Posterior nutcracker phenomenon with Down syndrome

Abstract

The patient was a 24-year-old man with a history of Down syndrome who presented himself with a 9-year history of intermittent gross painless hematuria with anemia. There were no external signs of trauma on physical examination except a pale appearance. Laboratory investigations revealed the hemoglobin and hematocrit levels were 6.2 g/dL and 22.5%, respectively. Although his family witnessed another episode of gross hematuria few weeks before admission, urinalysis on admission showed no evidence of hematuria. An initial abdominal ultrasonography showed normal size and echogenicity of both kidneys without definite focal lesion. However, computed tomography of the abdomen revealed entrapment of a retroaortic left renal vein between the aorta and the vertebral column (Fig. 1), indicating posterior nutcracker syndrome. After consultation, it was decided that he should undergo conservative follow-up. Figure 1 Abdominal CT of the patient. (A) The arrowhead indicates dilated left renal vein at the renal hilum. (B) The arrowhead indicates the passing of the left renal vein between the aorta and the vertebral body. The retroaortic left renal vein, also known as posterior nutcracker syndrome, is a rare congenital phenomenon. Because patients with Down syndrome usually have a decreased risk for vascular anomalies because of increased vascular endothelial growth factor inhibitors from an extra copy of chromosome 21, posterior nutcracker syndrome comorbid with Down syndrome is especially a rare diagnosis.