A 25-year-old female presented with a 2-day history of right-sided abdominal pain, nausea and vomiting. She had multiple emergency department visits for lower back pain for the last 3 years. CT scan of abdomen showed right advanced chronic hydronephrosis secondary to ureteropelvic junction (UPJ) stenosis. Labs revealed normal renal functions. UPJ stenosis was found to be chronic on further review of prior CT scan done approximately 1 year ago. She underwent nuclear MAG3 renal scan which showed obstructed right kidney with 35% functioning. CT with contrast showed right aberrant renal artery supplying the lower pole of the right kidney crossing over and causing UPJ stenosis. Surgical pyeloplasty was planned.
Discussion:
The symptom of vascular UPJ obstruction may include colicky mid-abdominal pain, nausea and vomiting. Early hydronephrosis can be subtle and lead to delayed diagnosis with potential loss of renal functions. Patients can be mislabeled as drug-seeking. This patient had chronic back pain for many years which could be due to the aberrant renal artery causing UPJ stenosis.
Conclusions:
Ureteropelvic junction (UPJ) obstruction is usually intrinsic and is most common in children. Aberrant renal arteries are present in about 30% of adult individuals. Aberrant renal arteries to the inferior pole cross anterior to the ureter and may cause hydronephrosis, which if left untreated can potentially lead to loss of kidney tissue. Early diagnosis of aberrant renal artery using CTA/MRA can prevent irreversible renal damage.