The aims of this study were to evaluate: (1) associations of vitamin D with the presence/severity of Hashimoto’s thyroiditis (HT) and (2) correlations of vitamin D with thyroid-related phenotypes. Total 25(OH)D (vitamin D in the text) was measured from stored serum samples of 461 HT patients and 176 controls from a Croatian Biobank of HT patients (CROHT). (1) Vitamin D levels, and proportions of vitamin D deficiency, were compared between HT cases and controls. HT patients were additionally divided into two groups (MILD and OVERT) to take into account HT severity. (2) Correlations between vitamin D and 10 clinical phenotypes in all HT patients and two subgroups of HT patients were tested using the Spearman correlation test. Our analyses were adjusted for age, gender, BMI, smoking status and seasonality of blood sampling. (1) No significant differences in vitamin D levels, or proportions of vitamin D deficiency, were detected between HT patients of all disease stages and controls. However, a nominally significant difference in vitamin D levels between MILD and OVERT subgroups (OR = 1.038, p = 0.023) was observed. Proportions of individuals with vitamin D deficiency during winter–spring were high: all HT cases (64.69%), MILD (60.64%), OVERT (68.7%), controls (60.79%). (2) A nominally significant negative correlation between vitamin D and TSH in all HT patients (r = −0.113, p = 0.029) and a positive correlation between vitamin D and systolic blood pressure in OVERT HT patients (r = 0.205, p = 0.025) were identified. Our study indicates that there is no association between vitamin D and HT; however, there may be a subtle decrease in vitamin D levels associated with overt hypothyroidism.

Cataract is a rare manifestation of ocular complication at an early phase of T1DM in the pediatric population. The pathophysiological mechanism of early diabetic cataract has not been fully understood; however, there are many theories about the possible etiology including osmotic damage, polyol pathway, and oxidative stress. The prevalence of early diabetic cataract in the population varies between 0.7 and 3.4% of children and adolescents with T1DM. The occurrence of diabetic cataract in most pediatric patients is the first sign of T1DM or occurs within 6 months of diagnosis of T1DM. Today, there are many experimental therapies for the treatment of diabetic cataract, but cataract surgery continues to be a gold standard in the treatment of diabetic cataract. Since the cataract is the leading cause of visual impairment in patients with T1DM, diabetic cataract requires an initial screening as well as continuous surveillance as a measure of prevention and this should be included in the guidelines of pediatric diabetes societies.

Aim/Hypothesis. To examine whether children with DMT1 are less physically fit than healthy children and to assess whether an elevated level of HbA1c was associated with decreased physical fitness among children with diabetes.Methods. The study was conducted using case-control methodology. The cases were 100 children with T1DM, 7–17,9 years. Study subjects underwent a 6MWT, where distance measured, heart rate, and oxygen saturation was recorded.Results. Results of the 6MWT for children with T1DM and controls were 601.3 ± 86.1 meters versus 672.1 ± 60.6 meters, respectively (P<0.001). The cases were divided into two subgroups, one with HbA1c levels >8% and one with HbA1c <8%. Results for both groups were inferior to the controls (P<0.001). The posttest pulse rate in all subjects was higher than the pretest pulse rate (P<0.001). Pulse oxygen levels were lower than controls at the pretest measurement (P<0.001), and for both cases and controls, pulse oxygen levels decreased after test (P=0.004). However, the change in oxygen saturation did not differ between the groups (P=0.332).Conclusions. Children with T1D are less fit than matched controls. The level of HbA1c did not affect the physical fitness of children with T1D.

Summary This is a case report of a child with chronic hyponatremia due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) as a paraneoplastic manifestation of olfactory neuroblastoma (OFN). We hereby report a clinical presentation as well as a pragmatic approach to one of the most common electrolytic disorders in the pediatric population and have emphasized the necessity of involving the sinonasal area in the diagnostic procedure while evaluating possible causes of SIADH. This report indicates that the chronicity of the process along with the gradual onset of hyponatremia occurrence is responsible for the lack of neurological symptoms at the moment of disease presentation. Learning points Hyponatremia is not infrequently attributed to SIADH. Paraneoplastic syndromes are uncommon but they should be considered in the differential diagnosis of pediatric SIADH. Chronic insidious hyponatremia may not be associated with clear neurological symptoms despite its severity. Abstract Summary This is a case report of a child with chronic hyponatremia due to the syndrome of inappropriate antidiuretic hormone secretion (SIADH) as a paraneoplastic manifestation of olfactory neuroblastoma (OFN). We hereby report a clinical presentation as well as a pragmatic approach to one of the most common electrolytic disorders in the pediatric population and have emphasized the necessity of involving the sinonasal area in the diagnostic procedure while evaluating possible causes of SIADH. This report indicates that the chronicity of the process along with the gradual onset of hyponatremia occurrence is responsible for the lack of neurological symptoms at the moment of disease presentation. Learning points Hyponatremia is not infrequently attributed to SIADH. Paraneoplastic syndromes are uncommon but they should be considered in the differential diagnosis of pediatric SIADH. Chronic insidious hyponatremia may not be associated with clear neurological symptoms despite its severity.

Background: Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) is a rare monogenetic autosomal recessive disorder caused by a mutation in the autoimmune regulator (AIRE) gene characterized by complex phenotypic characteristics discovered over years of follow-up. Methods: 7 patients were recruited in this case series in a period of the last 37 years from Southern Croatia. All patients were screened for AIRE R257X mutations. Results: This study group had a mean current age of 25.3 years (age range from 5.4 to 40.2 years), while the mean age at the onset of the disease was 6.5 years (age range from 0.7 to 9.2 years) and with a mean follow-up period of 17.8 years. The overall prevalence of APECED syndrome is estimated to be 1 in 75,000. The most common initial manifestation of the disease was onychodystrophy, while the first major component of APECED syndrome was chronic mucocutaneous candidiasis. Conclusions: APECED is a ‘‘multi-faced’’ disease based on the very unpredictable and inconsistent onset of major components. Furthermore, based on our results, we suggest that onychodystrophy could be included as a warning sign of APECED syndrome.