Refractory Isoniazid-Resistant Miliary TB or Something More?

Abstract

SESSION TITLE: Fellow Case Report Poster - Chest Infections II SESSION TYPE: Affiliate Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM INTRODUCTION: Miliary nodular pattern is defined by diffuse and symmetrically distributed micronodules (<3mm) within the lungs, and often pedagogically associated with hematogenously disseminated tuberculosis (TB). However, the differential is broader. CASE PRESENTATION: 57-year-old Chinese man, former smoker, with chronic HBV, history of incompletely treated pulmonary TB in 1996 presented with progressive dry cough, dyspnea, weight loss, fevers, chills, and night sweats. Chest x-ray showed bilateral diffuse nodularity, and sputum culture grew Mycobacterium tuberculosis. He was started on IRPE for miliary TB. Course was complicated by asymptomatic liver transaminitis requiring treatment discontinuation after 3 weeks. IRE/Levofloxacin were substituted. He was admitted to the hospital for worsening dyspnea and cough with concern for possible resistance. The original sputum culture revealed INH resistance but susceptibility to other first line agents, and he was discharged on RPE/Moxifloxacin. He was readmitted for medication noncompliance and new hypoxia. CT chest showed persistent diffuse pulmonary nodules, biapical scarring and emphysema. Liver biopsy showed concern for drug-induced versus autoimmune hepatitis, and he was started on prednisone and tenofovir, as well as a liver-sparing regimen of amikacin, ethambutol and moxifloxacin. He continued to worsen. Open lung biopsy of two different lobes revealed lung adenocarcinoma in both surgical specimens. DISCUSSION: The differential diagnosis of miliary pattern on chest imaging includes TB, metastatic disease, fungal infections, sarcoidosis, and pneumoconioses. Unlike miliary TB (micronodules ranging from 1 to 3mm), miliary metastatic lesions may have variable sizes (up to 1cm). Although this case had a number of reasons to anchor on a diagnosis of miliary TB, it is important to keep a broader differential for miliary pattern, and re-think the diagnosis when patients are not improving on appropriate therapy. CONCLUSIONS: We report a case of advanced stage lung adenocarcinoma appearing in a miliary nodular pattern in the setting of concurrent tuberculosis. Patients with diffuse miliary nodules, especially for those whose symptoms do not improve after tuberculosis treatment, should be evaluated for other diagnoses, such as cancer. Reference #1: Oikonomou, A et al. Mimics in chest disease: interstitial opacities. Insights Imaging. 2013;4:9-27. DISCLOSURE: The following authors have nothing to disclose: Kathleen Doo, Deepak Pradhan No Product/Research Disclosure Information