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Abdominal tuberculosis
Abdominal tuberculosis indicates tubercular involvement of gut, abdominal lymph nodes, peritoneum, either individually or in various combinations.
Intestinal tuberculosis commonly affects ileocaecal region in 70% of patients. This is possibly related to:
Increased physiological stasis.
Increased rate of fluid and electrolyte absorption.
Minimal digestive activity.
Abundance of lymphoid tissue.
Other areas which can get affected include ascending colon, jejunum, sigmoid colon, rectum, duodenum, stomach and oesophagus.
Aetiology
Mycobacterium tuberculosis.
Routes of spread
Intestinal tuberculosis.
Haematogenous spread from the primary lung focus in childhood, with later reactivation Ingestion of bacilli in sputum from active pulmonary focus.
Direct spread from adjacent organs.
Through lymph channels from infected nodes.
Peritoneal tuberculosis.
Spread from lymph nodes.
Spread from intestinal lesions.
Spread from tubercular salpingitis in females.
Pathology
Intestinal tuberculosis
Three types.
Ulcerative (60%).
Multiple superficial ulcers largely confined to the epithelial surface of the ileocaecal area.
Long axis of ulcers perpendicular to the long axis of the gut segment involved (c.f. in typhoid fever, long axis of intestinal ulcers lies parallel to the long axis of the segment involved).
Cicatrical healing of these circumferential ulcers results in strictures.
Occlusive arterial changes may produce ischaemia and contribute to the development of strictures.
Rarely, endarteritis may produce massive bleeding.
Hypertrophic (10%).
Seen in ileocaecal tuberculosis.
Found more often in malnourished adults.
Consists of scarring, fibrosis, along with local hypertrophic mass. Can be confused with malignancy. o Ulcero-hypertrophic (30%).
Combination of both hypertrophic and ulcerative forms.
Found more often in relatively well nourished adults.
Presents with a right iliac fossa lump constituted by hypertrophic ileocaecal area, mesenteric fat and lymph nodes.
Peritoneal tuberculosis
Peritoneum studded with multiple yellow-white tubercles.
Peritoneum is thick and hyperaemic with a loss of its shiny luster.
The omentum is also thickened.
Occurs in three forms:
Wet type presents with ascites.
Encysted (loculated) type presents with a localised abdominal swelling.
Fibrotic type presents with abdominal masses composed of mesenteric and ornental thickening, with matted bowel loops felt as lumps in the abdomen. Adhesions may involve the bowel loops producing subacute intestinal obstruction.
A combination of these types is also common.
Lymph nodal tuberculosis
Involvement of mesenteric lymph nodes.
Nodes may become palpable as rounded masses (tabes mesenterica).
Usually seen in young adults.
May be confused with lymphoma.
Clinical features
Predominantly seen in young adults.
Clinical presentation acute, chronic or acute on chronic.
Common symptoms include fever, pain, diarrhoea, constipation, alternating constipation and diarrhoea, weight loss, anorexia and malaise.
Pain either colicky due to luminal compromise, or dull and continuous when the mesenteric lymph nodes are involved.
Abdominal examination may reveal no abnormality or a doughy feel.
A well-defined, firm, usually mobile mass is often palpable in the right lower quadrant of the abdomen.
Associated lymphadenitis produces mass.
Abdominal distention due to ascites.
Complications
Haemorrhage.
Perforation.
Subacute intestinal obstruction.
Fistula formation (between skin and intestine or between two loops of intestines).
Malabsorption (ileocaecal tuberculosis common cause of malabsorption in India). Various causes of malabsorption include:
Bacterial overgrowth in a stagnant loop.
Bile salt deconjugation.
Diminished absorptive surface due to ulceration.
Involvement of lymphatics and lymph nodes.
Differential diagnosis
Tropical sprue.
Amoebiasis. Worm infestation.
Lymphoma.
Crohn's disease.
Colonic malignancy.
Investigations
Raised ESR, anaemia and hypoalbuminaemia.
Chest X-ray.May show evidence of active or old tubercular lesion.
Plain X-ray of abdomen.
Calcified lymph nodes.
Dilated bowel loops with multiple air-fluid levels due to obstruction.
Air under diaphragm and dilated loops due to perforation.
Barium meal.
May show hypermotility (accelerated intestinal transit).
Hypersegmentation of the barium column ("chicken intestine").
Precipitation, flocculation and dilution of the barium.
Luminal stenosis with smooth but stiff contours ("hour glass stenosis").
Multiple strictures with segmental dilatation of bowel loops.
Stierlin sign—a defect characterised by failure of the diseased segment to retain barium which is otherwise normally retained by adjacent un-involved segments. Appears as a narrowing of terminal ileum with rapid emptying into a shortened caecum.
String sign—a thin stream of barium seen in the terminal ileum.
Note:
Both Stierlin and String signs can also be seen in Crohn's disease, and hence, are not specific for tuberculosis.
Barium enema.
Wide gaping of ileocaecal valve with narrowing of the terminal ileum ("Fleischner" or "inverted umbrella sign").
Fold thickening and contour irregularity of terminal ileum shrunken in size ("conical caecum").
Pulled up caecum due to contraction and fibrosis of the mesocolon.
Loss of normal ileocaecal angle and dilated terminal ileum, appearing suspended from a retracted, fibrosed caecum ("goose neck deformity").
Localised stenosis opposite the ileocaecal valve with a rounded off smooth caecum and a dilated terminal ileum ("purse string stenosis").
Abdominal ultrasound.
Intra-abdominal fluid (free or loculated; with or without debris and septae).
Localised fluid between radially oriented bowel loops due to local exudation from the inflammed bowel (interloop ascites; "Club sandwich" or "sliced bread" sign).
Lymphadenopathy, discrete or matted with heterogenous echotexture due to caseation.
Uniform and concentric bowel wall thickening in the ileocaecal region (vs. eccentric thickening at the mesenteric border found in Crohn's disease and variegated appearance of malignancy).
Contrast-enhanced CT scan.
Symmetric circumferential thickening of caecum and terminal ileum.
Regional lymph nodes.
Mesenteric thickening.
Ulceration or nodularity within the terminal ileum, along with narrowing and proximal dilatation.
Ascitic fluid of high attenuation value.
Thickened peritoneum and enhancing peritoneal nodules.
Omental thickening seen as an omental cake appearance.
Caseating lymph nodes with hypodense centers and peripheral rim enhancement.
Retroperitoneal nodes (periaortic and pericaval) almost never seen in isolation, unlike lymphoma.
Ascitic fluid examination.
Biopsy of peritoneum.
Punch.Laparoscopic.Colonoscopy.Mucosal nodules and ulcers in colon.Biopsy from the edge of ulcers.
Treatment
Anti-tubercular treatment similar to treatment of pulmonary tuberculosis.
Surgery.
Strictureplasty for strictures which reduce the lumen by 50% or more and which cause proximal dilation.
Resection of segment having multiple strictures.
Treatment of perforation.
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