12. Interstitial Lung Disease Flashcards Preview

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Flashcards in 12. Interstitial Lung Disease Deck (36):
1

what are the major categories of Interstitial Lung disease?

-Idiopathic Pulm Fibrosis
-due to Occupational/Environmental inhalants
-Drug-related
-Sarcoidosis
-Circulatory
-Assoc'd with connective tissue disorders
-Radation-based

2

symptoms of ILD?

dyspnea, cough

3

physical findings with ILD?

fine crackles, clubbing, findings related to underlying disease process

4

Effects of ILD on lung function: compliance?

decreased due to inflammation and/or deposition of collagen. altered pressure/volume relationship in lungs in ILD

5

Effects of ILD on lung function: diffusion?

impaired. due to incr thickness of the interface. thickened by interstitial inflammation, and/or deposition of collagen.

6

Effects of ILD on lung function: V/Q?

mismatch. ILD impacts the lungs unequally/heterogeneous.

7

what happens to the lung areas that are less compliant than others?

receive less ventilation than normal areas (remember compliance = dV/dP, so if you apply the same pressure to a less compliant area, it will receive less volume/less ventilation)

8

most patients with ILD have a restrictive or obstructive pattern?

restrictive

9

Lung volume in ILD: incr or decr?

decr.

10

flow rates in ILD?

decr, but increased relative to lung volume. flow rates vary as a function of elastic recoil. since elastic recoil is increased, flow rate is increased.

11

ILD: DLCO?

lower due to diffusion impairment

12

what is idiopathic pulmonary fibrosis?

fibrosing disease of unknown etiology, generally seen in elderly.

13

what is the pathologic finding in IPF?

UIP: usual interstitial pneumonia.

14

what is the sequence of events in IPF?

stimulus (known or unknown) --> alveolitis (accumul of inflam cells in interstitium)--> derangement of alveolar-capillary units (interstitial edema) --> loss of alveolar-capillary units for gas exchange (ie fibrosis)

15

does IPF require inflammation

no, can occur independently of inflammation.

16

what is the established therapy for IPF?

there is none: used to be anti-inflammatories, but those barely worked. (note this is only IPF, not all ILD)

17

what is the mean survival time for IPF?

3yrs from dx

18

what are the occupational/environmental inhalants that contribute to ILD?

-dusts (silica/asbestos)
-moldy hay (Farmer's Lung)
-gases/fumes/vapors/aerosols

19

what drugs may cause ILD?

cancer drugs (methotrexate)
antibiotics

20

what is sarcoidosis?

multi-system disorder characterized by granulomatous inflammation. thorax is most common site of involvement.

21

why are patients with ILD dyspneic?

-inc work of breathing (lower compliance, more dead space)
-stimulation of vagal fibers

22

why do patients with ILD have cough?

Interstitial inflammation may stimulate vagal fibers

23

why is there decr compliance in ILD?

deposition of collagen --> decr compliance

24

what are the lung volumes in ILD: TLC, FRC, RV, VC

Everything is reduced!
-TLC reduced: stuff lungs. Makes it harder to inflate, resp muscles have to work harder
-FRC detd by recoil v. chest wall.
-Decr RV: because of incr recoil, minimizes air trapping
-Decr VC

25

why is there an incr FEV1/FVC ratio in ILD?

increased recoil. subranormal flow rates for volume

26

in ILD, what is the change to patency of small airways?

due to fibrosis, tends to keep more airways patent at smaller volumes/pressures. contrast with emphysema which has collapse.

27

what is the pattern for C02 removal with ILD?

pts tend to be hypocapnic.
Increase in ventilation offsets the increase in physiological dead space

28

what PFT patterns might make you think of ILD?

low diffusing capacity, high ratio

29

why would an ILD patient take quick shallow breaths?

to minimize discomfort.

30

Structure/function relationship summary

Decreased compliance
Restriction of the lung
Decreased diffusing capacity
Hypoxia that worsens with exercise
Increased VD/VT

31

what does IPF look like on radiology?

honeycombing

32

ILD: if not inflammation, what is the problem?

possibly a genetic predisposition to profibrotic cytokines/growth factors that cause fibrosis.

33

what is erythema nodosum, and in what condition do we see it?

sarcoidosis

34

what is adenolathy? when do we see it?

lymph node swelling. see in sarcoidosis

35

Drug induced ILD: what are the most common drugs involved?

Large number of agents
Most common:
Cancer chemotherapy (bleomycin, carmustine)
Amiodarone (anti-arrythmic)
Nitrofurantoin (abx)

36

How does Bleomycin factor into ILD?

Occasional cause of ILD
Important model of lung injury
Role of TGF-β, TNF-α
Mechanism: oxidant injury
Occurrence modified by:
Oxygen
Radiation