Evaluation of hematuria, proteinuria, and hypertension in adolescents

Evaluation of Proteinuria and Hematuria in Ambulatory Setting

Proteinuria and/or hematuria are common findings in ambulatory settings. Proteinuria can be glomerular and/or tubular in origin and it may be transient, orthostatic, or persistent. Persistent proteinuria may be indicative of a serious kidney pathology. Hematuria, which denotes the presence of an increased number of red blood cells in the urine, can be gross or microscopic. Hematuria can originate from the glomeruli or other sites of the urinary tract. Asymptomatic microscopic hematuria or mild proteinuria in an otherwise healthy child is less likely to be of clinical significance. However, the presence of both requires further workup and careful monitoring.

Interventional Management of a Rare Combination of Nutcracker and Wilkie Syndromes

Nutcracker and Wilkie syndromes are rare mesoaortic compression entities, and their association is even less common. Data on interventional treatment of these pathologies are still scarce, but results from limited case series are encouraging. We report the case of a previously healthy 45-year-old woman diagnosed with nutcracker and Wilkie syndromes who presented with macroscopic hematuria, intermittent pain in the left flank and hypogastric region, postprandial nausea, and unexplained significant weight loss. A successful endovascular approach with stent implantation in the left renal vein was performed, but the stent migrated toward the left kidney, and this acute complication was managed through an interventional strategy as well. At the three-month follow-up, the patient described a marked improvement in all symptoms, except for the macroscopic hematuria. As it was our strong belief that the approach was efficient, we further investigated the “hematuria”, which eventually led to the diagnosis of endometrial carcinoma. A hysterectomy and bilateral adnexectomy were planned, and chemoradiotherapy was initiated with the goal of preoperative tumor reduction. To our knowledge, this is the first reported case in which both Wilkie and nutcracker syndromes were effectively treated by stent implantation in the left renal vein, complicated with very early stent migration due to inadequate apposition to the less compliant venous lumen. The treatment of the duodenal compression was indirectly included in the stenting of the left renal vein, as reclaiming the venous lumen widened the aortomesenteric angle. The aim of this review is to discuss our center’s transcatheter experience with these rare disorders and explore the literature in order to establish the benefits and limitations of such an approach.

Nutcracker syndrome: diagnosis and therapy

Nutcracker syndrome (NCS) is an extrinsic compression of the left renal vein (LRV) by the superior mesenteric artery (SMA) anteriorly and aorta posteriorly resulting in renal vascular congestion manifesting as hematuria, proteinuria, orthostatic hypotension, pain, or even renal dysfunction. Long-standing venous compression can encourage collateral drainage pathways through gonadal and pelvic veins, which may explain reported symptom and syndrome overlap with pelvic congestion syndrome. Diagnosis can be challenging and variable, frequently involving a combination of ultrasound Doppler, cross-sectional, and invasive imaging. Often, intravascular pressure measurements are required to prove a renocaval pressure gradient to aid in a definitive diagnosis. Conservative management is appropriate, especially in children, who tend to outgrow the disorder. In the interim, medical management with angiotensin converting enzyme inhibitors (ACEIs) is a useful therapy to manage orthostatic hypotension in the pediatric population. In adults, invasive therapies are more frequently pursued. These are aimed at relieving the extrinsic compression on the LRV. The standard of care is renal vein transposition, with renal autotransplantation reserved for recalcitrant cases. Endovascular stenting is a less invasive option. Laparoscopic placement of an exovascular stent is a newer therapy intended to minimize trauma to the LRV. In this review, we will discuss the clinical manifestations, diagnostic criterion, imaging features, and conservative and surgical therapies for this condition.

Value of micro-proteinuria in combination with ultrasonography of the left renal vein in the diagnosis of orthostatic proteinuria

Background

This study aimed to evaluate the clinical value of micro-proteinuria in combination with ultrasonography of the left renal vein (LRV) in the diagnosis of orthostatic proteinuria (OP).

Methods

The patients with suspected OP received West test, upright lordotic position test, Robinson test, ultrasonography of the LRV, and detection of morning urine micro-proteinuria and micro-proteinuria after activity. The sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV and NPV), positive and negative likelihood ratios (PLR and NLR) and Youden's index (YI) for micro-proteinuria, ultrasonography of the LRV and both of them in the diagnosis of OP were analyzed.

Results

From January 2013 to January 2018, 75 patients (M/F: 38/37) were recruited. Sixty patients were diagnosed with OP (M/F: 29/31, median age at onset: 10.6±2.80 years); 15 patients had no OP (M/F: 9/6, median age at onset: 10.9±3.25 years); the LRV entrapment, urine Alb/Cr, IgG/Cr, and NAG/Cr after activity were significantly different between OP group and non-OP group (Z=-3.55, -4.10, -4.01, -3.04, P<0.05). The area under the curve (AUC) of urine Alb/Cr, IgG/Cr, NAG/Cr, and the ratio of anteroposterior (AP) for LRV in the hilar and narrow portions (a/b) was 0.84, 0.84, 0.76 and 0.58, respectively, and the best cut-off value was 13.2 mg/mmol, 2.52 mg/mmol, 0.64 U/mmol and 4.06, respectively. The combination of ultrasonography of the LRV and elevated micro-proteinuria after activity could achieve the Se, Sp, PPV, NPV, PLR (weighted by prevalence, W), NLR (W) and YI at 93.3% (95% CI: 0.83-0.98), 66.7% (95% CI: 0.39-0.87), 91.8% (95% CI: 0.81-0.97), 71.4% (95% CI: 0.42-0.90), 11.2 (95% CI: 4.82-26.00), 0.40 (95% CI: 0.17-0.97) and 60%, respectively, in the diagnosis of OP.

Conclusions

The micro-proteinuria in combination of ultrasonography of the LRV is helpful for the preliminary screening of OP in patients with suspected OP.

Renal vein obstruction and orthostatic proteinuria: a review

OBJECTIVES

The cause of orthostatic proteinuria is not clear but may often relate to obstruction of the left renal vein in the fork between the aorta and the superior mesenteric artery (=renal nutcracker). However, reports dealing with proteinuria only marginally refer to this possible cause of orthostatic proteinuria. We analysed the corresponding literature.

RESULTS

Five reports addressed the frequency of renal nutcracker in 229 subjects with orthostatic proteinuria. Their age ranged between 5.2 and 17 years (female-to-male ratio: 0.96:1.00). Imaging studies demonstrated renal nutcracker in 156 (68%) subjects. Renal nutcracker was also demonstrated in 9 anecdotal reports for a total of 53 subjects with postural proteinuria. Very recently, 13 Italian subjects with orthostatic proteinuria associated with renal nutcracker were reassessed 6 years after the initial diagnosis: in nine subjects, both orthostatic proteinuria and renal nutcracker had disappeared; in three, both orthostatic proteinuria and renal nutcracker had persisted; and in one, orthostatic proteinuria had persisted unassociated with renal nutcracker.

CONCLUSIONS

These data provide substantial support for renal nutcracker as a common cause of orthostatic proteinuria.

Utility of renal imaging in the diagnostic evaluation of obese childhood primary hypertension

Although childhood primary hypertension (CP-HTN) associated with obesity is considered an earlier manifestation of typical adult-onset primary hypertension (adult-HTN), the recommendations for diagnostic evaluation are not identical in the two conditions. In particular, renal imaging is not recommended in adult-HTN, but is still currently recommended in CP-HTN. In this study, the clinical value of renal imaging in the initial diagnostic evaluation of CP-HTN was determined. A retrospective chart review was conducted of older and overweight children (> 7 years of age) evaluated in the pediatric nephrology clinic at the University of Florida from 1999 to 2004 for hypertension. The final highly selected study group was composed of obese or overweight children (body mass index > 85th percentile for age and gender) with otherwise unremarkable history, physical examination, and urinalysis. Renal imaging was performed (ultrasound in 49, computed tomography in one) in 50 patients (M:F = 28:22; age range, 7-20 years) with clinical features compatible with CP-HTN, and was normal in all patients. In this study, renal imaging did not add any clinical value to the initial evaluation of CP-HTN associated with obesity. Larger studies may confirm that the evaluation of CP-HTN in older obese children could be similar to guidelines for evaluation of adult-HTN.

Hypertension in a young golfer

A collegiate freshman golfer was hypertensive at her preparticipation physical exam (PPE). Further investigation revealed coarctation of the aorta with secondary hypertension that had been asymptomatic. The PPE is a good forum for hypertensive screening because it may be one of the few times an apparently healthy adolescent is seen by any physician. This case emphasizes the need to screen for silent hypertension and discern its cause in adolescents.