A 40-year-old man presented with sudden-onset left-sided chest pain of two days duration. The pain was severe, pleuritic in nature and relieved by non-steroidal anti-inflammatory drugs (NSAIDS). There was a history of self-limited intermittent dry cough over the preceding 3 months and occasional exertional dyspnea. The patient gave a history of recurrent upper respiratory tract infections (URTIs) and a single episode of pneumonia in childhood. There was also a history of URTIs and bronchitis in adulthood for which he was prescribed brief courses of various antibiotics once or twice a year in recent years. Chest radiographs done during these more recent episodes were clear. There was no prior history of previous diagnosis of pulmonary tuberculosis (TB). He had a 10-year history of smoking which stopped 10 years prior to presentation. Physical examination revealed a respiratory rate of 20 cycles per minute, oxygen saturation of 98% on room air and vesicular breath sounds with reduced air entry at the bases. The remainder of the vital signs and physical examination were normal.
Full blood count showed a total white blood cell count of 4.4x109/L (ref 4.0-11.0 x109 /L) with relative neutropenia and eosinophilia. Other parameters of the full blood count were within normal limits. Erythrocyte sedimentation rate (ESR) was 13 mm in the first hour and the HIV I and II screen was non-reactive. Chest radiograph and computed tomography (CT) scan are shown in Figure 1. A 12-lead electrocardiogram and cardiac troponins showed no evidence of myocardial ischemia or infarction. A 2D echocardiogram showed no regional wall motion abnormalities. D-dimer was within normal limits and angiography of pulmonary vessels showed no filling defect. Flexible bronchoscopy with bronchoalveolar lavage (BAL) showed a hyperemic and inflamed trachea down to the left main bronchus, lingula and left lower lobe with some patchy hyperemic spots. The right bronchopulmonary tree was unremarkable. Routine bacterial culture of BAL fluid revealed no growth and cytology showed features suggestive of chronic inflammation. He was placed on oral moxifloxacin 400mg daily and azithromycin 500mg daily was added to patient s regimen a few days later. The chest pain improved with antibiotic therapy and the patient was discharged home to complete a 10-day course of oral antibiotics.
Acid-fast bacilli (AFB) smear performed on bronchoalveolar fluid became available after discharge and was positive. The patient was placed empirically on rifampicin, isoniazid, pyrazinamide, ethambutol (RHZE) and pyridoxine for presumed pulmonary TB while awaiting drug susceptibility testing. A few weeks after the commencement of RHZE, the report of the culture of the BAL fluid indicated the isolation of Mycobacterium chelonae subspecie abscessus and Mycobacterium immunogenum. No susceptibility data were made available. Anti-TB therapy was stopped and the patient was placed on Azithromycin and Rifampicin, which he took for about 10 months. He had a repeat bronchoscopy with BAL about 2 months after his initial presentation; all bacterial and mycobacterial cultures and cytology were negative and there were no abnormal findings on bronchoscopy. A chest X-Ray and CT scan at the end of therapy, almost a year after initial presentation showed no abnormality (Figure 2).