Department of Laboratory Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, No. 1 Shuaifu Yuan, Dongcheng District, Beijing, 100730, PR China.
Department of Ultrasound, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, 100730, China.
BMC Nephrol. 2023 Jul 31;24(1):225. doi: 10.1186/s12882-023-03279-y.
Nutcracker syndrome (NCS) caused by left renal vein (LRV) entrapment, is one of the most common causes of orthostatic proteinuria. In stereotype, orthostatic proteinuria is often accompanied by left renal vein obstruction and is found in young and underweight individuals. Here, we report a rare case with orthostatic proteinuria in an old obese female caused by a rare type of congenital inferior vena cava (IVC) interruption.
A 65-year-old obese woman, who suffered from fluctuated proteinuria, had been misdiagnosed as chronic glomerulitis for 30 years. Instead of having any sign of NCS, she had a unique type of IVC interruption. Most venous blood from infrarenal IVC and right kidney drained into her LRV, and then through the expanded communicating vessel, drained into the left ascending lumbar vein which extended as hemiazygos vein. To the best of our knowledge, this is one of the first cases reported of orthostatic proteinuria attributed to the subsequent hemodynamic irregularity caused by IVC interruption without nutcracker phenomenon.
Adult-onset orthostatic proteinuria is relatively rare, hard to be recognized and could be misdiagnosed as chronic glomerulonephritis. The case provided a novel differential diagnostic condition for those who suffered from fluctuated proteinuria of unknown causes.
胡桃夹综合征（NCS）由左肾静脉（LRV）受压引起，是体位性蛋白尿的最常见原因之一。在典型情况下，体位性蛋白尿常伴有左肾静脉梗阻，多见于年轻和消瘦的个体。在这里，我们报告了一例罕见的老年肥胖女性因罕见的先天性下腔静脉（IVC）中断引起的体位性蛋白尿病例。
一名 65 岁肥胖女性，出现波动性蛋白尿，30 年来一直被误诊为慢性肾小球肾炎。她没有任何 NCS 的迹象，而是有一种独特类型的 IVC 中断。下腔静脉肾下段和右侧肾脏的大部分静脉血流入她的 LRV，然后通过扩张的交通血管流入左侧升腰静脉，该静脉延伸为半奇静脉。据我们所知，这是首例报道的由于 IVC 中断导致胡桃夹现象以外的后续血流动力学异常引起的体位性蛋白尿病例。
成人发病的体位性蛋白尿较为罕见，难以识别，可能被误诊为慢性肾小球肾炎。该病例为那些患有不明原因波动性蛋白尿的患者提供了一种新的鉴别诊断条件。
