Restrictive Pulmonary Disorders Kelly I

What antibody increases the risk of interstitial lung disease in systemic sclerosis, and what does it target?

Anti-Scl-70, which targets DNA topoisomerase I. ⭐

What do asbestos bodies look like microscopically?

Elongated, beaded or dumbbell-shaped fibers coated with iron, sometimes engulfed by macrophages. ⭐

What gives asbestos bodies their brown appearance, and which stain highlights them?

Their iron coating appears brown on H&E and blue with Prussian blue stain. ⭐

Where are asbestos-related pleural plaques commonly identified on CT?

Along the chest wall and diaphragm. ⭐

What is the most common manifestation of asbestos exposure?

Pleural plaques.

Are asbestos bodies found within pleural plaques?

No. They are found in lung tissue affected by asbestosis, rather than within the plaques.

What is the most important initial step when evaluating suspected interstitial lung disease?

A complete history, especially occupational/environmental exposures, smoking, medications, systemic disease, family history and radiation.

What is the key histologic feature of UIP emphasized by Dr. Kelly?

Temporal heterogeneity: patchy lung injury of different ages, with normal lung, active injury and established fibrosis beside one another.

What histologic finding represents active injury in UIP?

Fibroblastic foci, containing proliferating fibroblasts/myofibroblasts.

What distribution of fibrosis is characteristic of UIP/IPF?

Predominantly subpleural and lower-lobe fibrosis.

What is the characteristic end-stage appearance of UIP/IPF?

Honeycomb lung, with fibrosis, architectural destruction and cystic airspaces.

What does UIP describe, and how does it relate to IPF?

UIP is a histologic and radiologic pattern characteristic of IPF. IPF is the clinical diagnosis after excluding identifiable causes.

What is the key distinction between UIP and NSIP?

UIP: injury of different ages. NSIP: relatively uniform injury at the same stage of development.

How does the prognosis of NSIP compare with IPF/UIP?

NSIP generally has a substantially better prognosis.

What findings are generally absent in classic NSIP?

Fibroblastic foci, honeycombing, hyaline membranes and granulomas.

What systemic disease category is commonly associated with NSIP?

Connective tissue diseases.

When should cryptogenic organizing pneumonia be suspected clinically?

When presumed infectious pneumonia fails to improve with antibiotics.

What are the characteristic histologic structures in organizing pneumonia?

Masson bodies: polypoid plugs of fibroblasts/myofibroblasts in loose connective tissue within alveoli, alveolar ducts and sometimes bronchioles.

What combination defines Caplan syndrome?

Rheumatoid arthritis + inorganic dust exposure/pneumoconiosis + pulmonary rheumatoid nodules.

What occupational exposures suggest silicosis?

Mining, engineered-stone fabrication, sandblasting and demolition.

What is the characteristic microscopic appearance of a silicotic nodule?

Whorled, densely hyalinized collagen, often surrounded by dust-laden macrophages.

What does polarized microscopy reveal in silicosis?

Birefringent silica/silicate particles.

What characteristic lymph-node calcification can occur in silicosis?

Eggshell calcification of hilar lymph nodes.

What infection is particularly associated with silicosis?

Tuberculosis, because silica impairs macrophage function.

How does silica exposure affect lung-cancer risk?

It increases lung-cancer risk independently of cigarette smoking.

What occupational history suggests asbestos exposure?

Shipbuilding, insulation work, mining, fabrication and brake work.

Which lung regions are predominantly affected by asbestosis?

The lower lobes, particularly subpleural regions.

How do smoking and asbestos exposure interact in causing lung cancer?

They produce a synergistic increase in lung-carcinoma risk.

In asbestos-exposed patients, which is more common: lung carcinoma or mesothelioma?

Lung carcinoma, despite mesothelioma’s classic association with asbestos.

Which asbestos fibers did Dr. Kelly emphasize as particularly harmful, and why?

Amphibole fibers: straight, stiff, needle-like fibers that penetrate deeply and persist in the lungs.

What occupational lung disease can closely mimic sarcoidosis?

Chronic beryllium disease, which also produces noncaseating granulomas.

What helps distinguish chronic beryllium disease from sarcoidosis?

A beryllium exposure history and a positive beryllium lymphocyte proliferation test (BeLPT).

What classic combination suggests pulmonary sarcoidosis?

Bilateral hilar lymphadenopathy and noncaseating granulomas, sometimes with skin, eye or other systemic involvement.

Why did Dr. Kelly repeatedly call sarcoidosis a diagnosis of exclusion?

Other causes of granulomas must be excluded, including infections, occupational exposures, hypersensitivity reactions and foreign material.

What laboratory finding can support sarcoidosis but is not diagnostic?

Elevated serum ACE.

What are asteroid bodies in sarcoidosis?

Star-shaped cytoplasmic inclusions within multinucleated giant cells.

What are Schaumann bodies in sarcoidosis?

Concentrically laminated calcified inclusions within multinucleated giant cells.

Are asteroid and Schaumann bodies specific for sarcoidosis?

No. They support the diagnosis in the appropriate clinical setting.

Which hypersensitivity mechanism did Dr. Kelly emphasize for chronic hypersensitivity pneumonitis?

Type IV, T-cell-mediated hypersensitivity.

What exposure causes farmer’s lung?

Thermophilic actinomycetes in moldy hay.

What exposure causes bagassosis?

Moldy sugarcane dust.

What exposure causes bird breeder’s or bird fancier’s lung?

Avian proteins from bird droppings and feathers.

What BAL finding supports hypersensitivity pneumonitis?

Lymphocytosis, often with lymphocytes accounting for more than 50% of recovered cells.

What histologic findings characterize hypersensitivity pneumonitis?

Bronchiolocentric lymphocytic interstitial inflammation and loosely formed noncaseating granulomas.

What intervention did Dr. Kelly emphasize as essential in hypersensitivity pneumonitis?

Identify and remove the antigen exposure early to prevent progressive fibrosis.

Where do smoker’s macrophages accumulate in desquamative interstitial pneumonia (DIP)?

Diffusely within alveolar airspaces, with relatively mild interstitial fibrosis.

Where is the injury centered in respiratory bronchiolitis-associated ILD (RB-ILD)?

Around respiratory bronchioles, with pigmented macrophages, chronic inflammation and peribronchiolar fibrosis.

What is the key histologic distinction between DIP and RB-ILD?

DIP is diffuse and alveolar; RB-ILD is bronchiolocentric.

What intervention is central to treating DIP and RB-ILD?

Smoking cessation.

Which cell marker did Dr. Kelly specifically emphasize for pulmonary Langerhans cell histiocytosis?

CD1a.

What characteristic ultrastructural finding identifies Langerhans cells?

Tennis-racket-shaped Birbeck granules on electron microscopy.

What inflammatory cells commonly accompany pulmonary Langerhans cell histiocytosis?

Eosinophils.

What material fills the alveoli in pulmonary alveolar proteinosis (PAP)?

Acellular, granular, eosinophilic proteinaceous surfactant material.

What happens to the alveolar walls and inflammation in classic PAP histology?

The walls remain relatively preserved, with minimal inflammation despite extensive airspace filling.

What causes the most common, autoimmune form of PAP?

Anti–GM-CSF antibodies, which impair alveolar macrophage function and surfactant clearance.