A 14-year-old girl presented to the emergency department with epigastric and right upper quadrant abdominal pain. She stated that the pain had been intermittent with occasional flare-ups throughout the past year, but the symptoms had progressively worsened over the past month. Her symptoms were triggered by eating, especially high-fat foods, and were associated with nausea, vomiting, and diarrhea. Previous abdominal ultrasonography and hepatobiliary iminodiacetic acid scan imaging had not demonstrated a clear cause. Abdominopelvic computed tomographic scan revealed an enlarged right kidney and an atretic right renal vein secondary to thrombosis, as well as sclerosis with draining retroperitoneal venous varices (image A, arrow). 

Unilateral thrombosis accounts for more than 70% of cases of renal vein thrombosis, with more than 60% affecting the left vein.¹ A retrospective review found a lower likelihood of renal impairment in patients treated with heparin at the time of diagnosis.² The patient did not follow-up with the pediatric department for nephrology referral. Further workup would include evaluation for congenital, thrombophilic, autoimmune, and rheumatologic conditions.³