Obstructive Lung Disease

Question 1

Obstructive lung diseases

Answer 1

Characterized by airway narrowing, obstructive lung diseases restrict air movement and often cause air trapping.

Etiologies of OLDs are seen in mnemonic ABCT (Asthma, bronchiectasis, cystic fibrosis/COPD, Tracheal or bronchial obstruction

Question 2

Asthma

Answer 2

Defined as reversible airway obstruction secondary to bronchial hyperreactivity, airway inflammation, mucous plugging and smooth muscle hypertrophy

BEWARE - all that wheezes is not asthma.

Suspect in kids with multiple episodes of croup and URIs associated with dyspnea

Question 3

history and physical for Asthma

Answer 3

1) Presents with cough, episodic wheezing, dyspnea, and/or chest tightness. Symptoms often worsen at night or early in morning
2) Exam reveals wheezing, prolonged expiratory duration (lower I/E), accessory muscle use, tachypnea, tachycardia, hyperresonance, and possible pulsus paradoxus
3) Reduced breath sounds and low O2 sat are late signs

Question 4

Dx of asthma

Answer 4

1) ABGs: Mild hypoxia and respiratory alkalosis. Normalizing PCO2, respiratory acidosis, and more severe hypoxia may indicate fatigue and impending respiratory failure
2) Spirometry/PFTs: Low FEV1/FVC. Peak flow is diminished acutely. Increased RV and TLC. PFTs are often normal between exacerbations.
3) CBC. Possible eosinophilia
4) CXR: Hyperinflation
5) Methacholine challenge: Tests for bronchial hyperresponsiveness. Useful when PFTs are normal but asthma is still suspected.

Question 5

Treatment of asthma

Answer 5

In general, avoid allergens or any potential triggers. Management is as follows

Acute:
1) O2, bronchodilating agents (short acting B agonists are first line), ipratropium (never use alone for asthma), systemic steroids, magnesium (for severe exacerbations)

2) Maintain a low threshold for intubation in severe cases or acutely in patients with a PCO2 over 50 or PO2 below 50.

Chronic:
1) Administer long acting inhaled bronchodilators and/or inhaled corticosteroids, systemic steroids, cromolyn or rarely theophylline

2) Montelukast and other leukotriene antagonists are oral adjuncts to inhalant therapy

Meds for asthma exacerbation = ASTHMA

Albuterol
Steroids
Theophylline (rare)
Humidified O2
Magnesium (severe exacerbations)
Anticholinergics

Question 6

B2 agonists mechanism

Answer 6

Albuterol: Short acting. Relaxes bronchial smooth muscle

Salmeterol: Long acting for ppx

Question 7

Corticosteroids mechanism

Answer 7

Inhaled: First line for long term control of asthma

Beclomethasons, prednisone: Inhibit the synthesis of virtually all cytokines

Question 8

Muscarinic antagonists mechanism

Answer 8

Ipratropium: Competitively blocks muscarinic receptors, preventing bronchoconstriction

Question 9

Methylxanthines mechanism

Answer 9

Theophylline: Likely causes bronchodilation by inhibiting phosphodiesterase, thereby decreasing cAMP hydrolysis and increasing cAMP. Usage is limited bc of its narrow therapeutic-toxic index (cardiotoxic, neurotoxic)

Question 10

Cromolyn mechanism

Answer 10

Prevents the release of vasoactive mediators from mast cells. Useful for exercise-induced bronchospasm. EFFECTIVE ONLY FOR PPX of asthma. Not effective during an acute attack. Toxicity is rare.

Question 11

Antileukotrienes mechanism

Answer 11

Zileuton: A 5-lipoxygenase pathway inhibitor. Blocks conversion of arachidonic acid to leukotrienes

Montelukast, zafirlukast: Block leukotriene receptors

Question 12

Mild intermittent asthma

Answer 12

2 days/w or less
2 nights/m or less

FEV1 is 80% or more

No daily meds. PRN short acting bronchodilator.

Question 13

Mild persistent asthma

Answer 13

More than 2/w but less than 1/d
More than 2 nights/m

FEV1 is 80% or more

Daily low dose inhaled steroids. PRN short acting dilator

Question 14

Moderate persistent asthma

Answer 14

Daily symptoms
More than 1 night/w

FEV1 60-80

Low to medium dose inhaled steroids plus long acting inhaled B agonists. PRN short acting dilator

Question 15

Severe persistent asthma

Answer 15

Continual or frequent symptoms

FEV1 less than 60

High dose inhaled steroids plus long acting inhaled B agonists. Possible PO steroids. PRN short acting dilators

Question 16

Bronchiectasis

Answer 16

A disease caused by cycles of infection and inflammation in the bronchi/bronchioles that lead to fibrosis, remodeling, and permanent dilation of bronchi

Question 17

History and physical of bronchiectasis

Answer 17

1) Presents with chronic cough accompanied by frequent bouts of yellow or green sputum production, dyspnea, and possible hemoptysis and halitosis
2) Associated with a history of pulmonary infections, hypersensitivity, cystic fibrosis, immunodeficiency, localized airway obstruction, aspiration, autoimmune disease, or IBD
3) Exam reveals rales, wheezes, rhonchi, purulent mucus and occasional hemoptysis

Question 18

Dx of bronchiectasis

Answer 18

1) CXR: shows increased bronchovascular markings and TRAM LINES (parellel lines outlining dilated bronchi as a result of peribronchial inflammation and fibrosis)
2) High resolution CT: dilated airways and ballooned cysts are seen at the end of the bronchus (mostly lower lobes)
3) Spirometry shows a reduced FEV1/FVC ratio consistent with obstruction

Question 19

Tx of bronchiectasis

Answer 19

1) Antibiotics for bacterial infections. Consider inhaled steroids
2) Maintain bronchopulmonary hygiene (cough control, postural drainage, chest PT)
3) Consider lobectomy for localized disease or lung transplant for severe disease

Question 20

Asthma triggers

Answer 20

Allergens, URIs, cold air, exercise, drugs, stress

Question 21

Normal PFTs

Answer 21

1) FEV1 (percent of FVC): More than 75
2) RV (percent of predicted): 80-120
3) FVC (percent of predicted): More than 80

Question 22

Obstructive PFTs

Answer 22

1) Mild: FEV1 60-75, RV 120-150.
2) Moderate: FEV1 40-60, RV 150-175
3) Severe: FEV1 less than 40, RV above 200

Question 23

Restrictive PFTs

Answer 23

1) Mild: FVC 60-80, FEV1 Above 75, RV 80-120
2) Moderate: FVC 50-60, FEV1 above 75, RV 70-80
3) Severe: FVC less than 50, FEV1 above 75, RV 70

Question 24

Inhaled Corticosteroids side effect

Answer 24

Corticosteroids are inhaled in a RUSH and can lead to THRUSH

Question 25

COPD

Answer 25

A disease with lower lung function associated with airflow obstruction. Generally secondary to chronic bronchitis or emphysema, which are distinguished as follows:

1) Chronic bronchitis: productive cough for more than 3 months per year for 2 consecutive years
2) Emphysema: terminal airway destruction and dilation that may be secondary to smoking (centrilobular) or to alpha 1 antitrypsin deficiency (panlobular)

Question 26

History and physical for COPD

Answer 26

1) Symptoms are minimal or nonspecific until the disease is advanced
2) The clinical spectrum includes the following (most patients are a combination of the 2 phenotypes

Emphysema (pink puffer): Dyspnea, pursed lips, minimal cough, reduced breath sounds, late hypercarbia/hypoxia. Patients often have a thin, wasted appearance. Pure emphysematous patients tend to have few reactive episodes between exacerbations

Chronic bronchitis (blue bloater): Cyanosis with mild dyspnea, productive cough. Patients are often overweight with peripheral edema, rhonci, and early signs of hypercarbia/hypoxia

3) Look for the classic barrel chest, use of accessory muscles, JVD, end expiratory wheezing, and muffled breath sounds

Question 27

Dx of COPD

Answer 27

1) CXR: Hyperinflated lungs, reduced lung markings with flat diaphragms, and a thin-appearing heart and mediastinum are seen. Parenchymal bullae or subpleural blebs (pathognomonic of emphysema) are also seen
2) PFTs: Low FEV1/FVC. Normal or low FVC. Normal or high TLC (emphysema, asthma). Low DL of CO (emphysema)
3) ABG: Hypoxemia with acute or chronic respiratory acidosis (high PCO2)
4) Consider a gram stain and sputum culture in setting of fever or productive cough, especially if infiltrate is seen on CXR

Question 28

Tx of COPD - acute exacerbation

Answer 28

1) O2, inhaled B agonists and anticholinergics. IV plus or minus inhaled steroids, antibiotics. Severe cases benefit from BiPAP
2) Consider intubation in the setting of severe hypoxemia or hypercapnia, impending respiratory fatigue or AMS

Question 29

Tx of COPD - chronic

Answer 29

1) Smoking cessation, inhaled B agonsts, anticholinergics, systemic or inhaled steroids
2) Supplemental O2 if resting PaO2 is less than 55 or SaO2 is 89% or less, or in the setting of cor pulmonale, pulmonary HTN, a Hct above 55% or nocturnal hypoxia
3) Give pneumococcal and flu vaccines

Question 30

COPD oxygen goals

Answer 30

In COPD patients with chronic hypercapnia, high concentrations of O2 may suppress patients’ hypoxic respiratory drive

Supplemental O2 titrated above 90% for more than 15h a day and smoking cessation are the only interventions proven to improve survival in patients with COPD