Studies in infants with hypoxic-ischemic encephalopathy (HIE) due to perinatal asphyxia have generally focused on neurological outcomes. Although acute kidney injury (AKI) rate decreased in advent of therapeutic hypothermia (TH), it is still a common and important entity. In this retrospective study, we aimed to investigate the risk factors for AKI in HIE patients treated with hypothermia. Infants treated with TH due to HIE were reviewed retrospectively and infants who developed AKI and not were compared. Ninety-six patients were enrolled in the study. AKI developed in 27 (28%) patients and 4 (14.8%) of them were stage III AKI. In the AKI group, gestational age of the patients was significantly higher ( p = 0.035), the 1st minute Apgar score was significantly lower ( p = 0.042), and convulsions (p = 0.002), amplitude-integrated electroencephalography disorders ( p = 0.025), sepsis ( p = 0.017), need for inotropic therapy ( p = 0.001), need of invasive mechanical ventilation ( p = 0.03), and systolic dysfunction in echocardiography ( p = 0.022) were significantly higher. In logistic regression tests, Apgar score at the 1st minute was found to be independent risk factor for developing AKI. AKI has the potential to worsen the neurological damage and correlates with morbidities of perinatal asphyxia. It is important to determine the incidence and risk factors for developing AKI in this delicate group of patients to prevent further renal damage.

Introduction: Although COVID-19 generally follows a mild course in children, a subset required hospitalization during the early pandemic period. Data from the pre-vaccination phase remain important for understanding risk factors associated with severe disease, particularly in upper-middle-income healthcare settings. The aim of this manuscript is to evaluate the clinical, laboratory, and radiological characteristics of hospitalized children with COVID-19 and to compare findings according to disease severity. Material and methods: This retrospective study included 97 children hospitalized with confirmed COVID-19 between October and December 2020 at a tertiary center in Türkiye. Patients were classified as non-severe or severe. Demographic, clinical, laboratory, radiological, and outcome data were compared between groups. Results: Of 97 patients, 75 (77.3%) were non-severe and 22 (22.7%) were severe. Severe patients were significantly older (median age: 136.5 months vs. 18 months, p = 0.036) and more frequently had ≥2 infected household contacts (p=0.034). Cough, dyspnea, and comorbidities were more common in severe cases. Severe disease was associated with lymphopenia, higher neutrophil-to-lymphocyte ratio, elevated CRP and D-dimer levels, increased troponin, and greater CT severity (all p<0.05). Conclusions: During the early pandemic period, older age, multiple household contacts, comorbidities, elevated inflammatory and cardiac biomarkers, and more extensive radiological involvement were associated with severe disease among hospitalized children. In exploratory multivariable analyses, D-dimer remained significantly associated with disease severity. These findings are specific to the early pandemic period before the emergence of SARS-CoV-2 variants and pediatric vaccination and require validation in contemporary pediatric cohorts.

Background/Objectives: Serum vitamin B12 testing is frequently ordered in pediatric outpatient practice, either routinely or incidentally as part of broad laboratory panels or in response to symptoms and nutritional concerns; however, how the yield of low serum vitamin B12 results varies across age groups and testing indications remains poorly defined. The primary focus was age-related variation in low serum vitamin B12 results, with recorded testing indications examined as a secondary question and symptom-specific analyses considered exploratory. Methods: This single-center retrospective study analyzed testing episodes from children aged 0–18 years attending general pediatric outpatient clinics in 2025. Outcomes were <200 pg/mL (primary) and <300 pg/mL (secondary). Two blinded physicians classified testing indications. Cluster-robust regression evaluated age, sex, and indication; 18 symptom indicators were evaluated in age- and sex-adjusted models with Benjamini–Hochberg correction. Results: Of 34,744 episodes, 34,721 were valid; 5.8% were <200 pg/mL and 27.5% were <300 pg/mL. Low-result yield (<200 pg/mL) showed a bimodal age pattern: 7.9% at ages 0–2 years, 2.3% at 3–5 years, and 10.6% at 15–18 years. The number of tests per low result ranged from 9.4 at ages 15–18 years to 42.8 at ages 3–5 years. Routine or incidental testing comprised 63.9% of episodes; crude yield by indication ranged from 4.9% to 7.3%. Compared with 6–11 years, adjusted odds were higher at 0–2 years (aOR 2.81, 95% CI 2.44–3.24) and 15–18 years (aOR 3.92, 95% CI 3.42–4.51). No indication independently predicted the primary outcome; no symptom remained significant for that outcome after false discovery rate correction. Conclusions: The yield of low serum vitamin B12 results was strongly age-dependent and bimodal, with higher-yield periods during the first two years of life and adolescence. Broad retrospectively recorded testing indications were not independently associated with results < 200 pg/mL after adjustment for age and sex. These findings support age-informed assessment alongside clinician-directed testing.