HomeTB pleural-space disease can range from simple TB pleural effusion to TB empyema. Fever, unilateral pleuritic chest pain and cough are the most frequent presenting symptoms in TB pleural effusion. Dyspnea, night sweats and weight loss are also common.113 TB pleural effusion is typically paucibacillary and often culture negative.113 In some patients, TB pleural effusion may spontaneously resolve within 2 to 4 months without treatment; however, up to 65% will subsequently develop active TB within the following 5 years.114
TB empyema is less common than TB pleural effusion and characterized by purulent pleural space and presence of acid-fast bacilli on fluid microscopy.115
TB pleural effusions are usually unilateral and can occur on either side of the chest.15,115,116 Effusions are usually small to moderate in size but in some cases can occupy over two-thirds of the hemithorax.15,116 Co-existing parenchymal abnormalities on chest x-ray are reported in 19 to 67% of patients.17,116,117 Chest computed tomography (CT) imaging usually demonstrates smooth pleural thickening with an associated effusion. Parenchymal abnormalities on chest CT are reported in up to 86% of cases.117,118 Pleural ultrasound can assist in diagnostic procedures for pleural TB, but imaging findings are nonspecific.119
Even in patients without parenchymal abnormalities on chest x-ray, the yield of induced sputum culture for M. tuberculosis is over 50%.15,120 TB pleural fluid is exudative and typically straw colored. Pleural fluid glucose may be low or normal. Pleural fluid pH is usually above 7.3. The majority of TB pleural effusions are lymphocyte predominant. However, a neutrophil predominance may be seen in the very early stages of infection or if TB empyema develops.113,121 Pleural fluid adenosine deaminase (ADA) testing is not used in Canada (see Chapter 3: Diagnosis of Tuberculosis Disease and Drug-resistant Tuberculosis). Diagnosis is based on bacteriologic confirmation (positive acid-fast bacilli [AFB] smear and/or positive culture and/or NAAT), histologic confirmation (granulomas with or without necrosis, and with or without positive AFB smears on pleural biopsy) or typical radiological features with confirmed TB in other sites. The diagnostic yield(s) for pleural TB microbiologic investigations are summarized in Table 1.
Good practice statement
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In patients with suspected TB pleural effusion, pleural fluid should be sent for cell count and differential, protein, glucose, pH, lactate dehydrogenase, acid-fast bacilli smear and culture, Gram stain and culture, nucleic acid amplification test and cytology.
If pleural and sputum samples are nondiagnostic, pleural biopsy should be considered for definitive diagnosis, given higher diagnostic yield from tissue samples. Timing of pleural biopsy (waiting for final pleural/sputa mycobacterial culture results versus expedited biopsy if NAAT and smears are negative) should be determined on a case-by-case basis, based on patient’s clinical scenario.
Biopsy samples should be sent for AFB smear, NAAT and culture (in saline) and for histopathology in cytolyte/formalin. Either image-guided closed or thoracoscopic pleural biopsy can be performed, dependent on local resources and expertise.
3.2.1. Pleural TB treatment
Data from multiple observational studies has demonstrated high rates of treatment completion with low relapse rate with 6 months of therapy. Medical treatment of TB pleural effusion results in successful outcomes in more than 85% of patients.122–125
Based on data from a Cochrane review, adjunctive corticosteroids may accelerate the resolution of pleural fluid and reduce pleural thickening. However, there is no evidence that steroids impact lung function and steroids are associated with adverse effects.126
Two small randomized trials have compared therapeutic drainage (thoracentesis or chest tube) and found conflicting results.123,127 In one study, chest tube drainage did not reduce residual pleural thickening or improve end-of-treatment forced vital capacity (FVC).133 In the second study, thoracentesis was associated with less residual fluid and a higher FVC at the end of treatment, though the difference was minimal and likely not clinically significant.137
Recommendations
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We conditionally recommend six months of standard anti-TB therapy for treating drug susceptible pleural TB (poor evidence).
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We conditionally recommend against routine adjunctive corticosteroid use for pleural TB (poor evidence).
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We conditionally recommend against routine therapeutic thoracentesis/chest tube drainage for pleural TB-associated effusions (poor evidence).
Good practice statement
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In patients with significant dyspnea, therapeutic thoracentesis may be considered on a case-by-case basis to relieve symptoms.
Fevers usually resolve within 2 weeks of treatment initiation but may take up to 2 months for full resolution in some cases.113,128 Paradoxical radiologic worsening may occur early after initiation of therapy in up to 26% of patients.118 In most cases, pleural fluid resolves after 6 weeks but may last up to 3 months.128
TB empyema is diagnosed based on the presence of purulent fluid in a patient with TB pleural space infection.115 Based on expert opinion, drainage and/or decortication is recommended in addition to standard anti-TB therapy.113,129 There are limited data to guide the optimal composition/duration of therapy or the use of adjunctive treatments such as intrapleural thrombolytics.129,130 Consultation with a TB expert is recommended in this setting.
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