Upper urinary tract obstruction occurs when part of the ureter -- the tube that connects the kidney to the bladder -- becomes blocked and prevents the flow of urine. If urine backs up into one or both kidneys as a result of the blockage, the bean-shaped organ(s) can dilate (hydronephrosis) and, over time, lead to permanent kidney damage.
Upper tract obstructions can result for a variety of different reasons, and often vary by age. In children, the causes are most often congenital (present at birth), and include ureteroplevic junction abnormalities, ectopic ureters, or duplicated or duplex collecting systems. In adults, the condition can result from injury to urinary tract structures, kidney stones, or various types of cancers. Determining the underlying cause will help urologists know which treatment approach will work best.
Treatment for Congenital Causes of Upper-Tract Obstruction
In children, genetic malformations are the most common causes of upper urinary tract obstruction and are typically treated by using a number of different surgical procedures, including:
- Pyeloplasty: This procedure corrects structural abnormalities that block the junction between the ureter (a tube that carries urine from the kidney to the bladder) and renal pelvis (the uppermost part of the ureter where it connects to the kidney).
- Ureteropyelostomy: This approach corrects an ectopic ureter, which is one that terminates anywhere other than the bladder (e.g., the urethra or the vagina). In this procedure, part of the ectopic ureter is repositioned so that it connects, appropriately, to the lower part of the kidney and improves urine drainage from the kidney to the bladder.
- Nephrectomy: Like a ureteropyelostomy, a nephrectomy is also used to correct an ectopic ureter. In this procedure, the portion of the kidney that drains into the ectopic ureter is removed.
- Bladder Reconstruction Surgery: This surgery may be performed to help correct problems posed by a duplicated collecting system is present. A urinary tract typically includes two kidnesy, each with one ureter attached. A duplicated or duplex collecting system is when one or both kidneys have two ureters instead of one. While these systems are often perfectly functional, when one ureter drains the upper part of the kidney and the other drains the lower portion, the result can force urine to reflux back up the urinary tract. In these cases, bladder reconstruction surgery may be required to remove the abnormal ureter.
Treatment for Acquired Causes of Upper-Tract Obstruction
Acquired (non-inherited) causes of obstruction in adults can result from trauma to the urinary tract, kidney stones, enlarged prostate (also known as benign hyperplasia or BPH), or various cancers. Treatment varies based on the underlying condition impacting the patient, but may include:
- Stents: When a ureter has been traumatized or injured, dense scar tissue can form and cause an obstruction. Stents are thin tubes that are placed in the ureter to prop it open and improve the flow of urine from the kidneys.
- Nephrostomy tubes: These tubes are inserted directly into the kidney through incisions in the patient’s back. They can be used to bypass an obstruction caused by kidney stones, trauma, or scar tissue that develops in the ureter.
- Extracorporeal shock wave lithotripsy or ESWL: ESWL is used to treat kidney, bladder, and ureter stones that are 10 mm in diameter or smaller. This minimally invasive approach produces shock waves -- applied outside of the body (extracorporeally) -- to shatter the stone into smaller pieces that should be more easily passed through the ureter, bladder, and urethra. Once the stone is fragmented, the pieces are more easily able to pass through the urinary tract spontaneously. Although the procedure is effective, more than one treatment may be needed.
- Ureteroscopy: Ureteroscopy is used to remove stones that are stuck in the ureter. A slender viewing device called a ureteroscope is passed through the urethra and the bladder into the ureter to visualize the stone. Then, the urologist inserts a flexible basket into the ureter to capture and remove the stone. This procedure can be used in conjunction with ESWL to remove stone fragments that may not be capable of passing through the ureter on their own.
- Medications: When an enlarged prostate places pressure on the urethra, forcing it to narrow or close, medications can be used to reduce the gland's size and restore urine flow. Alpha-blockers such as tamsulosin (Flomax), alpha-reductase inhibitors such as finasteride (Proscar) and dutasteride (Avodart), or herbal therapies such as saw palmetto can all be used to treat enlarged prostate.
- Catheterization: Catheterization (inserting a tube directly into the bladder) helps prevent urine from backing up into the kidneys (hydronephrosis) and causing damage. In this procedure, the patient is taught how to guide a catheter from the urethra to the bladder in order to drain urine every six hours. This method works particularly well for patients who have an obstruction due to an enlarged prostate.
- Holmium laser enucleation of prostate (HoLEP): This procedure is also used to treat BPH. A holmium laser is passed through the urethra to vaporize part or all of the prostate, which alleviates constriction. the procedure has a minimal risk of bleeding and infection, but patients receiving this procedure will be required to stay in the hospital one to two days.
- Open prostatectomy: If the prostate is significantly larger than normal, an open prostatectomy may be needed. In this procedure, an incision is made in the abdomen to access and remove all or part of the prostate. The procedure requires general anesthesia and patients must remain in the hospital for several days following surgery.
- Chemotherapy, Radiation or Surgery: Various types of malignancies -- including uterine, bladder, kidney and cervical cancers -- can cause upper-tract obstruction if they press on or impede the urinary tract system. Treatments vary depending on cancer type, but may include chemotherapy, radiation, or surgery.
References
Benign prostatic hyperplasia. (2010). American Urological Association.
Jorres, A., Ronco, C., Kellum, J.A. (2010). Management of acute kidney problems. New York: Springer.
Management of ureteral calculi: Diagnosis and treatment recommendations. (2007). American Urological Association.
Obstructive uropathy. (2012). The Merck Manual.
Surgical management of stones. (2011). Urology Care Foundation.
