Interstitial lung disease

Question 1

What are the common features of diffuse interstitial lung disease?
(3)

Answer 1

(1) Diffuse and chronic involvement of pulmonary connective tissue (interstitium)
(2) Restrictive pattern of pulmonary function tests
(3) Reduced ability of the lung to expand

Question 2

What is the end result of interstitial lung disease if left untreated?

Answer 2

Pulmonary fibrosis - honeycomb lung

Question 3

What are the different etiologies of interstitial lung disease?
(7)

Answer 3

(1) Pneumoconiosis
(2) Infectious interstitial pneumonitis
(3) Chemical
(4) Physical (radiation pneumonitis)
(5) Hypersensitivity pneumonitis
(6) Heart failure
(7) Smoking-related interstitial lung disease

Question 4

What is pneumoconiosis?

Answer 4

Non-neoplastic lung reaction to inhalation of mineral dusts, organic dust, and chemical fumes

Question 5

What is pathogenesis of pneumoconiosis?

5

Answer 5

Severity determined by:
(1) Dust concentration
(2) Duration of exposure
(3) Effectiveness of mucociliary apparatus
(4) Particle size (1-5 microns, 1-2 microns reach alveoli)
Once in the lung, (5) particles are phagocytosed by macrophages

Question 6

What is anthracosis and what are its implications?

3

Answer 6

(1) Deposition of carbonaceous material in the lungs
(2) No functional impairment of lungs (no scarring or destruction of interstitial tissue)
(3) Carbon ingested by alveolar and interstitial macrophages, leads to blackening of the lungs

Question 7

What are characteristics of silicosis?

4

Answer 7

(1) Pneumoconiosis resulting from inhalation of silicon dioxide crystals
(2) Most prevalent occupational disease in the world
(3) Occurs in sandblasters, miners, and stone cutters
(4) Slowly progressive nodular and fibrosing disease

Question 8

What is the pathology of silicosis?

4

Answer 8

(1) Fibrotic nodules in lung parenchyma with concentric laminations, centered around fixed structures (ex. vasculature)
(2) Hilar lymph node involvement (with or without calcification)
(3) Pleural fibrosis and adhesions
(4) Synergistic with tuberculosis

Question 9

What are the clinical manifestations of silicosis?

3

Answer 9

(1) Classified as simple (nodules 1 cm) silicosis
(2) Egg shell calcificatoin of hilar lymph nodes on chest x-rays
(3) Reduction in ventilatory capacity and decrease in diffusing capacity, dependent on extent of interstitial fibrosis

Question 10

What are the characteristics of complicated coal worker’s pneumoconiosis?
(3)

Answer 10

(1) Coal macules (>1 cm diameter) associated with chronic inflammation, dense fibrosis, and constriction of entrapped structures
(2) Fibrosis and calcification of hilar lymph nodes
(3) Tuberculosis particularly aggressive

Question 11

What are asbestos-related diseases

6

Answer 11

Associated with single exposure to asbestos (doesn’t occur slowly over time like in coal miner’s pneumoconiosis)

(1) Localized fibrous plaques on pleura (asbestos-defining disease)
(2) Diffuse pleural fibrosis
(3) Pleural effusions
(4) Interstitial fibrosis
(5) Bronchogenic carcinoma (aka lung cancer)
(6) Mesothelioma

Question 12

What is the pathogenesis of asbestos-related diseases?

5

Answer 12

(1) Two forms of asbestos fibers
(a) Serpentine - flexible and curly
(b) Amphibole - straight and brittle
(2) Only amphibole fibers associated with mesothelioma
(3) Both serpentine and amphibole fibers cause pulmonary fibrosis
(4) Carcinogenesis because toxic chemicals adsorbed onto asbestos fibers
(5) Eventual fibrosis

Question 13

What is berylliosis and what are its types?

2

Answer 13

(1) Chemical pneumonitis due to beryllium exposure

(2) Acute and chronic berylliosis

Question 14

What are the characteristics of acute berylliosis?

4

Answer 14

(1) Interstitial edema and inflammation
(2) Epithelial cell reaction
(3) Associated with aerospace industry
(4) May be fulminant (sudden) and result in death, may regress completely, or may progress to chronic berylliosis

Question 15

What are the characteristics of chronic berylliosis?

3

Answer 15

(1) Interstitial and pleural fibrosis
(2) Non-caseating granuloma with birefringent calcite bodies
(3) Respiratory failure

Question 16

What are the different types of hypersensitivity pneumonitis?
(4)

Answer 16

(1) Farmer’s lung - dust from warm, humid hay
(2) Pigeon breeder’s lung - proteins from serum, feathers, and feces of birds
(3) Humidifier or air-conditioner lung - thermophilic bacteria in water heater reservoirs
(4) Byssinosis - cotton fibers, affects textile workers

Question 17

What is the clinical course of hypersensitivity pneumonitis?

5

Answer 17

(1) Acute attacks follow inhalation of antigenic dust
(2) Fever, dyspnea, cough, leukocytosis
(3) Diffuse and nodular infiltrates on x-ray
(4) Acute restrictive pattern on pulmonary function tests
(5) Slowly progressive respiratory failure, similar to other interstitial lung diseases

Question 18

What is usual interstitial pneumonitis?

3

Answer 18

(1) Acute idiopathic pulmonary fibrosis, (2) also known as Hamman-Rich Syndrome, that (3) affects mostly elderly men

Question 19

What is the clinical course of usual interstitial pneumonitis?
(5)

Answer 19

(1) Progressive respiratory insufficiency with hypoxemia and cyanosis
(2) Secondary pulmonary hypertension due to extensive fibrosis
(3) Cor pulmonale (enlargement of right side of heart) eventually results
(4) Disease course is unpredictable and fibrosis progresses rapidly over the course of weeks to months
(5) Median survival less than 5 years

Question 20

What is the morphology of usual interstitial pneumonitis?

5

Answer 20

(1) Process is patchy and temporally heterogeneous (areas that are fibrotic in various stages of fibrosis)
(2) Areas of more recent damage admixed with normal lung
(3) Organization of exudate with interstitial fibrosis
(4) Diseased areas always alternate with normal-appearing lung parenchyma
(5) Honeycomb lung (end-stage fibrosis)

Question 21

What is desquamative interstitial pneumonitis (DIP)?

4

Answer 21

(1) Interstitial pneumonitis associated with marked accumulation of alveolar macrophages within alveolar spaces
(2) Unknown cause
(3) Affects middle-aged men and women
(4) Name is a misnomer because no desquamation or shedding of alveolar lining cells into alveolar space
(5) Temporally homogeneous (contrasted with temporal heterogeneity of usual interstitial pneumonitis)

Question 22

What is the clinical course of desquamative interstitial pneumonitis?
(4)

Answer 22

(1) Non-specific clinical presentation: slow development of cough, dyspnea
(2) Often a history of recent viral respiratory tract infection
(3) X-ray - migratory patchy opacities or bilateral lower-lobe interstitial infiltrates
(4) Good prognosis - most patients improve gradually on steroid therapy, unlike in usual interstitial pneumonitis

Question 23

What is lymphocytic interstitial pneumonia?

3

Answer 23

(1) Interstitial pneuonitis with diffuse lymphoid infiltrates in the interstitium
(2) May be idiopathic
(3) Associated with HIV infection - AIDS-defining illness in children

Question 24

What are the features of lymphocytic interstitial pneumonia?

5

Answer 24

(1) Diffuse infiltration of alveolar septa by chronic inflammatory cells
(2) Alveolar architecture is preserved
(3) Cough, progressive dyspnea
(4) Varied prognosis - disease may regress or progress to end-stage lung disease
(5) Steroids and cytotoxic agents may help

Question 25

What is the pathogenesis of sarcoidosis?

4

Answer 25

(1) Inappropriate host immunological response
(2) Interactions between T cells and activated macrophages, similar to delayed hypersensitivity
(3) Sequestration of T-helper cells in lung, resulting in decreased circulating T-helpers
(4) Hyperactive B-cells and increased immunoglobulin levels

Question 26

What is sarcoidosis?

Answer 26

(1) Systemic disease with noncaseating granulomas in many tissues and organs
(2) Unknown cause
(3) Possibly a delayed hypersensitivity type of response to an antigen

Question 27

What are the histologic features of sarcoidosis?

8

Answer 27

(1) Granuloma
(a) Usually non-caseating
(b) Dense, well-formed, lack surrounding inflammation
(c) Distributed along pulmonary lymphatics
(d) Frequent inclusions in giant cells
(2) Interstitial inflammation
(a) Interstitial infiltrates of lymphocytes and plasma cells
(b) May develop interstitial fibrosis with honeycombing

Question 28

What is the prognosis of sarcoidosis?

Answer 28

(1) Highly variable and unpredictable clinical course
(2) May present as single episode or chronic disease with alternating periods of activity and remission
(3) 70-80% recover with no significant permanent damage, 10-20% have permanent pulmonary function loss, and 2-5% die

Question 29

What are the clinical features of sarcoidosis?

Answer 29

(1) May be asymptomatic or present with cough and dyspnea
(2) Chest infiltrates with hilar adenopathy
(3) Variable reduction in ventilatory capacity, decreased diffusing capacity, and airway obstruction

Question 30

What is the morphology of noncaseating granulomas in sarcoidosis?
(5)

Answer 30

(1) Aggregates of tightly clustered epitheloid histiocytes
(2) Langhans or foreign body-type giant cells
(3) No central necrosis
(4) Schaumann bodies - laminated concretions of calcium and protein
(5) Asteroid bodies - stellate inclusion in giant cells

Question 31

What collagen vascular diseases may cause interstitial lung disease?
(8)

Answer 31

(1) Scleroderma - causes diffuse pulmonary fibrosis
(2) Lupus erythematosis - causes patchy fibrosis and rarely severe lupus pneumonitis
(3) Rheumatoid arthritis:
(a) chronic pleuritis
(b) diffuse interstitial pneumonitis and fibrosis
(c) Intrapulmonary rheumatoid nodules
(d) Rheumatoid nodules with pneumoconiosis
(e) Pulmonary hypertension

Question 32

What are cryptogenic organizing pneumonia and bronchiolitis obliterans-organizing pneumonia?
(7)

Answer 32

(1) Frequent patterns of lung response to different injuries:
(a) infections
(b) inhaled toxins
(c) drugs
(d) collagen-vascular disease
(e) graft-vs-host disease
(2) Results in polypoid plugs of loose, young fibrous tissue filling bronchioles (bronchiolitis obliterans) and alveoli (organizing pneumonia)

Question 33

What is an issue with the diagnosis of mesothelioma?

Answer 33

Mesothelioma has many similar features to adenocarcinoma and other cancers, so special stains must be used for diagnosis

Question 34

What is the clinical presentation of patients with interstitial lung disease?
(7)

Answer 34

(1) Progressive dyspnea with exertion
(2) Persistent nonproductive cough
(3) Pulmonary symptoms associated with:
(a) underlying disease
(b) drugs
(c) occupational exposure
(d) environmental exposure

Question 35

What are the physical exam findings of a patient with interstitial lung disease?
(4)

Answer 35

(1) Crackles
(2) Cyanosis
(3) Digital clubbing
(4) Secondary manifestations of hypoxia

Question 36

What are the laboratory findings of a patient with interstitial lung disease?
(4)

Answer 36

(1) Pulmonary function tests: restrictive ventilatory pattern with decreased diffusion
(2) Chest x-ray: diffuse interstitial infiltrates
(3) CT scan: ground-glass opacity, nodular pattern, fibrotic pattern, honeycomb cysts
(4) Arterial blood gas: hypoxemia with increased A-a gradient

Question 37

What will pulmonary function tests reveal in interstitial lung disease?
(4)

Answer 37

(1) Reduced FEV1 (forced expiratory volume in first second) and FVC (forced vital capacity)
(2) FEV1/FVC ratio normal
(3) Reduced total lung capacity
(4) Reduced diffusing capacity

Question 38

What are the different types of findings on chest x-ray in interstitial lung disease and how do they appear?
(4)

Answer 38

(1) Linear
(2) Reticular - swirls
(3) Nodular
(4) Reticulonodular

Question 39

How is interstitial lung disease classified?

3

Answer 39

ILD of known cause:

(1) Exposure
(2) Systemic disease - sarcoidosis, scleroderma
(3) Genetic

ILD of unknown cause:

(d) Idiopathic interstitial pneumonias - UIP, DIP, BOOP/COP
(e) Specific pathology

Question 40

Which drugs can induce interstitial lung disease?

4

Answer 40

(1) Bleomycin (chemotherapy)
(2) Amiodarone (for cardiac arrhythmias)
(3) Methotrexate (immunosuppressant)
(4) Radiation injury

Question 41

How is idiopathic pulmonary fibrosis treated?

Answer 41

Nintedanib and pirfenidone to reduce decline in FVC