Pulm Week 2 Flashcards
(210 cards)
Obstructive lung disease is caused by airway narrowing due to… (2)
1) Intrinsic airway narrowing (bronchospasm, plugging, inflammation/edema
2) Collapse (“floppy” airways) - decreased radial tethering or decreased airway integrity
Obstructive disease has increased lung volumes due to _______ and results in…(2)
due to incomplete emptying of alveoli - hard to exhale
1) Hyperinflation → increases RV, ERV, and thus FRC by decreasing IC
2) Flattening of the diaphragm → mechanical disadvantage
(Flat diaphragm generates less inspiratory pressure due to increased radius of curvature AND must generate more tension in order to generate same intrapleural pressure)
Increased airway resistance in obstructive disease result in…
increased work of breathing
Bronchoprovocation testing in asthma, vocal cord dysfunction, and emphysema
Asthma: REVERSIBLE
- Should go completely back to normal with bronchodilator
- Methacholine challenge: people with asthma react at level of 5 or less
Vocal Cord Dysfunction: minimally reversible with bronchodilator
Emphysema: no reversibility to bronchodilators
Asthma
- chronic inflammation of airways associated with airway hyperresponsiveness
- Recurrent episodes of wheezing, breathlessness, chest tightness, and coughing particularly at night or in the early morning
- Episode associated with airflow obstruction that is reversible spontaneously or with treatment
Types of asthma (Extrinsic vs. Intrinsic)
Extrinsic (Allergic): initiated by type I hypersensitivity reaction induced by exposure to an outside agent
-Mostly IgE mediated
Intrinsic (nonseasonal, nonallergic): initiated by diverse, non-immune mechanisms (ASA ingestion, viral infection, cold, inhaled irritants, stress, exercise)
- Chronic, persistent
- Altered arachidonic acid metabolites (increases leukotrienes, decreased prostaglandins - ASA)
Airway narrowing in asthma occurs due to…
Inflammation: inflammatory cells + inflammatory mediators
Structural airway changes
Structural airway changes in asthma (3)
1) Increase in airway smooth muscle cells due to hypertrophy and hyperplasia
2) Blood vessel proliferation
3) Mucus hyper-secretion (increased goblet cells and size of submucosal glands)
Clinical features of asthma (7)
1) Intermittent - PFTs can be normal between exacerbations
2) Reversibility of airflow obstruction
3) Cough, dyspnea, wheezing
4) Exacerbations with exposure to: exercise, cold air, allergens, air pollution, infection
5) Normal to increased DLCO
6) Bronchoprovocation demonstrates hyperreactivity
7) Severity of asthma determines by frequency of symptoms
Physical exam findings in asthma (3)
- May be normal in stable disease
- Respiratory distress: increased rate, use of accessory muscles
- Wheezing (expiratory)
- Distinguish inspiratory stridor (VCD) from expiratory wheezing (asthma)
Acute asthma
1) Hyperinflation
(shortened diaphragm)
2) Breathing occurs on flatter part of PV curve - more pressure required to get similar change in volume
3) Accessory muscle use
4) INCREASED WORK OF BREATHING
5) Can improve symptoms with bronchodilation → facilitates exhalation
Pathology of airways during acute asthma
Airway inflammation, edema, and mucus plugging lead to gas trapping and airflow obstruction in acute asthma
→ unable to fully exhale before taking next breath → breaths “stack” up on one another → increase lung volumes
Vocal cord dysfunction
inappropriate vocal cord motion results in airflow obstruction
Variable extrathoracic obstructive pattern due to adduction of vocal cords during inspiration
Physical exam findings in VCD
Symptoms mimic asthma (share similar triggers also) - Often coexists with asthma
- Stridor mistaken for wheezes - stridor = inspiratory
- Flow-volume loop suggestive (extrathoracic obstructive pattern)
- Diagnosed by fiberoptic laryngoscopy
Treatment of VCD
Acute: anxiolytics, helium-oxygen mixture
Long term: speech therapy, underlying triggers
COPD
fixed airflow limitation, FEV1/FVC less than 70%
3rd leading cause of death in the US
Smoking is a big risk factor
Chronic Bronchitis
Increased airway resistance due to changes in airway structure (edema, mucous, fibrosis)
-May have overlapping features with asthma
- Produces TONS of mucous
- -> Impaired ventilation
Diagnosis of chronic bronchitis
Productive cough at least 3 months over the past 2 years without other cause
Physical exam findings of chronic bronchitis (4)
1) *Cough, rhonchi, wheezing
2) Prolonged expiratory phase
3) Purse-lip breathing
4) Tripod positioning
Emphysema
- Loss of normal alveolar spaces with enlargement of distal airspaces
- Increased lung compliance
- Impaired gas exchange
- Dynamic airway collapse
What causes increased lung compliance in emphysema?
- Decreased elastic tissue
- Loss of balance between proteases and antiproteases in lung (alpha-1-antitrypsin deficiency)
- Increased apoptosis of alveolar cells
- Impaired repair mechanisms
What causes dynamic airways collapse in emphysema?
“floppy” airways and loss of elasticity of surrounding tissue allow for collapse
Physical exam findings in emphysema (5)
1) *Diminished breath sounds
2) *Hyper-resonant
3) Prolonged expiratory phase
4) Purse-lip breathing
5) Tripod positioning
Acute COPD exacerbation
- Increased cough, sputum volume and purulence, increased wheezing
- Worsening obstruction on PFTs
- Unchanged CXR
- Precipitated by infection, pollution PE, or unknown factors
Implications:
-Increased work of breathing due to hyperinflation, increased airway resistance