Misdiagnosis of Crohn’s disease in a patient with intestinal tuberculosis would generally result in treatment with glucocorticoids and biologic agents, which then has the potential to cause disease progression that leads to increased morbidity and mortality. A new Case Record summarizes.
An 80-year-old man presented with anorexia, weight loss, abdominal pain, diarrhea, and an ileocecal mass. 18F-fluorodeoxyglucose uptake was present in several pulmonary nodules, the stomach, and the terminal ileum. A diagnosis was made.
Clinical Pearl
• What diseases are included in the differential diagnosis of an ileocecal mass in an elderly patient?
Cancers of the colon and small bowel are relatively common in elderly patients. A carcinoid tumor can involve the ileocecal valve and appendix and may cause the carcinoid syndrome if the disease metastasizes to the liver. Primary gastrointestinal lymphoma may also occur in the region of the ileocecal valve and the appendix. Although Crohn’s disease can occur anywhere throughout the gastrointestinal tract, it commonly affects the ileocecal valve and terminal ileum. Crohn’s disease can be manifested at any age, including in an 80-year-old patient. Bacterial, fungal, and mycobacterial infection can occur at the ileocecal valve, cecum, and terminal ileum.
Clinical Pearl
• Are tissue samples positive for acid-fast bacilli in most cases of intestinal tuberculosis?
Tissue samples are positive for acid-fast bacilli in only 25 to 30% of cases of intestinal tuberculosis. The use of molecular techniques, such as polymerase-chain-reaction (PCR) assays of fresh biopsy specimens, can improve the diagnostic yield.
Figure 4. Biopsy Specimens Obtained during Colonoscopy.
Morning Report Questions
Q: Describe some of the endoscopic and histologic features of Crohn’s disease and intestinal tuberculosis.
A: On endoscopy, the lesion associated with Crohn’s disease is predominantly ulcerative, but polypoid lesions are seen with expansion of lamina propria and lymphoid structures; a mass that appears to be fungating is rare. On histologic examination, granulomas are seen in 20 to 25% of cases. The endoscopic appearance of intestinal tuberculosis is relatively indistinguishable from that of Crohn’s disease. Ulcerative, polypoid, and fungating lesions can be present. Granulomas are seen in 20 to 25% of cases. In patients with Crohn’s disease, mucosal injury has a cobblestone appearance with aphthous and longitudinal rake ulcers, whereas in patients with intestinal tuberculosis, the ulcers are transverse in orientation.
Q: Are Crohn’s disease and intestinal tuberculosis easy to differentiate?
A: Distinguishing between Crohn’s disease and intestinal tuberculosis is a challenge, because there is marked overlap in the clinical presentation and the radiographic, laboratory, and endoscopic findings, as well as in the presence of granulomas on histologic examination. Both diseases have an insidious onset. Diarrhea, hematochezia, and extraintestinal manifestations are more common in patients with Crohn’s disease. Intestinal tuberculosis can target extrapulmonary sites in a manner that resembles the classic extraintestinal manifestations of Crohn’s disease, such as reactive arthritis, erythema nodosum, and uveitis. Ascites and fever are more commonly seen in patients with intestinal tuberculosis. Both diseases involve the ileum and colonic segments of the bowel. Isolated involvement of the terminal ileum is commonly seen in patients with Crohn’s disease, whereas involvement of the ileocecal area and a patulous ileocecal valve is seen in patients with intestinal tuberculosis. The granulomas associated with intestinal tuberculosis are more frequent and confluent and larger than those associated with Crohn’s disease.