Intraabdominal Tuberculosis: Usual Pattern of Presentation
Intraabdominal tuberculosis most commonly presents with the triad of fever (70-84%), abdominal pain (65-88%), and weight loss (36-72%), with the ileocecal region and terminal ileum involved in 50-90% of cases. 1, 2
Anatomical Distribution Pattern
- The ileocecal region and terminal ileum are the predominant sites, accounting for 50-90% of gastrointestinal TB cases, making this the most critical area to evaluate 1, 2
- Intestinal TB represents 58-60% of all abdominal TB cases 1
- Importantly, up to 85% of patients with abdominal TB have no pulmonary involvement, so absence of lung disease does not exclude the diagnosis 1
Clinical Presentation Pattern
Constitutional Symptoms
- Fever occurs in 70-84% of cases, often accompanied by night sweats 1, 3
- Weight loss is present in 36-72% of patients 1, 3, 4
- Anorexia affects 30-84% of patients 3, 4
Abdominal Manifestations
- Abdominal pain occurs in 65-88% of cases 1, 3, 4
- Ascites is present in 30-67% of cases, which may be free or loculated 1, 3
- Abdominal mass is palpable in 13-42% of patients, often in the right lower quadrant due to ileocecal involvement 3, 4
- Change in bowel habits occurs in approximately 39% of cases 3
High-Risk Populations
Heightened suspicion is mandatory in specific patient groups 1:
- Immigrants from endemic areas (Asia, Africa) 1
- HIV/AIDS patients and other immunocompromised individuals 1, 5
- Patients on immunosuppressive therapy 2
Common Complications
The presentation pattern is often complicated by:
- Intestinal obstruction due to strictures or ileocecal narrowing 1, 2
- Perforation, particularly in ulcerative type TB, requiring surgical intervention 1, 2
- Fistula formation in advanced cases 1
Critical Diagnostic Pitfall
The presentation can closely mimic Crohn's disease, particularly with ileocecal involvement, but features such as night sweats, positive tuberculin skin test, and concomitant pulmonary tuberculosis favor TB over Crohn's disease 2, 1. Treating presumed Crohn's disease with immunosuppression when the patient actually has tuberculosis can lead to fulminant TB progression and death 1, making accurate differentiation essential.
Laboratory Findings Pattern
- Low hemoglobin with raised C-reactive protein in >90% of cases 6
- Tuberculin skin test is positive in only 22-27% of patients, making it unreliable for diagnosis 6, 3
- Acid-fast bacilli on ascitic fluid smear are rarely positive 6
Imaging Pattern
- CT scan abnormalities are present in 80-100% of cases when performed, showing ascites, peritoneal lesions, or enlarged lymph nodes 3, 4
- Conglomerate lymph nodes >20mm with peripheral enhancement and central hypodensity are characteristic CT findings 7
- Ultrasound reveals positive findings in 66% of tested patients 4