The influence of Epstein–Barr-associated infection upon pituitary-thyroid system in children at different periods of the disease

BACKGROUND: The interest in infectious mononucleosis caused by the Epstein–Barr virus (EBV) is currently apparent. Epstein–Barr virus reaches tropism for reticular and lymphoid tissues, does not eliminate from the body and causes an immunopathological process in which the endocrine system develops. Thyroxine (T₄), triiodothyronine (T₃), and thyroid-stimulating hormone determinations are the most widely used diagnostic tests to assess thyroid function. AIM: To study changes in T₃, T₄, thyroid-stimulating hormone in children of older sex and age at the height and convalescence of infectious mononucleosis, the period of Epstein–Barr virus. MATERIALS AND METHODS: Under the supervision of the child were 94 aged from 1 to 17 years, among them from 1 to 5 years – 22%, from 5 to 10 years — 39%, from 10 to 15 years — 27%, from 15 to 17 years — 12% , diagnosed with Epstein–Barr virus – mononucleosis, moderate severity. The diagnosis was made on the basis of clinical, anamnestic and laboratory data. The studies leading to the diagnosis were carried out in the laboratory of the Saint Petersburg State Pediatric Medical University. In addition to routine settings (clinical minimum), detection of M- and G- antibodies to Epstein–Barr virus, detection of the genome in the blood by PCR, determination of the levels of T₃, T₄, thyroid-stimulating hormone by enzyme-linked immunosorbent assay in blood serum. RESULTS: Regular changes in T₃ concentrations were registered in both girls and boys of all three age groups: the concentration of T₃, T₄ in the period of the peak of the disease was reduced compared to the period of convalescence. Significant changes in thyroid-stimulating hormone were registered in girls and boys of all three age groups: the concentration of thyroid-stimulating hormone during the peak of the disease slightly decreased compared to the period of convalescence in boys and increased compared to the period of convalescence in girls. CONCLUSIONS: The changes in the levels of T₃, T₄, thyroid-stimulating hormone in children during the peak of infectious mononucleosis depends on the severity of the disease, the presence and nature of complications.