Diffuse Parenchymal Lung Disease

Question 1

What is the path feature differentiating UIP from other idiopathic interstitial pneumonias?

Answer 1

Temporal heterogeneity

Question 2

Surgical lung biopsy is not needed to establish the diagnosis of UIP if HRCT shows characteristic findings (subpleural site, basal predominance, reticular abnormality, honeycombing, and absence of features inconsistent with UIP).

Question 3

What are the known genetic associations with pulmonary fibrosis?

Answer 3

Mutations in hTERT and hTR are risk factors for pulmonary fibrosis underlying the inheritance in 8–15% of familial cases. In these families, IPF is inherited as an autosomal dominant trait with age- dependent penetrance.

Question 4

Histologically, respiratory bronchiolitis–associated interstitial lung disease is indistinguishable from respiratory bronchiolitis. Respiratory bronchiolitis– associated interstitial lung disease is characterized by clinical evidence of interstitial lung disease (impairment shown on pulmonary function tests and x-rays) and the finding of respiratory bronchiolitis on lung biopsy.

Question 5

Which ILDs are most commonly associated with smoking?

Answer 5

Respiratory bronchiolitis– associated interstitial lung disease

desquamative interstitial pneumonia

pulmonary Langerhans cell histiocytosis.

Smoking cessation is a critical component of therapy.

Question 6

Pulmonary arterial hypertension develops in > 15% of patients with systemic sclerosis/ scleroderma. It can be an isolated complication or secondary to ILD. These patients have a high mortality rate. Elevated levels of endothelin-1 cause enhanced vasoconstriction, vascular endothelial cell proliferation, smooth muscle hypertrophy, and irreversible vascular remodeling in the lungs

Question 7

LAM is associated with which gene mutations?

Answer 7

LAM is associated with tuberous sclerosis complex, which is a multisystem genetic disorder caused by mutation of the TSC1 or TSC2 gene.

Question 8

Which cells are pathognomic of pulmonary Langerhans cell histiocytosis on bronchoalveolar lavage?

Answer 8

BAL showing > 5% CD1a- positive cells is virtually diagnostic of pulmonary Langerhans cell histiocytosis.

Question 9

Angiotensin-converting enzyme is created by granulomas and can be elevated in any granulomatous disease. Granulomas also produce calcitriol, which can lead to hypercalcemia.

Question 10

What are normal BAL CD4/CD8 ratios and those in patients with sarcoidosis?

Answer 10

CD4/CD8 ratio 1.5–2.0 = normal
CD4/CD8 ratio >3.5 = suggestive of sarcoidosis

Question 11

How does the BAL CD4/CD8 ratio differ in HSP and sarcoidosis?

Answer 11

CD4/CD8 ratio 1.5–2.0 = normal
CD4/CD8 ratio >3.5 = suggestive of sarcoidosis

Question 12

What exposures can mimic sarcoidosis?

Answer 12

Nearly identical clinical and pathologic features can be seen in berylliosis, so a detailed exposure history is key.

BERYLLIOSIS

Question 13

What exposures can mimic sarcoidosis?

Question 14

What causes acquired pulmonary alveolar proteinosis?

Answer 14

Antibodies against GM- CSF

Question 15

What imaging pattern is strongly suggestive of pulmonary alveolar proteinosis?

Answer 15

Crazy paving pattern

Question 16

Infections in PAP?

Answer 16

PAP MAN infections:
Pulmonary
Alveolar
Proteinosis
Mycobacteria
Aspergillus
Nocardia

Question 17

Is tracheobronchopathia osteochondroplastica associated with amyloid disease?

Answer 17

No, tracheobronchial amyloid is its own disease entity but can present very similarly. Submucosal involvement (posterior wall) is seen only with tracheobronchial amyloid disease.

Question 18

What are the causes of noninfectious cystic lung disease?

Answer 18

Lymphangioleiomyomatosis

lymphocytic interstitial pneumonia

Langerhans cell histiocytosis

Birt-Hogg- Dube

rare forms of malignancy

Question 19

How is infectious pneumonia distinguished from lipoid pneumonia on imaging?

Answer 19

CT scan shows fewer Hounsfeld units compared with typical infectious consolidations.

Question 20

Which interstitial lung disease resembles acute silicosis histologically and on imaging?

Answer 20

Secondary pulmonary alveolar proteinosis, which causes alveolar filling with proteinaceous material that consists mostly of phospholipids and surfactant, staining with periodic acid–Schiff reagent (silicoproteinosis). Other exposures with similar findings are aluminum, silica, titanium, cement, insulation, sawdust, paint, varnish, chlorine, nitrogen dioxide, and fertilizer.

Question 21

Which autoimmune disease is associated with Caplan syndrome?

Answer 21

Rheumatoid arthritis.
Caplan syndrome is a nodular reaction that occurs in individuals exposed to coal dust who also have rheumatoid arthritis or who will have rheumatoid arthritis within the next 5–10 years. The nodules can vary in diameter (0.5–5.0 cm) and are usually multiple, bilateral, and peripherally located. They contain a necrotic center surrounded by lymphocytes and plasma cells and a very small amount of coal dust.

Question 22

Which pneumoconiosis is associated with melanoptysis?

Answer 22

Coal workers’ pneumoconiosis.

Melanoptysis is the expectoration of black sputum containing carbonaceous particles. It occurs when a conglomerate of nodules cavitates and ruptures into the airway. Melanoptysis has also been reported with freebase cocaine smoking, malignant melanoma, and aspergilloma caused by Aspergillus niger, as well as in progressive massive fibrosis caused by silicosis.

Question 23

Anthracosis is the accumulation of coal dust within the lungs. It is often asymptomatic and can be seen in people living in large urban areas where there is significant air pollution.

Question 24

There is a multiplicative risk of lung cancer in patients who are exposed to asbestos and smoke cigarettes. The relative risk of cigarette smokers with asbestos exposure is nearly 60.

Question 25

Giant odd-appearing multinucleated cells (i.e., cannibalistic cells) can be seen in patients exposed to cobalt. This is also known as giant cell interstitial pneumonitis

Question 26

What blood or bronchoalveolar lavage test is used to assist in diagnosing chronic beryllium disease?

Answer 26

Beryllium lymphocyte proliferation test

Question 27

Bronchoalveolar lavage fluid from patients with hypersensitivity pneumonitis is characterized by an elevated percentage of lymphocytes, typically > 50%. There is proliferation of CD8+ T-lymphocytes, resulting in inversion of the CD4/CD8 ratio.

Question 28

What are the characteristic pathologic changes of hypersensitivity pneumonitis?

Answer 28

Cellular bronchiolitis or airway-centered inflammation, an interstitial mononuclear cell infiltrate, and small, poorly formed nonnecrotizing granulomas. Conditions that may appear similar on biopsy include sarcoidosis (well-formed granulomas), other granulomatous infections (i.e., tuberculosis, fungal diseases), UIP, fibrosing NSIP, organizing pneumonia, and drug- induced lung disease.

Question 29

What properties of toxic gases and fumes determine their pattern of lung injury?

Answer 29

Water solubility, duration of exposure, and depth of inhalation. For example, more water-soluble gases such as chlorine cause more upper-airway irritation and symptoms than less water-soluble agents such as nitrogen dioxide, which cause more small airways disease and alveolar damage.

Question 30

Reactive airways dysfunction syndrome is a type of irritant-induced occupational asthma that occurs after exposure to high doses of a single irritant.

Question 31

Which transcription factor is responsible for most of the adaptive changes that occur during acclimatization?

Answer 31

Hypoxia-inducible factor-1α stimulates vascular endothelial growth factor, which itself stimulates angiogenesis and nitric oxide synthesis. These changes result in greater blood flow and oxygen delivery to tissues.

Question 32

Factors associated with very low risk in patients with coronary artery syndromes include age < 65 years, ejection fraction > 45%, first event, and no complications or further planned interventions. These patients may fly as soon as 3 days after the event. Low-risk patients, those with no symptoms and ejection fraction > 40%, may fly as soon as 10 days after the event.

Question 33

Air travel should be avoided until 7 days after radiographic resolution of pneumothorax.

Question 34

Air travel after diving should be postponed for at least 12 hours in patients who have dived once per day. For those who have dived multiple times or have required decompression stops, flying should be postponed for at least 48 hours.

Question 35

In diving medicine, which gas law explains the pathophysiology of most types of barotrauma?

Answer 35

Boyle’s law. At a constant temperature, the volume of a gas is inversely proportional with the pressure to which it is subjected.

Question 36

Which gas law explains the pathophysiology behind decompression sickness and nitrogen narcosis?

Answer 36

Henry’s law. At a constant temperature, the amount of a gas dissolved in a liquid is directly proportional to the partial pressure of that gas.

Question 37

What condition contraindicates hyperbaric oxygen therapy?

Answer 37

Untreated pneumothorax