A pelvic kidney is a congenital condition where a kidney is located in the pelvis rather than its usual position in the upper abdomen. This anatomical variation, also known as simple renal ectopia, occurs because the kidney failed to complete its upward movement during fetal development. Although present at birth, it is usually an isolated finding. For many individuals, a pelvic kidney does not cause symptoms and is discovered incidentally later in life.
Defining the Anatomical Anomaly
The kidneys develop in the pelvis during early fetal growth. They normally “ascend” to their final location in the upper abdomen by about the ninth week of gestation. A pelvic kidney results when this upward migration fails entirely, leaving the organ near the brim of the pelvis.
The reasons for this failure are not fully understood, but it is thought to be related to an interruption in the normal developmental process. This might involve issues with the blood vessels supplying the kidney or factors that physically block its movement. Although the location is anomalous, the kidney itself is structurally normal and functions properly in most cases.
The pelvic kidney often exhibits a different orientation and is supplied by multiple, shorter blood vessels branching off nearby arteries. Its lower position means the ureter, the tube that carries urine to the bladder, is also shorter than usual. This condition affects approximately 1 in 1,000 to 2,500 people and is most often unilateral, meaning only one kidney is misplaced.
How a Pelvic Kidney is Detected
The diagnosis of a pelvic kidney is frequently made incidentally, as the condition often remains asymptomatic. The most common time for detection is during a routine prenatal ultrasound around the 20th week of pregnancy, where a sonographer may notice the kidney’s unusual location.
If not found before birth, the condition is often discovered later when a person undergoes imaging for an unrelated issue, such as abdominal pain or gynecological concerns. Tests like a computed tomography (CT) scan, magnetic resonance imaging (MRI), or an abdominal ultrasound can reveal the misplaced organ. The kidney may also be found when a person presents with symptoms related to a complication, such as a urinary tract infection (UTI) or kidney stones.
If an initial ultrasound is inconclusive, a radionuclide scan may be used to evaluate the anatomy and functional capability. For children, a voiding cystourethrography (VCUG) may be performed to check for vesicoureteric reflux, a backflow of urine sometimes associated with the condition.
Monitoring and Management Strategies
Management involves observation and regular monitoring if the kidney is functioning well and causing no symptoms. Since the condition is benign, treatment is reserved for when complications arise. Long-term follow-up with a specialist, such as a pediatric nephrologist or urologist, is recommended to track the kidney’s health.
The unusual position slightly increases the risk of certain health issues due to the altered anatomy. People with a pelvic kidney may develop UTIs, kidney stones, or hydronephrosis (swelling due to blocked urine flow). These complications are caused by the shorter, sometimes kinked ureter or the kidney’s altered rotation, which impairs proper urine drainage.
If complications occur, treatment focuses on resolving the specific issue. Antibiotics are used for infections, and non-surgical procedures are employed for kidney stones. Surgical intervention is rare, reserved only for severe complications like complete ureter blockage or recurrent infections. Specialists may recommend protective gear for children during high-impact sports to safeguard the exposed kidney.