Inflammatory bowel disease (IBD) consists of two major types of diseases: ulcerative colitis (UC) and Crohn's disease. Ulcerative proctitis refers to lesions confined to the rectum: ulcerative rectosigmoid colitis, left or distal ulcerative colitis, extensive colitis, and total colitis. Crohn disease (CD) is a disease characterized by an unknown cause and transvaginal inflammation of the gastrointestinal tract. Crohn's disease may involve the entire digestive tract from the mouth to the perianal area:
About 80% of patients have intestinal involvement, usually in the distal ileum, and 1/3 of patients have only ileitis.
About 50% of patients have colitis, which is affected by both the ileum and the colon.
Approximately 20% of patients have lesions confined to the colon. Compared with rectal involvement in patients with ulcerative colitis, one-half of Crohn's disease patients with colitis are not affected by the rectum.
About one-third of patients have perianal lesions.
About 5%-15% of patients are mainly affected by oral or gastroduodenal involvement, while fewer patients are affected by esophagus and proximal small intestine. This topic will discuss the clinical manifestations, diagnosis and differential diagnosis of Crohn's disease.
Clinical manifestations — The clinical manifestations of Crohn's disease are more variable than ulcerative colitis. The patient may have had symptoms for many years before diagnosis. Significant features of Crohn's disease are fatigue, long-term diarrhea with abdominal pain, weight loss, and fever, with or without gross bleeding.
Abdominal Pain — Sick abdominal pain is a common manifestation of Crohn's disease, regardless of the distribution of the lesion. The transmural properties of inflammation lead to fibrous stenosis. These stenosis often lead to recurrent small bowel obstruction or colonic obstruction, the latter being less common. Patients with lesions confined to the distal ileum often present with pain in the lower right abdomen. Occasionally, pati