Mycobacterium intracellulare Pleurisy Identified on Liquid Cultures of the Pleural Fluid and Pleural Biopsy
A 69-year-old man was admitted to our hospital with chief complaints of a 1-month history of dyspnea of Medical Research Council grade fourth, left pleuritic chest pain, anorexia, and general weakness. He experienced a 1-month history of aggravated cough and sputum. He had a 40 pack-year smoking history and a medical history of hypertension and idiopathic pulmonary fibrosis since the year of 2005. He had been treated with mucolytic drug (acetylcystein 600 mg t.i.d.) for one year. However, he had not been treated with immunosuppressive agents including steroid. In 2006, the patient underwent percutaneous coronary intervention for the right coronary artery. He denied any other past medical history.\nOn admission, He had vital signs such as blood pressure 104/66 mm Hg, pulse rate 80 beats/min, respiratory rate 26 breaths/min, and body temperature 36.9℃. On physical examination, He had an acute ill-looking appearance on the face. Chest auscultation revealed diminished breathing sounds on the left lower lung fields with fine crackles on the both lower lung fields. Other results of the physical examination were non-specific.\nLaboratory findings showed white blood cell counts 8,200/mm3, hemoglobin 11.0 g/dL, platelet counts 396,000/mm3, aspartate aminotransferase 82 IU/L, alanine aminotransferase 64 IU/L, total bilirubin 0.7 mg/dL, and alkaline phosphatase 216 IU/L. Arterial blood gas analysis on room air yielded pH of 7.49, PaO2 of 65 mm Hg, PaCO2 of 33 mm Hg, and HCO3- of 25 mEq/L.\nChest radiography revealed the left pleural effusion and reticular densities in the bibasilar area (). High-resolution computed tomography revealed a moderate amount of pleural effusion on the left side and multifocal ill-defined patchy reticular opacities with honeycombing lesions in both lower lobes of the lung ().\nTo diagnose and treat this pleural effusion, he underwent a thoracentesis and pleural biopsy. On pleural effusion analysis, there were such findings as pale yellow color, specific gravity 1.010, red blood cell counts 1,100/mm3, white blood cell counts 1,800/mm3 with 4% neutrophils and 88% lymphocyte, pH 7.2, protein 5.4 g/dL, lactate dehydrogenase 282 U/L, glucose 73 mg/dL, albumin 2.5 g/dL, ADA 142 IU/L, negative acid-fast staining, non-specific cytology, and negative real-time polymerase chain reaction for M. tuberculosis. Pleural biopsy showed chronic granulomatous inflammation, but Ziehl-Neelsen stain failed to demonstrate the organism. Hence, he was tentatively diagnosed with tuberculous pleurisy. We prescribed isoniazid (300 mg/day), rifampicin (600 mg/day), ethambutol (1,200 mg/day) and pyrazinamide (1,500 mg/day). Following the initiation of standard treatment for tuberculosis, M. intracellulare was identified using a polymerase chain reaction-restriction fragment length polymorphism method and liquid cultures of the pleural effusion and pleural biopsy. Also, three consecutive sputum examination on admission revealed all negative Ziehl-Neelsen stain, but M. intracellulare was isolated in all liquid cultures one month later. Based on these findings, he was treated with azithromycin (250 mg/day), rifampicin (600 mg/day), and ethambutol (800 mg/day). One month later, chest radiograph showed that pleural effusion was improved on the left side (). At a 1-month follow-up, the patient was clinically well. The patient is scheduled to receive the treatment for the next one and a half year.