Konstantinos Kakleas

IgA vasculitis (IgAV) is the most common systemic vasculitis in childhood. Its seasonal distribution and frequent respiratory or gastrointestinal prodromes implicate environmental exposures. However, microbiological detection temporally proximate to disease onset is insufficient to establish causality in an individual patient. To critically evaluate infectious exposures associated with pediatric IgAV, we distinguished epidemiological associations from incidental detection and infectious mimics, and separate direct IgAV evidence from mechanisms extrapolated from IgA nephropathy or general mucosal immunology. PubMed and MEDLINE were searched from inception through 6 August 2026 and supplemented by backward and forward citation tracking. Controlled-vocabulary and free-text terms addressed IgAV, pediatric populations, infection, specific pathogens, microbiota, vaccination, and immune mechanisms. The broad query retrieved 1,174 records before deduplication. Because screening was not prospectively logged, deduplicated screening and full-text counts could not be reconstructed; accordingly, no systematic-review or PRISMA completeness claim is made. Comparative evidence was most consistent for group A streptococcal exposure and population-level circulation of seasonal respiratory bacteria. Evidence for Mycoplasma pneumoniae , Helicobacter pylori in selected phenotypes, SARS-CoV-2, and specific enteric or parasitic infections was of lower certainty and was frequently case-based. Pediatric vaccine studies did not demonstrate a consistent excess risk. Evidence supports convergence of mucosal IgA induction, IgA1-containing immune complexes, complement activation, FcαRI-mediated myeloid signaling, neutrophil extracellular traps, and endothelial injury. Causal attribution requires integrated assessment of temporality, anatomical source, microbiological specificity, background exposure prevalence, and alternative diagnoses. Infectious investigations should be restricted to circumstances in which identification of a treatable infection, persistent antigen source, or immunosuppression-related hazard would alter management.

Background: Pediatric transfers to tertiary hospitals may vary according to geographic origin and referral pathways and may impose substantial healthcare costs. However, data regarding pediatric transfer pathways, tertiary hospital-level care/admission, and transport-related expenditure in Greece remain limited. Methods: We conducted a retrospective observational study of children aged 0–16 years transferred to a tertiary children’s hospital in Athens, Greece, during 2022–2023. Transfers were classified as prehospital emergency medical service (EMS) transports or interfacility transfers. Post-transfer outcomes were analysed using a predefined binary endpoint: ED/short-stay discharge versus tertiary hospital-level care/admission. Potentially avoidable transfers were identified using conservative predefined resource-utilization criteria. Transport costs were analysed descriptively according to transport modality and geographic region. Results: A total of 423 pediatric transfers were analysed, including 216/423 (51.1%) prehospital EMS transports and 207/423 (48.9%) interfacility transfers. Overall, 224/423 children (53.0%) required tertiary hospital-level care/admission, whereas 199/423 (47.0%) were managed as ED/short-stay discharges. Importantly, only 54/199 ED/short-stay discharge cases met the stricter criteria for potential avoidability, representing 54/423 (12.8%) of all transfers. Ground ambulance accounted for most transfers, whereas air and sea transport accounted for only 12.1% of transfers, but 97.0% of transport-related expenditure. In unadjusted pathway-level analysis, interfacility transfer was associated with higher odds of tertiary hospital-level care/admission than prehospital EMS transport (OR 3.72, 95% CI 2.49–5.57; p < 0.001) and accounted for 93.8% of total transport costs. Conclusions: Most pediatric transfers resulted in tertiary hospital-level care/admission, and only a minority met the predefined criteria for potential avoidability. A substantially higher proportion of interfacility transfers resulted in tertiary hospital-level care/admission, and these transfers accounted for a disproportionate share of recorded transport expenditure.

Background: The increasing incidence of cannabis consumption and marijuana legalization in many countries worldwide has led to a growing exposure of the pediatric populations, leading to a steady increase in the number of unintentional cannabis intoxications in children and infants. Edible cannabis formulations have gained popularity, sometimes being 10-times stronger compared to the old ones, leading to neurological defects (dizziness, altered mental status, and generalized neurological dysregulation) in vulnerable pediatric individuals. Case presentation: We report a case of unintentional cannabinoid intoxication in a child experiencing altered mental status. After elimination of differential diagnoses, a toxic origin was considered, and biological testing led to the diagnosis of cannabis intoxication. Conclusions: Reporting similar cases is of great importance for increasing awareness among healthcare providers, thereby facilitating rapid diagnosis and therapeutic evaluation, especially in vulnerable populations.

Summary: Mediterranean children with allergic rhinitis from Athens, Greece, showed age‐dependent aeroallergen sensitisation patterns. Polysensitization predominated and was independently associated with asthma/wheeze.

Background: Pediatric transfers to tertiary hospitals may reflect disparities in regional healthcare capacity and impose substantial healthcare costs. However, data regarding pediatric transfer pathways, tertiary-care utilization, and transport-related expenditure in Greece remain limited. Methods: We conducted a retrospective observational study of children aged 0–16 years transferred to a tertiary children's hospital in Athens, Greece, during 2022–2023. Transfers were classified as prehospital emergency medical service (EMS) transports or interfacility transfers. Post-transfer outcomes were analysed using a predefined binary endpoint: ED/short-stay discharge versus tertiary hospital-level care/admission. Potentially avoidable transfers were identified using conservative predefined resource-utilization criteria. Transport costs were analysed descriptively according to transport modality and geographic region. Results: A total of 423 pediatric transfers were analysed, including 216/423 (51.1%) prehospital EMS transports and 207/423 (48.9%) interfacility transfers. Overall, 224/423 children (53.0%) required tertiary hospital-level care/admission, whereas 199/423 (47.0%) were managed as ED/short-stay discharges. Importantly, only 54/199 ED/short-stay discharge cases met the stricter criteria for potential avoidability, representing 54/423 (12.8%) of all transfers. Ground ambulance accounted for most transfers, whereas air and sea transport accounted for only 12.1% of transfers, but 97.0% of transport-related expenditure. Interfacility transfers were substantially more likely than prehospital EMS transports to require tertiary hospital-level care/admission (OR 3.72, 95% CI 2.49–5.57; p < 0.001) and accounted for 93.8% of total transport costs. Conclusions: Most pediatric transfers were associated with clinically meaningful tertiary-level care, and only a minority met predefined criteria for potential avoidability. Interfacility transfers demonstrated substantially higher tertiary-care utilization and disproportionately concentrated transport expenditure, highlighting the importance of strengthening regional pediatric capacity and optimizing referral networks to improve the efficiency of pediatric transfer systems.

Background and Clinical Significance: Overlap of diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS) in children is a rare but life-threatening metabolic emergency. The coexistence of hyperosmolality and ketoacidosis increases neurologic vulnerability and complicates fluid and insulin management. Early identification and osmolality-guided therapy are essential to prevent cerebral edema and other complications. This case describes a 5-year-old boy with new-onset type 1 diabetes mellitus (T1D) presenting with DKA/HHS overlap two weeks after influenza vaccination—an unusual temporal association without proven causality. Case Presentation: A previously healthy 5-year-old presented with progressive polyuria, polydipsia, nocturnal enuresis, fatigue, and drowsiness. Two weeks earlier, he had received the influenza vaccine. Examination revealed moderate dehydration without Kussmaul respiration or altered consciousness. Laboratory evaluation showed glucose 45.9 mmol/L (826 mg/dL; reference 3.9–7.8 mmol/L), venous pH 7.29 (reference 7.35–7.45), bicarbonate 12 mmol/L (reference 22–26 mmol/L), moderate ketonuria, and measured serum osmolality 344 mOsm/kg (reference 275–295 mOsm/kg), fulfilling diagnostic criteria for DKA/HHS overlap. After an initial 20 mL/kg 0.9% NaCl bolus, fluids were adjusted to maintenance plus approximately 10% deficit using 0.45–0.75% NaCl according to sodium/osmolality trajectory. Intravenous insulin (approximately 0.03–0.05 IU/kg/h) was initiated once blood glucose no longer decreased adequately with fluids alone and had stabilized near 22.4 mmol/L (≈400 mg/dL). Dextrose was added when glucose reached 13.9 mmol/L (250 mg/dL) to avoid rapid osmolar shifts. Hourly neurological and biochemical monitoring ensured a glucose decline of 2.8–4.2 mmol/L/h (50–75 mg/dL/h) and osmolality decrease ≤3 mOsm/kg/h. The patient recovered fully without cerebral edema or neurologic sequelae. IA-2 antibody positivity with low C-peptide and markedly elevated HbA1c confirmed new-onset T1D. Conclusions: This case highlights the diagnostic and therapeutic challenges of pediatric DKA/HHS overlap. Osmolality-based management, conservative insulin initiation, and vigilant monitoring are crucial for preventing complications. The temporal proximity to influenza vaccination remains incidental.

As the pediatric COVID-19 landscape evolves, it is essential to evaluate whether SARS-CoV-2 infection predisposes children to allergic disorders. This narrative review synthesizes current epidemiological and immunological evidence linking pediatric COVID-19 with new-onset atopy. Epidemiological data remain heterogeneous: large Korean and multinational cohorts report increased risks of asthma and allergic rhinitis following COVID-19, whereas U.S. cohorts show neutral or protective associations, highlighting geographic and methodological variability. Mechanistic insights provide biological plausibility: epithelial injury and the release of alarmin cytokines (IL-33, IL-25, TSLP) promote Th2 polarization and ILC2 expansion, while epigenetic “scars” (e.g., LMAN2 methylation changes) and hematopoietic stem cell reprogramming may sustain long-term Th2 bias. Cytokine memory involving IL-7 and IL-15 contributes to altered T- and B-cell homeostasis, whereas disrupted regulatory T-cell function may reduce tolerance thresholds. Paradoxical trade-offs exist, such as ACE2 downregulation in allergic airways, which may lower viral entry but simultaneously amplify type-2 inflammation. Together, these processes suggest that SARS-CoV-2 infection could foster a pro-allergic milieu in susceptible children. Although current evidence is inconclusive, integrating epidemiological surveillance with mechanistic studies is crucial for predicting and alleviating post-COVID allergic outcomes. Longitudinal pediatric cohorts and interventions targeting epithelial alarmins or microbiome restoration may hold promise for prevention.

Background/Objectives: Gestational diabetes mellitus (GDM) and maternal obesity are major global health gestation-related conditions associated with several adverse maternal and neonatal outcomes. GDM is a common gestational metabolic disorder, presented usually during the second or third trimester of pregnancy with maternal hyperglycemia due to insulin intolerance. Maternal obesity, defined as a BMI of a woman during gestation ≥ 30 kg/m², has been associated with maternal complications such as GDM, fetal macrosomia and others. Methods: The presented article is a narrative review. The aim of this study was to review scientific evidence and conduct a comprehensive analysis of GDM and maternal obesity (“diabesity”) and its immediate and late complications for both maternal and fetal/offspring wellbeing. Results: This review highlighted that gestational hyperglycemia results in oxidative and nitrogen stress development and that maternal obesity may have an impact similar to maternal diabetes, as it may cause fetal macrosomia and cardiometabolic complications later in life. Conclusions: Optimal diabetic control is responsible for the prevention of oxidative stress in diabetic pregnancies. Similarly, pregnant women should exercise regularly, receive folic acid supplementation and avoid excess weight gain during pregnancy. Breastfeeding during the first months of life has a positive impact on weight monitoring in infants born to mothers with diabesity and may be crucial in the prevention of obesity and metabolic syndrome later in life.

Purpose Adolescents with type 1 diabetes mellitus (T1DM) may differ from their healthy peers with respect to sexual behavior. The aim of this study was to explore sexual behaviors of T1DM adolescents in Greece in comparison with healthy peers. Methods The study population included 174 Greek adolescents, of whom 58 were T1DM adolescents (mean ± SD age 16.3 ± 2.0 years, disease duration 6.7 ± 3.5 years, and HbA1c:8.0 ± 1.3%), and 116 healthy controls (matching 1:2 for school, class, and gender). Anonymous self-reported questionnaires were used to evaluate sexual education and behavior. Results T1DM adolescents had sexual experience at a significantly lower percentage than healthy peers (74.1% vs. 87.4%, p = 0.033). The average age of first sexual intercourse was similar for both groups (15.9 ± 1.8 years vs. 15.2 ± 1.5 years for T1DM and controls, respectively). In the control group, boys had sexual intercourse two times more frequently than girls and those in the T1DM group three times more frequently. Maternal education level (β = -1.47, p = 0.014) and HbA1c (β = -0.63, p = 0.49) were independently negatively associated with age at first sexual experience and first sexual intercourse (maternal education: β = -1.53, p = 0.003, HbA1c: β = -0.92, p < 0.001), respectively. Conclusion A significant percentage of the T1DM adolescents had sexual experience or intercourse. However, fewer T1DM adolescents had sexual experience compared to their healthy peers, with girls having less frequent sexual intercourse than boys. Maternal education level and glycemic control were negatively associated with age at sexual debut. The above findings underline the need for early sexual education of adolescents with or without diabetes for the prevention of unfavorable outcomes.

Over the past few decades, the scientific community has been highly concerned about the obesity epidemic. Artificial sweeteners are compounds that mimic the sweet taste of sugar but have no calories or carbohydrates; hence, they are very popular among patients suffering from diabetes or obesity, aiming to achieve glycemic and/or weight control. There are four different types of sweeteners: artificial, natural, rare sugars, and polyols. Artificial and natural sweeteners are characterized as non-nutritional sweeteners (NNSs) since they do not contain calories. The extended use of sweeteners has been reported to have a favorable impact on body weight and glycemic control in patients with type 2 diabetes (T2DM) and on tooth decay prevention. However, there is concern regarding their side effects. Several studies have associated artificial sweeteners’ consumption with the development of insulin resistance, nonalcoholic fatty liver disease (NAFLD), gastrointestinal symptoms, and certain types of cancer. The present review focuses on the description of different types of sweeteners and the benefits and possible deleterious effects of the chronic consumption of NNSs on children’s health. Additionally, possible underlying mechanisms of the unfavorable effects of NNSs on human health are described.