Nutcracker phenomenon presenting as loin pain haematuria syndrome.

A 19-year-old female presented with bilateral severe loin pain associated with recurrent macroscopic haematuria. A provisional diagnosis of loin pain haematuria syndrome was made; the severity and frequency of pain led to referral to the pain management service. Alternative diagnoses were considered. Although previous reports of obstruction of the left renal vein have not described pain of this severity, magnetic resonance angiography was performed; it showed obstruction of the left renal vein as it passed between the superior mesenteric artery and aorta, i.e. the nutcracker phenomenon. Both pain and haematuria resolved fully after autotransplantation.