Duplex Kidney Case

The occurrence of finding a duplex kidney (duplicated collecting system) is not uncommon. Duplicated collecting systems are almost always asymptomatic incidental findings. Duplication of a ureter might be partial or complete. The kidneys go through a complicated series before you are born. When one of those steps are missed or performed in an unusual manner it can cause an abnormality. We present a case for review in which the patient was experiencing flank pain that turned in to kidney stones lodged in a malrotated kidney with a complete duplicated collecting system. This condition was detected with the use of sonography and confirmed with computed tomography (CT), both are considered great diagnostic tools in diagnosing these conditions.
This patient had been experiencing a sudden onset of colicky right-sided flank pain, nausea, and hematuria for 3 days and her symptoms were not getting any better. She had a prior history of bilateral urolithiasis and had a bilateral ureteroscopy done earlier this year. An ultrasound was performed on the patient’s right side in which two small stones were discovered in the kidney. Both stones were measured, the largest approximately 2mm. The patient assumed she could pass the stones and thought no further evaluation was needed. Five days later, the patient came back to the department with bilateral flank pain. Another ultrasound was performed which confirmed that both kidneys measured normal in size, however this time kidney stones were present in both kidneys. The same two stones were still in the right kidney and a larger stone was discovered within the left kidney that measuring more than 8mm in length. Hydronephrosis was present in the left kidney along with an ureteropelvic junction (UPJ) obstruction. The ureteropelvic junction (UPJ) is where the kidney meets the ureter. While performing the ultrasound we noticed what appeared to be a moderate to severe case of hydronephrosis present in the left
It is more common in women than men and out of the 0.8%, it is bilateral in 20% of instances. In the fetus, ureteral development begins at four weeks starting with the ureteral bud. The ureteral buds determine the entire collecting system and branch off from the mesonephric duct. If two ureteral buds are formed, the inferior ureter drains the lower pole and the superior ureter drains the upper pole. The lower pole ureter will implant early causing a shorter submucosal tunnel and an association with vesicoureteral reflux. The upper pole ureters are more susceptible to obstruction if associated with ureteroceles or ectopic insertion. Duplication is believed to be autosomal dominant in inheritance with incomplete penetrance and have highest prevalence in Caucasian females (Cohen, 1976). Most patients remain asymptomatic, however, recurrent urinary tract infections, flank pain, incontinence, and hematuria can occur. These duplex systems are usually found incidentally on abdominal examinations or during surgery. Imaging modalities that may help identify this condition are ultrasound, nuclear medicine, intravenous urography, and CT. With this condition, the upper pole of the kidney is more likely to demonstrate hydronephrosis. The dilation can mimic the appearance of a simple renal cyst and can lead to diagnostic confusion. What can be done if the