大脳誘発電位および飲水負荷試験からみたfunctional dyspepsiaの内臓知覚の検討(シンポジウム:機能性胃腸症(Functional Dyspepsia)の病態を巡る脳腸相関,2008年,第49回日本心身医学会総会(札幌))  [in Japanese] Evaluation of Visceral Sensitivity using Cerebral Evoked Potentials and Water Load Test in Functional Dyspepsia(Symposium/Brain-gut Interaction in the Pathophysiology of Functional Dyspepsia)  [in Japanese]

目的Rome IIIでは,functional dyspepsia(FD)を食後愁訴症候群(PDS)と心窩部痛症候群(EPS)に分類している.その病態に内臓知覚異常が有力視されているが,PDSとEPSの内臓知覚異常において相違があるかどうか明らかではない.そこで,大脳誘発電位法と飲水負荷試験の2つの内臓知覚検査を用いてFDの内臓知覚について検討した.方法Rome III診断基準を満たす未受診FD有症被験者(FD non-consulter〔FD-NC〕)および健常者を対象とした.A:FD-NC 16例,健常者16例,経鼻的に挿入した電極で食道粘膜を電気刺激した.自覚症状の程度で感覚,不快,痛覚の3閾値を同定し,それぞれの閾値時の大脳誘発電位を導出し,各閾値時の電流(mA)と大脳誘発電位の出現潜時(ms)と自己記入式症状スコア(GSRS)との関連を評価した.B:FD-NC 16例(PDS 8例,EPS 8例),健常者16例に飲水負荷試験を施行した.被験者に飲水量を知られないようチューブストローで室温のミネラルウォーターを5分間で可能なだけ飲水させ,飲水前後に上腹部症状の強度を0〜4点で自己記入させた.PDSとEPSそれぞれの飲水量を評価した.結果A:FD-NCでは電気刺激による痛覚閾値が低下傾向を示し(p=0.076),大脳誘発電位N2とP2で有意な潜時の短縮がみられた(p<0.05).B:飲水量は,健常者平均853ml,PDS 863ml,EPS 800mlで同等であったが,PDSでは飲水による誘発腹部症状が高値と遷延を示した.EPSでは症状強度と推移はPDSほど顕著ではなかった.結論FD-NCでは内臓知覚情報伝達プロセスの変調が示唆された.さらに,PDSでは消化管刺激による知覚過敏性と持続性が示されたが,EPSではこの傾向は顕著ではなかった.

Background & aim: Functional dyspepsia was reclassified into meal-induced dyspepsia as postprandial distress syndrome (PDS) and epigastric pain dyspepsia as epigastric distress syndrome (PDS) in Rome III. Gastric hypersensitivity has been reported to be one of the pathogenetic mechanism of functional dyspepsia, however, it is not known whether subcategories of PDS and EPS demonstrate differencies in gastric hypersensitivity. Therefore we evaluated gastric sensation by the cerebral evoked potential and the water load test in functional dyspepsia patients. Methods: Sixteen FD subjects, fulfilling Rome III criteria for functional dyspepsia, were recruited by ad posters, and were served as functional dyspepsia non-consulters (FD-NC), and 16 healthy subjects (HS) without any dyspeptic symptoms as control participated. All subjects had gastrointestinal endoscopy, urea breath test to rule out any possible pathogenesis, and Gastrointestinal Symptoms Rating-Scale questionnaire (GSRS) for quantitative symptomatic evaluation. Study A): Visceral sensation and evoked cerebral potentials through electrical stimulation of esophageal mucosa at the level of 37cm from nostril were evaluated in 16 subjects with FD-NC and 16HSs. Study B): Water load test was performed to evaluate tolerable volume and subjective symptoms in 16 subjects with FD-NC (8 PDS, 8 EPS) and 15 HSs. Water load test was performed with rapid water drink within 5 minutes at room temperature, and subjective symptoms were evaluated in ordinate scale up to 30 minutes. Results: All subjects had no organic disease in upper GI tract nor Helicobacter pylori infection. FD-NCs showed significantly higher GSRS score than that in HSs. A): FD-NCs had lower pain threshold to the esophageal electrical stimulation than HSs (p=0.076). Latency of N2 and P2 of evoked potential were significantly shorter in FD-NCs than HSs (p<0.05). B): Consumed water volume in WLT were not remarkably different between HSs (mean 853ml), PDS subjects (863ml) and EPS subjects (800ml). However symptom scores of gastric discomfort and fullness were higher and lasted longer in PDS subjects than that in HSs. In EPS subjects, epigastric pain was not induced by WLT. Conclusions: FD-NCs small in intensity but significant symptoms in GSRS scores. Such changes might be correlated with altered brain processing for visceral perception. Subjects with PDS demonstrated significant in intensity and longer duration of symptoms provoked by WLT, which suggest that gastric hypersensitivity and/or impaired gastric accommodation are major candidates for pathogenesis of dyspeptic symptoms in PDS. As WLT did not induce epigastric pain symptom in subjects with EPS, which suggest that mechanical gastric stimulation is not the main factor for the pathogenesis of symptoms of EPS.