Crr Week 6: Interstitial Lung Disease/ Restriction (Welch)

Front 1

What is restrictive lung disease characterized by?

Back 1

Reduced expansion of lung parenchyma accompanied by decreased total lung capacity

(Robbins)

Front 2

What is obstructive lung disease characterized by?

Back 2

Limitation of airflow usually resulting from an increase in resistance caused by partial or complete obstruction at any level

(Robbins)

Front 3

What are the major diffuse obstructive disorders?

Back 3

1. Emphysema
2. Chronic bronchitis
3. Bronchiectasis
4. Asthma

Front 4

What happens to the total lung capacity, FVC, and expiratory flow rate in patients with obstructive disorders?

Back 4

Total lung capacity is either normal or increased
FVC is decreased
*DECREASED expiratory flow rate (measured by FEV1)

*The ratio of FEV1 to FVC is characteristically decreased

Front 5

Is FEV1/FVC characteristically decreased in obstructive or restrictive diseases?

Back 5

Obstructive disease

(FEV1 is decreased because expiratory flow rate is decreased due to obstructed airways).

Front 6

With interstitial lung disease, can hypoxemia be readily corrected with oxygen supplementation?

Back 6

YES.

Front 7

Is carbon dioxide excretion preserved in interstitial lung disease?

Back 7

YES
Even though oxygen diffusion is impaired, CO2 diffusion is normal

(This differs from obstructive pulmonary diseases)

Front 8

Give an example of a drug that can cause interstitial lung disease.

Back 8

Nitrofurantoin
(antibiotic used to treat chronic UTIs)

Front 9

Give a laundry list of various interstitial lung diseases with known etiologies.

Back 9

1. Occupational lung disease
2. Drug or poison-induced lung disease
3. Hypersensitivity alveolitis
4. Radiation pneumonitis
5. Infections
6. Chronic pulmonary edema
7. Uremic pneumonitis
8. Lymphangitic carcinomatosis

Front 10

Give a laundry list of restrictive diseases with unknown etiologies

Which are the most common?

Back 10

1. Idiopathic interstitial pneumonia <--- VERY COMMON
2. Respiratory bronchiolitis with interstitial lung disease (RB-ILD)
3. Desquamative interstitial pneumonia (DIP)
4. Bronchiolitis obliterans organizing pneumonia (BOOP)
5. Cryptogenic organizing pneumonia
6. Sarcoidosis <-- MOST COMMON
7. Lymphocytic infiltrative disease
8. Vasculitis
9. Diffuse alveolar hemorrhage
10. Eosinophilic granuloma
11. Diffuse amyloidosis

Front 11

How can you differentiate between usual idiopathic interstitial pneumonia and non-specific idiopathic interstitial pneumonia?

Which is a better prognosis?

Back 11

Distinction is made via CT scan and sometimes biopsy

Non-specific interstitial pneumonia is a better prognosis (corticosteroids used)

Front 12

"Honeycombing" on CT scan is characteristic of what sort of lung disease?

Back 12

Idiopathic interstitial lung disease

Front 13

Sarcoidosis can lead to interstitial lung disease. What are the various stages of sarcoidosis?

What is the treatment?

Back 13

Stage 1: bilateral hylar adenopathy with no pulmonary infiltrates
Stage 2: Hylar adenopathy with pulmonary infiltrates present
Stage 3: Resolved hylar nodes with pulmonary infiltrates present
Stage 4: Distortion with fibrotic infiltrates

Corticosteroids can be used for stages 1, 2, and 3

Front 14

What are the 2 mechanisms for reduced compliance as a result of interstitial lung disease?

Back 14

1. Lung shrinkage
2. Decreased distensibility

Front 15

Why is expiratory flow rate decreased with emphysema?

Back 15

Airways tend to collapse, impairing air flow, due to destruction of alveoli and interstium
(decreased elastin)

Front 16

Why do expiratory flow rates tend to be normal with interstial lung disease?

Back 16

The interstitium is infiltrated and stiff, so airways are held open.

Front 17

What kind of breathing pattern is typical in patients with interstitial lung disease?

Back 17

Rapid, shallow breathing

Taking deep breaths is impaired by stiffness of lungs (decreased compliance), but airflow through airways is normal. So rapid, shallow breathing can compensate for not being able to take deep breaths

Front 18

What happens to the Vital Capacity with restrictive lung disease?

Back 18

Decreased VC

Front 19

What happens to the FEV1 with restrictive lung disease?

Back 19

Relatively normal

Front 20

What happens to the FEV1/FVC ratio with restrictive lung disease?

Back 20

Normal or increased

Front 21

What happens to the TLC with restrictive lung disease?

Back 21

Decreased

Front 22

List 3 types of intrapulmonary restrictive diseases.

Back 22

1. Parenchymal infiltration or alveolar filling (space-occupying diseases)
*Pneumonia, pulmonary edema, interstitial lung disease
2. Lung resection
3. Atelectasis

Front 23

What are the different types of extrapulmonary restrictive diseases?

Back 23

1. Space-occupying abnormalities
(pleural effusion, pneumothorax, tumor)
2. Respiratory muscle weakness

Front 24

Is exercise-induced hypoxemia a common feature of interstitial or obstructive lung disease?

What causes the hypoxemia?

Back 24

Interstitial lung disease

1. Fall in mixed venous PO2
2. Incomplete equilibrium between alveolar gas and end-capillary blood due to diffusion block

Front 25

What causes a pulmonary shunt?

Back 25

When alveoli are perfused with blood as normal, but ventilation fails to supply to perfused region
(V/Q = 0)

Front 26

When does hypoventilation occur over the course of interstitial lung disease?

Back 26

Terminally

Front 27

What causes reduced diffusing capacity for carbon monoxide in ILD?

Back 27

Decreased alveolar-capillary membrane surface area

Front 28

What is the primary cause of resting hypoxemia in ILD?

Back 28

Ventilation-perfusion mismatching and low VaQ units

(Intrapulmonary shunting is the main cause of hypoxemia (inadequate blood oxygen) in pulmonary edema and conditions such as pneumonia in which the lungs become consolidated)