LAUSR

A 51-year-old woman was referred to our hospital due to uncontrolled hypertension. This patient was taking candesartan as an antihypertensive for several years. Even with an antihypertensive drug, her blood pressure was measured as 171/114 mm Hg. She did not have any previous illnesses related to hypertension. Hematuria and pyuria were not observed in the urine test. The plasma renin activity was <0.07 ng/mL/h, serum aldosterone was 20.9 pg/mL, blood urea nitrogen was 11 mg/dL, and creatinine was 0.75 mg/ dL. Three-dimensional reconstructed computed tomography (CT) images showed a dilated left renal vein. In the axial and sagittal images, the left renal vein, which is severely narrowed between the aorta and the vertebral column, can be seen (Figure 1). A shunt was observed between left renal vein and splenic vein (Figure 2A), and a splenic varix related to a renosplenic shunt was shown (Figure 2B). However, this patient had no liver cirrhosis. Extrinsic compression in the left renal vein between the aorta and the vertebral column is called the “posterior nutcracker phenomenon.” This patient was in the posterior nutcracker phenomenon, and there was an additional renosplenic shunt without a left ovarian varix. The cause of the shunt was probably due to increased blood pressure in the left renal vein. This patient did not show clinical symptoms associated with compression of the left renal vein, such as hematuria or pain, presumably because the renosplenic shunt was formed early, and the blood pressure of the left renal vein remained low. There are 3 methods of treating the nutcracker syndrome: conservative, surgical, and endovascular stenting. Surgical methods include transposition, autotransplantation, and bypass. In this case, there was no past history of intra-abdominal surgery, and it seems that renosplenic bypass occurred spontaneously after hypertension of the left renal vein. The prognosis of a renosplenic shunt is not yet well known, and a renosplenic shunt is very rare in the absence of liver cirrhosis. In this case, blood in the left renal vein was mainly drained through the renosplenic shunt, and a small amount of blood was drained into the interior vena cava as was shown on a dynamic CT scan. No other hemodynamic changes were observed. And there were no other abnormalities associated with the renosplenic shunt based on various tests to date. Thus, no other treatments, including intervention, proceeded for the renosplenic shunt. However, since blood flow to the splenic vein and portal vein was increased, follow-up is needed for changes that may occur in a hypertensive situation with the portal vein. This case was found incidentally on a CT scan during the evaluation of uncontrolled hypertension, and after changing the Figure 1. Contrast-enhanced CT image shows compression of the renal vein between the aorta and vertebra body (arrow). A indicates aorta; CT, computed tomography; LRV, left renal vein.