乳幼児における結核家族検診, 特に初感染に対する予防内服の有用性 EFFICACY OF TUBERCULOSIS CONTACTS INVESTIGATION AND TREATMENT, ESPECIALLY OF PREVENTIVE THERAPY IN INFANTS AND YOUNG CHILDREN
[目的] 今後の乳幼児接触者検診における方針決定に役立てるため, 現行の検診の有用性, 特に予防内服の発病阻止効果を後方視的に検討した。 [対象と方法] 活動性肺結核患者と家庭内接触して接触者検診に来院し, 少なくとも2年間経過観察できた0～4歳児273名とした。 [結果] 初回検診で発病児は273名中60名 (22%), 発病が疑われた児は37名 (14%) であった。すべての発病, 発病が疑われた児において治療は完了され, 再燃を認めなかった。26名 (9%) が未感染と診断された。その25名において発病を認めなかったが, 1名に2カ月後の2回目検診時に発病を認めた。150名 (55%) が初感染と診断され, 6カ月間イソニアジド (10mg/kg/日) を服用した。服薬開始直後, 1名に発病が認められた。他の149名において内服は完了されて発病を認めず, 服薬中に血清GOT, GPTが100単位/Lを超す肝機能障害を生じなかった。 [考察] 現状の家族検診は有用であり, 発病の有無を明確にして治療, 予防内服を行えば再燃, 発病をほぼ完全に, 安全に阻止していることを示した。また, 感染の証拠が得られずに未感染とされた児を含めて未発病家庭内接触乳幼児全員に, 予防内服を躊躇なく始めることが潜在結核感染症を減少させる選択肢の1つであることを示唆する。
[Background] Although large clinical trials reported in 1960s suggested that preventive therapy in subjects with tuberculosis (TB) infection reduces the risk of developing TB by 70-90%, the therapy in our TB clinic seems to be more effectiveness.<BR>[Objective] We retrospectively evaluated the efficacy of the present contacts investigation, especially of preventive therapy for further improvement of TB control for children.<BR>[Methods] We examined 273 asymptomatic infants and children younger than five years who had household contacts with active TB patients and visited our clinic for contact investigation. After the diagnosis at the first visit to our TB clinic, they were treated and/or observed for at least two years to assess whether contact investigations and following treat ment are appropriate. Since infants less than a year are under developed in cellmediated immunity and their tuberculous lymphadenopathy can be overlooked on standard chest radio graphs, chest CT scans were added.<BR>[Results] At their first visit, 60 (22%) out of 273 subjects were diagnosed as TB, and 37 (14%) were suspected as TB. We treated them by combinations of and-TB medicines including isoniazid and rifampin for six to 12 months, and they did not relapse during the observation period. Twenty-six subjects (9%) were diagnosed uninfected. However, a threeyear-old girl developed bilateral hilar lymphadenopathy two months later when the reexamination was done. A hundred and fifty subjects (55 %) were diagnosed to have TB infection. They received preventive therapy with isoniazid (10 mg/kg/day) for six months. Among them, a fourmonth-old boy developed TB disease soon after starting to take isoniazid and was treated by the combination of and-TB medicines. Other 149 subjects completed the therapy, and none of them developed disease during the observation period. There was no increase in serum GOT and/or GPT to >100 IU/L within one month after starting to take isoniazid.<BR>[Conclusion] The present contacts investigations and treatments in our TB clinic are useful ways to find out and control TB diseases and infections, and it might be suggested to start the sixmonths preventive therapy after active TB has been ruled out in all infants and children who had close contacts with active TB patients for preventing TB disease and latent TB infection in the future even their clinical and laboratory examinations do not suggest infection.
結核 78(11), 677-682, 2003-11-15
JAPANESE SOCIETY FOR TUBERCULOSIS