HIV-associated tuberculous lymphadenitis: the importance of polymerase chain reaction (PCR) as a complementary tool for the diagnosis of tuberculosis - a study of 104 patients

Abstract

BACKGROUND: Lymphadenitis is common in HIV-positive patients. Diagnosis of the infections associated with this condition is complex, particularly in the case of tuberculosis. Rapid and specific detection of Mycobacterium tuberculosis (M. tuberculosis) is fundamental in ensuring adequate treatment. In addition, frequent causes of lymphadenitis such as those associated with lymphoma and histoplasmosis, among others, must be eliminated as possible causes. OBJECTIVES: To evaluate the accuracy of polymerase chain reaction as a tool for the diagnosis of lymphadenitis resulting from M. tuberculosis. METHODS: In this study, a protocol was developed using the following procedures: direct microscopy using Ziehl-Neelsen staining, culture in Lowenstein-Jensen medium, histology and polymerase chain reaction. RESULTS: A total of 104 patients were included in the study. According to histopathology, 38 patients (36%) were found to have nonspecific chronic lymphadenitis, 27 (26%) had tuberculous lymphadenitis, 11 patients (10.5%) had lymphoma and 9 (8.7%) had histoplasmosis. When Lowenstein-Jensen culture was performed, positive tests for tuberculous lymphadenitis increased by 30%. With polymerase chain reaction, M. tuberculosis DNA was detected in 6 out of 38 samples of non-specific chronic lymphadenitis. Three of these patients were followed up, developed symptoms of tuberculosis and were cured following specific treatment. CONCLUSION: The data obtained in this study suggest that all cases of lymphadenopathies should be submitted to histopathology, Lowenstein-Jensen or Ogawa culture and polymerase chain reaction. Polymerase chain reaction may prove to be useful in providing an early and accurate detection of cases of extrapulmonary tuberculosis in HIV-positive patients with lymphadenopathies, avoiding empirical treatment and the possible development of resistant strains.

Cutaneous tuberculosis: diagnosis, histopathology and treatment - Part II

“…In this test, Mtb DNA present in a sample of fresh tissues, blood or a paraffin block is amplified and it can then be identified, confirming the presence of mycobacteria. 14,15 …”

Diagnosis of extrapulmonary tuberculosis by PCR

“…Various gene targets such as IS6110, 16S rRNA gene, IS1081, 65 kDa and MPB-64 have been employed to diagnose TB lymphadenitis by PCR from FNA or formalin-fixed paraffin-embedded tissues with varying sensitivities and specificities (Totsch et al, 1996;Pahwa et al, 2005;Osores et al, 2006;Nopvichai et al, 2009;Sharma et al, 2010b;Cortez et al, 2011;Derese et al, 2012; Table 1). Within M. tuberculosis complex, M. tuberculosis and Mycobacterium bovis are the major causative agents of TB lymphadenitis.…”

“…EPTB has become more common since the advent of human immunodeficiency virus (HIV) infection (Cabandugama et al, 2011;WHO, 2011). EPTB constitutes about 15-20% of TB cases and can constitute up to 50% of TB cases in HIV-infected individuals (Noussair et al, 2009;Peto et al, 2009;Cortez et al, 2011). As India has high burden of TB cases, thus proportionately higher number of EPTB cases are also observed in this country (WHO, 2011).…”

Pathological findings in patients with HIV infection and lymphadenopathies

“…La mayoría de los trabajos sobre adenopatías en estos pacientes se ha llevado a cabo en países donde la tuberculosis es endémica (India, Brasil, Irán, Zambia y Malasia) y donde, además, el número de pacientes con sida es alto y el acceso al tratamiento antirretroviral altamente efectivo es bajo, al igual que en nuestro país (3,5,6,(13)(14)(15)(16)(17)(18)(19). A diferencia de estos estudios, en los cuales la mayoría de los ganglios estudiados se evaluaron mediante una biopsia por aspiración con aguja fina, todos los pacientes en este estudio se sometieron a biopsia por escisión de ganglio linfático.…”

“…Dadas las condiciones epidemiológicas mencionadas, era predecible que la infección más común fuera la tuberculosis (casi la mitad), lo cual coincide con los datos publicados en otras series, donde la frecuencia ha oscilado entre el 26 y el 67 % (3,6,(13)(14)(15)(16)(17)(18)(19). En un estudio en Sudáfrica, Maartens, et al, encontraron una frecuencia mucho mayor de tuberculosis (92 %) (5), diferencia que probablemente se deba a la mayor incidencia de esta enfermedad en ese país (860 casos por 100.000 habitantes, en comparación con 26 por cada 100.000 en Colombia) (20) y porque, además, en dicho estudio la población evaluada incluyó solo a pacientes con sospecha de tuberculosis y con baciloscopia de esputo negativa.…”