Obstructive Lung Disease Flashcards Preview

CVPR: Pulmonary > Obstructive Lung Disease > Flashcards

Flashcards in Obstructive Lung Disease Deck (26)
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1

Asthma general characteristics

  • chronic inflammatory disorder
  • associated w/airway hyperresponsiveness ==>
  • recurrent episodes of wheezing, breathlessness, chest tightness, and coughing
  • reversible spontaneously or w/treatment

2

Airway inflammation in Asthma

  • persistant inflammation ==> most prominent @ medium-sized bronchi
  • inflammatory cells involved =
    • mast cells
    • eosinophils
    • T lymphocytes
    • dendritic cells
    • neutrophils

3

Structural airway changes in asthma

  • increased smooth muscle cells 
  • blood vessel proliferation
  • mucus hyper-secretion (increased goblet cells + submucosal glands)

4

Control of Airway diameter

  • neural regulation
    • parasympathetic (cholinergic) motor neurons via vagus ==> aCH stimulates smooth muscle contraction
    • nonadrenergic noncholinergic receptors (excitatory and inhibitory)
  • Beta-adrenergic ==> increase intracell cAMP ==> smooth muscle relax
  • ion channels: Ca2+ and K+

5

Physiologic consequences of asthmatic airflow obstruction

  • increased resistance to airflow (accentuated during expiration) ==> air trapping ==> hyperinflation
  • hyperinflation ==> flattening of diaphragm ==> inefficient msucular respiratory effort

6

Mechanics of diaphragm in obstructive lung disease

  • Muscle fibers of the flattened (shortened) diaphragm cannot generate adequate tension ==> operating @ suboptimal point on length-tension curve
  • in addition to overcoming increased airway resistance, the asthmatic must use less efficient respiratory muscles to inflate their lungs.
  • these pathophysiologic effects increase oxygen consumption and carbon dioxide production by the diaphragm (and other respiratory muscles).  

7

PFTs in Asthma

  • exacerbation ==> obstructive pattern
    • DECREASE in FEV1/FVC that usually responds to beta-adrenergic agent
      • improvement = >12% or >200mL
    • increase in TLC, RV and FRC due to air trapping
  • may look normal in between episodes

8

Bronchoprovocation testing in possible asthmatics

  • serial spirometry after inhaling progressively high concentrations of methacholine (histamine analog)
  • PC20 = concentration required to lower FEV1
    • several times lower in asthmatics than healthy people
  • Can also be performed using exercise as bronchoprovocation

9

Goals of asthma therapy & strategies

  • reduce airway tone
    • beta-agonists (albuterol)
    • anti-cholinergers
    • leukotriene inhibitors
    • methylxanthines = PDE inhibitor ==> increase intracell cAMP
  • reduce inflammation
    • corticosteroids
    • mast cell stabilizers
    • leukotriene inhibitors
    • Anti-IgE therapy

10

Acute asthma treatment

  • systemic corticosteroids
  • inhaled bronchodilators (beta-agonists, anticholinergics)
  • possibly: positive pressure ventilation or mechanical vent

11

Asthma severity classification system

12

COPD general characteristics

  • irreversible airflow limitation 
  • FEV1/FVC < .7
  • risk factors:
    • smoking
    • inhaled biomass smoke
    • occupational exposures
  • subtypes:
    • emphysema
    • bronchitis
    • chronic obstructive asthma

13

Characteristics of Chronic Bronchitis

  • Clinical: productive cough for 3 months per year over 2 year period w/out other explanation
  • airway epithelium ==> squamous metaplasia
  • disease of airways (vs. emphysema = disease of parenchyma)
  • increased airway resistance due to changes in airway structure ==> impaired ventilation
  • normal DLCO
  • minimal reversibility 

14

Characteristics of Emphysema

  • enlargement of air spaces distal to terminal bronchioles accompanies by destruction of their walls
  • airflow obstruction due to airway collapse during expiration
  • most common cause = smoking
  • may also be cause by alpha1 anti-trypsin deficiency

15

Pathophysiology of chronic bronchitis

  • limitation of airflow (particularly expiratory)
  • resistance due to excessive mucous secretion + bronchial wall inflammation/thickening

16

Pathophysiology of ephysema

  • limitation in airflow rates (expiratory)
  • loss of alveolar-capillary surface area + loss of elastic recoil

17

PFTs for COPD

  • FEV1/FVC < /7
  • RV, FRC, and TLC are all increased
  • Chronic bronchitis = normal DLCO
  • Emphysema = low DLCO

18

Clinical presentation of COPD

  • dyspnea
  • cough, wheezing, chronic sputum production
  • evidence of hyperinflation
  • limited diaphragm movement + use of accessory muscles
  • purse-lipped breathing
  • tripodding 
  • breath/heart sounds diminished
  • prolonged forced expiratory time

19

Severity of COPD

  • GOLD classification. Survival is associated with the FEV1 as well. The lower the FEV1, the poorer the survival. 

  • Other contributors: severity of symptoms, risk of exacerbations and comorbid conditions. 

    • Zero to one exacerbation per year is considered low risk for exacerbations, while >= 2 per year is considered high risk for future exacerbations.

20

COPD treatment

  • releave sx and reduce severity of exacerbations
  • agents to relax airway: inhaled anticholinergics, beta-agonists
  • agents to decrease inflammation/edema: corticosteroids
  • smoking cessation
  • respiratory rehab, O2 therapy, lung transplant 

21

Bronchiectasis characteristics

  • abnormal dilation of proximal medium-sized bronchi (cartilage-containing airways)
    • destruction of muscular and elastic components of airway walls
  • common associated conditions:
    • chronic bacterial infection ==> large quantities of foul-smelling sputum
  • leads to impaire tracheobroncial clearance ==> predisposes to airway colonization and infection

22

Common causes of bronchiectasis

  • severe pulmonary infection
  • bronchial obstruction
  • primary ciliary dyskinesia
  • immunodeficiency
  • cystic fibrosis

23

Cystic Fibrosis characteristics

  • CFTR mutation ==> dysfxnl chloride transport
  • recurrent sinus/pulmonary infections
  • PMN recruitment ==> widespread airway inflammation/decstruction ==> bronchiectasis
  • respiratory sx, GI sx, failure to thrive
    • pancreatitis, diabetes, male infertility
  • dx via sweat test

24

Cystic Fibrosis Tx

  • CFTR modulators
  • antibiotics
  • bronhcodilators
  • nebulized hypertonic saline
  • inhaled DNAase I
  • Chest physiotherpay
  • exercise
  • lung transplant

25

Bronchiolitis characteristics

  • inflammation of the membranous bronchioles
  • children = usually viral illness ==> fever, cough, dyspnea
  • adults = toxic gases, immune-mediated, drugs, transplant reject
  • auscultatory hallmark: inspiratory squeak

26

Upper airway obstruction characteristics

  • patterns of obstruction: variable extrathoracic obstruction, variable intrathoracic obstruction, and fixed obstruction