Introduction TB can involve any part of GIT from mouth toanus, peritoneum & pancreatobiliary system. Very varied presentation possible ⇒TB of GIT- 6th most frequent extrapulmonary site.
HIV & TB Before era of HIV infection > 80% TBconfined to lung Extrapulmonary TB increases with HIV 40 –60% TB in HIV+ pt - extrapulmonary Globally, propotion of coinfected pt > 8 % ~ 0.4 million people in India coinfected. 16.6% abdominal TB pt in Bombay HIV +.
Incidence & severity ofabdominal TB will increase withthe HIV epidemic
Pathogenesis Mechanisms by which M. tuberculosis reach theGIT: Hematogenous spread from primary lung focus Ingestion of bacilli in sputum from active pulmonary focus. Direct spread from adjacent organs. Via lymph channels from infected LN
Most common site - ileocaecal region Increased physiological stasis Increased rate of fluid and electrolyte absorption Minimal digestive activity Abundance of lymphoid tissue at this site.
Distribution of tuberculous lesionsIleum > caecum > ascending colon > jejunum>appendix > sigmoid > rectum > duodenum> stomach > oesophagus More than one site may be involved
Peritoneal involvement occurs from : Spread from LN Intestinal lesions or Tubercular salpingitis Abdominal LN and peritoneal TB may occur withoutGIT involvement in ~ 1/3 cases.
Peritoneal tuberculosis occurs in 3 forms.• Wet type - ascitis.• Encysted (loculated) type - localized swelling.• Fibrotic type - masses composed of mesenteric &omental thickening, with matted bowel loops.
Clinical Features Mainly disease of young adults ~ 2/3 of pt. are 21-40 yr old Sex incidence equal. Clinical presentation → Acute / Chronic / Acute onChronic.
Tuberculosis of esophagus Rare ~ 0.2% of total cases By extension from adjacent LN Low grade fever / Dysphagia / Odynophagia /Midesophageal ulcer Mimics esophageal Ca
Gastroduodenal TB Stomach and duodenum each ~ 1% of total cases Mimics PUD - shorter history, non response to t/t Mimics gastric Ca. Duodenal obstruction - extrinsic compression by tuberculousLN Hematemesis / Perforation / Fistulae / Obstructive jaundice Cx-Ray usually normal Endoscopic picture - non specific
Ileocaecal tuberculosis Colicky abdominal pain ‘Ball of wind’ rolling in abdomen Borborygmi Right iliac fossa lump - ileocaecal region,mesenteric fat and LN
Obstruction Most common complicationPathogenesis Hyperplastic caecal TB Strictures of the small intestine--- commonly multiple Adhesions Adjacent LN involvement → traction, narrowing and fixation ofbowel loops.
Perforation 2ndcommonest cause after typhoid Usually single and proximal to a stricture Clue - TB Chest x-ray, h/o SAIO Pneumoperitoneum in ~ 50% cases
Malabsorption Pathogenesis bacterial overgrowth in stagnant loop bile salt deconjugation diminished absorptive surface due to ulceration involvement of lymphatics and LN
Segmental / Isolated colonic tuberculosis Involvement of the colon without involvement of theileocaecal region 9.2% of all cases Multifocal involvement in ~ 1/3 (28% to 44%) Median symptom duration <1 year
Colonic tuberculosis Pain --- predominant symptom ( 78%-90% ) Hematochezia in < 1/3 - usually minorOverall, TB accounts for ~ 4% of LGI bleeding Other features--- fever / anorexia / weight loss /change in bowel habits
Rectal and Anal Tuberculosis Hematochezia - most common symp. Due to mucosaltrauma by stool Constitutional symptoms Constipation Rectal stricture Anal fistula – usually multiple
Diagnosis and Investigations Non specific findings--- Raised ESR Positive Mantoux test Anemia Hypoalbuminaemia
Immunological Tests ELISAResponse to mycobacteria variable & reproducibility poorValue of immunological tests remain undefined
Ascitic fluid examination Straw coloured Protein >3g/dL TLC of 150-4000/µl, Lymphocytes >70% SAAG < 1.1 g/dL ZN stain + in < 3% cases + culture in < 20% cases
Adenosine Deaminase (ADA)Aminohydrolase that converts adenosine inosine ADA increased due to stimulation of T-cells bymycobacterial Ag Serum ADA > 54 U/L Ascitic fluid ADA > 36 U/L Ascitic fluid to serum ADA ratio > 0.985 Coinfection with HIV → normal or low ADA
ColonoscopyColonoscopy - mucosal nodules & ulcers Nodules Variable sizes (2 to 6mm) Non friable Most common in caecum especially near IC valve. Tubercular ulcers Large (10 to 20mm) or small (3 to 5mm) Located between the nodules Single or multiple Transversely oriented / circumferential contrast to Crohns Healing of these ‘girdle ulcers’→ strictures Deformed and edematous ileocaecal valve
Colonoscopic Diagnosis 8 –10 Bx from ulcer edge Low yield on histopath as mainly submucosal disease Granulomas in 8%-48% Caseation in ~ 1/3 (33%-38%) of + cases AFB stains - variable Culture positivity in 40% Combination of histology & culture ⇒ diagnosis in 60%
Laparoscopic Findings Thickened peritoneum with tubercles- Multiple, yellowish white, uniform (~ 4-5mm) tubercles Peritoneum is thickened & hyperemic Omentum, liver, spleen also studded with tubercles. Thickened peritoneum without tubercles Fibro adhesive peritonitis Markedly thickened peritoneum and multiple thick adhesionsCaseating granulomas + in 85%-90% of Bx
Management ATT for at least 6 months including 2 months of Rif, INH,Pzide and Etham However in practice t/t often given for 12 to 18 months 2 recent reports → obstructing lesions may relieve with ATTaloneHowever most will need surgery
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