The clinical characteristics of Chinese patients with unilateral renal agenesis

Renal agenesis: A meta-analysis of its prevalence and clinical characteristics based on 15 641 184 patients

Our objective was to analyse the newest relevant data on worldwide prevalence and associated symptoms of renal agenesis (RA). This meta-analysis builds on previous systematic reviews to include bilateral RA, its symptoms and data on gender, unilateral RA and anomaly location prevalence. Review of available data included records in English and other languages from PubMed, Embase, ScienceDirect, Web of Science, SciELO, BIOSIS, Current Content Connect Korean Journal Database and Russian Citation Index and Google. A total of 15 641 184 patients were analysed in relation to the prevalence of RA. The pooled prevalence of RA was 0.03% (95% CI: 0.03%-0.04%). Based on 500 subjects, a pooled prevalence of 47.96% (95% CI: 31.55%-64.58%) for unilateral and 52.04% (95% CI: 35.42%-68.45%) for bilateral RA has been set. Our study presents the newest generalized findings on bilateral RA. There appears to be universal disease and symptom prevalence with minor differences between world regions, although quality of future observational research should include genomic data. This will provide even further insight into the prognosis of various renal anomalies and their etiologies.

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.

Management of the congenital solitary kidney: consensus recommendations of the Italian Society of Pediatric Nephrology

In recent years, several studies have been published on the prognosis of children with congenital solitary kidney (CSK), with controversial results, and a worldwide consensus on management and follow-up is lacking. In this consensus statement, the Italian Society of Pediatric Nephrology summarizes the current knowledge on CSK and presents recommendations for its management, including diagnostic approach, nutritional and lifestyle habits, and follow-up. We recommend that any antenatal suspicion/diagnosis of CSK be confirmed by neonatal ultrasound (US), avoiding the routine use of further imaging if no other anomalies of kidney/urinary tract are detected. A CSK without additional abnormalities is expected to undergo compensatory enlargement, which should be assessed by US. We recommend that urinalysis, but not blood tests or genetic analysis, be routinely performed at diagnosis in infants and children showing compensatory enlargement of the CSK. Extrarenal malformations should be searched for, particularly genital tract malformations in females. An excessive protein and salt intake should be avoided, while sport participation should not be restricted. We recommend a lifelong follow-up, which should be tailored on risk stratification, as follows: low risk: CSK with compensatory enlargement, medium risk: CSK without compensatory enlargement and/or additional CAKUT, and high risk: decreased GFR and/or proteinuria, and/or hypertension. We recommend that in children at low-risk periodic US, urinalysis and BP measurement be performed; in those at medium risk, we recommend that serum creatinine also be measured; in high-risk children, the schedule has to be tailored according to kidney function and clinical data.

Retrospective evaluation of children with unilateral renal agenesis

BACKGROUND

Children born with unilateral renal agenesis (URA) are thought to have a risk of developing hypertension, proteinuria, and progressive chronic kidney disease (CKD). The present study aimed to evaluate the long-term prognosis and clinical characteristics of children with URA.

METHODS

The study included 171 patients aged < 18 years diagnosed as URA who were followed-up for ≥ 1 year and 121 healthy controls matched for age, gender, and BMI.

RESULTS

Median age at diagnosis was 2 years (IQR: 1 month-16 years) and the incidence of URA in males (65.4%) was higher than in females. Among the patients, 21 (12.2%) had other urinary system anomalies. It was noted that 2.3% of the patients had proteinuria, 15.2% had hyperfiltration, and 2.9% had CKD. Hypertension based on ambulatory blood pressure monitoring (ABPM) was diagnosed in 18 (10.5%) of the patients, of whom 10 had masked hypertension. Diastolic blood pressure in the URA patients was significantly higher than in the healthy controls. The incidence of hypertension and CKD was significantly higher in the patients with other urinary system anomalies.

CONCLUSIONS

Patients with a single functional kidney should be periodically evaluated throughout their lifetime for urine protein, blood pressure, and kidney functions. The most remarkable finding of this study is the importance of the use of ABPM for evaluating blood pressure in pediatric URA patients, especially for the detection of masked hypertension and the non-dipper phenomenon, which cannot be achieved with office blood pressure measurement.

Renal agenesis associated with contralateral ectopic ureter and hydroureteronephrosis

Congenital anomalies of the kidney and the urinary tract such as renal agenesis and ectopic ureter have complex development. These anomalies have variable presentations and associations. In this report, we highlight the case of a young man with congenital renal agenesis presenting for a urinary tract infection. Abdominal and pelvic computed tomography imaging revealed the rare association of renal agenesis with contralateral ectopic ureter and subsequent hydroureteronephrosis. A urinary tract infection can be the presenting complication of such association, and a long follow-up is needed to anticipate the management.

Identifying risk factors for chronic kidney disease stage 3 in adults with acquired solitary kidney from unilateral nephrectomy: a retrospective cohort study

Background

We aimed to examine the risk factors for chronic kidney disease (CKD) stage 3 among adults with ASK from unilateral nephrectomy.

Methods

We retrospectively collected data from adult patients with ASK between January, 2009 and January, 2019, identified from a tertiary hospital in China. The clinical data were compared between patients who developed CKD stage 3 and those who did not develop CKD stage 3 during follow-up.

Results

In total, 172 patients with ASK (110 men; median 58.0 years) were enrolled, with a median follow-up duration of 5.0 years. During follow-up, 91 (52.9%) and 24 (14.0%) patients developed CKD stage 3 and end-stage renal disease, respectively. Multiple regression analyses showed that age (odds ratio [OR] 1.076, 95% confidence interval [CI] 1.039–1.115, p < 0.001), diabetes (OR 4.401, 95% CI 1.693–11.44, p = 0.002), hyperuricemia (OR 2.733, 95% CI 1.104–6.764, p = 0.03), a history of cardiovascular disease (CVD) (OR 5.583, 95% CI 1.884–18.068, p = 0.002), and ASK due to renal tuberculosis (OR 8.816, 95% CI 2.92–26.62, p < 0.001) were independent risk factors for developing CKD stage 3 among patients with ASK.

Conclusions

Regular follow-up of renal function is needed among adult patients with ASK. Optimal management of diabetes, hyperuricemia, and CVD may reduce their risk of CKD stage 3, especially among those that undergo unilateral nephrectomy for renal tuberculosis.

Physiology and Pathophysiology of Compensatory Adaptations of a Solitary Functioning Kidney

Children born with a solitary functioning kidney (SFK) have an increased risk of hypertension and kidney disease from early in adulthood. In response to a reduction in kidney mass, the remaining kidney undergoes compensatory kidney growth. This is associated with both an increase in size of the kidney tubules and the glomeruli and an increase in single nephron glomerular filtration rate (SNGFR). The compensatory hypertrophy and increase in filtration at the level of the individual nephron results in normalization of total glomerular filtration rate (GFR). However, over time these same compensatory mechanisms may contribute to kidney injury and hypertension. Indeed, approximately 50% of children born with a SFK develop hypertension by the age of 18 and 20–40% require dialysis by the age of 30. The mechanisms that result in kidney injury are only partly understood, and early biomarkers that distinguish those at an elevated risk of kidney injury are needed. This review will outline the compensatory adaptations to a SFK, and outline how these adaptations may contribute to kidney injury and hypertension later in life. These will be based largely on the mechanisms we have identified from our studies in an ovine model of SFK, that implicate the renal nitric oxide system, the renin angiotensin system and the renal nerves to kidney disease and hypertension associated with SFK. This discussion will also evaluate current, and speculate on next generation, prognostic factors that may predict those children at a higher risk of future kidney disease and hypertension.