Intestinal tuberculosis refers to a chronic, specific infection caused by Mycobacterium tuberculosis affecting the intestines. Surgical intervention for intestinal tuberculosis is typically required in cases where the disease leads to intestinal strictures, perforation, inflammatory masses, or bleeding.
Etiology and Pathology
Intestinal tuberculosis can be classified as primary or secondary. Primary intestinal tuberculosis is rare and occurs as a result of direct infection of the gastrointestinal tract by Mycobacterium tuberculosis, most commonly observed in children. Secondary intestinal tuberculosis is more common, with pulmonary tuberculosis being the most frequent primary site. Repeated swallowing of sputum containing Mycobacterium tuberculosis in patients with open pulmonary tuberculosis may lead to secondary intestinal tuberculosis. Occasionally, hematogenous spread (e.g., in miliary tuberculosis) may cause the condition. Tuberculosis of the pelvis or kidneys may also spread directly to the intestinal tract.
The bacteria primarily target the lymphatic tissue in the intestinal wall, which is why the pathological lesions are most frequently located in the ileocecal region and terminal ileum. Pathologically, the disease manifests as either ulcerative or hyperplastic types, although both forms may coexist.
The ulcerative form is more common and often presents with multiple lesions. Its characteristic features include ulcers that are typically annular, with their long axis perpendicular to the intestinal lumen. Lesions initially affect the lymphatic tissue in the intestinal wall, which coalesce and undergo caseous necrosis, eventually forming mucosal ulcers. Scar formation and fibrous contraction during ulcer healing can result in luminal strictures.
The hyperplastic form of intestinal tuberculosis is less common and is characterized by extensive tuberculous granuloma formation and fibrosis in the submucosa, resulting in mucosal elevations resembling pseudopolyps, along with shallow ulcerations. Intestinal wall thickening and hardening, as well as adhesions to surrounding tissues, can lead to luminal narrowing and intestinal obstruction.
Clinical Manifestations
Intestinal tuberculosis often accompanies systemic tuberculosis, presenting with symptoms such as low-grade fever, night sweats, fatigue, weight loss, and anorexia. Abdominal symptoms vary depending on the type of intestinal lesion.
The ulcerative form typically manifests as chronic, dull abdominal pain, with occasional colicky pain, predominantly in the right lower abdomen or peri-umbilical area. Symptoms generally worsen after meals and improve following defecation. Patients may experience diarrhea, or alternating diarrhea and constipation, along with mild tenderness in the right lower abdomen.
Patients with annular strictures caused by the ulcerative form or those with hyperplastic intestinal tuberculosis are more likely to present with features of lower intestinal partial obstruction. Abdominal examination may reveal visible intestinal patterns, high-pitched bowel sounds, and a firm, fixed, tender mass in the right lower abdomen. Such findings require differentiation from conditions like intestinal cancer.
Intestinal tuberculosis can lead to perforation into the abdominal cavity. The slow process of perforation often results in localized adhesions and encapsulation, forming localized intra-abdominal abscesses. If the abscess ruptures into adjacent segments of the intestine, enteroenteric fistulas may occur. If it ruptures externally, enterocutaneous fistulas may develop.
Diagnosis and Differential Diagnosis
A history of tuberculosis and systemic manifestations of the disease serve as important diagnostic indicators. Laboratory findings may include decreased hemoglobin levels, accelerated erythrocyte sedimentation rate (ESR), and elevated C-reactive protein (CRP). Abdominal CT imaging may show thickening of the cecum, ileocecal valve, and terminal ileum.
Barium studies may reveal "skip lesions" (also known as the Stierlin sign), characterized by incomplete or absent luminal filling and characteristic "pencil-like" compression markings at affected intestinal segments. Colonoscopy can identify pathological changes in the ileocecal region and terminal ileum, with biopsy samples providing material for acid-fast staining, Mycobacterium tuberculosis culture, or PCR testing to confirm the diagnosis.
Differential diagnosis is necessary to distinguish intestinal tuberculosis from other conditions such as Crohn's disease or malignancies of the ileocecal region. Particular caution is required when differentiating from Crohn's disease, as the treatment approaches differ significantly.
Treatment
Medical therapy is the primary treatment modality for intestinal tuberculosis. Surgical intervention is reserved for cases involving complications. Preoperative measures generally include appropriate antituberculous therapy and supportive care, unless emergencies necessitate immediate surgery.
Indications for surgery include:
- Acute or chronic intestinal obstruction caused by small intestinal strictures;
- Perforation resulting in peritonitis, localized abscesses, or enteroenteric or enterocutaneous fistulas;
- Uncontrolled intestinal bleeding;
- Localized hyperplastic lesions in the ileocecal region or colon that cannot reliably exclude malignancy.
The choice of surgical procedure depends on the specific condition:
- Resection and anastomosis may be performed for strictures causing obstruction. Segmental resection is preferred for multiple lesions, while extensive resections are typically avoided.
- For acute intestinal perforation, resection of the affected bowel segment is recommended, as simple repair of the perforation has a high risk of failure.
- Hyperplastic lesions in the ileocecal region or those suspicious for malignancy may require ileocecal or right hemicolectomy.