Seminars in respiratory and critical care medicine
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Bronchioles are noncartilaginous small airways with internal diameter of 2 mm or less, located from approximately the eighth generation of purely air conducting airways (membranous bronchioles) down to the terminal bronchioles (the smallest airways without alveoli) and respiratory bronchioles (which communicate directly with alveolar ducts and are in the range of 0.5 mm or less in diameter). Bronchiolar injury, inflammation, and fibrosis may occur in myriad disorders including connective tissue diseases, inflammatory bowel diseases, lung transplant allograft rejection, graft versus host disease in allogeneic stem cell recipients, neuroendocrine cell hyperplasia, infections, drug toxicity (e.g., penicillamine, busulfan), inhalation injury (e.g., cigarette smoke, nylon flock, mineral dusts, hard metals, Sauropus androgynous); idiopathic, common variable immunodeficiency disorder, and a host of other disorders or insults. The spectrum of bronchiolar disorders is wide, ranging from asymptomatic to fatal obliterative bronchiolitis. In this review, we discuss the salient clinical, radiographic, and histological features of these diverse bronchiolar disorders, and discuss a management approach.
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Hermansky-Pudlak syndrome (HPS) is a multisystemic autosomal recessive disorder characterized by oculocutaneous albinism, bleeding diathesis, and lethal pulmonary fibrosis (PF) in some HPS subtypes. During middle adulthood, ground-glass opacities, reticulation, and traction bronchiectasis develop with progression of PF. HPS is an orphan disease occurring in 1 in 500,000 to 1,000,000 individuals worldwide, though the prevalence is 1 in 1,800 in individuals with Puerto Rican heritage. ⋯ Diagnosis and management of HPS-related comorbidities represent a challenge to physicians, and a multidisciplinary clinical approach is necessary for early detection, health management, and surveillance of PF in patients with HPS types 1, 2, and 4. Treatment options for individuals with HPS-PF include pirfenidone and lung transplantation. In this article, we describe the epidemiology, genetics, clinical manifestations, and management of HPS.
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The interstitial lung diseases (ILDs) are a group of progressive disorders characterized by chronic inflammation and/or fibrosis in the lung. While some ILDs can be linked to specific environmental causes (i.e., asbestosis, silicosis), in many individuals, no culprit exposure can be identified; these patients are deemed to have "idiopathic interstitial pneumonia" (IIP). ⋯ Diverse ILD clinical phenotypes can be seen within a family, and available evidence suggests underlying genetic risk is the primary determinant of disease outcomes. Together, these FIP studies have provided unique insights into the pathobiology of ILDs, and brought focus on the unique issues that arise in the care of patients with FIP.
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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.