PATHOPHYS: COPD Flashcards
What is COPD?
A disease state characterized by airflow limitation (usually progressive) that is NOT fully reversible.
How do you measure airflow limitation in COPD?
Reduced FEV1
How do you determine if airflow limitation is irreversible?
you have <200 mL)reversibility after bronchodilator application
ON TEST
What accompanies the airflow limitation associated with COPD?
abnormal inflammatory response (CD8+ T cell response with neutrophils and macrophages)
ON TEST
What two mechanisms underlie airflow limitation in COPD?
- Small Airway Disease (inflammation, fibrosis, mucous plugs, etc.)
- Parenchymal destruction (loss of alveolar attachments, decrease in elastic recoil)
True or false: COPD is the third leading cause of death in the USA and worldwide.
TRUE
What is the primary cause of COPD?
cigarette smoke
typically need 20 pack years
Why is it important for COPD patients to quit smoking?
Over time, the FEV1 decreases drastically in smokers compared to non-smokers (if you have COPD, you already have low FEV1 and you will decrease quicker into disability and death)
List some risk factors for COPD.
- Cigarette smoke
- Occupational dust and chemicals
- Environmental tobacco smoke
- Indoor and outdoor air pollution
- Age
When do people become symptomatic for COPD?
In 40s, but do not get dyspnea until 50s or 60s
True or false: spirometry is required to make the diagnosis of COPD.
TRUE! (FEV1/FVC < 0.7)
True or false: people with a long history of poorly-treated asthma may go on to develop COPD.
TRUE: they develop an irreversible airflow obstruction that is indistinguishable for COPD
What is the clinical definition of chronic bronchitis?
Production of sputum (chronic or recurrent cough) for 3 months in 2 consecutive years.
What are the 3 major physical cues that you look for in a physical exam of a COPD patient?
1) Airflow limitation (prolonged expiration)
2) Hyperinflation (Pink puffer/barrel chest)
3) Impairment of breathing mechanics (use of accessory muscles)
True or false: Static lungvolumes decrease in advanced COPD due to obstruction.
FALSE: they increase due to air trapping
What is a major may to differentiate between COPD and asthma?
DLCO is reduced in COPD patient with predominant emphysema (alveolar problem) and NOT in asthma (airway problem)
What are the 2 major clinical patterns of COPD?
1) Blue bloaters
2) Pink puffers
What makes blue bloaters blue?
central cyanosis due to chronic respiratory failure increasing PCO2
What bloats blue bloaters?
heart failure leads to pulmonary edema (crackles) and edema of ankles
What makes pink puffers puff?
They need to create “auto-PEEP” in order to keep airway from collapsing during exhalation (they have mostly emphysema)
What is the hypoxemia and hypercapnia due to in people with chronic bronchitis dominant COPD?
V/Q imbalance
What type of respiratory failure is seen in blue bloaters?
Type II
Do pink puffers have hypercapnia?
no- they increase their minute ventilation enough to maintain PCO2 within normal range
What makes pink puffers so thin/cachetic?
High energy expenditure
True or false: pink puffers commonly get home oxygen.
FALSE: pink puffers have preserved O2 saturation due to their high minute ventilation
What inflammatory cells are involved in asthma versus COPD?
Asthma: CD4+ T cells, eosinophils
COPD: CD8+ T cells, macrophages, neutrophils
What is the Reid Index? What is it used to diagnose?
Reid Index is the bronchial gland depth as a fraction of total bronchial wall thickness. It must be > 0.36 in order to diagnose chronic bronchitis
What size airways are affected by chronic bronchitis?
> 2 mm
What is the difference between chronic bronchitis and chronic bronchiolitis?
chronic bronchiolitis is present in airways < 2mm
What is emphysema?
an abnormal enlargement of air spaces distal to terminal bronchioles
What is a bullae?
Emphysematous space > 1 cm in diameter
How does emphysema lead to airway collapse?
loss of alveolar attachments leads to dynamic airway collapse during EXHALATION
Where do you see abnormalities in the flow volume loop of pure chronic bronchitis?
Airway obstruction is seen in inspiration AND expiration (due to airway narrowing)
Where do you see abnormalities in the flow volume loop of pure emphysema?
Airflow obstruction during expiration only
Which has increased lung volumes due to hyperinflation: pure chronic bronchitis or pure emphysema?
pure emphysema
Decreased DLCO in pure emphysema is due to what?
Destruction of alveoli and alveolar capillaries
True or false: VC is decreased in pure emphysema.
TRUE! Even though TLC and RV are incresed
What are the most common causes of COPD exascerbation?
1) Bacterial infection of tracheobronchial tree
2) Viruses
3) Air pollution
When should antibiotics be given to a COPD patient?
1) 3 cardinal symptoms: increased dyspnea, increased sputum volum, increased sputum purulence
2) Patients who require mechanical ventilation
What is the most important drug in hypoxic patients?
oxygen with goal to maintain SAO2 > 90% at all times
What is the caveat in supplemental oxygen effectiveness?
it must be worn 15-24 hours a day to be effective
What must PaO2/SAO2 be to put patient on long term oxygen therapy?
PaO2 < 88%
