Entrapment of the Left Renal Vein: A Rare Cause of Proteinuria
Bibliographic record
Abstract
To the Editor: A 26-year-old man visited our institution for evaluation of proteinuria. He intermittently presented with acute urinary retention. Other urological evaluations were unremarkable. Urinalysis exhibited trace proteins without hematuria. Renal duplex and enhanced computed tomography (CT) of the abdomen and pelvis were performed. The duplex ultrasound typically demonstrated aortomesenteric anatomy with entrapment of the left renal vein (LRV) (Fig. 1). The diameters of the LRV at the hilar and aortomesenteric portions were measaured as 11 mm and 1.2 mm, respectively. The duplex ultrasound also indicated a significantly higher ratio of the peak systolic velocity (PSV) to the hilar renal vein PSV at the point of renal vein compression (> 6). This observation demonstrates the diminished volume of flow and dampened pulsatility upon spectral analysis of the left renal vein. Enhanced CT angiography revealed compression of the left renal vein between the aorta and the superior mesenteric artery (Fig. 2). The Nutcracker syndrome is defined as a rare cause of hematuria and flank pain caused by compression of the left renal vein between the aorta and the superior mesenteric artery where it passes at the point of bifurcation of the arteries [1]. The observed compression causes venous hypertension and the formation of renal venous collaterals leading to the subsequent rupture of the septum between the veins and the collecting system, and finally, resulting in hematuria and flank pain [2, 3]. In this particular patient case, although rare, the nutcracker should be included as the potential cause of proteinuria in addition to hematuria in the absence of other renal diseases. References
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.006 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.003 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.007 | 0.005 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".