Adenosine Deaminase Diagnostic Testing in Pericardial Fluid

Detection of drug-resistant Mycobacterium tuberculosis in pericardial fluid culture and its correlation with cartridge based nucleic acid amplification test and adenosine deaminase activity

BACKGROUND

Pericardial effusion is the accumulation of fluid in the pericardial cavity. In nations with high tuberculosis (TB) load, TB is the most common cause of pericardial effusion. 1-2% of patients with pulmonary TB develop Pericardial TB worldwide. Multi-drug-resistant (MDR) TB, including extrapulmonary TB (EPTB) cases, are rising in number. Adenosine Deaminase (ADA) is an enzyme in lymphocytes and myeloid cells, which has certain immune functions in the body. ADA levels are increased in inflammatory conditions, like pleural, pericardial, or joint effusions, of bacterial etiology, granulomatous conditions, neoplasms, and autoimmune pathologies. TB is the only lymphocytosis involving disease with increased ADA levels. MDR EPTB is rare, but cases are on the rise, and tuberculous pericardial effusion is one such example. Hence, it is important to know the percentage of cases detected by a culture that can be identified by cartridge-based nucleic acid amplification test (CBNAAT), their resistance patterns, and to identify potential markers like ADA, which can help in early identification of cases. The objectives of this study were to identify the Mycobacterium tuberculosis (MTB) bacilli in culture, and correlate them with cartridge-based nucleic acid amplification test (CBNAAT) results and their drug-resistance, in the Pericardial tubercular effusion, and to find if Adenosine Deaminase (ADA) levels can be used as a predictor of the presence of MTB in pericardial fluid.

METHODOLOGY

We enrolled 52 patients with moderate to large tuberculous pericardial effusion, based on pericardial fluid analysis, CBNAAT, and culture methods, between January 2021 and December 2021.

RESULTS

The mean age of the patients was 41.85 + 17.88 years, with a median of 38 years. Males made up 57.7% of the total patients. MTB was detected in 16 (30.8%) patients in the CBNAAT evaluations. 14 (87.5%) of the CBNAAT-positive TB patients were sensitive to Rifampicin, whereas the remaining 2 (12.5%) were resistant to Rifampicin on CBNAAT. MTB was found to be growing in 8 (15.38%) drug sensitivity test cultures. Out of these 8, 6 were sensitive to first-line drugs, whereas 2 were resistant to both Isoniazid and Rifampicin. The presence of cough was found to have a significant difference between CBNAAT-detected MTB positive and negative patients (p = 0.020), whereas an insignificant difference was found for the presence of hypertension, diabetes mellitus, obesity, dyspnea, or fever. There was also an insignificant difference between the number of patients positive for the Tuberculin skin test, between the two groups. ADA was significantly higher in the MTB-detected CBNAAT group (85.91 + 37.60U/L vs 39.78 + 24.31U/L, p = 0.005), whereas the total leukocyte count, lymphocytes, neutrophils, random blood sugar levels, and serum protein levels had no significant difference. The area under the Receiver Operator Curve (CBNAAT positive: dependent variable; ADA: test result variable) was 0.854 (null hypothesis rejected), with a standard error of 0.078.

CONCLUSIONS

Culture is the gold standard method to diagnose tuberculosis. Detection of MTB on pericardial fluid culture is very uncommon, though in our study, culture came out positive in 16% of patients, and 4% were resistant to rifampicin and isoniazid. Higher ADA levels in pericardial fluid are an indicator of tuberculous pericardial effusion.

Extrapulmonary Tuberculosis—An Update on the Diagnosis, Treatment and Drug Resistance

Pathogenic Mycobacterium tuberculosis complex organisms (MTBC) primarily cause pulmonary tuberculosis (PTB); however, MTBC are also capable of causing disease in extrapulmonary (EP) organs, which pose a significant threat to human health worldwide. Extrapulmonary tuberculosis (EPTB) accounts for about 20–30% of all active TB cases and affects mainly children and adults with compromised immune systems. EPTB can occur through hematogenous, lymphatic, or localized bacillary dissemination from a primary source, such as PTB, and affects the brain, eye, mouth, tongue, lymph nodes of neck, spine, bones, muscles, skin, pleura, pericardium, gastrointestinal, peritoneum, and the genitourinary system as primary and/or disseminated disease. EPTB diagnosis involves clinical, radiological, microbiological, histopathological, biochemical/immunological, and molecular methods. However, only culture and molecular techniques are considered confirmatory to differentiate MTBC from any non-tuberculous mycobacteria (NTM) species. While EPTB due to MTBC responds to first-line anti-TB drugs (ATD), drug susceptibility profiling is an essential criterion for addressing drug-resistant EPTB cases (DR-EPTB). Besides antibiotics, adjuvant therapy with corticosteroids has also been used to treat specific EPTB cases. Occasionally, surgical intervention is recommended, mainly when organ damage is debilitating to the patient. Recent epidemiological studies show a striking increase in DR-EPTB cases ranging from 10–15% across various reports. As a neglected disease, significant developments in rapid and accurate diagnosis and better therapeutic interventions are urgently needed to control the emerging EPTB situation globally. In this review, we discuss the recent advances in the clinical diagnosis, treatment, and drug resistance of EPTB.

Pericarditis tuberculosa en paciente inmunocompetente. Reporte de caso

La pericarditis tuberculosa es una rara manifestación extrapulmonar que afecta a menos del 4% de los pacientes con tuberculosis (TB), con alta morbimortalidad ante diagnósticos tardíos, especialmente en aquellos pacientes inmunocomprometidos. Su presentación es inespecífica y la sintomatología deriva de la velocidad de instauración del derrame pericárdico, registrándose casos mortales debido a taponamiento cardiaco. La confirmación diagnóstica se obtiene con la identificación de la micobacteria en muestra de pericardio o líquido pericárdico, con una alta tasa de sospecha fundamentada en pruebas adicionales como la cuantificación del interferón gamma no estimulado, lisozima pericárdica y adenosina desaminasa (ADA) en liquido pericárdico. El tratamiento consiste en una combinación de terapia antituberculosa, drenaje pericárdico, y corticoesteroides como adyuvantes. Se presenta el caso de un varón de 64 años inmunocompetente, fumador frecuente en el pasado, con una alta sospecha diagnostica para TB, confirmada con resultado positivo para ADA (55,8 UI/L) en fluido pericárdico permitiendo iniciar un tratamiento adecuado con mejoría clínica posterior durante el seguimiento.