The metabolic syndrome (MS) is a clinical entity of substantial heterogeneity, represented by the combination of obesity (especially central obesity),insulin resistance, impaired glucose tolerance, atherogenic dyslipidemia (high triglyceride levels and low levels of HDL-cholesterol (HDL-C)), and hypertension. Childhood obesity has become more common as a result of urbanization, bad diets, and more sedentary lifestyles.

The incidence of metabolic syndrome is ten times higher in children with obesity, and a special risk factor is the presence of obesity in the pediatric population, the classification of metabolic syndrome is based on standards set by the International Diabetes Federation (IDF).

Our goal is to summarize the diagnostic procedure of metabolic syndrome as well as comorbidity based on conventional methods and modern imaging procedures by analyzing the published papers.

Bronchiolitis is an acute viral disease of lower respitatory pathways in children under 2 years of age. It is manifested by coughing, whistling and refusing food intake. The most common cause of bronchiolitis is a respiratory syncytial virus. Vitamin D is a steroid hormone which is synthesized in the skin after sun exposure or food intake. With discovery of Vitamin D receptors and hydroxylated enzymes in immune cells, a potential role for Vitamin D in maintaining immune homeostasis was seen. It has been established that Vitamin D induces a change of the antimicrobial polypeptide, cathelicidin, which has both antibacterial and antiviral roles.

Hypoglycemia is defined asplasma glucose level sufficiently low to result in neurological damage. In the new-born age, the incidence of hypoglycemia ranges from 0.4-11.4%. Etiologically, low levels of plasma glucose can result from the hormonal or metabolic disorders; high doses of insulin, drug poisoning, liver disease or systemic disorders. The most common cause of severe and permanent hypoglycemia in the neonatal age group is congenital hyperinsulinism - the result of pancreatic cells hyperplasia and/or adenoma. Between two and five years of age, the most common form of hypoglycemic state is ketotic hypoglycemia of childhood, caused by limited amount of substrate. Diagnostic criteria include biochemical confirmation of low of glucose and/or high insulin levels, blood hormone testing (epinephrine, cortisol, growth hormone, glucagon levels), as well as metabolic screeningfor gluconeogenesis, glycogenolysis, and lipolysis disorders and disarrangements of fatty acid oxidation. Therapy is directed towards the substrate supplementation and the application of medications and fuels aiming atrapid attainment of normoglycemia (fruit juices, parenterally applied glucose and dextrose, glucagone, corticosteroid therapy); diazoxide and somatostatin therapy is indicated for patients with hyperinsulinemia.

Introduction: Vitamin D Deficiency (VDD) is defined as the level of 25(OH)D in the serum < 30 ng/ml. According to the contemporary research, even the slight vitamin D deficiency can adversely affect our body in many ways. Numerous studies indicate that vitamin D deficiency is very common in children. The study aimed to research the frequency of vitamin D deficiency in infants and toddlers, the connection between VDD and iron deficiency anemia (IDA), as well as the correlation between 25-hydroxycholecalciferol (25(OH)D) and haemoglobin (Hb) in the examinees. Method: The study includes 150 children, 73 (49%) newborns and 77 (51%) infants. Vitamin D status was determined through the amount of 25(OH)D in blood, using the electrochemiluminescence. Results: Vitamin D Deficiency was found in 58% of infants and toddlers (severe vitamin D deficiency was found in 16% of examinees, vitamin D deficiency was found in 23% of examinees, while vitamin D insufficiency was found in 19% of examinees). Vitamin D deficiency (VDD) and anaemia were found in 80% of examined infants and toddlers. VDD was found in 49% of newborns that were not anaemic. We have observed the substantial difference between the examinees suffering from both anaemia and VDD and the examinees suffering from VDD only. Conclusion: The highest level on anaemia was found in the children with severe vitamin D deficiency, while in the examined infants and toddlers, there was a connection between the level of 25(OH)D and Hb in the serum.