Uncovering risk factors for kidney injury in children with a solitary functioning kidney

Children with a solitary functioning kidney (SFK) have an increased risk of kidney injury. The exact risk of and risk factors for kidney injury remain unknown, which impedes personalized care. Here, we recruited a nationwide multicenter cohort of 944 patients with SFK to get more insight into this by consenting patients born in 1993-2020 and diagnosed with congenital or acquired SFK before adulthood. The median follow-up was 12.8 years and four indications of kidney injury were studied: urine protein-creatinine ratios, blood pressure, estimated glomerular filtration rate and use of anti-hypertensive/proteinuric medication. For each indicator except medication use, separate cut-off values for any injury and severe injury were used. Survival analyses indicated that at 18 years of age, any or severe kidney injury were present in 75% and 39% of patients with congenital SFK, respectively. Risk factors for kidney injury included kidney agenesis as cause of the SFK, anomalies in the SFK, and high body mass index at last follow-up. Kidney agenesis and being overweight were specifically associated with proteinuria and high blood pressure, whereas anomalies in the SFK were associated with reduced estimated glomerular filtration rates. The high prevalence of kidney injury in patients with SFK emphasizes the need for long-term follow-up, in which lifestyle is an important topic to address. More research into the etiological role of risk factors will help to translate our findings into individualized care strategies. Thus, our study shows that a significant proportion of children with SFK will develop kidney injury over time.

Unilateral renal agenesis as an early marker for genetic screening in Kallmann syndrome

Isolated GnRH Deficiency (IGD) that is either displayed as Kallmann Syndrome (KS) or normosmic idiopathic hypogonadotropic hypogonadism (nIHH) is a rare Mendelian disorder with wide clinical and genetic variability. Apart from the arrest of pubertal development, IGD is also characterized by a variety of non- reproductive features including unilateral renal agenesis (URA), midline defects, dental & ocular defects and many more. In this analysis we explored the role of unilateral renal agenesis, as a screening tool for detection of genetic changes associated with IGD. We performed detailed genetic screening with Sanger sequencing in 14 genes associated with Isolated GnRH Deficiency as well as screening of intragenic deletions in the gene of anosmin 1-ANOS1 with MLPA. No genetic variation was detected, suggestive of an alternative genetic cause for URA in these normosmic patients, highlighting the necessity of further genetic screening.

Correlation between hypertrophy and risk of hypertension in congenital solitary functioning kidney

PURPOSE

Solitary functioning kidney (SFK) may be associated to hypertrophy, hypertension and chronic kidney disease. We evaluated blood pressure (BP) of children with congenital SFK comparing agenesis to multicystic dysplastic kidney (MCDK) and correlated BP profiles with renal dimensions of affected and contralateral kidney.

METHODS

We compared 40 patients with MCDK, grouped for either treatment options (A: conservative vs B: nephrectomy) or involution time (A1: before 4 years-of-age vs A2: persistence-of-MCDK), to 10 unilateral agenesis (C). Patients were evaluated with ultrasound, scintigraphy, office-ambulatory BP monitoring.

RESULTS

Compensatory hypertrophy was demonstrated in most of the subjects, without differences between subgroups, with an increase over time (p < 0.001). A1-C showed an overall percentage of hypertrophy significantly higher than A2-B (83%-88% vs 70%-73%, respectively; p = 0.03); moreover, cumulative risk to develop hypertension in A1-C is significantly higher compared to A2-B in office and ambulatory BP monitoring (p = 0.03). Insufficient dipping in systolic and/or diastolic BP was found in 82% children, without differences between subtypes.

CONCLUSIONS

Patients with a small/absent dysplastic kidney have an increased risk to develop hypertrophy and hypertension compared to patients with a large residual, regardless of nephrectomy. ABPM revealed absent dipping in most patients with SFK, warning further investigations in apparently not symptomatic patients.

Retrospective study to identify risk factors for chronic kidney disease in children with congenital solitary functioning kidney detected by neonatal renal ultrasound screening

To evaluate the prognostic significance of factors frequently associated with a reduction in renal mass, such as prematurity, low birth weight, and congenital anomalies of kidney and urinary tract (CAKUT), in patients with solitary functioning kidney (SFK) and investigate signs of early renal injury due to glomerular hyperfiltration damage or dysplasia in the remaining kidney.Retrospective observational study of congenital SFK diagnosed and followed at a tertiary care hospital over a period of 10 years in which 32,900 newborns underwent routine neonatal abdominal ultrasound screening. We analyzed age at diagnosis, sex, gestational age, anthropometric measurements at birth and prenatal and neonatal ultrasound findings, in addition to follow-up data corresponding to imaging findings (ultrasound, micturating cystourethrography, dimercaptosuccinic acid renal, and scintigraphy), ipsilateral CAKUT, compensatory hypertrophy, and renal injury in the form of albuminuria, blood pressure, and estimated glomerular filtration rate (eGFR).In total, 128 congenital SFK cases were detected (1 per 257 live births). Of these, 117 (91.4%) were diagnosed by neonatal ultrasound screening and 44.5% of these had been previously identified by prenatal ultrasound. Neonatal ultrasound had a specificity of 100% and a sensitivity of 92.1%. Forty-five patients (35.2%) had ipsilateral CAKUT and the most common type was urinary collecting system anomalies (75.5%). Over a median follow-up of 6.3 years (1-10 years), compensatory renal hypertrophy was observed in 81 patients (63.7%), most of whom had ipsilateral CAKUT (76.1% vs 56.6% of patients without ipsilateral CAKUT). Albuminuria and hypertension were observed in 3.12% and 5% of patients, respectively, and both were associated with ipsilateral CAKUT (P < .05). In addition, 75% of albuminuria cases (P = .031), 83.3% of hypertension cases (P = .004), and 100% of decreased eGFRcases (P = .031) were significantly associated with CAKUT (renal parenchymal anomaly category), being the strongest predictor of GFR the presence or absence of CAKUT.Neonatal ultrasound screening is useful for the early diagnosis of SFK. The presence of ipsilateral CAKUT should be evaluated in all patients with SFK as congenital anomalies of the renal parenchyma are associated with a poorer prognosis. Because morbidity from CAKUTs may not develop until adulthood, patients should be closely followed throughout life.

A Case of Acrorenal Syndrome

Urinary tract anomalies are common and comprise about 20% to 30% of total congenital anomalies. This spectrum consists of many different anomalies of the urinary tract that may be syndromic or nonsyndromic with different etiologies. In this case report, a patient with single kidney and urinary tract signs is introduced that was diagnosed accidentally. The finding of different anomalies in different organ systems should lead us to examination of the intactness of the urinary tract. In these disorders, if there is no need for immediate intervention, long-term follow-up can be helpful to postpone chronic kidney disease progression.