minimally invasive method using small incisions. This method can also be performed using robotic arms. This option allows surgeons to perform the procedure with more precision, control, and flexibility. This method reduces the many risks of open surgery. Because of this, patients are able to enjoy faster recovery time.

During surgery, the surgeon will focus on removing anything that blocks the ureter. These may include blood clots and kidney stones. The surgeon will then leave a stent in the treated area to keep it open.

The prognosis for patients depends on the cause, location, and degree of obstruction. Any delay in treatment can put the patients at risk of permanent kidney damage. Treatment for this condition is daily dialysis or a kidney transplant.


  • Gulmi FA, Felsen D, Vaughan ED. The pathophysiology of urinary tract obstruction. Walsh PC, Retik AB, eds. Campbell’s Urology. 7th ed. Philadephia, Pa: WB Saunders and Co; 1998. 342-385.

  • Thomas AW, Cannon A, Bartlett E, et al. The natural history of lower urinary tract dysfunction in men: minimum 10-year urodynamic follow-up of untreated bladder outlet obstruction. BJU Int. 2005 Dec. 96(9):1301-6.

  • Kidney failure: Choosing a treatment that’s right for you. National Institute of Diabetes and Digestive and Kidney Diseases.

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