The ureter drains urine from the kidney into the bladder. Not simply a
tube, the ureter is an active organ that propels urine forward by muscular
action. It has a valve at its bottom end that prevents urine from flowing
backward into the kidney. Normally there is one ureter on each side of the
body for each kidney. However, among the many abnormalities of ureteral
development, duplication is quite common. Ureters may also be malformed in
a variety of ways—some harmful, others not.
There are many different types of ureter anomalies. Ureters can be
duplicated completely or partially, they can be in the wrong place, they
can be deformed, and they can end in the wrong place. The trouble these
abnormalities bring is directly related to their effect on the flow of
urine. As long as urine flows normally through them, and only in one
direction, no harm is done. A description of ureter anomalies follows.
Duplication of ureters is quite common, either in part or completely.
Kidneys are sometimes duplicated as well. Someone may have four kidneys
and four ureters or two kidneys, half of each drained by a separate
ureter, or a single kidney with two, three, or four ureters attached. As
long as urine can flow easily in the correct direction, such malformations
may never be detected. If, however, one of the ureters has a dead end, a
stricture or stenosis (narrowing), or a leaky ureterovesical valve
(between the ureter and bladder), infection is the likely result.
Stricture or stenosis of a ureter prevents urine from flowing freely.
Whenever flow is obstructed in the body—urine, bile, mucus, or any
other liquid—infection follows. Ureters can be obstructed anywhere
along their course, though the ureterovesical valve is the most common
A ureter may have an ectopic (out-of-place) orifice (opening): it may
enter the bladder, or even another structure, where it does not belong and
therefore lack an adequate valve to control reflux.
The primary ureter, or a duplicate, may not even reach the bladder, but
rather terminate in a dead end. Urine will stagnate there and eventually
A ureter can be perfectly normal but in the wrong place, such as behind
the vena cava (retrocaval ureter), the large vein in the middle of the
abdomen. In this case the ureter may be pinched by the vena cava so that
flow is hindered. Other abnormal locations may also lead to compression
and impaired flow.
Besides infection, urine that backs up causes the ureter and the kidney to
expand or dilate. Eventually, the kidney stops functioning because of the
back pressure. This condition is called hydronephrosis (a kidney swollen
The urogenital system is more likely than any other organ system to have
birth defects, and they can occur in endless variety. Congenital ureter
anomalies affect as many as one in every 160 individuals.
Causes and symptoms
In general, the causes of birth defects are multiple and often as of 2004
unknown. Furthermore, the precise cause of specific birth defects has only
rarely been identified. Such is the case with congenital ureteral
Practically the only symptom generated by ureteral abnormalities is
urinary tract infection. A lower tract infection, in the bladder, is
. In children it may cause
and systemic symptoms, but in adults it causes only cloudy, burning, and
frequent urine. Upper tract infections, by contrast, can be serious for
both adults and children, causing high fevers, back
, severe generalized discomfort, and even leading to kidney failure or
septicemia (infection spreading throughout the body by way of the blood
In rare cases, urine from an ectopic ureter will bypass the bladder and
dribble out of the bottom somewhere, through a natural orifice like the
vagina or a completely separate unnatural opening.
—Present at birth.
—Also called a contrast medium, this is usually a barium or
iodine dye that is injected into the area under investigation. The dye
makes the interior body parts more visible on an x-ray film.
—A diagnostic procedure in which a hollow lighted tube
(cystoscope) is used to look inside the bladder and the urethra.
—Out of place or located away from the normal position.
—A ureter that is located behind the vena cava blood vessel.
—A systemic infection due to the presence of bacteria and their
toxins in the bloodstream. Septicemia is sometimes called blood
—A sphincter (an opening controlled by a circular muscle),
located where the ureter enters the bladder, that keeps urine from
flowing backward toward the kidney.
—Refers to both the urinary system and the sexual organs, which
form together in the developing embryo.
Sometimes the recurring infections caused by flow abnormalities can be
treated with repeated and changing courses of
. Over time, the infecting germs develop resistance to most treatments,
especially the safer ones. If it can be done safely, it is better to
repair the defect surgically. Urologists have various approaches to urine
drainage that range from simply reimplanting a ureter into
the bladder, in such a way that an effective valve is created, to
building a new bladder out of a piece of bowel.
There are botanical and homeopathic treatments available for urinary tract
infection. None can take the place of correcting a problem that is
occurring because of a malformed or dysfunctional organ system. Once
correction of the cause is addressed and there is unimpeded flow of urine,
adequate fluid intake can contribute to prevention of future infections.
As long as damage to the kidneys from infection or back pressure has not
become significant, the surgical repair of troublesome ureteral defects
produces excellent long-term results in the great majority of cases.
Monitoring for recurrent infections is always a good idea, and occasional
checking of kidney function will detect hidden ongoing damage.
The cause of congenital ureter anomalies is not known. There is no
Colberg, John W. "Urologic Abnormalities of the Genitourinary
Tract." Chapter 21, section 16, in
, 21st ed. Edited by Colin D. Rudolph and Abraham M. Rudolph. New York:
McGraw-Hill, 2003, pp. 1735–39.
Joffre, F., et al.
Radiological Imaging of the Ureter.
Secaucus, NJ: Springer, 2003.
American Association of Clinical Urologists.
1111 N. Plaza Dr., Suite 550, Schaumberg, IL 60173. Web site:
"Congenital Ureter Anomalies."
Dr. Joseph F. Smith Medical Library.
Available online at
December 9, 2004).
Available online at
(accessed December 9, 2004).