Abstract: TH-PO0534
Case of Isolated Proteinuria That Resolves with Rest
Session Information
- Glomerular Diseases: IgAN, IgA Vasculitis, and More
October 22, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Patel, Sahil, University of Virginia, Charlottesville, Virginia, United States
- Bassil, Emmanuel Javier, University of Virginia, Charlottesville, Virginia, United States
- Lobo, Peter I., University of Virginia, Charlottesville, Virginia, United States
Introduction
Nutcracker syndrome, often undiagnosed, is a rare condition where the left renal vein (LRV) is compressed between the aorta and superior mesenteric artery (SMA) resulting in flank pain, hematuria or proteinuria.
Case Description
We present an asymptomatic 63 year-old woman with no past history with 1+ protein on dipstick. Urine albumin-creatinine ratio (uACR) was 368mg/g and urine protein-creatinine ratio (uPCR) was 0.57 g/g. All of her blood work and imaging were otherwise normal. She was started on Losartan 12.5mg daily. A few months later, she reported developing frothy urine and ankle edema. Repeat studies showed a uACR of 4,722 mg/g and a uPCR of 6.69 g/g but other results were normal. The kidney biopsy showed mild nephrosclerosis but otherwise was normal. She was asked to repeat uACR after laying supine for 8 hours followed by another uACR at the end of the same day, after ambulating. Supine uACR was undetectable; whereas end-of-day uACR was 374mg/g. She had a dupplex ultrasound that showed a narrow appearance of the LRV as it coursed between the aorta and SMA although her aortomesenteric angle was 55 degrees (normal 30-65). Given the normal angle and the length of narrowing of the LRV, there was a concern for stenosis. The next step is for the patient to have a computed tomography venogram to evaluate the vasculature.
Discussion
Our patient had normal foot processes on biopsy despite nephrotic range proteinuria. When in an upright position the angle between SMA and aorta decreases causing a greater degree of compression resulting in increased backpressure and higher proteinuria. While supine, the compression is lessened as the angle increases resulting in undetectable levels of proteinuria. Clinicians should have high suspicions for nutcracker syndrome in patients with isolated proteinuria especially with positional fluctuations.
Narrowing of the left renal vein