Nutcracker syndrome

In medicine, the nutcracker syndrome — also known as nutcracker phenomenon, renal vein entrapment syndrome, or mesoaortic compression of the left renal vein — is a compression of the left renal vein between the abdominal aorta (AA) and superior mesenteric artery (SMA). The popular name "nutcracker syndrome" derives from the fact that, in the sagittal view, the SMA and AA (with some imagination) appear to be a nutcracker crushing a nut (the renal vein).

Signs and symptoms
The syndrome is associated with hematuria, which can lead to anemia, abdominal complaints or pain (classically left flank pain ), nausea, and/or vomiting, due to compression of the duodenum which also passes between the SMA and abdominal aorta). Because 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.

Unusual manifestations of the nutcracker syndrome include varicocele formation and varices in the lower limbs.

Diagnosis
Nutcracker syndrome can be diagnosed with:
 * Left renal venography — considered to be the gold standard test.
 * Computed tomography (CT).
 * Abdominal ultrasonography — not definitive but has been found to be useful.

Treatment
Treatment depends on the severity and symptoms. Treatments include:
 * Endovascular stenting.
 * Renal vein re-implantation.
 * Gonadal vein embolization.