Seminars in respiratory and critical care medicine
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Amyloidosis is the term given to abnormal deposition of misfolded precursor proteins at single or multiple sites, leading to organ dysfunction or clinical signs and symptoms. Pulmonary manifestations are nonspecific and may be associated with several amyloid protein subtypes, commonly AL (light chain) and AA (autoimmune) amyloids. Signs or symptoms of amyloid disease may often involve more of the clinical abnormalities of other affected organs than the lungs themselves. ⋯ Lymphadenopathy with or without calcification and pleural effusions has also been reported. Directed therapy is initiated in response to clinical signs or symptoms often as a result of systemic or secondary diseases or conditions. Long-term prognosis is more dependent on the extent of organ involvement where morbidity is often the highest in those with multisystemic disease.
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Combined pulmonary fibrosis and emphysema (CPFE) is a clinical entity characterized by the combination of upper lobe emphysema and lower lobe fibrosis, the latter owing to various interstitial lung diseases. These patients have a characteristic lung function profile, with relatively preserved dynamic and static lung volumes, contrasting with a significant reduction of carbon monoxide transfer. The pathogenic mechanisms leading to the coexistence of emphysema with fibrosis remain unclear and different theories have been proposed. ⋯ The syndrome of CPFE represents a distinct pulmonary manifestation in the spectrum of lung diseases associated with connective tissue diseases. Currently, there are no established recommendations regarding the management of patients with CPFE. We provide a review on the existing knowledge of CPFE regarding the epidemiology, pathogenesis, clinical manifestations, radiologic appearance, complications, prognosis, and possible treatment options.
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Nonspecific interstitial pneumonia (NSIP) is a complex disorder commonly associated with other conditions such as connective tissue diseases (CTDs) and environmental exposures. Although idiopathic NSIP has been recognized as a separate clinical entity, recent studies have suggested that a proportion of these cases have autoimmune features suggestive of underlying CTDs. The diagnosis of NSIP usually carries a better prognosis compared with idiopathic pulmonary fibrosis but has an unpredictable natural history. ⋯ There is a lack of consensus on the optimal management strategy of NSIP. Early clarification of the goals of therapy and close monitoring for the progression of disease is important across the spectrum of NSIP irrespective of its etiology. Although immunosuppressive and immunomodulatory agents are commonly used for severe and progressive disease, the therapeutic landscape of NSIP is constantly evolving as the role of newer agents such as antifibrotic therapies is being explored.
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Pulmonary Langerhans cell histiocytosis (PLCH) is a diffuse cystic lung disease that is strongly associated with exposure to cigarette smoke. Recently, activating pathogenic mutations in the mitogen-activated protein kinase pathway have been described in the dendritic cells in patients with PLCH and have firmly established PLCH to be an inflammatory myeloid neoplasm. ⋯ Smoking cessation is the cornerstone of treatment in patients with PLCH and can lead to disease regression or stabilization in a substantial proportion of patients. Further insight into the underlying molecular pathogenesis of PLCH has paved the way for the future development of disease-specific biomarkers and targeted treatment options directed against the central disease-driving mutations.