Restrictive/Inflammatory Lung Disease Flashcards

1
Q

Restrictive vs. Obstructive Lung Disease (Compliance/Airway resistance)

A
  • Obstructive ==> Increased compliance + increased airway resistance
  • Restrictive ==> Decreased compliance + decreased airway resistance
  • Obstructive disease primarily increases resistive pressure, Pr. Restrictive disease increases the work required to distend the lung, the Pel.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Compliance of respiratory equation

A
  • 1/Ctot = 1/Clung + 1/Ccw
  • Ctot = Compliance of the total system
  • Clung = Compliance of the lung
  • Ccw = Compliance of the chest wall
  • **compliance of the respiratory system may be affected by changes in compliance of either chest wall or lung or both
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mechanisms of decreased lung compliance

A
  1. Increased thickness of the lung interstitium
    • deposition of elastic/connective tissue (e.g. fibroblasts)
    • increase in inflammatory cells
  2. Increased lung water
    • CHF
  3. Increased alveolar surface tension
    • ​​==> alveolar collapse ==> reduced compliance
    • can occur due dilution from pulmonary edema
    • abnormal sufractant production/fxn
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Acute dx resulting from abnormal surfactant production

A
  • Respiratory distress syndrome in premature infants is a result of inadequate surfactant production due to immature lung development.
  • Acute respiratory distress syndrome (ARDS) results in dysfunctional surfactant due to injury to type 2 alveolar cells + pulmonary edema in this disorder dilutes the surfactant + inflammation and injury in the interstitium that decreases compliance.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Restrictive Lung Disease impact on TLC, FRC, RV and PV curve

A
  • TLC, FRC and RV are all decreased
  • PV curve is flatter and shifted down
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Restrictive Lung disease impact on airflow measures

A
  • Airflows in pulmonary fibrosis/ILD are supranormal for a given lung volume because the airways are dilated due to traction applied from adjacent parenchyma (“traction bronchiectasis”)
  • Spirometry will show a normal or elevated FEV1/FVC ratio.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Restrictive disease impact on gas-exchange

A
  • impaired gas-exchange (decrease in DLCO) due to:
  • decreased lung volumes
  • decreased alveolar capillary SA
  • increased wall thickness ==> decreased diffusion
  • V/Q mismatch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Mechanisms that decrease chest wall compliance

A
  • burns: third degree burns form a thick eschar that limits chest wall excursion
  • obesity- increases soft tissue mass and decreased ability of the chest wall to move
  • kyphoscoliosis- deformity of the spine (lateral and anterior displacement)
  • ankylosing spondylitis- inflammatory disease which causes ossification of the ligamentous structures of the spine (the bamboo spine). This restricts movement of the ribs.
  • respiratory muscle weakness - paralysis of the muscles, neuromuscular disease
  • pleural fibrosis/thickening- restricts expansion of the lung within the thoracic cavity
  • pleural effusion - fluid in pleural cavity limits lung expansion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Restrive disease due to chest wall vs. lung interstitium

A
  • both: decreased lung volumes, normal airflow
    • except: muscular weakness ==> normal FRC but low effort-dependent PFT measures
  • Lung: decreased DLCO/Va (gas-exchange adjusted for alveolar volume)
  • Chest wall: normal DLCO/Va
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Technique to measure compliance of lung w/out the effects of chest wall

A
  • Pressure-volume curves plotted using a manometer
  • manometer is passed into the mid-esophagus ==> estimation of pleural pressure
  • in the body box a patient exhales slowly from TLC and lung volumes are measured periodically using Boyle’s Law
  • The volume is correlated to the pleural pressure measured by manometer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Examples of mixed lung disorders + common PFT results

A
  • combination of obstructive and restrictive
  • e.g. an obese patient with asthma
  • combined pulmonary fibrosis and emphysema
  • Decrease in TLC or FRC (restrictive) + decrease in FEV1/FVC ==> markedly decreased DLCO
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

ILD definition & Common causes

A
  • ILD = “Interstitial Lung Disease” = generic term for heterogenous group of lung disorders
  • Autoimmune disease
  • Exposure to inorganic dusts (e.g. asbestos or silica)
  • Exposure to organic mlx ==> hypersensitivity pneumonitis
  • Drug effect
  • Idiopathic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Common approach to ILD dx

A
  • “clinical-radiologic-pathologic”
    *
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Common presentation of most ILDs

A
  • insidious onset of dyspnea on exertion
  • nonproductive cough
  • PFTs: restrictive pattern w/reduced diffusing capacity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Common findings for IPF vs. NSIP

A
  • IPF = idiopathic pulmonary fibrosis
    • 2-3 yr survival, unresponsive to therapy
    • CXR: traction bronchiectatsis, volume loss, honeycomb lung, paucity of ground glass
    • Histo: Usual Interstitial Pneumonia (UIP) = spacially and temporally heterogenous fibrosis + fibroblast foci
  • NSIP = non-specific interstitial pneumonia
    • less severe than IPF
    • CXR: traction bronchiectatsis, volume loss, usually associated w/ground glass
    • Histo: spatially and temporally homogenous, generally more cellular (vs. fibrotic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly