Ureteropelvic junction (UPJ) obstruction is a condition affecting the urinary system, where a blockage occurs at the connection between the kidney’s renal pelvis and the ureter. This obstruction hinders the normal flow of urine from the kidney to the bladder, causing it to accumulate within the kidney. Such a buildup can lead to kidney swelling, known as hydronephrosis, and potentially impair kidney function over time.
What is UPJ Obstruction?
The ureteropelvic junction (UPJ) is the funnel-shaped area within the kidney where urine collects before draining into the ureter. An obstruction at this junction means the pathway for urine drainage is narrowed or completely blocked, impeding its passage. This can lead to a backup of urine, causing the renal pelvis to expand and the kidney to swell.
While UPJ obstruction is often present at birth, termed congenital, it may not be diagnosed until adulthood. Acquired causes in adults include the formation of scar tissue from previous surgeries or inflammation, which can narrow the junction. Kidney stones, if they become lodged at the UPJ, can also create an obstruction. Additionally, trauma to the area or compression of the ureter by an abnormally positioned blood vessel can restrict urine drainage.
Recognizing the Symptoms
Adults with UPJ obstruction may experience a variety of symptoms, though some individuals have no noticeable signs. A common complaint is chronic or intermittent flank pain, which is pain in the side of the lower back or abdomen. This pain often intensifies with increased fluid intake, as the kidney struggles to drain the extra urine.
Other indicators include recurrent urinary tract infections (UTIs) due to the stagnant urine providing a breeding ground for bacteria. Hematuria, or blood in the urine, may also occur. In some instances, a palpable mass might be felt in the abdomen, representing the enlarged, swollen kidney. If left unaddressed, decreased kidney function can develop over time.
Diagnosing the Condition
Diagnosing UPJ obstruction typically begins with a thorough medical history review and a physical examination. Initial laboratory tests often include a urinalysis and urine culture to check for infection or blood. Blood tests are also performed to evaluate kidney function by measuring levels such as creatinine and blood urea nitrogen (BUN).
Imaging studies play a central role in confirming the diagnosis and determining the extent of the obstruction. An ultrasound is often used as an initial screening tool to visualize the kidney and detect hydronephrosis. A computed tomography (CT) scan provides detailed cross-sectional images of the kidneys, ureters, and bladder. Magnetic resonance imaging (MRI) offers another detailed view of the urinary tract structures. A diuretic renal scan, such as a Lasix renal scan or MAG3 scan, is a nuclear medicine test that assesses kidney function and precisely measures urine flow to confirm the blockage’s presence and severity.
Treatment Options and Recovery
For symptomatic UPJ obstruction in adults, surgical intervention is typically the primary treatment. The most common surgical procedure is pyeloplasty, which involves reconstructing the ureteropelvic junction to allow for proper urine drainage. This surgery aims to remove the blocked or narrowed section and reattach the healthy ends of the ureter and renal pelvis.
Pyeloplasty can be performed through various approaches. Open surgery involves a larger incision, while minimally invasive techniques such as laparoscopic pyeloplasty and robotic-assisted laparoscopic pyeloplasty are frequently utilized. These minimally invasive methods generally result in smaller incisions, reduced hospital stays, less pain, and quicker recovery times. Less common or temporary interventions, like stent placement or balloon dilation, might be considered in specific circumstances.
Post-operative care typically involves managing pain and ensuring proper healing. A ureteral stent may be placed temporarily to support the healing junction and facilitate urine drainage, usually removed a few weeks after surgery. Recovery timelines vary, but many individuals can return to normal activities within a few weeks to a couple of months. The long-term prognosis for kidney function after successful pyeloplasty is generally favorable.