Lauritano Ernesto Cristiano, Bilotta Anna Lisa, Gabrielli Maurizio, Scarpellini Emidio, Lupascu Andrea, Laginestra Antonio, Novi Marialuisa, Sottili Sandra, Serricchio Michele, Cammarota Giovanni, Gasbarrini Giovanni, Pontecorvi Alfredo, Gasbarrini Antonio
Internal Medicine Department, Catholic University of Sacred Heart, Gemelli Hospital, Largo A. Gemelli, 8, 00168 Rome, Italy.
J Clin Endocrinol Metab. 2007 Nov;92(11):4180-4. doi: 10.1210/jc.2007-0606. Epub 2007 Aug 14.
Small intestinal bacterial overgrowth is defined as an abnormally high bacterial population level in the small intestine. Intestinal motor dysfunction associated with hypothyroidism could predispose to bacterial overgrowth. Luminal bacteria could modulate gastrointestinal symptoms and interfere with levothyroxine absorption. The aims of the present study were to assess the prevalence and clinical pattern of bacterial overgrowth in patients with a history of overt hypothyroidism and the effects of bacterial overgrowth decontamination on thyroid hormone levels.
A total of 50 consecutive patients with a history of overt hypothyroidism due to autoimmune thyroiditis was enrolled. Diagnosis of bacterial overgrowth was based on positivity to a hydrogen glucose breath test. Bacterial overgrowth positive patients were treated with 1,200 mg rifaximin each day for a week. A glucose breath test, gastrointestinal symptoms, and thyroid hormone plasma levels were reassessed 1 month after treatment.
A total of 27 patients with a history of hypothyroidism demonstrated a positive result to the breath test (27 of 50, 54%), compared with two in the control group (two of 40, 5%). The difference was statistically significant (P < 0.001). Abdominal discomfort, flatulence, and bloating were significantly more prevalent in the bacterial overgrowth positive group. These symptoms significantly improved after antibiotic decontamination. Thyroid hormone plasma levels were not significantly affected by successful bacterial overgrowth decontamination.
The history of overt hypothyroidism is associated with bacterial overgrowth development. Excess bacteria could influence clinical gastrointestinal manifestations. Bacterial overgrowth decontamination is associated with improved gastrointestinal symptoms. However, fermenting carbohydrate luminal bacteria do not interfere with thyroid hormone levels.
小肠细菌过度生长被定义为小肠内细菌数量异常增多。与甲状腺功能减退相关的肠道运动功能障碍可能易导致细菌过度生长。肠腔内细菌可调节胃肠道症状并干扰左甲状腺素的吸收。本研究的目的是评估有明显甲状腺功能减退病史患者中细菌过度生长的患病率和临床模式，以及细菌过度生长清除对甲状腺激素水平的影响。
连续纳入50例因自身免疫性甲状腺炎导致明显甲状腺功能减退病史的患者。细菌过度生长的诊断基于氢葡萄糖呼气试验呈阳性。细菌过度生长阳性的患者每天服用1200mg利福昔明，持续一周。治疗1个月后重新评估葡萄糖呼气试验、胃肠道症状和甲状腺激素血浆水平。
共有27例甲状腺功能减退病史患者呼气试验结果呈阳性（50例中的27例，54%），而对照组中有2例呈阳性（40例中的2例，5%）。差异具有统计学意义（P<0.001）。腹部不适、肠胃胀气和腹胀在细菌过度生长阳性组中更为普遍。抗生素清除后这些症状明显改善。成功清除细菌过度生长对甲状腺激素血浆水平没有显著影响。
明显甲状腺功能减退病史与细菌过度生长的发生有关。过多的细菌可能影响临床胃肠道表现。清除细菌过度生长与胃肠道症状改善有关。然而，发酵碳水化合物的肠腔内细菌不会干扰甲状腺激素水平。
