Epidemiological perspective of drug resistant extrapulmonary tuberculosis

Table 3 Key issues in diagnosis of drug resistant-extrapulmonary tuberculosis

Issues in laboratory diagnosis

In general, the sensitivity of laboratory tests is often compromised

Due to pauci-bacillary nature of EPTB

Due to difficulty in obtaining an adequate sample

Risk associated with the sampling procedure (e.g., lumbar puncture, biopsy of deep lymph nodes, etc.)

Lack of accessibility of serial samples for monitoring the treatment response

Un-availability of reliable host biomarkers that can be analyzed in easily attainable specimens

Xpert-MTB-RIF test seems promising diagnostic tool but the negative test result does not rule out EPTB and it can only determine the resistance to rifampicin (not other crucial drugs)

Issues at programmatic/administrative level

Lack of focused programme (like pulmonary TB) in many high TB burden countries

Lack of reliable estimates on impact and magnitude of DR-EPTB

Although seeking microbiological, histopathological diagnosis and drug susceptibility testing is crucial, it is however not in routine practice (in many high TB burden countries)

Rapid molecular based diagnostic (Xpert-MTB-RIF) is still away from its accessibility at peripheral health care centers in many resource limited countries

Wide variation in diagnostic and treatment practices among health service providers (as reported in private sectors of India) that often do not comply with national or international standards

DR-EPTB: Drug resistant-extrapulmonary tuberculosis; MTB: Mycobacterium tuberculosis; RIF: Rifampicin; TB: Tuberculosis; EPTB: Extrapulmonary tuberculosis.