From the Guidelines
Diagnosis of tubercular ascites should be approached with a comprehensive evaluation including clinical assessment, laboratory tests, and imaging studies, prioritizing laparoscopy with peritoneal biopsy as the gold standard for diagnosis, as indicated by the most recent and highest quality study 1. The initial assessment should include a thorough history focusing on TB risk factors, physical examination, and basic laboratory tests like complete blood count and liver function tests.
- Ascitic fluid analysis is crucial, typically showing lymphocyte-predominant exudate with high protein levels (>2.5 g/dL), high adenosine deaminase (ADA) levels (>40 U/L), and a serum-ascites albumin gradient (SAAG) <1.1 g/dL.
- Microbiological confirmation should be attempted through acid-fast bacilli (AFB) staining and culture of ascitic fluid, though sensitivity is low (less than 20%) 1.
- PCR testing of ascitic fluid can provide rapid results with improved sensitivity.
- Imaging studies like ultrasound or CT scan may reveal peritoneal thickening, omental caking, and lymphadenopathy.
- Tuberculin skin test or interferon-gamma release assays can support the diagnosis but cannot distinguish between latent and active TB. In endemic areas or when clinical suspicion is high despite negative initial tests, a therapeutic trial of anti-tuberculosis therapy may be considered, with clinical response supporting the diagnosis, as suggested by 1 and 1. Key points to consider in the diagnosis of tubercular ascites include:
- The use of adenosine deaminase levels to distinguish between peritoneal TB and carcinomatosis, with an area under the receiver operating characteristic curve of 0.98; adenosine deaminase levels of <40 IU/mL are used to exclude TB 1.
- The role of laparoscopy with peritoneal biopsy in providing a definitive diagnosis, with sensitivity exceeding 85% 1.
From the Research
Diagnosis of Tubercular Ascites
- The diagnosis of tubercular ascites can be problematic, and delay in diagnosis and treatment can contribute to high mortality rates 2.
- Several studies have identified specific markers and tests that can aid in the diagnosis of tubercular ascites, including:
- Protein markers in ascitic fluid, such as a 30-kilodalton protein, a 65-kDa protein, a 14-kDa protein, and a 71-kDa protein 2.
- Image-guided percutaneous peritoneal biopsy, which can reveal caseating granulomas and acid-fast bacilli 3.
- Ascitic fluid analysis, including measurements of lactate dehydrogenase, glucose, and adenosine deaminase levels 4, 5.
- The serum-ascites albumin gradient can also be useful in distinguishing between cirrhotic and non-cirrhotic ascites, including tubercular ascites 4, 5.
- A combination of laboratory tests and clinical judgment is necessary for accurate diagnosis 5.
- Other tests, such as microscopy, culture, and nucleic acid amplification tests, can also be used to detect the presence of Mycobacterium tuberculosis in sputum and tissue samples 6.