|Year : 2021 | Volume
| Issue : 4 | Page : 475-477
Colonic tuberculosis masquerading as crohn's disease
Harveen Kaur, Dilbag Singh, NC Kajal
Department of Pulmonary Medicine, Government Medical College, Amritsar, Punjab, India
|Date of Submission||30-Aug-2021|
|Date of Decision||01-Sep-2021|
|Date of Acceptance||05-Oct-2021|
|Date of Web Publication||14-Dec-2021|
Department of Pulmonary Medicine, Government Medical College, Amritsar, Punjab
Source of Support: None, Conflict of Interest: None
Intestinal tuberculosis (TB) is a diagnostic challenge and can closely mimic Crohn's disease (CD) and colon cancer. These disease entities very closely resemble each other in symptomatology, imaging, appearance, and pathology. We present a case of colonic TB where the initial diagnostic workup was suggestive of CD. However, the detection of Mycobacterium tuberculosis in biopsy specimens confirmed the diagnosis.
Keywords: Colonic tuberculosis, colonoscopy, Crohn's disease, histopathological examination, mimicking, ultrasonography abdomen
|How to cite this article:|
Kaur H, Singh D, Kajal N C. Colonic tuberculosis masquerading as crohn's disease. Int J Mycobacteriol 2021;10:475-7
| Introduction|| |
Tuberculosis (TB) can occur throughout the body, with extrapulmonary involvement occurring in up to 20% of immunocompetent patients and in 50% of immunosuppressed patients. Worldwide, abdominal TB is the sixth most common form of extrapulmonary TB; usually secondary to dissemination from the lungs. In intestinal TB (ITB), ileocecal region is compromised in 90% of all cases. Crohn's disease (CD) is a chronic, granulomatous, and idiopathic disease that can affect the entire digestive tract. Colonic TB often mimics CD in clinical features and gross pathology. Both diseases present with clinical symptoms of weight loss, fever, abdominal pain, bowel obstruction, and diarrhea, and endoscopic findings of ulcerations, skip lesions, and terminal ileum involvement.
The diagnosis of colonic TB requires a high degree of suspicion, especially when encountering a patient from an endemic area, and the clinician must take into due consideration the patient's background, prior history of gastrointestinal and pulmonary infections, family history of GI diseases, and personal contacts with people who may have had TB.
Thus, ITB should be considered in the differential diagnosis of chronic intestinal disease. The differentiation between colonic TB and CD is important because if TB is suspected, empiric treatment with anti-tubercular therapy (ATT) should be considered.
| Case Report|| |
A 68-year-old male presented with chief complaints of multiple episodes of right-sided abdominal pain, fever with night sweats, vomiting, and a 28-pound weight loss over the previous 6 months. There was no history of rash, cough, joint pains, or the presence of blood in his stools. He had no previous history of TB. There was no family history of inflammatory bowel disease or colon cancer.
Physical examination revealed mild abdominal tenderness confined to the right lower quadrant. Initial laboratory evaluation revealed: Hemoglobin 13.0 gm%; WBC 13,900/mm3; PT 15 s; PTI 93.3%; INR 1.0. Liver function tests and renal profile were within normal limits. Blood cultures were negative, including those for acid-fast bacilli. Mantoux test was negative.
Chest X-ray examination presented no significant findings. Ultrasonography abdomen [Figure 1] revealed no evidence of any obvious bowel wall thickening. No free fluid seen in the peritoneal cavity.
|Figure 1: Ultrasound abdomen showed an echogenic thickened mesentery (15 mm) with mesenteric lymphadenopathy. No evidence of free fluid seen in the peritoneal cavity|
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Colonoscopy [Figure 2] showed multiple ulcers and inflammation in the terminal ileum, ascending colon, transverse colon, and rectum, along with gaping of ileocaecal valve. Histopathological examination (HPE) of colon biopsy sections, taken from the terminal ileum and ileocaecal valve region showed infiltration of the lamina propria by inflammatory cells, seen as lymphocytes forming aggregates, plasma cells, eosinophils, and neutrophils [Figure 3]. No evidence of dysplasia. No epithelioid cell granulomas seen. These findings raised the possibility of inflammatory Bowel disease (CD).
|Figure 2: Colonoscopy revealed multiple ulcers and inflammation in terminal ileum, ascending colon, transverse colon, and rectum, along with gaping of ileocaecal|
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|Figure 3: Histopathological examination of colon biopsy sections, taken the terminal and ileocaecal value region showed infiltration of the lamina propria by inflammatory cells seen as lymphocytes forming aggregates, plasma celles, eosinophils, and neutrophils. No evindence of dysplasia|
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Mycobacterium tuberculosis was detected on real-time polymerase chain reaction (PCR) testing of tissue sample obtained from terminal ileum during colonoscopy. The patient was initiated on ATT for 6 months' period, as per the body weight, and showed significant clinical improvement by the end of the treatment.
| Discussion|| |
Colonic TB can result from swallowing of infected droplets with direct seeding, contiguous spread from adjacent organs or hematogenous spread from active primary pulmonary or miliary TB, or rarely by ingestion of contaminated milk with bovine TB., Disease presentation can be acute, acute on chronic, or chronic and insidious. It may present as an inflammatory stricture, segmental ulcers and colitis, hypertrophic lesions resembling polyps or tumors, or rarely as diffuse tuberculous colitis.
The ileocaecal area is the most commonly involved area in colonic TB. The affinity of the tubercle bacillus for lymphoid tissue and areas of physiologic stasis facilitates the prolonged contact between the bacilli and the mucosa. Other areas of the colon involved are usually manifested as segmental colitis involving the ascending and transverse colon.
Colonic TB is more commonly seen in endemic areas or in immunocompromised state, whereas a history of younger age, presence of ulceration, and perianal disease supports the diagnosis of CD. Abdominal pain, weight loss, fever, and diarrhea are found in approximately 85%, 66%, 35%–50%, and 20% of patients, respectively.
The diagnosis is challenging since there are no specific clinical symptoms of large bowel TB, and only a quarter of patients have chest radiographs showing evidence of active or healed pulmonary infection., The clinical, radiological, and endoscopic picture is most likely to be confused with neoplasms or CD, and infrequently with amoeboma, GI histoplasmosis, Yersinia More Details infection, and periappendiceal abscess.
The diagnostic procedure of choice is colonoscopy and biopsy. Colonoscopic differentiation between TB and CD can be difficult since both entities may present themselves with mucosal ulcerations and nodularity, oedematous mucosal folds, aphthous ulcers, strictures, and pseudopolyps with luminal narrowing. Apart from routine HPE looking for caseating granulomas, appropriately stained slides should be prepared to look for AFB, and biopsies should be sent for culture. Biopsies should be taken preferably from the margins of ulcerations because granulomas are often submucosal. PCR, as a diagnostic modality for endoscopically or surgically obtained specimens, has become a more rapid diagnostic test with improved sensitivity and specificity, reported to be approximately 75%–80% and 85%–95%, respectively.
The treatment of colonic TB, should be instituted empirically with a full course of ATT despite negative test results. Medical management is effective, and there occurs rapid resolution of symptoms within 1–2 weeks. Conservative management is initially preferred even in patients requiring surgery, as there is reduced morbidity when elective surgery is performed 2–4 weeks after the institution of ATT. Typically, there occurs rapid resolution of symptoms upon treatment initiation.
| Conclusion|| |
Differentiating colonic TB from CD is exceedingly challenging as presentations of these diseases display significant overlap. A high index of suspicion is required for timely diagnosis of intestinal TB. It is important to consider colonic TB in the equivocal cases, as presented above, despite the negative diagnostic tests. It is extremely important to make a correct diagnosis in such cases, taking into account that steroid treatment may have potentially disastrous effects.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that their names and initials will not be published, and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]