Title : Diagnostic utility of bronchoalveolar lavage and computerized tomography in diagnosis of recurrence among sputum scarce and sputum negative treated pulmonary tuberculosis suspects
Objective: There are a large number of patients who present with chest symptoms of short duration at secondary and tertiary care centers with a background history of anti-tubercular therapy in the past. The literature regarding the evaluation and management of such patients is scarce. Therefore a study was planned with the aim of to assess the sensitivity, specificity and diagnostic accuracy of various CT chest findings, BAL GeneXpert, AFB and Culture (MGIT- 960) in diagnosing recurrence of pulmonary tuberculosis.
Methods: A prospective observational study was conducted in a tertiary care hospital of North India wherein 62 suspects with past history of treatment for pulmonary tuberculosis, who presented with symptoms suggestive of recurrence, were included. Patients underwent BAL and CT chest and other relevant investigations. They were followed up till treatment completion or clinical cure.
Results: A total of 62 patients were included in the final analysis. Recurrence of TB was present in 29 %( 18) of patients. The mean age of the patients with recurrent PTB was 27.5 years, 55.5% (10) were males and 44.5% (8) were females. Median duration between two episodes of PTB was 1.5 years. Cough was the universal symptom in these patients with recurrent symptoms (> 90%). Hemoptysis was predominant symptom among patients with Aspergillosis (66.6%). Mean CRP was higher among recurrent PTB groups compared to patients in another group (83.03 & 11.73 respectively) which was statistically significant. BAL Xpert® MTB/RIF and MGIT had good sensitivity (83.33% & 84.62% respectively), specificity (100% for both) and excellent diagnostic
accuracy (95.16% & 96.36%) for diagnosing recurrence in sputum negative and sputum scarce patient, (p<0.001). Among CT findings, necrotic mediastinal lymph nodes had a good diagnostic accuracy of 88.71% with AUC of 0.806, (p < 0.001).
Conclusion: BAL Xpert® MTB/RIF and MGIT, have good sensitivity (83.33% & 84.62%), specificity and excellent diagnostic accuracy (95.16% & 96.36%) for diagnosing recurrence in sputum negative and sputum scarce patient. The presence of mediastinal necrotic lymph node is the single most CT finding that can truly differentiate recurrent TB from post TB sequelae. Bronchoscopy & BAL should be considered for microbiological confirmation and sensitivity testing before embarking on unwarranted ATT initiation, in cases of suspected recurrence.