Letter from Myanmar

Tuberculosis (TB) is well known as a major infectious disease and one of the top 10 causes of death worldwide. TB can affect anyone, everywhere but it has a predilection for those with diabetes, human immunodeficiency virus (HIV), smoking and undernutrition. Myanmar, with 54 million people, has an incidence of all forms of TB of 322 per 100 000 population, with mortality of 36 per 100 000 population. Myanmar is one of the 30 high TB burden countries because of the emerging challenge of drug-resistant and HIV-associated TB, on top of the high prevalence of drug-susceptible TB.1 In Myanmar, clinicians, epidemiologists and administrators are collaboratively involved to tackle this prevalent infectious disease. The natural course and presentations of tuberculous infection in Myanmar do not go against what we have learnt. Primary infection is mostly irrelevant and seldom recognized clinically. In adults, pulmonary TB is the most common form—post-primary TB. The proportion of pulmonary TB was found to be 45.3–56.7% of all forms of TB according to the Medical Registry (2015–2019) of Mandalay General Hospital, one of the leading Myanmar tertiary hospitals.2 The typical presentation of gradual onset cough and constitutional symptoms with the chest x-ray (CXR) finding of parenchymal lesions is unremarkable for pulmonary TB. However, in some specific forms of TB such as endobronchial TB, intrathoracic lymphadenopathy and pleural TB, the diagnosis becomes tricky. Treatment of TB is not usually straightforward with standardized treatment in the setting of primary care. It sometimes needs to be tailored from a standardized regimen to either a modified regimen in those with chronic liver and renal diseases, or changed to an individualized regimen if there are drug side effects. Furthermore, TB has many respiratory complications even after active infection is successfully treated, especially in extensive disease. Post tuberculous bronchiectasis, fibrosis of the pleura and lung parenchyma, bronchial stricture and stenosis, recurrent haemoptysis and new development of obstructive airway disease are the common clinical encounters in our daily practice. In these settings, comprehensive knowledge on pulmonology, with skill and expertise in investigational tools are essential for successful management. In the entity of endobronchial TB, bronchoscopy followed by either endobronchial biopsy or bronchoalveolar lavage/bronchial washing are the standard diagnostic procedures. In the form of TB involving mediastinal lymph nodes, advanced diagnostic bronchoscopic procedure with endobronchial ultrasound-guided transbronchial needle aspiration and core biopsy are often used. Pleural TB is the most common form of extrapulmonary TB in our hospital practice. With regard to the diagnosis, thoracocentesis and pleural biopsy are the usual procedures. Routinely, pleural biopsy is taken in the form of closed pleural biopsy with ultrasound assistance. However, when it becomes an undiagnosed exudative pleural effusion, medical thoracoscopic pleural biopsy is the procedure of choice and it sometimes requires video-assisted thoracoscopic biopsy. It is usually confirmed by the histopathological finding of granulomatous lesions in pleural biopsy. Another auxiliary method in the diagnosis of pleural TB is the determination of adenosine deaminase, an enzyme liberated by activated lymphocytes.3 Laboratory aspects in our practice have expanded from sputum smear microscopy to molecular technologies. Historically, smear microscopy for acid-fast bacilli is an essential frontline tool. Molecular tests, such as Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) testing to detect DNA of Mycobacterium tuberculosis and mutations associated with resistance, are rapid and specific to rule out rifampicin resistance. Isolating the bacteria by solid culture, Lowenstein–Jensen media or liquid culture, Mycobacterium Growth Indicator Tube system-960 (Becton, Dickinson and Company, UK) and drug susceptibility testing for first- and second-line anti-tuberculous drugs using the line probe assay are important tests for drug-resistant TB (DR-TB) management.4 The QuantiFERON-TB Gold (Qiagen, Dusseldorf, Germany) test is a commercially available interferon-gamma release assay as an alternative to the tuberculin skin test for diagnosis of latent infection. Among the imaging investigations, CXR is a frontline tool both in hospitals and primary care as it is useful not only for the diagnosis of presumptive TB, but also valuable for identifying other lung diseases and people in need of follow-up. In recent years, Myanmar has achieved remarkable milestones in the management and control of TB, as stated in the World Health Organization (WHO) Global Tuberculosis Report (2020)5 and the sixth Joint Tuberculosis Monitoring Mission (2019) report. The dedications of tuberculogists, epidemiologists and care providers from public and private sectors are greatly appreciated for these achievements. The National Tuberculosis Program (NTP) Myanmar provides basic clinical TB services, diagnosis and registration through the public health network (Fig. 1). The program adopted the WHO-recommended DOTS strategy, later transformed to the Stop TB strategy and most recently in line with the End TB strategy.1 Standardized treatment for drug-susceptible TB constitutes 6 months of first-line drugs (2 months of isoniazid (H) + rifampicin (R) + pyrazinamide (Z) + ethambutol (E), followed by 4 months of HR). Previously treated patients undergo an Xpert MTB/RIF test prior to retreatment and an 8-month regimen (3 months of HRZE/5 months of HRE) is given to those without rifampicin resistance. The treatment success rate of drug-susceptible TB is up to 87% in registered patients.6 DR-TB is another challenging problem. The estimated multidrug-resistant TB prevalence was 5.1% in new cases and 27% in previously treated cases. The conventional 20-month long, injection-containing regimen is implemented as a management programme and achieved a treatment success rate of more than 75%. With regard to extensively DR-TB (XDR-TB), treatment regimens are based on drug susceptibility results of second-line drugs and includes new drugs (bedaquiline and delamanid).4 Very recently, we have started a transition plan of fully oral treatment for DR-TB. Furthermore, TB/HIV collaborative activities are established nationwide. With the impact of the coronavirus disease 2019 (COVID-19) pandemic, it is inevitable to have setbacks in the management of TB, together with other non-COVID diseases. Hence, a timely response has been taken in hospital and other settings so as not to delay diagnosis and effective treatment during the pandemic. The NTP also makes its way forward to accelerate and strengthen the management programmes. This road map of tuberculous infection control in Myanmar can be a strength for everyone around the region to strive towards achieving the targets of global TB control through these difficult times.