Nutcracker syndrome accompanied by hypertension: a case report and literature review

Nutcracker syndrome (NCS) refers to characteristic clinical symptoms that develop secondary to the nutcracker phenomenon (NCP), defined as compression of the left renal vein between the superior mesenteric artery and the aorta. A 22-year-old Chinese man presented with a 2-year history of hypertension and left flank pain after activity; his blood pressure fluctuated within 130-150/90-100 mmHg without treatment. He had microscopic hematuria (2+) and increased plasma renin activity. The findings of both color Doppler ultrasound and computed tomography angiography were consistent with a diagnosis of NCS. The patient had no history of familial hypertension or special medications. Secondary hypertension-related examinations showed no significant abnormalities. After placement of an endovascular stent in the left renal vein, normal blood flow resumed and the collateral circulation was reduced. Both the hypertension and flank pain were alleviated within 3 days after the intervention and did not reappear during the following 11 months. NCP/NCS accompanied by hypertension is very rare. The possibility of NCP/NCS should be considered when secondary hypertension cannot be explained by other factors. The mechanism by which hypertension is caused by NCP/NCS is rather complex and deserves further investigation.