Which of the following points is/are true concerning the diagnosis of Crohn’s disease?

b. In 10% of cases, Crohn’s disease cannot be distinguished from chronic ulcerative colitis based on clinical, radiologic, and pathologic criteria

c. Although no specific laboratory tests exist for Crohn’s disease, the erythrocyte sedimentation rate has evolved as a useful measure of disease activity

d. Specific endoscopic features encountered in Crohn’s disease which allow differentiation from ulcerative colitis include aphthous ulcers, cobblestoning, and skip areas 

A number of laboratory and radiographic studies as well as the role of endoscopy and biopsy are useful in the diagnosis and assessment of Crohn’s disease. Although no specific laboratory test exists for Crohn’s disease, acute-phase protein levels and erythrocyte sedimentation rate have evolved as measures of disease activity and severity. Endoscopic examination of the colon and rectum is often performed early in the diagnostic workup. In the presence of colorectal involvement, specific endoscopic features encountered which allow differentiation from ulcerative colitis include: aphthous ulcers, linear ulcers, cobblestoning, and asymmetric and discontinuous involvement. The radiologic examination is essential for differential diagnosis in delineating the extent or the severity of the disease primarily involving the small bowel. Barium contrast studies will disclose a number of specific features in patients with Crohn’s disease. A correlation, however, between the extent of the disease seen radiographically and clinical symptoms does not exist. Recurrent disease after surgical resection is often apparent radiologically before the development of clinical signs and symptoms.

The most important differential diagnosis is between Crohn’s disease and chronic ulcerative colitis, especially when the information is limited to the colon and rectum. Despite extensive clinical, radiologic, and pathologic evaluation, 5% to 10% of patients will be defined as having indeterminant colitis without clear-cut evidence of either condition.