Comparing axillary and mediastinal lymphadenopathy on CT in children with suspected pulmonary tuberculosis

Background: Radiographic demonstration of mediastinal lymphadenopathy is important for the diagnosis of pulmonary tuberculosis (PTB). Plain radiographs are unreliable for this and CT, which is relatively more expensive and carries a high radiation burden, remains the gold standard. No studies correlating the presence of axillary with mediastinal lymphadenopathy have been reported. Such a correlation would allow for clinical or ultrasound diagnosis of PTB via the axilla. Objective: To correlate the presence of axillary lymphadenopathy with mediastinal lymphadenopathy in children with suspected PTB. Materials and methods: CT scans were performed and reviewed in 100 children (prospectively recruited) with suspected PTB. The axilla and mediastinum were reviewed separately by covering the non-relevant sections on the CT scans prior to reading. Only nodes greater than 1 cm were regarded as pathological. Results: Mediastinal lymphadenopathy was present in 46% of children; 70% had lymphadenopathy in either axilla. Bilateral axillary lymphadenopathy was identified in 47%. Axillary lymphadenopathy showed a sensitivity of 74% and a specificity of 33% for the presence of mediastinal adenopathy. Bilateral axillary adenopathy had a sensitivity of 50% and a specificity of 56%. Conclusions: Axillary lymphadenopathy has a moderate sensitivity and low specificity for the presence of mediastinal and hilar lymphadenopathy in children with suspected PTB. Further research should be aimed at correlating ultrasound-detected axillary lymphadenopathy with FNA results in children.