[5] Respiratory Pathologies.pdf

Acute Lung Injury and Acute Respiratory Distress Syndrome

What disease category is characterized in the acute exudative stage by congestion, edema, inflammation, fibrin deposition, and diffuse alveolar damage?

Heavy, firm, red, and boggy

What is the gross morphology of the lungs in the acute exudative stage of Acute Respiratory Distress Syndrome (ARDS)?

Patchy ground-glass opacities with or without consolidation

How does the acute exudative stage of ARDS manifest radiologically?

Waxy hyaline membranes

What histological feature lines the alveolar walls in the acute exudative stage of ARDS?

Fibrin-rich edema fluid mixed with the remnants of necrotic epithelial cells

What do alveolar hyaline membranes consist of?

Type II pneumocytes proliferate, and granulation tissue forms in the alveolar walls and spaces

What happens during the proliferative or organizing stage of ARDS?

Permanent enlargement of airspaces distal to terminal bronchioles

What characteristic change defines Emphysema in Chronic Obstructive Pulmonary Disease (COPD)?

Elastases and oxidants released from inflammatory cells, particularly neutrophils

What causes tissue destruction in Emphysema?

Centriacinar distribution

What is the typical distribution of Emphysema in COPD, usually affecting the upper two-thirds of the lungs in smoking-related disease?

Panacinar pattern

What pattern of emphysematous change is particularly severe in patients with α1-antitrypsin deficiency?

Abnormally large alveoli separated by thin septa with focal centriacinar fibrosis

What is the microscopic morphology of advanced Emphysema?

Loss of attachments between alveoli and the outer wall of small airways

What specific structural loss occurs in Emphysema?

Decrease in the capillary bed area

What happens to the vascularity as alveolar walls are destroyed in advanced Emphysema?

Mucous gland hyperplasia and hypersecretion

What is the major pathologic change in Chronic Bronchitis?

Tobacco smoke and air pollutants

What is the etiology of Chronic Bronchitis?

Persistent productive cough for at least 3 consecutive months in at least 2 consecutive years

What is the clinical definition of Chronic Bronchitis?

Airway dilation and scarring

What is the major pathologic change in Bronchiectasis?

Persistent or severe infections

What is the etiology of Bronchiectasis?

Episodic wheezing, cough, dyspnea

What are the signs and symptoms of Asthma?

Smooth muscle hyperplasia, excess mucus, inflammation

What are the major pathologic changes in Asthma?

Immunologic or undefined causes

What is the etiology of Asthma?

Airspace enlargement; wall destruction

What is the major pathologic change in Emphysema?

Dyspnea

What is the sign or symptom of Emphysema?

Inflammatory scarring/obliteration

What is the major pathologic change in Small airways disease, or bronchiolitis?

Bronchus

What is the anatomic site for Chronic bronchitis, Bronchiectasis, and Asthma?

Acinus

What is the anatomic site for Emphysema?

Bronchiole

What is the anatomic site for Small airways disease, or bronchiolitis?

50–75 years

What is the typical age range of onset for Emphysema?

40–45 years

What is the typical age range of onset for Chronic bronchitis?

Severe; early

What is the characteristic timing and severity of Dyspnea in Emphysema?

Mild; late

What is the characteristic timing and severity of Dyspnea in Chronic bronchitis?

Late; scanty sputum

What are the characteristics of Cough in Emphysema?

Early; copious sputum

What are the characteristics of Cough in Chronic bronchitis?

Normal or slightly increased

What is the characteristic Airway resistance in Emphysema?

Increased

What is the characteristic Airway resistance in Chronic bronchitis?

Low

What is the characteristic Elastic recoil in Emphysema?

Normal

What is the characteristic Elastic recoil in Chronic bronchitis?

Well oxygenated

What is the typical Appearance of a patient with Emphysema?

Cyanotic

What is the typical Appearance of a patient with Chronic bronchitis?

Hyperinflation; normal heart size

What are the findings on the Chest radiograph for Emphysema?

Prominent vessels; large heart size

What are the findings on the Chest radiograph for Chronic bronchitis?

Occlusion of bronchi and bronchioles by thick, tenacious mucus plugs

What is the most striking gross finding in patients dying of acute severe asthma (status asthmaticus)?

Curschmann spirals

What characteristic finding in sputum or bronchoalveolar lavage specimens of patients with atopic asthma results from extrusion of mucus plugs from subepithelial mucous gland ducts or bronchioles?

Charcot-Leyden crystals

What histological finding in asthma is composed of the eosinophil-derived protein galectin-10?

Thickening of airway wall, sub-basement membrane fibrosis, increased vascularity, increase in submucosal gland size, and smooth muscle hypertrophy/hyperplasia

What are the characteristic histologic findings of asthma collectively called?

Muscular bronchoconstriction, acute edema, and mucus plugging

What is acute airflow obstruction in asthma primarily attributed to?

Diffuse interstitial fibrosis of the lung

What gives rise to restrictive lung diseases?

Reduced lung compliance and reduced FVC

What characteristics define restrictive lung diseases?

Normal

What is the ratio of FEV1 to FVC in restrictive lung diseases?

Idiopathic pulmonary fibrosis (IPF)

What is the prototypic restrictive lung disease characterized by patchy interstitial fibrosis and honeycombing?

Usual interstitial pneumonia (UIP)

What is the histologic pattern characteristic of IPF?

Patchy interstitial fibrosis, fibroblastic foci, and formation of cystic spaces (honeycomb lung)

What are the characteristics of the UIP histologic pattern?

Senescence of alveolar epithelium (due to telomere shortening), altered mucin production, and abnormal signaling in alveolar fibroblasts

What genetic analyses suggest roles for in the cause of IPF?

Increased local production of fibrogenic cytokines, such as TGF-β

What event is set in motion by injury to alveolar epithelial cells in IPF?

Nonspecific interstitial pneumonia (NSIP)

What chronic interstitial lung disease has a significantly better prognosis than UIP and may respond to immunosuppressive drugs?

Cryptogenic organizing pneumonia (COP)

What condition is characterized by balls of fibroblasts (Masson bodies) filling alveolar spaces, with relatively normal alveolar walls?

Corticosteroids

What treatment is effective for most patients with Cryptogenic organizing pneumonia?

Coal macules and coal nodules

What characterizes Simple coal workers’ pneumoconiosis?

Carbon-laden macrophages

What do coal macules consist of?

Dilated alveoli adjacent to coal macules

What change occurs in coal workers’ pneumoconiosis that can sometimes give rise to centrilobular emphysema?

Intensely blackened scars 1 cm or larger, up to 10 cm in greatest diameter

What characterizes Complicated coal workers’ pneumoconiosis (progressive massive fibrosis) grossly?

Dense collagen and pigment

What do the lesions of progressive massive fibrosis consist of microscopically?

Anthracosis

What is the most innocuous coal-induced pulmonary lesion, also seen in urban dwellers and tobacco smokers, where carbon pigment is engulfed by macrophages?

Alveolar or interstitial macrophages

What cell type engulfs inhaled carbon pigment in Anthracosis?

Hilar lymph nodes and upper zones of the lungs

What areas are most commonly involved in Silicosis in its early stages?

Hard, collagenous scars

What do the nodules coalesce into as Silicosis progresses?

Eggshell calcification

What radiographic finding in Silicosis is characterized by calcium surrounding a zone lacking calcification in the lymph nodes?

Central area of whorled collagen fibers with a peripheral zone of dust-laden macrophages

What is the hallmark lesion revealed by histologic examination in Silicosis?

Weakly birefringent silicate particles

What is revealed by polarized microscopy of Silicosis nodules?

Diffuse pulmonary interstitial fibrosis and the presence of asbestos bodies

What marks Asbestosis?

Golden brown, fusiform or beaded rods with a translucent center, coated with an iron-containing proteinaceous material

What are Asbestos bodies?

Respiratory bronchioles and alveolar ducts

Where does Asbestosis begin as fibrosis?

Lower lobes and subpleurally

Where does Asbestosis begin, in contrast to coal workers’ pneumoconiosis and silicosis?

Pleural plaques

What is the most common manifestation of asbestos exposure?

Well-circumscribed plaques of dense collagen that are often calcified

What are the characteristics of Pleural plaques?

Anterior and posterolateral aspects of the parietal pleura and over the domes of the diaphragm

Where do Pleural plaques develop most frequently?

Lung carcinomas and mesotheliomas

What two types of tumors develop in workers exposed to asbestos?

Cor pulmonale

What is a potential complication of Asbestosis due to scarring trapping and narrowing pulmonary arteries and arterioles?

Nonnecrotizing granulomas

What is the well-formed pathologic feature of Sarcoidosis?

Aggregates of tightly clustered epithelioid macrophages, often with giant cells

What are the nonnecrotizing granulomas of Sarcoidosis composed of?

Schaumann bodies and asteroid bodies

What characteristic inclusions are found within giant cells in Sarcoidosis granulomas (approximately 60% of cases)?

Multisystem disease of unknown etiology

What is Sarcoidosis defined as?

High levels of CD4+ Th1 T cells in the lung that secrete cytokines such as IFN-γ and IL-2

What immunologic abnormalities are characteristic of Sarcoidosis?

Lymph node enlargement, eye involvement, skin lesions, and visceral involvement

What are the clinical manifestations of Sarcoidosis?

90% of cases

What percentage of Sarcoidosis cases involve the lungs?

Interstitial pneumonitis and nonnecrotizing granulomas centered on bronchioles

What are the subacute changes characteristic of Hypersensitivity Pneumonitis?

Interstitial fibrosis with fibroblastic foci, honeycombing, and obliterative bronchiolitis

What is seen in the chronic phase of Hypersensitivity Pneumonitis?

Accumulation of numerous macrophages (smokers’ macrophages) with dusty brown pigment in the airspaces

What is the most striking finding in Desquamative interstitial pneumonia (DIP)?

Mild interstitial fibrosis, emphysema, and airway changes suggestive of obstructive lung disease

What conditions are often present in Desquamative interstitial pneumonia?

Lamellar bodies (composed of surfactant) within phagocytic vacuoles

What may the macrophages in Desquamative interstitial pneumonia contain, presumably derived from necrotic type II pneumocytes?

Dense, amorphous, protein-lipid granular precipitate filling the alveoli

What is the morphology of Pulmonary alveolar proteinosis (PAP)?

Type II pneumocyte hyperplasia

What cellular change is seen in Pulmonary alveolar proteinosis?

Small lamellar bodies with electron dense cores

What ultrastructural abnormality is diagnostic for ABCA3 mutation (a cause of surfactant dysfunction disorder)?

Main pulmonary artery or its major branches or at the bifurcation

Where do large emboli lodge in Pulmonary Embolism (PE)?

Saddle embolus

What is the name for a large embolus lodged at the bifurcation of the main pulmonary artery?

Compromised cardiovascular function (e.g., heart or lung disease)

In what patient population is pulmonary infarction more likely following PE?

Lines of Zahn

What feature in a thrombus distinguishes a pulmonary embolus from a postmortem clot?

Hemorrhagic

What is the classic appearance of a pulmonary infarct?

Wedge with the apex pointing toward the hilus of the lung

What shape does a pulmonary infarct typically take?

Ischemic necrosis of the alveolar walls, bronchioles, and vessels

What characterizes the hemorrhagic area histologically in a pulmonary infarct?