[Thyroid dysfunction in patients with small intestinal bacterial overgrowth].

Small intestinal bacterial overgrowth (SIBO), similarly as thyroid diseases, is characterized by chronic diarrhea or constipation, but it is not known whether there is a causal relationship between these disorders.

AIM: The aim of the study was to assess thyroid function indices in different clinical forms of SIBO.

MATERIALS AND METHODS: The study was performed in 34 patients with diarrhea predominant SIBO (group I), 30 with constipation predominant SIBO (group II) and 30 clinically healthy subjects (control group - K). Small intestinal bacterial overgrowth was assessed with lactulose hydrogen breath test (LHBT) using the breath-hydrogen analyzer (Gastrolyser, Bedfont). Serum thyrotropin (TSH), free triiodothyronine (FT3) and free thyroxine (FT4) levels were determined by immunochemical method (ELFA) and anti-thyroid peroxidase (ATPO) protein level by immunoenzymatic method (ELISA).

RESULTS: LHBT value was respectively in groups: K - 8,5 ± 2,9 ppm, I - 66,9 ± 16,9 ppm, II- 62,0 ± 15,5 ppm (p <0,001). The levels of hormones were similar in group K and I, whereas in group II differentiated: FSH 2,5 ± 0,7 vs. 3,8 ± 1,8 mU/L (p <0,05), FT3- 5,1 ± 1,2 vs. 3,7 ± 1,0 mU/L (p <0,05), FT4 - 14,1 ± 2,5 vs. 9,4 mU/L (p <0,01). In both groups of patients the levels of ATPO were statistically significantly higher than in the control group - respectively: K - 6,3 ± 3,1 IU/ml , I - 39,9 ± 23,4 IU/ml (p < 0,001), II - 94,1 ± 56,3 IU/ml (p <0,001).

CONCLUSIONS: Thyroid function may be impaired in patients with small intestinal bacterial overgrowth which should be taken into account in the diagnostic and therapeutic management of the diseases of these organs.