Epidemiology/awareness | Massive global disease burden that is well quantified; excellent awareness | Massive global disease burden that is poorly quantified; increasing awareness |
Control | Main focus of TB control programmes | Not a TB control priority |
Pathology | Usually “adult-type” cavitary lung disease | Usually intrathoracic lymph node disease |
Bacterial load/transmission/infection control | Multibacillary Highly infectious; strict infection control measures required to limit airborne aerosol transmission | Paucibacillary Low infection risk, but may be infectious if extensive lung involvement with/without cavities; epidemiological marker of transmission |
Drug resistance | Difficult to differentiate acquired from transmitted (primary) drug resistance | Usually transmitted (primary) drug resistance indicating recent transmission |
Exposure history | Important, but often neglected | Essential part of diagnostic work-up |
Risk of progression to disease after infection | Relatively low risk, unless immunocompromised or relevant comorbidities | Highly variable risk: greatest in the very young and/or immune compromised; time dependent: greatest within the first year after infection |
Preventive therapy | Limited individual benefit, except in immunocompromised; may assist to sterilise the “pool of latent infection” in areas with limited transmission according to the principle of TB elimination | Definite individual benefit, especially in very young (<5 years of age) and/or immunocompromised children |
Imaging studies | CXR mainly performed to evaluate the extent of lung involvement or to exclude active disease | CXR (both PA and lateral views) are the most informative study to perform for diagnostic/screening purposes |
Disease classification | Traditional pulmonary versus extrapulmonary distinction; the term “post-primary TB” is confusing and should best be replaced# | Diverse spectrum of pathology requires accurate disease classification; for reporting purposes, intrathoracic lymph node disease best classified as sputum smear-negative pulmonary TB |
Microbiological studies | Easy to collect adequate respiratory specimen Bacteriological confirmation usually achieved | Difficult to collect adequate specimen (young children cannot expectorate); bacteriological confirmation frequently absent; use of culture and Xpert MTB/RIF¶ improve yield, but highly dependent on disease manifestation |
Treatment | ≥4 drugs | ≥3 drugs, depending on likely organism load and severity of disease |
Prognosis | Excellent outcomes achievable with timely and appropriate treatment Rapid disease progression rare | Excellent outcomes achievable with timely and appropriate treatment Rapid disease progression not uncommon in very young or immunocompromised children Potentially grave outcome with delayed diagnosis |