The purpose of this narrative review is to analyze the most recent studies about the role of C-reactive protein (CRP) and procalcitonin (PCT), two of the main biomarkers of infection, in distinguishing viral from bacterial etiology, in predicting the severity of infection and in guiding antibiotic stewardship in children with community-acquired pneumonia (CAP). The studies examined reveal that both CRP and PCT play a valuable role in diagnosing pediatric CAP, though each has limitations. CRP has moderate accuracy in distinguishing bacterial from viral infections, but its elevated levels are not exclusive to bacterial infections; PCT, however, shows higher specificity for bacterial CAP, with studies confirming its ability to differentiate bacterial causes, especially in severe cases. When integrated with clinical findings, CRP and PCT improve the sensitivity of pneumonia diagnoses and help in predicting severe outcomes such as sepsis and empyema; furthermore, both biomarkers prove useful in guiding antibiotic therapy, with PCT showing a more dynamic response to treatment. However, even though CRP and PCT offer valuable insights into the diagnosis and management of pediatric CAP, their application should be always integrated with clinical assessment rather than used in isolation. More studies are needed to define standardized thresholds and decision algorithms that incorporate these biomarkers.

Renal diseases in childhood form a spectrum of different conditions with potential long-term consequences. Given that, a great effort has been made by researchers to identify candidate biomarkers that are able to influence diagnosis and prognosis, in particular by using omics techniques (e.g., metabolomics, lipidomics, genomics, and transcriptomics). Over the past decades, metabolomics has added a promising number of ‘new’ biomarkers to the ‘old’ group through better physiopathological knowledge, paving the way for insightful perspectives on the management of different renal diseases. We aimed to summarize the most recent omics evidence in the main renal pediatric diseases (including acute renal injury, kidney transplantation, chronic kidney disease, renal dysplasia, vesicoureteral reflux, and lithiasis) in this narrative review.

Background: Both direct and indirect effects of COVID-19 have been found in all age groups. In particular, adult data demonstrated significant changes in patients with chronic and metabolic disease (e.g., obesity, diabetes, chronic kidney disease (CKD), and metabolic associated fatty liver dysfunction (MAFLD)), while similar pediatric evidence is still limited. We aimed at investigating the impact of the COVID-19 pandemic lockdown on the relationship between MAFLD and renal function in children with CKD due to congenital abnormalities of the kidney and urinary tract (CAKUT). Methods: A total of 21 children with CAKUT and CKD ≥ stage 1 underwent a comprehensive evaluation within 3 months before and 6 months after the first Italian lockdown. Results: At follow-up, CKD patients with MAFLD presented higher BMI-SDS, serum uric acid, triglycerides, and microalbuminuria levels and lower eGFR levels than those without MAFLD (all p < 0.05). Higher ferritin and white blood cell concentrations were also found in patients with CKD diagnosed with MAFLD than peers without MAFLD (both p = 0.01). Compared to children without MAFLD, a higher delta of BMI-SDS, eGFR levels, and microalbuminuria levels was found in patients with MAFLD. Conclusions: Due to the negative influence of the COVID-19 lockdown on cardiometabolic health in childhood, a careful management of children with CKD is warranted.

Monitoring antibiotic use in the pediatric population is a challenge, especially when determining a relationship between specific pathogens, infections, and antibiotic use. We retrospectively analyzed the consumption of anti-methicillin-resistant Staphylococcus aureus (MRSA) drugs from 2017 to 2021 at Istituto Giannina Gaslini by means of defined daily dose (DDD) adopted for adults by World Health Organization. We observed a statistically significant increase in the use of daptomycin and ceftaroline, combined with a decrease in the use of vancomycin. In the same period, we observed an increase in the proportion of bloodstream infections due to MRSA with vancomycin minimally inhibitory concentration (MIC mg/L) = 1, that represented the 100% of cases in 2021. This aspect was combined with the observation that in the 59% of cases, where vancomycin plasma concentrations were evaluated, it was not possible to achieve a ratio of the 24-h area under the concentration–time curve and MIC (AUC_0–24/MIC) of vancomycin ≥ 400 mg/L. This study confirms that DDD can be used in pediatrics to monitor antibiotic consumption in relationship with infections epidemiology. Moreover, it describes the presence of vancomycin MIC creep for MRSA also in pediatrics and the difficulties in obtaining effective vancomycin plasma concentrations in children.

Background: Parvovirus B19 (PVB19) is a small, nonenveloped, single-stranded DNA virus commonly causing asymptomatic infections or mild, flu-like symptoms. In children, PVB19 can lead to various clinical conditions, including erythema infectiosum, arthropathy, transient aplastic crisis and papular-purpuric eruptions, among others. Methods: We present 3 pediatric cases treated at Luigi Sacco University Hospital in Milan, Italy, in March 2024, each demonstrating distinct manifestations of PVB19 infection. Case 1 involved a 7-year-old girl with a maculopapular rash and panniculitis-like symptoms. Case 2 described an 8-year-old boy with a maculopapular rash, vasculitis component and mild thrombocytopenia. Case 3 focused on a 7-year-old girl with petechial and purpuric eruptions and a mild decrease in platelets. Serological tests confirmed PVB19 infection in all cases. Results: The discussed cases highlight the heterogeneous clinical spectrum of PVB19 infection and emphasize its potential to cause thrombocytopenia even in healthy children. The recent surge in PVB19 cases in Europe, aligned with known epidemiological cycles, underscores the importance of vigilance in diagnosis, particularly during peak seasons. Additionally, concerning the role of serological testing in the diagnostic process, the potential for cross-reactivity among viral antigens is pointed out. Conclusion: PVB19 is a common infection with a broad range of clinical presentations. Awareness of its potential complications, including thrombocytopenia, even in nonimmunocompromised children, is crucial. Moreover, understanding the epidemiological patterns of PVB19 can aid in anticipating and managing outbreaks, thus minimizing its impact on pediatric health.