Extrapulmonary tuberculosis is becoming increasingly common in clinical practice, and tuberculous pleural effusion is the 2nd most common form of extrapulmonary tuberculosis, second only to lymph node tuberculosis, and occurs in approximately 5% of patients with tuberculosis.
1. Clinical features
Most present with acute onset, with symptoms appearing within 1 week in about 1/3 of patients and within 1 month in 2/3 of patients. The most common symptoms are pleuritic pain and dry cough. Although prevalent in young adults, pleural tuberculosis should be considered in any adult or older patient with unilateral pleural effusion. Typically a small to moderate amount of unilateral pleural effusion, usually not exceeding 2/3 of the unilateral pleural cavity, is a manifestation of chronic active infection in the pleural cavity, often caused by (1) primary progression from a combined massive pleural effusion, (2 direct spread of thoracic lymph node or subdiaphragmatic lesions to the pleural cavity, (3) hematogenous dissemination, and (4) post-pneumonectomy. Chronic tuberculous pustular chest can be found abnormally by routine X-ray chest film. Jin Minghua, Department of Thoracic Surgery, Shandong Provincial Chest Hospital
2.Diagnosis
Definitive diagnosis requires finding Mycobacterium tuberculosis in sputum, pleural effusion or pleural biopsy. The basis to support the diagnosis also includes finding tuberculous granuloma in pleura and increased adenosine deaminase in pleural effusion.
(1) Sputum examination
The conventional wisdom is that sputum examination for pleural tuberculosis without pulmonary lesions should be negative and non-infectious. However, one study showed that even in patients with normal lung parenchyma on line chest radiographs, the positive rate of induced sputum culture was still up to 55%.
(2) Tuberculin test
In areas with low incidence of TB or no vaccine, a positive tuberculin test result is often a strong evidence for diagnosis, but 1/3 of patients still have a negative tuberculin test. This is mainly because of (1) immunosuppressed state or severe malnutrition, (2) recent infection, (3) suppression of peripheral blood-specific lymphocytes by circulating monocytes, and (4) chelation of purified protein derivatives of lymphocytes in the pleural cavity. However, when the tuberculin test was repeated after 6 to 8 weeks, the results became positive in almost all cases.
(3) Imaging examination
Ultrasonography reveals fibrin bands of various lengths, mobile microsegments, encapsulated pleural effusion, pleural hypertrophy, and occasional pleural nodules. Enhancement scans can show associated substantial lung injury as well as lymphadenopathy, thus improving diagnostic accuracy. In addition, complications such as pleural hypertrophy, calcification, restrictive exudate, pustular chest, and bronchopleural fistula can be identified.
(4) Thoracentesis
a. Pleural fluid examination
Typical straw yellow clarified fluid, sometimes cloudy or plasma, but definitely not obvious blood; the nature is usually exudative, and the cell count of pleural effusion shows mainly neutrophils in the early stage of the disease, but the lymphocytes gradually become the main cells during successive thoracentesis.
b.Pleural effusion smear and culture
The detection rate of antacid bacilli in this method is <10%
c. Polymerase chain reaction
Polymerase chain reaction is positive in 100% of culture-positive pleural effusions, while it is positive in only 30%-60% of culture-negative pleural effusions.
(5) Pleural biopsy
Since its first application in 1955, mural pleural biopsy has become the most sensitive method for diagnosis. Histological examination of pleural tissue may reveal granulomatous inflammation, caseous necrosis, or antacid bacilli. In 50% to 97% of patients, pleural biopsy reveals granulomas, and 39% to 80% of patients have Mycobacterium avium cultured. Even in cases where no granulomas are found, the biopsy tissue should be examined for acid-fast bacilli. Other granulomatous pleurisy, such as fungal disease! nodular disease, rheumatoid arthritis, and nocardia need to be ruled out.
(6) Thoracoscopy
Thoracoscopy is widely used in the diagnosis of pleural tuberculosis and malignancy, and can detect yellowish-white nodules, erythema, and extensive adhesions on the wall pleura, as well as bite examination of suspected lesions, especially in the region of the cribriform angle. A study comparing various diagnostic tools concluded that thoracoscopy is the most accurate, with 100% histologic accuracy and 76% culture positivity rate.
3.Treatment
(1) Anti-tuberculosis drugs
Correct diagnosis and treatment are important. According to the treatment guidelines of short course therapy, a standard protocol should be used for patients with severe disease with extensive or bilateral pleural effusion and positive sputum smear (acute treatment with 4 drugs: isoniazid, rifampin, pyrazinamide, ethambutol for 2 months, followed by maintenance with isoniazid and rifampin for 4 months).
(2) Glucocorticoids
The anti-inflammatory effect of glucocorticoids is utilized to accelerate the absorption of pleural effusion and prevent pleural adhesions during the anti-TB process. Hormonal therapy for co-infection is not recommended at this time.
(3) Pleural fluid aspiration or drainage
In addition to anti-tuberculosis treatment, patients should be thoroughly drained of pleural fluid as soon as possible.
(4)Thoracoscopic treatment
Tuberculous pleurisy history within 4 weeks, after treatment by thoracentesis aspiration, closed drainage of the chest cavity, chest cavity flushing and injection of anti-TB and urokinase drugs, there is still fluid accumulation and has formed wrapping and separation, called refractory tuberculous pleurisy, and tuberculous pustules in the early stage of mechanization, with edema, thickening and brittle texture of the fibrous plate of the dirty layer, both of which are feasible for TV thoracoscopic thoracic contouring. Clean up the pleural cavity under direct view of thoracoscopy: separate the adhesion zone with operating forceps, remove the fibrinous membrane and necrotic tissue with forceps or negative pressure, unblock and eliminate all the wrapped cavities, remove the residual fluid with negative pressure, carefully peel off the thickened membrane on the surface of the dirty and wall pleura, and if the attachment of the dirty layer pleura cannot be completely peeled off, it should be removed with multi-point forceps to reduce the pressure on the surface of the dirty layer pleura and promote lung reopening. Flush the pleural cavity with warm saline. A drainage tube is placed at the operation port, and postoperative flushing and drug injection treatment can be continued. After there is no residual cavity and no fluid accumulation, the tube is removed and oral anti-tuberculosis drugs are continued.