PMC8531841_01
The clinical course of the patient.. APAP, autoimmune pulmonary alveolar proteinosis; CT, computed tomography; DLco, carbon monoxide diffusing capacity; FEV1%, forced expiratory volume 1.0 (sec) percent; MAC, Mycobacterium avium complex; PSL, prednisolone; RECAM, treatment with rifampicin, ethambutol, and clarithromycin; VA, alveolar volume; VC, percent vital capacity.
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In a health check-up, an abnormal shadow was seen on a chest radiograph (Fig. 1). In addition, PFTs after 5 months of treatment with RECAM showed slight improvements (Fig. 1).
Chest computed tomography (CT) on the first visit to a nearby hospital demonstrated patchy bilateral ground-glass attenuation (GGA) (A). The patient was followed-up on suspicion of interstitial pneumonia, and the GGA in both lungs worsened gradually (B-D). Chest CT at the time of diagnosis of autoimmune pulmonary alveolar proteinosis demonstrated nodules in both lungs (dotted area) (D), and cavities were visible within the nodules after 1 week (dotted area) (E). After a 6-month treatment with rifampicin, ethambutol, and clarithromycin, the GGA and nodules were improved remarkably (F).. APAP, autoimmune pulmonary alveolar proteinosis; MAC, Mycobacterium avium complex.
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Chest computed tomography (CT) showed bilateral ground-glass attenuation (GGA) (Fig. 2A), and the patient was followed-up on suspicion of interstitial pneumonia. The bilateral GGA gradually worsened (Fig. 2B). However, because his symptoms and imaging findings did not improve (Fig. 2C), corticosteroids treatment was tapered and discontinued after 2.5 months. Chest CT performed at the time of diagnosis revealed multiple new nodular shadows and diffuse GGA with a crazy-paving appearance (Fig. 2D). These nodular shadows were accompanied by cavities on CT images taken after 1 week (Fig. 2E). After 4 months of treatment with rifampicin (450 mg/day), ethambutol (750 mg/day), and clarithromycin (800 mg/day) (RECAM), not only had the SpO2 increased but the imaging findings also remarkably improved (Fig. 2F).
The bronchoalveolar lavage fluid had a milky appearance (A). Transbronchial lung biopsy specimen demonstrated peripheral air spaces filled with granular eosinophilic amorphous material (B, hematoxylin and eosin staining, x 100). The material was positive in periodic acid-Schiff staining (C, x 100) and hydrophilic surfactant proteins A staining (D, x 100).
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One month before his first visit to our department, APAP was diagnosed based on a positive serum anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) antibody, bronchoalveolar lavage fluid (BALF) findings, and transbronchial lung biopsy results (Fig. 3).