11-2: 12/8: Interstitial Lung Disease

Front 1

What is pulmonary interstitium?

Is ILD limited to the pulmonary interstitium?

Back 1

Space between BM of alveolar epithelium and pulmonary capillary epithelium

Note: ILD doesn't just affect interstitium, affects alveoli, small airways, vessels

Front 2

Define pneumoconioses.

Back 2

Disorders due to INorganic dust exposure.

Ex: coal miners

Doesn't require immune-specific response, will affect everyone given enough exposure

Front 3

Define hypersensitivity pneumonitis.

Back 3

Disorders due to inhalation of
ORGANIC dusts

Ex: farmer's lung

Must develop immune response; not everyone exposed to this substance will develop diz

Front 4

What 2 features are exhibited by all diffuse parenchymal lung diseases?

Back 4

Inflammn (alveolitis)
Fibrosis (collagen)

Front 5

How does alveolitis appear on pathologic specimen?

Back 5

Cell infiltrate: lots of blue dots

Front 6

Pathologic appearance of granulomas.

Granulomas are a form of ______.

Back 6

Epitheliod histiocytes, GIANT CELLS (big cell with many blue dots inside)

Granuloma = form of inflammn

Front 7

Honeycombing on pathologic specimen indicates _______.

Back 7

Fibrosis

Front 8

Describe each phase of Diffuse Parenchymal Lung Disease.

Back 8

1) Initiating stimulus (toxin or antigen)
2) Propagation: inflammn due to direct injury, recruitment, or mediator release
3) Fibrosis (abnl healing): degradation of fnal tissue, synthesis of fibrous scar tissue

Front 9

DPLD is associated with V/Q _____.

Back 9

Mismatch

Front 10

Pathophysiologic changes of DPLD (general).

Back 10

Dec'd lung compliance
Dec'd lung vols
Impaired diffusion
V/Q mismatch
Pulm HTN

Front 11

Effect of DPLD on compliance.

Explain pathophysiology.

How does this affect breathing?

Back 11

DEC'd compliance:
Excess collagen-->inc'd elastic recoil

Now require greater pressure to achieve same volume change

Inc'd work of breathing-->dypnea; rapid shallow breathing pattern

Front 12

Effect of DPLD on lung volumes.

Explain pathophysiology.

Back 12

DEC'd lung volumes.
-Reduction in TLC, FVC, FRC, RV
-Inc'd lung recoil favors collapse/smaller volumes

Front 13

Effect of DPLD on FEV1/FVC.

Explain pathophysiology.

Back 13

Normal to inc'd bc of inc'd elastic recoil and radial traction on airways.

Front 14

Which airways are affected by DPLD?

Back 14

Small airways--affected by peribronchiolar inflammn, fibrosis; results in narrowing (scarring, mucus production) of airway

V/Q mismatch prob results

LARGE AIRWAYS NORMAL

Front 15

Why does DLPD result in hypoxemia? How does this differ in an exercise state?

What are PaCO2 values like?

Back 15

DLPD-->hypoxemia bc of V/Q mismatch;

Worsens during exercise due to DIFFUSION DEFECT (reduced RBC transit with inc'd Q prevents equilibrium of PaO2 with PAO2); also loss of SA > membrane thickness

PaCO2 normal or reduced

Front 16

Why does DLPD result in pulmonary hypertension?

Back 16

Reduced SA of pulm vasculature:
-Compression of vessels, inflammn of vessels, destruction of vessels
-Chronic hypoxemia-->pulm vasoconstriction
-Worsens during exercise--inability to recruit

Front 17

Presentation and physical exam findings of DLPD.

X-ray signs?

Back 17

Dyspnea on exertion progressing to SOB at rest

Velcro crackles at bases
Clubbing (hypoxia)
Cor pulmonale

CXR: interstitial infiltrates: reticular (net-like), nodular, honeycombing

Up to 10% can have normal CXR!

Front 18

PFTs in DPLD.

Back 18

Dec'd DLCO
Dec'd TLC
NL/Inc'd FEV1/FVC

Front 19

Type of pneumoconiosis.

Back 19

Silicosis
Asbestosis
Coal-Miner Lung

NO TREATMENT
Need respiratory protection for workers.

Front 20

Silicosis:
Affected populations
Hallmark Feature
Lobes Preferred

Back 20

Quarry workers
Sandblasters
Foundry workers
Stonecutters

Hallmark feature: enlarged, calcified LNs

Prefers upper lobes (apical)

Front 21

Coal Worker's Pneumoconiosis:
Hallmark Feature
Lobes Preferred

Back 21

Black particles (black lung)

Appears as coal dust surrounded by cellular/fibrotic infiltrate

Prefers apical lobes

Front 22

Asbestosis:
Populations Affected
Hallmark Feature
Lobes Preferred

Back 22

Affects insulation, shipyard, construction workers; plumbers, mechanics

Hallmark: Ferruginous bodies (red dumbbell)--macs attempt to barrage asbestos particle with iron; can penetrate pleural space

Note: asbestos is a silica (fibrous silicate)

Prefers basilar lobes

Front 23

Hypersensitivity Pneumonitis:
Populations Affected
Pathophysiology
Lobes Preferred

Back 23

Farmer's lung, pigeon breeder's lung

Minority of those exposed become sick

This is a delayed-type hypersensitivity (T-cell) rxn

Apical preference

Front 24

Drug-Induced Pneumonitis:
Offending agents
General/Histologic features

Back 24

Chemotherapeutic agents
Nitrofurantoin
Amiodarone

(variety of mechs: direct toxicity, oxidant injury, hypersens rxn)

Presents with fever, ephilia

Front 25

Radiation Pneumonitis:
Affected Populations
Onset (Acute vs Chronic)
Features (Acute vs Chronic)

Back 25

Those with lymphomas, BrCa, LungCa who undergo radiation

Acute: 1-3 mos post-tx; toxicity to endothelial cells more than Type I cell

Chronic: 6-12 mos post-tx; fibrosis, small blood vessel damage

Front 26

Idiopathic Pulmonary Fibrosis:
Hallmark Path Finding

Back 26

Fibroblast foci

Poor prognosis

Basilar Preference

Front 27

Sarcoidosis:
What is it?
Involved organs?
Clinical findings?

Back 27

Systemic disorder forming noncaseating granulomas; inflammn

Lungs most frequently involved--affects LNs, skin, eyes, heart, liver, bone, brain

Depressed cell-mediated immunity (skin allergy test) due to CD4 cells at site of dz and not in blood

Granulomas inc Vit D-->hyperCa2+ in blood and urine
Elevated ACE (Ag Conv Enz) (for vit D act)

Front 28

Clinical course of sarcoidosis?

Back 28

Characterized by flare-ups and spontaneous remissions. Course is variable.

May progress to severe scarring, extensive bullous formation.