S6112 A Pinch Too Close: A Diagnostic Challenge in a Young Patient With Chronic Pelvic Pain

Introduction: Nutcracker syndrome is characterized by compression of the left renal vein (LRV) between the abdominal aorta and superior mesenteric artery (SMA). This can lead to gastrointestinal symptoms such as nausea, vomiting, abdominal pain, and early satiety, often linked to associated SMA syndrome. Elevated LRV pressure may cause pelvic congestion, resulting in chronic pelvic pain alongside the aforementioned symptoms. Diagnosis is frequently delayed, requiring a comprehensive workup to confirm. Case Description/Methods: A 41-year-old woman presented with a medical history of microscopic hematuria, persistent dyspeptic symptoms including chronic nausea and vomiting, and a 16-year history of chronic pelvic pain. She experienced a 20-pound weight loss, resulting in a BMI of 18 kg/m2. Initial evaluation began several years prior. An upper endoscopy in 2019 indicated duodenal compression. Subsequent computed tomography angiography of the abdomen and pelvis revealed a reduced aorta-SMA distance of 7 mm (abnormal if <9 mm), suggestive of SMA syndrome. However, the aorta-SMA angle was normal at 28 degrees, which is typically reduced in SMA syndrome. Due to worsening symptoms, a left renal venogram was performed in 2025, measuring mean LRV pressures of 10, 9, and 11 mmHg and mean inferior vena cava (IVC) pressures of 7, 7, and 9 mmHg, yielding a mean pressure gradient of 2.5 mmHg. Pending interventional radiology evaluation, the patient was managed with neuromodulatory therapy. Discussion: The normal LRV-IVC pressure gradient is less than 1 mmHg. While a gradient exceeding 3 mmHg is diagnostic for nutcracker syndrome, diagnosis is multifactorial and should not rely solely on pressure measurements. Patients with longstanding compression may develop extensive collateral venous decompression, leading to lower pressure gradients and presenting with chronic pelvic pain rather than classic symptoms like hematuria or flank pain. Younger patients or those with intermittent compression may also exhibit lower gradients, particularly if imaging occurs during periods of reduced hemodynamic stress. Management should be tailored to the individual, integrating clinical symptoms, imaging findings, and hemodynamic data. In cases of severe, persistent symptoms, renal vein compression may be considered even with a low-pressure gradient, emphasizing the importance of a comprehensive approach to diagnosis and treatment.