Venous thromboembolism (VTE) in children is a rare condition. An increased incidence has been observed in the last few years due to several factors, such as increased survival in chronic conditions, especially chronic kidney disease (CKD), use of catheters, and increased sensitivity of diagnostic tools. VTE includes deep vein thrombosis (DVT) and pulmonary embolism (PE). VTE in children is associated with a two to six times higher mortality risk and a 5–10% prevalence of post-thrombotic syndrome. Overall, 5% of VTE episodes in children are associated with chronic kidney disease. The etiology of VTE in chronic kidney disease covers a wide range of pathologies. Various types of thrombotic complications may occur during long-term use of a chronic dialysis catheter. VTE occurs in 3% of children with nephrotic syndrome (NS). The risks for VTE and arterial thromboembolism (ATE) were particularly high in the first 6 months after the onset of NS. Other causes of VTE are graft rejection due to thrombosis of vascular anastomoses after kidney transplantation (3%) and autoimmune diseases (lupus nephritis, antiphospholipid syndrome). In this state-of-the-art overview, we have reviewed the physiologic and pathologic mechanisms underlying pediatric thrombosis and updated current diagnostic and treatment options, emphasizing personal experience as well.

Sarcoidosis is a non-necrotizing granulomatous inflammatory multisystemic disorder of unknown etiology. In children, as in adults, it can involve a few or all organ systems to a varying extent and degree, entailing multisystemic manifestations. Kidney involvement in pediatric-onset adult-type sarcoidosis is rare, with a wide range of renal manifestations, most of them related to calcium metabolism. Children with renal sarcoidosis tend to be more symptomatic than adults, although male patients have a higher prevalence. We present the case of a 10-year-old boy who presented with advanced renal failure with nephrocalcinosis and important hepatosplenomegaly. The diagnosis was established by histopathological examination, with consequent cortisone therapy and hemodialysis. This review emphasizes that sarcoidosis should be considered in the differential diagnosis of pediatric patients with acute kidney insufficiency or chronic kidney disease of an unknown etiology. As far as we know, this is the first study regarding extrapulmonary sarcoidosis in children from Romania.

Vesicoureteral reflux (VUR) is the most frequent congenital urinary tract malformation and an important risk factor for urinary tract infections (UTIs). Up to 50% of children with VUR may develop reflux nephropathy (RN), and the diagnosis and monitoring of renal scars are invasive and costly procedures, so it is paramount to find a non-invasive and accurate method to predict the risk of renal damage. Neutrophil gelatinase-associated lipocalin (NGAL) has already proven to be a good predictive biomarker in acute kidney injuries, but there are few studies that have investigated the role of NGAL in primary VUR in children. Our aim is to review the predictive value of urine NGAL (uNGAL) as a non-invasive biomarker of RN in children with primary VUR, as well as its ability to predict the evolution of chronic kidney disease (CKD). Based on our analysis of the available original studies, uNGAL can be an accurate and reliable biomarker of RN and its progression to CKD. Some studies suggested a good correlation between VUR severity and uNGAL levels, but other studies found no significant correlation. The relationship between VUR severity and uNGAL levels is likely complex and influenced by factors such as UTIs, the timing of the urine sample collection, and the age and overall health of the patient.

Thrombotic microangiopathy can present itself in the form of several clinical entities, representing a real challenge for diagnosis and treatment in pediatric practice. Our article aims to explore the evolution of two rare cases of pediatric thrombotic thrombocytopenic purpura (TTP) and atypical hemolytic uremic syndrome (aHUS) with extremely similar clinical pictures, which, coincidentally, presented at approximately the same time in our hospital. These cases and our literature review demonstrate the multiple facets of thrombotic microangiopathy, which can produce various determinations and salient manifestations even among the pediatric population. TTP and aHUS may represent genuine diagnostic pitfalls through the overlap of their clinical and biological findings, although they develop through fundamentally different mechanisms that require different therapeutic approaches. As a novelty, we underline that COVID-19 infection cannot be excluded as potential trigger for TTP and aHUS in our patients and we predict that other reports of such an association will follow, raising a complex question of COVID-19’s implication in the occurrence and evolution of thrombotic microangiopathies. On this matter, we conducted literature research that resulted in 15 cases of COVID-19 pediatric infections associated with either TTP or aHUS. Taking into consideration the morbidity associated with TTP and aHUS, an elaborate differential diagnosis and prompt intervention are of the essence.

Acute kidney injury (AKI) occurs frequently in critically ill children, having an incidence of up to 26.9% and is associated with high morbidity and mortality in pediatric intensive care units (PICU). Currently, the decrease in the glomerular filtration rate is calculated using the serum creatinine levels. Nevertheless, there may be a 48 h delay between the renal injury and measurable increase in creatinine. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) has been validated in relation to cardiopulmonary bypass in children, being able to detect AKI before the functional change proven by the rise in serum creatinine. Our aim was to study the utility of using uNGAL in the management of critical pediatric patients admitted to our hospital in a six month period, more specifically, its capacity to predict AKI development, alone and in the association with the renal angina index (RAI). Twenty-eight critically ill children aged from 1 day to 15 years have been included. We found that an increase in uNGAL in day 1 of admission in the PICU was significantly correlated with a decrease in creatinine clearance but not anymore in day 3. However, in our sample uNGAL did not show a significant predictability for AKI development nor the supplementary incorporation of RAI into the prediction model. Therefore, apart from cardiac surgery, the efficacy and utility or uNGAL in the management of critically ill children is still questionable. For the best prediction, we will need to incorporate not only the RAI or other PICU scores, but other biomarkers such as KIM-1, urinary cystatin, and IL 18 in larger samples.