Pulmonary sarcoidosis: an update

Sarcoidosis is a multisystem disease characterized by the presence of noncaseating granulomas, the exact etiology of which is yet to be determined. Pulmonary involvement occurs in the majority of patients and its severity ranges from asymptomatic involvement of mediastinal lymph nodes to progressive pulmonary fibrosis and chronic respiratory failure that is insensitive to treatment. Diagnosis of pulmonary sarcoidosis requires a compatible clinical picture supported by radiologic and pathologic data. A recent development in establishing the diagnosis of pulmonary sarcoidosis is endobronchial ultrasound that increases the yield of transbronchial needle aspiration of hilar and/or mediastinal lymph nodes. Fluorodeoxyglucose positron emission tomography (FDG-PET) is highly sensitive in detecting occult sites of disease and is of value in guiding biopsies of these sites. A combined imaging modality using both FDG-PET and CT scan is more sensitive than PET alone and is now the standard of care in patients requiring biopsies of active lesions. Biologic agents like anti-tumor necrosis factor antibodies are being used as second line treatment in those patients dependent on steroids or in cases of refractory sarcoidosis. Lung transplantation is the final option in suitable patients with end-stage pulmonary sarcoidosis.