Impact of endoscopy in Crohn's disease

Dans la maladie de Crohn, on distingue deux types de lésions endoscopiques: évolutives ou cicatricielles. Elles sont fréquemment associées. Par leur localisation au niveau du tube digestif, ces lésions définissent le type de maladie. L'iléocoloscopie est utile dans le diagnostic de la maladie par l'inventaire des lésions initiales, et la réalisation de biopsies précieuses dans le diagnostic différentiel des colites (recto-colite ulcéro-hémorragique, colites infectieuses). Cet examen n'est répété que dans le but de résoudre un nouveau problème clinique, par exemple en apportant des informations qui modifient le traitement. En cas de colite grave, la coloscopie permet de dépister des surinfections mais aussi les ulcérations profondes qui sont des signes endoscopiques de gravité et de mauvais pronostic. Après résection iléo-caecale, une iléocoloscopie retrouve, dans la grande majorité des cas, des signes endoscopiques de récidive qui, s'ils sont importants, prédisent une évolution clinique défavorable et incitent à une modification thérapeutique. La coloscopie systématique après 8 à 10 ans d'évolution contribue au dépistage des lésions néoplasiques probablement sous-estimées dans les formes coliques de maladie de Crohn. Elle participe également au traitement de complications de la maladie: dilatation de sténoses bénignes, localisation et traitement des hémorragies basses. L'endoscopie haute, l'échoendoscopie, l'entéroscopie, la vidéocapsule et la cholangiopancréatographie rétrograde perendoscopique sont d'autres techniques endoscopiques utiles dans des indications précises

Apport de l'endoscopie dans la maladie de Crohn

Two types of endoscopic lesions are observed in Crohn's disease (CD): active lesions or scars, frequently associated. Following their localization at different sites of the digestive tract, they are defining the type of disease. Ileo-colonoscopy is an important step of the initial characterization of the lesions, completed with biopsies helpful for the differential diagnosis between CD and ulcerative colitis or infectious colitis. An endoscopy is only repeated in front of a new clinical problem or when a change of treatment is required. In case of severe colitis, colonoscopy may detect septic lesions as well as deep ulcers indicating severe evolution with a bad prognosis. After surgery, in most of the cases ileocolonoscopy detects recurrent lesions whose severity is linked to an unfavourable clinical evolution and permits therapeutic adaptation. Since the risk of colorectal cancer in CD predominant in the colon is probably underestimated, a systematic colonoscopy after 8 to 10 years of evolution should be performed for the screening of malignant lesions. Colonoscopy is also useful for the treatment of complications of CD, i.e. dilatation of benign strictures, as well as localization and treatment of distal bleeding. Upper digestive tract endoscopy, endosonography, enteroscopy, videocapsule and endoscopic retrograde cholangio-pancreatography are other contributive methods within the field of correct indications

Assessment of the new immunological test Hemoblot for detecting occult blood in faeces

Hemoblot, a new immunological faecal occult blood test, produced by Gamma, Angleur, Belgium, was characterized and compared with another immunological test (HemeSelect, SmithKline Diagnostics, USA) and with a guaiac test (Hemoccult II, SmithKline Diagnostics). The analytical sensitivity of Hemoblot is 0.15 mg haemoglobin/g faeces and the test is specific for human haemoglobin. In addition, 135 symptomatic patients who had to undergo a colonoscopy were tested using the three tests. Two criteria were considered for the analysis: (1) the blood criterion: any pathology likely to cause colorectal or other bleeding; and (2) the precancerous-cancerous criterion: the pathology being either a colorectal polyp > 0.5 cm or a colorectal cancer. Considering both criteria, the sensitivity of Hemoblot was significantly higher than the sensitivity of Hemoccult: 38% and 23%, respectively, for the blood criterion; and 54% and 29% for the precancerous-cancerous criterion. Sensitivity and specificity did not differ statistically between Hemoblot and HemeSelect but Hemoblot was faster and simpler to perform. It could be widely used in mass screening