Regional enteritis (Crohn's disease)
Regional enteritis, as the name suggests, is a disease in which there is inflammation of parts of the intestines. Portions of the intestine become thick walled, with marked narrowing of the lumen. When seen under the microscope, there is inflammation characterized by the presence of clusters of cells called granulomas. These granulomas are somewhat similar to those seen in tuberculosis. Along with cells of inflammation these granulomas contain cells "giant cells", which are large cells with several nuclei. Regional enteritis was first described by Crohn in 1932, and is also therefore called Crohn's disease.
Crohn's disease usually affects the end of the small intestine, but may cause disease in the colon, and less often in other parts of the alimentary canal.
Crohn's disease is a chronic disease that usually affects young caucasian adults. It is common among Jews, and rare in non-white Asians. There is a tendency to occur in families. The most frequent symptoms are unexplained fatigue, weight loss, abdominal discomfort or pain, fever, loss of appetite and vomiting. During an acute exacerbation of the disease the pain may occur in the right lower abdomen, and often strongly mimics the features of appendicitis. The diagnosis is often made during surgery for an appendectomy! Patients often develop the symptoms of intestinal obstruction: pain, vomiting, cessation of stools and abdominal distension. At other times diarrhea may be present, and treatment for worms or amebic infestation is often given. In fact the clinical picture is so variable that it is difficult to diagnose, and some patients are inevitably diagnosed as having a psychiatric illness. Some patients have extra-abdominal features, such as ankylosing spondylitis. The risks of gallstones, urinary stones and of amyloidosis is increased.
The diagnosis is made by barium X-rays of the small intestine and colon. CT scan and endoscopy may help in a few cases. Acute illness may be confused with appendicitis, and chronic involvement of the colon may be difficult to distinguish from ulcerative colitis. Crohn's disease may resemble intestinal tuberculosis, and in developing countries where tuberculosis is common a diagnosis is not easy to make.
In a few patients, especially those who present with an acute episode, the illness is not progressive. In the majority however the disease advances to involve more and more of the intestine, with episodes of obstruction and formation of internal fistulas. There is no specific therapy, and most treatment is symptomatic. Antidiarrheals are used for episodes of diarrhea. 5 ASA compounds, used for ulcerative colitis, are also used in Crohn's disease, but have less efficacy. Persistent active disease may require steroids, usually in the form of oral prednisolone. Newer developments are the use of special formulations of steroids which have fewer side effects, like budesonide; and a completely new drug called infliximab which is said to neutralize the action of tumour necrosis factor, and so help in inducing remission.
Intra-abdominal complications such as obstruction, fistula formation or perforation with abscesses may need surgery. Crohn's disease patients may need an operation many times.