SHORT COMMUNICATION The nutcracker syndrome: an underrecognized cause of hematuria Muhammad Waseem & Ruchi Upadhyay & Gerard Prosper Received: 14 November 2011 / Accepted: 16 May 2012 / Published online: 14 June 2012 # Springer-Verlag 2012 Abstract Nutcracker syndrome (NCS) is an uncommon cause of hematuria. It refers to the compression of the left renal vein between the aorta and superior mesenteric artery. It can cause both microscopic and gross hematuria. Hematuria may be associated with left flank pain. The diagnosis of NCS is often delayed. Most patients may have symptoms for many years and non-diagnostic evaluations before accurate diagno- sis can be established. It should be included in the differential diagnosis of unexplained hematuria. The diagnosis and treat- ment of nutcracker syndrome are discussed. Conclusion: NCS is a rare but treatable clinical condition. An inclusion of this entity in the differential diagnosis of patients with unknown cause of hematuria and flank pain can achieve efficient man- agement of this condition. Keywords Hematuria . Nutcracker syndrome . Flank pain . Renal vein entrapment syndrome Case report A 17-year-old boy was brought to the Emergency Depart- ment (ED) because of left flank pain and blood in the urine. He had a prior history of intermittent flank pain for 2 months and had visited the ED on three prior occasions with similar complaints. He had no fever, vomiting, or diarrhea. He also denied any trauma to the abdomen or back. There were no other associated symptoms and no prior urinary or sexually transmitted infections. Past medical history was remarkable for two hospitaliza- tions for similar complaints in association with left flank pain. On both occasions, the patient was discharged on conservative management. His family history was positive for renal dis- eases; his father had chronic renal failure of unknown etiology and was on hemodialysis. On arrival in ED, the patient was alert and active but appeared uncomfortable. His vital signs were: temperature, 98.2 °F; heart rate, 75 beats per minute; respiratory rate, 18 breaths per minute; and blood pressure, 102/64 mmHg. His body weight was 58 kg, height 173 cm, BMI 19.8, and Tanner stage of 4. He had left flank tenderness. His abdo- men was soft and non-distended without any palpable masses. The remainder of his physical examination includ- ing genital examination was unremarkable. Initial laboratory values were as follows: serum sodium 138 mmol/L, potassium 4.4 mmol/L, chloride 101 mmol/L, bicarbonate 27 mmol/L, glucose 91 mg/dL, blood urea nitro- gen 21 mg/dL, and creatinine 1.0 mg/dL. The urine specimen with centrifugation showed a pH of 6.0, specific gravity 1.021, RBCs massive (not dysmorphic) and two to five white blood cells but no casts. Hematuria persisted on multiple urinalyses. CBC showed a WBC count of 7.0×10 3 / μL, he- moglobin level of 13.6 g/dL and platelet count of 266,000× 10 3 / μL with 69 % neutrophils and 21 % lymphocytes. C3 and C4 were 82.2 mg/dL (75–140) and 9.34 mg/dL (10–34), respectively. IgA was 237 mg/dL (88–410). A computed tomography scan of the abdomen was obtained, demonstrating compression of the left renal vein between the aorta and the superior mesenteric artery (Fig. 1). M. Waseem (*) : R. Upadhyay Department of Emergency Medicine, Lincoln Medical & Mental Health Center, 234 East 149th Street, Bronx, NY 10451, USA e-mail: waseemm2001@hotmail.com G. Prosper Department of Pediatrics, Lincoln Medical & Mental Health Center, 234 East 149th Street, Bronx, NY 10451, USA Eur J Pediatr (2012) 171:1269–1271 DOI 10.1007/s00431-012-1761-1