Crohn病診断基準の問題点―臨床の立場から

The Points at Issue Concerning Diagnostic Criteria for Crohn's Disease: From the Standpoint of Clinicians

要旨　Crohn病が疑われたが，確定診断が困難であったアフタ性大腸炎症例の臨床経過を検討し，現在のCrohn病診断基準における問題点を探った．Crohn病診断基準の副所見を有する疑診例では7例中5例，副所見を持たない慢性アフタ性大腸炎例では8例中1例がその後の経過観察によりCrohn病の確診を得られており，現行の診断基準の有用性が確認された．確定診断の根拠として非乾酪性類上皮細胞肉芽腫の検出によるものが多数を占めていたが，生検個数あたりの肉芽腫検出率は連続切片を作製しても必ずしも高くなかった．また，Crohn病確定診断が得られた5症例のうち4例は何らかの肛門症状の既往を持ち，2例では経過中に再び肛門病変の出現を認めた．初期病変から成るCrohn病の確定診断には，肉芽腫検出率を向上させる工夫や他の補助診断法の開発，診断基準の項目として肛門病変の再検討が必要と考えられた．

　To clarify the points at issue concerning diagnostic criteria for Crohn's disease (CD), we analyzed the clinical course of 15 patients with aphthoid colitis, which was difficult to distinguish from CD. Five of 7 (71%) patients, who were suspected of CD at the initial colonoscopy, progressed to definite CD, but only one (13%) of 8 patients with aphthoid colitis progressed to definite CD. This result indicates that the present criteria are useful for the diagnosis of CD.

　Most of the patients, who progressed to defined CD, were diagnosed for CD because of the histological detection of granulomas. However, the positive rates for granulomas per biopsied specimens were relatively low even in these CD patients. Four of 5 patients, who had progressed to CD, had past histories of anal lesions. Interestingly, two of these patients had recurrent perianal fistula or abscess before the appearance of longitudinal ulcers or granulomas. To diagnose CD in the earlier stage, it is necessary to improve the detection of granuloma by observing the serial sections, and to investigate new histopathological findings for diagnosis and to add the findings of anal lesions to the diagnostic criteria as accessory findings.