S0500 Intestinal Methanogen Overgrowth (IMO) in Parkinson's Disease: High Prevalence and Correlation With Constipation

Abstract

INTRODUCTION: Recent ACG guidelines have defined intestinal methanogenic overgrowth (IMO) and described its clinical significance. The prevalences of small intestinal bacterial overgrowth (SIBO) and IMO in Parkinson's disease (PD) are unclear. SIBO in PD is linked to worse motor symptoms. Treatment of SIBO can improve motor function in PD. Our aim is to quantify the prevalence of SIBO and IMO in Parkinson's disease (PD) subjects with constipation compared to patients with unexplained GI symptoms undergoing glucose breath testing (GBT). METHODS: After an overnight fast and day of low-CHO diet, subjects brushed their teeth and rinsed their mouth with antiseptic mouthwash 2h before test. During GBT, 75 g of glucose dissolved in 250 mL water was administered. Breath samples were obtained at baseline and 15 min intervals for 2 h. Samples are collected in a bag (QuinTron Instrument Company, Inc.) and alveolar gas was analyzed for both H2 and CH4 levels by chromatography (QuinTron Micro Analyzer, QuinTron, Inc.). SIBO was defined as H2 rise of ≥20 ppm from baseline and/or CH4 rise of ≥10 ppm. IMO was defined as any measured CH4 ≥ 10 ppm. Daily bowel movements were assessed by prospective stool diary. Constipation was defined by <3 complete spontaneous bowel movements (CSBMs)/week. RESULTS: Nineteen patients with PD (68.2 ± 7.0 years, F/M = 6/13) underwent breath testing and compared to 158 subjects with unexplained GI symptoms (47.4 ± 15.3 years, F/M = 119/39). 31.6% (6/19) of PD subjects had SIBO versus 23.4% (37/158) of subjects with unexplained GI symptoms (P = 0.95), shown in Table 1. 52.6% (10/19) of PD subjects had IMO compared to 14.6% (23/158) subjects with unexplained GI symptoms (P < 0.001). 36.8% (7/19) had < 3 CSBMs per week. There was significant correlation between constipation and IMO, but not SIBO, Table 2. Higher maximum methane levels during GBT also significantly correlated with the presence of constipation. CONCLUSION: Rates of SIBO are similar between PD subjects with constipation and symptomatic patients undergoing GBT. More than half and significantly more PD subjects with constipation than symptomatic patients undergoing GBT have IMO. IMO and higher methane levels correlate with constipation in PD quantified by a stool diary. Methanogens may play a critical role in non-motor symptoms of PD patients such as constipation. ACKNOWLEDGEMENT: Parkinson's Foundation Translational Research Award.Table 1.: SIBO and IMO prevalence in subjects with PD vs unexplained GI symptomsTable 2.: Correlation between IMO, maximum methane level, and SIBO with constipation