Comparative evaluation of clinical, cytological and microbiological profile in abdominal vs. cervical lymph nodal tuberculosis with special emphasis on utility of Auramine-O staining

Abstract

Context: Extrapulmonary tuberculosis (EPTB) especially abdominal lymph nodal tuberculosis (LNTB) poses a unique diagnostic challenge. The clinical, cytological, and microbiological profiles, especially with respect to the use and role of Auramine –O (AO) stain, are not as well characterized in abdominal LNTB as cervical LNTB and were evaluated in the present comparative study. Subjects and Methods: This study was conducted in the Department of Pathology of a tertiary care hospital in Shillong, Meghalaya in 540 clinical suspected cases of tuberculosis who underwent FNAC. The smears were submitted for Leishman's stain for cytological analysis, along with ZN and Auramine O stain for demonstration of the organism, analyzed, and scored and the results were compared with culture wherever available. The results from abdominal and cervical lymph nodal tuberculosis were compared using Microsoft Excel and SPSS software. Results: Out of 540 cases, most were tuberculosis (266) followed by reactive lymphadenitis (162), malignancy, and acute necrotizing lesion. On comparing, abdominal lymph nodes ( n = 163) were more likely to reveal cheesy/purulent material macroscopically, necrotizing lymphadenitis along with ZN stain and Auramine positivity ( P < 0.05) while cervical lymph nodes ( n = 66) revealed a higher proportion of granulomatous lymphadenitis and culture positivity ( P < 0.05). The sensitivity, NPV, and diagnostic accuracy of AO stain (85.9%, 48.0%, and 62.3%) were higher as compared to ZN stain (47.4%, 39.3%, and 51.9%) with culture as the gold standard. The combined sensitivity of Ziehl Neelsen stain and Auramine stain was 92.05%. Conclusion: Cytological and microbiologic features of abdominal LNTB differ from cervical LNTB. Moreover, AO stain increases the smear positivity, is almost twice as sensitive as ZN stain and should be used as an adjunct in cytological material wherever available.

Diagnosis of extrapulmonary tuberculosis by ultrasound-guided biopsy: A retrospective comparison study

“…Unexpectedly, the sensitivity (%65.3 [56.3-73.2] vs 56.1% [47.0-64.9], p = 0.16) of the smear was slightly higher than that of the culture. Compared to direct smears, centrifugally concentrated specimens can increase the sensitivity of the smear by 10-30%( Perera and Arachchi, 1999 ; Peterson et al., 1999 ), and the Auramine O staining used in this study had a higher sensitivity (66-85.9% vs 30-60%) than Ziehl-Neelsen staining ( Marais et al., 2008 ; Laifangbam et al., 2009 ; Hooja et al., 2011 ; Runa et al., 2011 ; Assefa et al., 2021 ; Gulati et al., 2021 ), but the NaOH used to digest the specimens may have reduced the viability of mycobacteria or even killed mycobacteria ( Mtafya et al., 2019 ; Stephenson et al., 2021 ). Auramine O staining is not able to distinguish between dead or live bacteria, but culture only detects viable bacteria, thus NaOH used in sample pre-treatment may result in lower sensitivity of culture than smear.…”

“…Bold means the P value is less than 0.05, with a statistical difference. Laifangbam et al, 2009;Hooja et al, 2011;Runa et al, 2011;Assefa et 2021;Gulati et al, 2021), but the NaOH used to digest the specimens may have reduced the viability of mycobacteria or even killed mycobacteria (Mtafya et al, 2019;Stephenson et al, 2021). Auramine O staining is not able to distinguish between dead or live bacteria, but culture only detects viable bacteria, thus NaOH used in sample pre-treatment may result in lower sensitivity of culture than smear.…”

Histopathological Review of Granuloma in Diagnosis of Tuberculosis Lymphadenitis (TBL)

“…In instances like this study, where systemic signs and symptoms seldom appear, identification of TBL can become challenging. 17 We assess the histopathology by grouping the granulomas' histological features depending on the histomorphology features of TBL. The histological tissues that showed the presence of a well-formed granuloma consisting of necrosis caseous, epithelioid cells, and Langhan's cells were considered as type 1 in 47% of cases, followed by type 2 in 25%, and type 3 with no granuloma, which was 28% case.…”