Histopathology revealed architectural distortion, with an inflammatory process with lymphoplasmacytic infiltration and cryptitis, suggestive of CD. Immunohistochemistry for Cytomegalovirus and histochemistry for acid-fast bacillus (AFB) in Ziehl- Neelsen stain were negative.

The patient was referred to our hospital for further diagnosis and treatment. At admission, she had a normocytic/normochromic anemia (Hg 11.7 g/dL, MCV 89 fL), without leukocytosis, but with elevated CRP (8.02 mg/dL) and ESR (57 mm/h). She had folic acid deficiency, with normal iron and vitamin B12 levels. Human immunodeficiency virus, hepatitis C virus, cytomegalovirus, Epstein Barr virus, and herpes simplex virus serologies were negative, and she was immune to hepatitis B virus. Stool cultures and Clostridium difficile toxin were negative. An abdominal ultrasound revealed circumferential parietal thickening of the ascending colon and increased echogenicity of the adjacent adipose planes.

Discussion and Conclusion

Both CD and gastrointestinal TB are characterized by chronic granulomatous inflammation in the gastrointestinal tract, with clinical features including abdominal pain, recurrent partial intestinal obstruction, fever, anorexia, weight loss, chronic diarrhea, hematochezia, perianal disease, and extraintestinal manifestations like arthralgia, aphthous ulcers, and dermatologic and ocular manifestations. Although longer duration of disease, perianal disease, and extraintestinal manifestations favored a diagnosis of CD, and fever and night sweats favored a diagnosis of TB, none of these features are specific [4].

The most common site of gastrointestinal TB is an ileocecal location, followed by the jejunum and colon. The esophagus, stomach, and duodenum are rarely involved. The most common symptom of jejunal and ileocecal TB is bowel obstruction, whereas abdominal pain and change in bowel habits are the most frequent symptoms in colonic TB. However, isolated involvement of the colon is only present in about 10% of gastrointestinal TB. The cecum is the most common site of colonic involvement, but it is usually in contiguous involvement with the terminal ileum [4].

Among the endoscopic features, the presence of longitudinal ulcers, aphthous ulcers, cobblestoning, and skip lesions are more common in CD, whereas the presence of transverse ulcers and patulous ileocecal valve are more common in gastrointestinal TB. Concerning pathology findings, architectural abnormalities such as crypt distortion/branching/shortening and irregular mucosal surface, though more common in CD, are also seen in gastrointestinal TB. Granulomas are more frequently seen in gastrointestinal TB and are usually larger, confluent, dense, located in submucosa, and characterized by central caseation, which is almost pathognomonic of TB. Since intestinal TB is a paucibacillary disease, positive AFB staining in mucosal biopsies has a sensitivity of only 2.7–37.5%. The sensitivity of AFB culture varies from 19 to 70% and PCR for AFB in endoscopic biopsies is not exclusive for gastrointestinal TB. CT findings more commonly seen in patients with CD are long-segment involvement, skip lesions, and presence of comb sign. On the other hand, lymph nodes larger than 1 cm favor gastrointestinal TB. It is also important to emphasize that chest radiograph evidences active/healed pulmonary TB in only up to 25% of patients with gastrointestinal TB [4].

To help differentiate CD from gastrointestinal TB, predictive scores have been suggested, although external validation for various populations is still lacking. However, these studies emphasize predictive features for each disease. Concerning clinical features, diarrhea, hematochezia, presence of perianal disease, and extraintestinal manifestations significantly favored CD, whereas fever, night sweats, lung involvement, and ascites significantly favored gastrointestinal TB. Inflammatory markers, such as CRP or ESR, are inconsistently included in these models due to the disparity of results. The endoscopic, radiologic, and pathologic findings previously discussed here are also included in these predictive models [5, 6].

Most patients with gastrointestinal TB respond well to antibacillary therapy, which must be maintained for at least 6 months. With resolution of gastrointestinal symptoms, an endoscopy to confirm mucosal healing is not necessary [2].

This case report evidences the importance of a high level of suspicion of gastrointestinal TB when evaluating a patient with colonic ulcers favoring a CD diagnosis, even in a nonendemic country. Although the patient in this case did not have symptoms suggestive of active pulmonary TB, later we discovered that she had had previous contact with a bacilliferous relative, having already been treated for latent TB.

We would also like to emphasize that the patient in the presented case had some clinical manifestations favoring CD diagnosis, such as hematochezia and absence of fever, night sweats, or respiratory complaints. The patient also had duodenal and distal colonic involvement, with crypt distortion and mesenteric fat hypertrophy, favoring CD. However, chest radiograph and CT scan were suggestive of TB. Although nonnecrotic, the presence of multiple locoregional lymph nodes also favored the diagnosis of gastrointestinal TB.

Immunocompromised patients are particularly prone to present atypical forms of TB, such as gastrointestinal and disseminated TB. Therefore, it is widely recommended to screen for latent TB in all patients who are expected to start immunosuppressive therapy, such as patients with CD. Most of the overt TB cases are due to reactivation of latent infection, occurring approximately 12 weeks after the initial exposure to infliximab, usually within the first 6 months of therapy. This drug is associated with a 5-fold increased risk of reactivation of TB in the first 52 weeks after initiation of therapy [7]. Although it is standard of care to perform a chest radiograph and an IGRA test before starting immunosuppressive therapy in CD, the sensitivity of these tests for gastrointestinal TB is approximately 25 and 80%, respectively [4]. Additionally, IGRA results often take time and can be positive in either active or latent TB. Therefore, it is fundamental to obtain a complete past medical history, previous contacts with infectious diseases, and travelling history when evaluating a patient with a presumptive diagnosis of inflammatory bowel disease.

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Statement of Ethics

The authors have no ethical conflicts to disclose.

Disclosure Statement

The authors have no conflicts of interest to declare.