Ureteropelvic Junction (UPJ) Obstruction

Ureteropelvic junction obstruction is a blockage where the kidney’s drainage tube meets the kidney, causing urine backup and potential kidney damage.

The kidneys filter your blood, removing waste. That waste is delivered as urine through a tube called the ureter, which takes the urine to the bladder.

When the connection between the ureter and the kidney (called the renal pelvis) becomes blocked, urine builds up in the kidneys. This buildup of urine can cause damage to the kidneys.

UPJ obstruction is most common in children, though it can also happen in adults. In children, UPJ obstruction is usually caused by a congenital problem (meaning you are born with it).

Learn more about UPJ obstruction, including its causes, symptoms, diagnosis, treatment, and potential risks and complications in both children and adults.

What is ureteropelvic junction (UPJ) obstruction?

UPJ obstruction is a congenital or acquired blockage at the ureteropelvic junction, where the kidney (renal) pelvis connects to the ureter. This obstruction prevents normal urine flow, leading to urine buildup in the kidney (hydronephrosis) and potential kidney damage if left untreated.

What causes of UPJ obstruction?

UPJ obstruction happens when the area where the ureter and renal pelvis becomes blocked. In children, this is often caused by congenital defects. A baby may be born with a birth defect that makes their ureter narrow or kinked. This blocks the flow of urine from the kidneys.

In adults, UPJ obstruction may be caused by the buildup of scar tissue in the area. This can happen as a result of previous surgery, infections, or kidney stones. Tumors or masses (including a renal mass) near the ureteropelvic junction can also cause compression or narrowing.

What are the symptoms of UPJ obstruction?

Symptoms of UPJ obstruction can vary in severity. In some cases, symptoms can come and go, rather than being constant. Symptoms may include:

• Abdominal mass: Palpable mass in the abdomen due to swollen kidney.
• Urinary tract infections (UTIs): Frequent infections due to impaired urine flow.
• Pain: Intermittent or constant abdominal or flank pain.
• Nausea and vomiting: Often associated with pain episodes.
• Hematuria: Presence of blood in urine, which can be visible or microscopic.
• Decreased kidney function: Signs of impaired kidney function if the obstruction is chronic.

How is UPJ obstruction diagnosed?

A health care provider may use a variety of tests to help diagnose UPJ obstruction. Tests and methods may include:

• Symptom assessment: Detailed inquiry about pain, urinary symptoms, and any history of infections or kidney stones.
• Medical history: Review of any related medical conditions, previous surgeries, or urinary abnormalities.
• Physical examination: Palpation of the abdomen to detect masses or tenderness.
• Ultrasound: Initial imaging modality to detect hydronephrosis and assess kidney structure.
• CT scan: Detailed imaging to confirm obstruction and evaluate the extent of hydronephrosis and kidney condition.
• Diuretic renography: Nuclear scan to assess kidney function and the degree of obstruction by measuring how urine flows from the kidneys.
• MRI/ MR urography: Advanced imaging to visualize the urinary tract and assess for obstruction.
• Voiding cystourethrogram (VCUG): X-ray study with contrast to evaluate the bladder and urethra, particularly useful in children to rule out vesicoureteral reflux.
• Intravenous pyelogram (IVP): X-ray imaging with contrast dye to visualize the kidneys, ureters, and bladder, showing abnormalities in urine flow.

How is UPJ obstruction treated?

Some UPJ obstructions in infants may improve without treatment. A health care provider may use regular ultrasounds to monitor the ureteropelvic junction obstruction during the first 18 months. If the condition does not improve on its own, surgery may be needed.

Treatment for UPJ obstruction requires surgery.

The primary surgical treatment for UPJ obstruction is pyeloplasty. During this procedure, a urologist removes the obstruction and reattaches the ureter to the kidney. Pyeloplasty can be performed as open, laparoscopic, or robotic surgery, depending on the situation.

Another procedure, called endopyelotomy, uses an endoscope to widen the narrow area of the UPJ. This usually involves using a stent to help drain the area for a short period to help with healing.

Medicine may also be used to manage pain from UPJ obstruction and treat or prevent UTIs.

Post-operative care

• Monitoring: Close monitoring for signs of infection, healing of the surgical site, and overall kidney function.
• Stent management: Temporary stent placement to ensure proper healing and urine flow, with subsequent removal in a few weeks.
• Follow-up imaging: Regular ultrasounds and renography to ensure resolution of the obstruction and normal kidney function.

Potential risks and complications

Complications of untreated UPJ obstruction

• Progressive kidney damage: Chronic obstruction can lead to kidney dysfunction and loss of kidney function (renal failure).
• Recurrent infections: Ongoing urinary tract infections increasing the risk of kidney damage.
• Stones formation: Stasis of urine can lead to the formation of kidney stones.

Long-term considerations

• Monitoring kidney function: Regular follow-up with kidney function tests and imaging studies.
• Management of underlying conditions: Ongoing treatment of any underlying conditions contributing to UPJ obstruction.
• Lifestyle adaptations: Dietary modifications and hydration to support kidney health and prevent stone formation.
• Strictures: Scar tissue formation leading to re-obstruction.

Impact on quality of life

• Physical comfort: Effective treatment can alleviate symptoms and prevent further kidney damage, significantly improving daily functioning and comfort.
• Emotional support: Providing counseling and support to address anxiety, depression, and the psychological impact of living with UPJ obstruction or undergoing treatment.
• Lifestyle freedom: Increased confidence and independence in engaging in work, hobbies, and social activities.

Ureteropelvic junction (UPJ) obstruction is a condition that can significantly impact kidney function and quality of life if left untreated. Early diagnosis and appropriate intervention are crucial for preventing complications and improving outcomes. Understanding the causes, symptoms, diagnostic methods, and treatment options is essential for effective management. If you or a loved one is experiencing symptoms of UPJ obstruction, consulting with a health care provider and a specialized urologist will help develop a comprehensive treatment plan tailored to your specific needs and circumstances.