Response to treatment is monitored by monthly sputum smear microscopy and culture. Older children who had microbiological confirmation of TB disease should also be encouraged to produce respiratory samples for monitoring whenever possible. Treatment response can also be monitored through regular clinical assessment of signs and symptoms of TB disease, and children should be monitored for changes in weight, height and BMI using age-appropriate growth charts. Repeat radiological assessment during treatment is not always necessary because some radiological abnormalities may persist throughout and beyond treatment completion but do not necessarily indicate poor response or failure of treatment. However, radiological deterioration and new abnormalities (compared with baseline) may assist in identifying poor treatment response; hence, radiological assessment should be repeated if clinically indicated. The updated definition of treatment failure includes situations where a patient’s treatment regimen has been terminated or permanently changed to a new treatment regimen, owing to:
- no clinical or bacteriological response to treatment;
- adverse drug reaction; or
- evidence of additional drug resistance to medicines in the regimen.
The treatment outcome definitions and reporting framework for patients who received the 9-month alloral MDR/RR-TB regimen is the same as for patients who received the longer regimens (Chapter 10) (58). Bacteriological treatment failure is marked by persistent positive sputum culture from month 6 to the end of treatment. Treatment failure can be considered earlier than 6 months if it is accompanied by significant clinical decline consistent with TB disease progression. Permanent discontinuation due to adverse reactions or acquired drug resistance of one of the key medicines (bedaquiline, fluoroquinolone, ethionamide/linezolid or clofazimine, or two or more of the remaining medicines in the regimen), or high-dose isoniazid, ethambutol or pyrazinamide will lead to the treatment failure consideration.
All patients receiving shorter regimens should be followed up for clinical re-assessment (ideally over a 12-month period) beyond treatment completion, to monitor for potential relapse.