In medicine, the nutcracker syndrome (NCS) — is a clinically manifest variant of nutcracker phenomenon, renal vein entrapment syndrome, or mesoaortic compression of the left renal vein. It results most commonly from the compression of the left renal vein between the abdominal aorta (AA) and superior mesenteric artery (SMA), although other variants exist. The name derives from the fact that, in the sagittal plane and/or transverse plane, the SMA and AA (with some imagination) appear to be a nutcracker crushing a nut (the renal vein). There is a wide spectrum of clinical presentations and diagnostic criteria are not well defined, which frequently results in delayed or incorrect diagnosis. This condition is not to be confused with superior mesenteric artery syndrome, which is the compression of the third portion of the duodenum by the SMA and the AA.
Since the left gonad drains via the left renal vein it can also result in left testicular pain in men or left lower quadrant pain in women. Nausea and vomiting can result due to compression of the splanchnic veins. An unusual manifestation of NCS includes varicocele formation and varicose veins in the lower limbs. Another clinical study has shown that nutcracker syndrome is a frequent finding in varicocele-affected patients and possibly, nutcracker syndrome should be routinely excluded as a possible cause of varicocele and pelvic congestion.
^Oteki T, Nagase S, Hirayama A, et al. (July 2004). "Nutcracker syndrome associated with severe anemia and mild proteinuria". Clin. Nephrol.62 (1): 62–5. PMID15267016.
^ abBarnes RW, Fleisher HL, Redman JF, Smith JW, Harshfield DL, Ferris EJ (October 1988). "Mesoaortic compression of the left renal vein (the so-called nutcracker syndrome): repair by a new stenting procedure". J. Vasc. Surg.8 (4): 415–21. doi:10.1067/mva.1988.avs0080415. PMID3172376.
^ abHilgard P, Oberholzer K, Meyer zum Büschenfelde KH, Hohenfellner R, Gerken G (July 1998). "[The "nutcracker syndrome" of the renal vein (superior mesenteric artery syndrome) as the cause of gastrointestinal complaints]". Dtsch. Med. Wochenschr. (in German) 123 (31–32): 936–40. doi:10.1055/s-2007-1024101. PMID9721569.
^ abRudloff U, Holmes RJ, Prem JT, Faust GR, Moldwin R, Siegel D (January 2006). "Mesoaortic compression of the left renal vein (nutcracker syndrome): case reports and review of the literature". Ann Vasc Surg20 (1): 120–9. doi:10.1007/s10016-005-5016-8. PMID16374539.