Nutcracker Syndrome as an Uncommon Cause of Isolated Hematuria in Adults

Nutcracker Syndrome—How Well Do We Know It?

The Nutcracker phenomenon is a rare asymptomatic compression of the left renal vein. Among various types of this condition, the entrapment of the left renal vein between the superior mesenteric artery and abdominal aorta is common. This phenomenon could affect underweight individuals because of the paucity of adipose tissue in the retroperitoneum, which decreases the angle between the superior mesenteric artery and the aorta. Symptomatic compression of the left renal vein is known as Nutcracker syndrome. Duplex sonography of renal veins and contrast-enhanced abdominal computed tomography are commonly used to diagnose the Nutcracker phenomenon and syndrome.

The nutcracker syndrome is defined by the compression of the left renal vein between the aorta and superior mesenteric arteries, accompanied by a classic, but less specific, symptomatology. We reported a case of a 37-year-old woman who had been investigated because of intermittent gross hematuria of unknown origin. Computed tomographic angiography revealed compression of the left renal vein as it ran between the superior mesenteric artery and the abdominal aorta, associated with significant dilation of the left ovarian vein. The nutcracker syndrome, caused by compression of the left renal vein by the aorta and superior mesenteric arteries, is probably more prevalent in women, and it is caused by specific situations, such as renal ptosis and paucity of retroperitoneal fat. Hematuria, a typical symptom, is due to rupture of the thin-walled septum separating the veins of the urinary collecting system. Imaging tests may help with the diagnosis. The best treatment is still elusive, but there are several surgical approaches, such as intravascular stenting, and also a conservative management. Diagnosis is usually delayed, and the syndrome should be included in the differential of hematuria of unknown origin.

Nutcracker syndrome due to left-sided inferior vena cava compression and treated with superior mesenteric artery transposition

Nutcracker phenomenon or renal vein entrapment is classically seen as a compression of renal vein in between abdominal aorta and superior mesenteric artery with patients being asymptomatic or clinically manifested in the form of nutcracker syndrome as proteinuria, hematuria, flank pain, pelvic congestion in women, and varicocele in men. In this report, we are presenting a case of rare variant of nutcracker phenomenon along with brief review of anatomy, pathophysiology, public health, and clinical significance of nutcracker syndrome. On a routine dissection of an adult male cadaver, we noticed an unusual arrangement of the structures at the hilum of the left kidney showing entrapment of renal vein between left anterior inferior and posterior segmental renal arteries. The variation in the course of left anterior inferior segmental renal artery leads to compression of left renal vein at renal hilum. Therefore, we have named this rare abnormal anatomical entity as hilar nutcracker phenomenon. The structures in the right renal hilum are normal. The objective of this paper is to report an unusual but important variant of nutcracker phenomenon and also give collective knowledge of such anatomical variations in renal vasculature that will help in diagnosing and treating such rare renal disorder.

Nutcracker phenomenon (NCP) typically refers to the anatomical compression of the left renal vein (LRV) between the superior mesenteric artery (SMA) and abdominal aorta, resulting in an impeded outflow from the LRV. The impeded outflow is often accompanied by renal venous hypertension with hilar and ureteral dilatation1. Here, we report on a rare case of left-sided inferior vena cava (LIVC) crossing the aorta anteriorly towards the right side and leading to a unique form of fetal NCP. A 32-year-old woman, gravida 4 para 3, was referred to our fetal medicine unit at 25 + 3 weeks of gestation with a suspected abdominal vascular anomaly. Detailed examination using two-dimensional color Doppler imaging revealed an anomalous course of the fetal inferior vena cava (IVC). Using the high-definition flow Doppler ultrasonographic modality, a left-sided infrarenal portion of the IVC was observed, obliquely crossing to the right side, anteriorly to the abdominal aorta and inferiorly to the adjacent SMA, then continuing as a normally positioned, right-sided suprarenal IVC (Figure 1). Along its course, the infrarenal segment of the LIVC drained the LRV. Three- and four-dimensional (3D/4D) color Doppler with HDlive mode (Voluson E10, GE Healthcare, Zipf, Austria) allowed us to observe clearly the spatial relationships between the anomalous IVC, aorta and SMA. Careful evaluation of the vasculature demonstrated that the SMA, due to its acute downward angle, entrapped the LIVC as it crossed over the aorta to the right side, bringing about a rare type of fetal NCP (Figure 2). Among the various anomalies of IVC reported in the literature, the prevalence of LIVC is between 0.2% and 0.5%2. During the 10th week of gestation, when venous system development is completed, the mature singular IVC comprises five confluent segments2–4. In caudal to cranial order, these segments are (1) the iliac veins, derived from the posterior cardinal veins; (2) the infrarenal segment, derived from a persistent portion of the right supracardinal vein; (3) the renal segment, derived from the anastomosis between the right supracardinal and subcardinal veins; (4) the suprarenal segment, derived from a persistent portion of the right subcardinal vein; and (5) the hepatic segment, derived from the vitelline vein (Figure 3). In rare cases, the left supracardinal vein persists instead of the right supracardinal vein, which in turn regresses, leading to the development of LIVC. Normally, the infrarenal LIVC drains into the LRV, which crosses the abdominal aorta anteriorly to join the right renal vein and proceed cranially as a right-sided suprarenal IVC5, 6. In our case, the LRV drained into the infrarenal LIVC on its route, and the LIVC itself crossed the aorta anteriorly towards the right side in a way that resembles two tango dancers during one of their dance moves (Tango sign, Figure 4). This anatomical variant led to this unusual form of fetal NCP. Although, in the present case, we did not detect any signs of renal vein hypertension or dilatation of the collecting system, these morphological changes may manifest later in life due to the changes occurring in systemic vascular pressures following delivery. Many cases of NCP remain asymptomatic. However, NCP may lead to nutcracker syndrome, which is defined by the characteristic clinical symptoms associated with demonstrable morphological features of NCP. Clinical symptoms may present during childhood or adult life and include hematuria, orthostatic proteinuria, flank or abdominal pain, varicocele, pelvic venous congestion syndrome and chronic fatigue syndrome, all of which are secondary to venous hypertension and are often aggravated by physical activity7. The added value of 3D/4D color Doppler and its ability to improve diagnostic accuracy have been investigated over the last decade and proved to be indispensable8. Similarly, in our case, prenatal sonographic visualization of the NCP would not have been possible without applying 3D/4D color Doppler with HDlive mode. Once again, this modality proved useful for examining the spatial relationships within the abdominal vasculature, facilitating our understanding of the idiosyncratic morphology and informing our consultation with the family, regarding possible future complications. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.

Nutcracker syndrome (NS) refers to symptomatic compression of the left renal vein (LRV) between the abdominal aorta and superior mesenteric artery with potential symptoms including hematuria, proteinuria, left flank pain, and renal venous hypertension. No consensus diagnostic criteria exist to guide endovascular treatment. We aimed to evaluate the specificity of LRV compression to NS symptoms through a retrospective study including 33 NS and 103 control patients. The size of the patent lumen at point of compression and normal portions of the LRV were measured for all patients. Multiple logistic regression analyses (MLR) assessing impact of compression, body mass index (BMI), age, and gender on the likelihood of each symptom with NS were obtained. NS patients presented most commonly with abdominal pain (72.7%), followed by hematuria (57.6%), proteinuria (39.4%), and left flank pain (30.3%). These symptoms were more commonly seen than in the control group at 10.6, 11.7, 6.8, and 1.9%, respectively. The degree of LRV compression for NS was 74.5% and 25.2% for controls (p < 0.0001). Higher compression led to more hematuria (p < 0.0013), abdominal pain (p < 0.006), and more proteinuria (p < 0.002). Furthermore, the average BMI of NS patients was 21.4 and 27.2 for controls (p < 0.001) and a low BMI led to more abdominal pain (p < 0.005). These results demonstrate a strong correlation between the degree of LRV compression on imaging in diagnosing NS.

Superior mesenteric artery syndrome (SMAS) and nutcracker syndrome (NCS) are rare vascular compression disorders caused by entrapment of the third portion of the duodenum and the left renal vein, respectively, between the abdominal aorta and the superior mesenteric artery (SMA). While both conditions share a common pathophysiological mechanism, their simultaneous occurrence remains exceptionally rare. We report the case of a 16-year-old male patient who presented with persistent epigastric pain, nausea, and bilious vomiting. Clinical history revealed recent unquantified weight loss, with a body mass index (BMI) of 17.5 kg/m². Contrast-enhanced computed tomography (CECT) demonstrated a markedly reduced aortomesenteric angle (14.3°) and distance (3.9 mm), consistent with SMAS, along with compression of the left renal vein, upstream dilation, and collateral venous pathways, supporting the diagnosis of concomitant NCS. Due to the severity of duodenal obstruction and failure of conservative management, the patient underwent a transmesocolic anisoperistaltic gastrojejunostomy. Postoperative recovery was uneventful, with complete resolution of gastrointestinal symptoms and satisfactory nutritional improvement at the three-month follow-up. As NCS was asymptomatic, it was managed conservatively with scheduled clinical and radiological surveillance. This case highlights the importance of comprehensive cross-sectional imaging in identifying dual vascular compression syndromes and emphasizes the need for individualized treatment strategies based on symptomatology and anatomical findings.

Double trouble: A case report of concurrent superior mesenteric artery syndrome and nutcracker syndrome in a previously healthy young adult.

INTRODUCTION: Nutcracker syndrome (NCS) is a rare condition caused by the compression of the left renal vein between the abdominal aorta and superior mesenteric artery. The purpose of the study was to evaluate our management of NCS. METHODS: Patients were retrospectively reviewed and sex, age, main symptoms at application, physical examination, radiological findings, laboratory examinations, and treatment were recorded. RESULTS: 23 patients (16 girls, 7 boys; age range, 5 to 16) diagnosed with NCS. Microhematuria was detected with 14 (60.8%) patients before diagnosis. And four of 9 (39.1%) were determined after diagnosis. Microhematuria was not detected in 5 (21.7%) of the patients. All patients (100%) had orthostatic proteinuria. 17 (73.9%) patients had mild, 3 (13.0%) patients had moderate and 3 (13.0%) had severe proteinuria. The mean diameter of the left renal vein (LRV) at the aortomesenteric (AM) portions and the hilar were 1.69mm±0.70 and 8.01mm±2.27. The mean angle between the superior mesenteric artery and LRV was 25.26º±7.98. DISCUSSION AND CONCLUSION: In the case of especially colic flank pain, hematuria, and proteinuria NCS should keep in mind in the differential diagnosis. Surgical management may supply more enough clinic improvement when the patient has a response to medical therapy.

Mesoaortic Compression of the Left Renal Vein (Nutcracker Syndrome): Case Reports and Review of the Literature

Weight loss as a potential trigger for nutcracker syndrome after a complex surgery: About a case report

A case of nutcracker syndrome: Treatment by mesoaortic transposition

AimSuperior mesenteric artery (SMA) syndrome is a rare condition whereby external compression of the third part of the duodenum by the SMA results in duodenal obstruction. Nutcracker phenomenon refers to...

IgA vasculitis is the most frequent type of vasculitis in children and progresses with the involvement of skin, gastrointestinal system, joints and glomerulonephritis. The most frequent findings of IgAV nephritis are microscopic hematuria and proteinuria ranging from trace amounts to nephrotic levels. The nutcracker syndrome (NCS) is a phenomenon that refers to compression of the left renal vein between the abdominal aorta and superior mesenteric artery. The presenting manifestations are hematuria, orthostatic proteinuria, abdominal pain or left flank pain. Herein we reported a case diagnosed with NCS with regard to persistent microscopic hematuria, intermittent macroscopic hematuria and a fluctuating proteinuria in non-nephrotic levels during the follow up of IgA vasculitis nephritis. A 4,5 year-old boy with rashes extending from the dorsal foot to the sacral regions, arthritis of the ankles and abdominal pain had been admitted to hospital and diagnosed with IgA vasculitis. The total urine analysis revealed +3 proteinuria, and +2 erythrocyte. Nephrotic range of proteinuria was detected in 24-hour urine analysis. The renal biopsy was in accordance with grade II IgA vasculitis nephritis according to the ISKDC classification. The patient was started on an ACE inhibitor and fish oil. In further follow-up, intermittent microscopic hematuria and non-nephrotic range of proteinuria reappeared. The amount of proteinuria was measured in the urine collected during the daytime and the nighttime urine and it was observed that the proteinuria was orthostatic. The patient was re-evaluated regarding etiologies for proteinuria and hematuria. Renal Doppler ultrasonography revealed that the angle between the abdominal aorta and SMA was 14 degrees. Abdominal computed tomography angiography demonstrated that the left renal vein was trapped between aorta and SMA, so the case was diagnosed with NCS. In conclusion, non-glomerular etiologies should be kept in mind in the differential diagnosis of patients with hematuria and/or proteinuria although they are being followed for glomerular pathologies.