TB Peritonitis

We discussed a case of a young man with unintentional weight loss and ascites. Our patient had a SAAG 0.9 in his ascitic fluid with ADA 48 with high protein and LDH. The patient required laparoscopy with peritoneal biopsies which yielded a diagnosis of peritoneal TB. Patient was started on RIPE.

Differential for SAAG <1.1 in ascitic fluid
SAAG<1.1 indicates that the ascites is not related to high portal pressure

Protein Poor (decreased oncotic pressure causing leak)

  1. Nephrotic syndrome
  2. Malnutrition
  3. Protein losing enteropathy (IBD)

Protein Rich (Increased capillary permeability or lymph node obstruction)

  1. Peritoneal carcinomatosis
  2. Pancreatitis
  3. TB
  4. Chylous ascites (Lymphoma causing lymphatic infiltration/obstruction)

Presentation of peritoneal TB

  • Ascites (93%) > abdominal pain > fevers

Diagnosis of peritoneal TB

  • SAAG <1.1 g/dL with high protein, high lymphocytes
  • ADA of >36 IU/L (High sensitivity ~100%, High specificity 97% wo cirrhosis; 30% with cirrhosis)
  • Acid-fast bacilli smear is positive in <3% cases (needs 5000 bacilli/mL to be positive)
  • Culture is higher yield but takes weeks to return (needs only 100 bacilli/mL to be positive), Sensitivity ~20%
  • MTB PCR is highly sensitive and specific, confirmatory diagnosis
  • Laparoscopic + Peritoneal biopsy with caseating granuloma confirmatory (multiple samples) 

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