5 WORLD GASTROENTEROLOGY NEWS OCTOBER 2017 Editorial | Expert Point of View | WCOG at ACG 2017 | WDHD News | WGO & WGOF News | WGO Global Guidelines | Calendar of Events sive procedure and not exempt from complications, is usually considered as the gold standard for the diagnosis. Laparoscopy allows direct observa-tion of the entire peritoneal space and allows peritoneal biopsies that can detect epithelioid granulomata with caseation. The peritoneal biopsies PCR showed higher diagnostic sensi-tivity compared to ascitic fluid 18. Three categories of laparoscopic appearance can be seen in peritoneal tuberculosis: (i) thickened peritoneum with multiple, yellowish white, and uniform sized (4–5mm) tubercles scattered over the peritoneum; (ii) thickened peritoneum and adhesions; and (iii) markedly thickened peri-toneum and multiple thick adhe-sions fixing intra-abdominal organs. Laparoscopy with combination of visual and histologic study has shown high sensitivity and specificity rates of 93% and 98% respectively 19. But, laparoscopy cannot be performed in approximately 14% of cases due to poor general condition or previous surgery with adhesions 20. Furthermore, complications can occur in 2.6 to 6.5% of cases includ-ing bleeding, infection and intestinal perforation. And laparoscopy mortal-ity can reach 5 % of cases 6, 18. Moreover, laparoscopy requires a stay in the hospital. It is expensive and is not available in all hospitals in devel-oping countries. Therefore, it is critical to find alternative non-invasive, rapid accurate tests to diagnose PT. This brings us to usefulness of ascitic adenosine deaminase (ADA) determination for diagnosis of perito-neal tuberculosis. Among these tests adenosine deaminase (ADA) in the ascitic fluid has been widely studied. ADA is an enzyme found in lympho-cytes, erythrocytes, and in the cerebral cortex 21. ADA is a purine-degrading enzyme that catalyzes the deamination of adenosine. Inosine is the result of this reaction. Number, matura-tion, and stimulation of lymphocytes increase ADA activity in body fluids; thus, ADA activity is increased in body fluids in infections, in rheu-matological diseases, and malignant lymphomas 21. Thus, immune cellular response against Mycobacterium tuberculo-sis intensifies the stimulation and the maturation of lymphocyte and increases ADA levels. In fact, many studies have investigated the diagnos-tic value of ascitic ADA for PT. In a recent meta-analysis including seven-teen studies and 1,797 patients, ascitic ADA determination pooled sensitivity and specificity were 0.93 and 0.94, re-spectively, for diagnosing PT indicat-ing a high diagnostic accuracy. In this meta-analysis, the diagnostic accuracy was not affected by the study setting (low or high TB prevalence areas) and the ADA cut-off (>35 or <35 U/L) 22. Former studies had concerns about ADA accuracy in cirrhotic patients 23. But in more recent studies, ascitic ADA had sensitivity and specificity lev-els over 90% 24, 25. Ascitic ADA levels can be influenced by HIV infection status, but even if adenosine deaminase levels in PT are lower in HIV positive patients compared to HIV negative patients, ADA still remains useful for PT diagnosis 26. Even if ADA level as diagnostic criteria for PT is more sensi-tive than empirical antituberculous therapy 25, in many areas especially in those with high TB prevalence areas, treatment for PT still remains empiri-cal and is only based on clinical judg-ment 24, 27. When laparoscopy is not available, not affordable, and if patients are inoperable, ascitic ADA can be cru-cial to make a quick diagnosis and to start empirical antituberculosis drugs 28. Otherwise, ADA can also orient the selection of patients who should have more invasive procedures such as laparoscopy. Conclusion PT is a real public health problem in endemic areas and remains a clinical challenge. Ascitic ADA determina-tion is an accurate, non-invasive, inexpensive, and rapid test that should be considered as a useful routine exam to indicate more invasive procedures such as laparoscopy. ADA may be used in very selective cases as an alter-native to laparoscopy. References 1. http://www.who.int/tb/publica-tions/ globalreport/en/. 2. Mehta JB, Dutt A, Harvill L, Mathews KM and all. Epidemiol-ogy of extrapulmonary tubercu-losis: a comparative analysis with pre-AIDS era. Chest 1991; 99: 1134–8. 3. Braun MM, Byers RH, Heyward WL and al. Acquired immunode-ficiency syndrome and extra-pul- …it is critical to find alternative non-invasive, rapid accurate tests to diagnose PT. Ascitic ADA determination is an accurate, non-invasive, inexpensive, and rapid test that should be considered as a useful routine exam to indicate more invasive procedures such as laparoscopy . When laparoscopy is not available, not affordable, and if patients are inoperable, ascitic ADA can be crucial to make a quick diagnosis and to start empirical antituberculosis drugs.
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