Diagnostic challenges of endobronchial tuberculosis in a child with lobar pneumonia

Abstract

Background Diagnosis of EBTB in children can be challenging, as symptoms are often non-specific. Early diagnosis and follow up with flexible bronchoscopy is important for prevention of long-term complications like bronchostenosis. Methods The clinical presentation and procedures performed in a patient leading to the diagnosis of EBTB were described to illustrate the roles of diagnostic tools in this condition. Case Report A teenage girl not having contact history of tuberculosis, presented acutely with symptoms and signs of left lower lobar pneumonia was subsequently diagnosed to have EBTB. Sputum smears for acid-fast bacilli were negative while blood test for tuberculosis interferon gamma release assay (IGRA) was positive suggesting TB infection. The features of collapse-consolidation of the left lower lobe in chest radiograph and the unsatisfactory response to empirical antibiotics led to further investigations. Multi-planar computerised tomography (CT) thorax demonstrated intraluminal hyperdensites obliterating the left main bronchus corresponded to the findings in flexible bronchoscopy of the narrowed left main bronchus with bronchial wall covered with large quantity of white necrotic tissue. The diagnosis of EBTB was confirmed by the biopsy findings of granulomatous inflammation and necrotic tissue consistent with mycobacterial infection, and rapid detection of Mycobacterium tuberculosis (MTB) complex DNA by PCR in the sputum and bronchoalveolar lavage (BAL) specimens. In a Japanese adult study, more than two thirds of patients with EBTB had diagnosis delayed for 2 months or more. Diagnosis of EBTB is more challenging in children especially in areas with high prevalence while a definitive adult contact is often absent and interpretation of PPD skin test is complicated by BCG vaccination. Expectoration of sputum for bacteriological diagnosis is difficult and gastric aspiration is often poorly tolerated. In suspicious cases, flexible bronchoscopy being the standard tool for diagnosis, classification and management of EBTB should be performed early. CT imaging is complementary while serological tests and molecular techniques to detect MTB-DNA have improved microbiological diagnostic yield. Conclusions The clinical and radiological features of EBTB may not be differentiated from other causes of community-acquired pneumonia. With a high index of suspicion in prevalent areas, timely diagnosis with the availability of various advanced diagnostic tools is important.