Comparison of chest radiograph findings in ambulatory and hospitalized children with pulmonary tuberculosis.

backgroundThe diagnosis of childhood tuberculosis (TB) is, in many instances, solely reliant on chest radiographs (CXRs), as they are often the only diagnostic tool available, especially in TB-endemic areas. Accuracy and reliability of CXRs for detecting TB lymphadenopathy may vary between groups depending on severity of presentation and presence of parenchymal disease, which may obscure visualization.

objectiveTo compare CXR findings in ambulatory versus hospitalized children with laboratory confirmed pulmonary TB versus other lower respiratory tract infections (LRTI) and test inter-rater agreement for these findings. MATERIALS AND

methodsRetrospective review, by two pediatric radiologists, of CXRs performed on children < 12 years old referred for evaluation of LRTI with clinical suspicion of pulmonary TB in inpatient and outpatient settings. Each radiologist commented on imaging findings of parenchymal changes, lymphadenopathy, airway compression and pleural effusion. Frequency of imaging findings was compared between patients based on location and diagnosis and inter-rater agreement was determined. Accuracy of radiographic diagnosis was compared to laboratory testing which served as the gold standard.

resultsThe number of enrolled patients was 181 (54% males); 69 (38%) were ambulatory and 112 (62%) were hospitalized. Of those enrolled, 87 (48%) were confirmed to have pulmonary TB, while 94 (52%) were other LRTI controls. Lymphadenopathy and airway compression were more common in TB patients than other LRTI controls, regardless of patient location. Parenchymal changes and pleural effusion were more common in hospitalized than ambulatory patients, regardless of patient diagnosis. Agreement for parenchymal changes was higher in the hospitalized group (kappa [κ] = 0.75), while agreement for lymphadenopathy (κ = 0.65) and airway compression (κ = 0.68) was higher in the ambulatory group. The specificity of CXRs for TB diagnosis (> 75%) was higher than the sensitivity (< 50%) for both ambulatory and hospitalized groups.

conclusionHigher frequency of parenchymal changes among hospitalized children may conceal specific imaging findings of TB such as lymphadenopathy, contributing to the poor reliability of CXRs. Despite this, the high specificity of CXRs shown in our results is encouraging for continued use of radiographs for TB diagnosis in both settings.