2 COPD Flashcards
Highest prevalence of COPD is among…
65-74 year olds
Men and women affected almost equally
Morbidity increases with age and is greater in males
Global Initiative for Chronic Obstructive Lung Disease (GOLD) definition:
Chronic obstructive pulmonary disease is a common, PREVENTABLE and TREATABLE disease that is characterized by persistent RESPIRATORY SYMPTOMS and AIRFLOW LIMITATION that is due to airway and/or alveolar abnormalities usually caused by SIGNIFICANT EXPOSURE TO NOXIOUS PARTICLES OR GASES.
What are the three clinical subtypes of COPD?
Chronic Bronchitis (predominant)
Emphysema (predominant)
Chronic Obstructive Asthma
Patients with Chronic Bronchitis are described as…
“Blue Bloaters” due to CYANOSIS and OVERWEIGHT body habitus
Hypoxemia and respiratory acidosis more common
Cor pulmonale from pulmonary HTN (b/c problems with both getting air in and out)
Patients with Emphysema are described as …
“Pink Puffers” because of pursed-lip breathing, skin color, and thin body habitus
Use a lot of accessory muscles to breath
Chronic bronchitis is defined as a chronic productive cough for ____________ with no other cause.
3 or more months during 2 consecutive years
Leads to structural changes:
• Mucous gland enlargement —> hyper secretion
• Bronchial squamous metastasis
• Loss of ciliary transport
In Chronic Bronchitis, inflammation of bronchial wall and infiltration of sub-mucosal layer is caused by ________
Neutrophils (vs eosinophils in asthma)
Chronic bacterial colonization and airway hyper-reactivity are thought to play an important role
Obstruction in chronic bronchitis is ….
Both inspiratory and expiratory
Hypoxemia and hypercapnia result form impeded ventilation
There is less parenchymal damage than emphysema
Pathologic enlargement of the air spaces distal to the terminal bronchioles due to destruction of the alveolar walls
Emphysema
Destructive process not clearly understood (may be too much elastase or too little antitrypsin activity)
Protease enzyme secreted by neutrophils and macrophages during inflammation
Neutrophil elastase - it destroys bacteria and host tissue (ie - elastin)
An inhibitor of neutrophil elastase
Alpha-1 Antitrypsin
When in deficiency there is breakdown of the lung structure by elastase
Describe what happens to the alveoli in emphysema
Reduced alveolar surface area available for gas exchange
Decreased elastic recoil
Loss of alveolar supporting structure = airway narrowing
Obstruction in emphysema is …
Mostly during exhalation
Not associated with significant hypoxemia until later in disease severity
Destruction of capillary beds in emphysema results in …
Reduced DLCO (diffusing capacity for carbon monoxide)
Chronic inflammation in asthma is primarily mediated by…
Eosinophils
Airway hyper-reactivity —> increased secretions, mucosal edema, constriction of bronchial smooth muscle —> airway obstruction
Is asthma reversible or irreversible?
Reversible!
Most common risk factor for COPD
Cigarette smoking - 80% of COPD patients, most have smoked at least 20 cigarettes a day for 20 or more years
Other risk factors: • Environment/occupation • Second hand smoke exposure • Airway hyper-responsiveness (asthma) • Genetic RF: alpha-1 antitrypsin deficiency (<1% of all cases)
How does cigarette smoking cause COPD?
Stimulates elastase enzymatic activity, causing degenerative changes in elastin and alveolar structures
Causes release of cytotoxic oxygen radicals from WBCs in lung tissue
Amount and duration contribute to disease severity
Examples of environmental exposures that can lead to COPD
Air pollution
Coal miners
Grain handlers
Metal molders
Workers exposed to dust
Cooking with biomass fuels (1/3 of the world)
A hereditary syndrome resulting in the early onset of emphysema (<1% of US cases)
Alpha-1 antitrypsin deficiency
Features of emphysema present at a younger age (≤45)
AAT is a protease inhibitor - inhibits elastase and several other proteolytic enzymes
The process of lung destruction is accelerated in smokers with AAT deficiency
Classic presentation of COPD
Dyspnea, chronic cough, and sputum production
Sx onset in 5th or 6gh decade of life
Most common early symptom is DYSPNEA ON EXERTION
Common comorbidities of COPD
CVD (HTN, CAD, stroke)
DM
Renal insufficiency
Osteoporosis
Psychiatric illness
Cognitive dysfunction
Gross physical exam findings in emphysema
Tripod positioning
Cyanosis
Tobacco staining of fingers (because the idiot is still smoking)
JVD, use of accessory muscles (neck and shoulder)
Pursed lip breathing
Why do patients with emphysema purse their lips?
In COPD, ordinary breathing allows early bronchial collapse on exhalation
Pursed-lip breathing achieves resistance to outflow at the lips, raising intrabronhial pressure, keeping the bronchi open. More air can thus be expelled.
More specific physical exam findings in Emphysema
Lungs:
Barrel chest (increased AP diameter)
Prolonged expiration
Increased resonance on percussion (b/c of air trapping)
Decreased breath sounds (distant), wheezing, and crackles at base
Heart: S3 gallop (if cor pulmonale), RV lift
ABD:
Hepatomegaly, pulm HTN if cor pulmonale
Ext:
Muscle wasting, peripheral edema
Altered structure (hypertrophy or dilation) and/or impaired function of the RIGHT ventricle that results from pulmonary HTN associated with diseases of the lung, vasculature, upper airway, or chest wall
Cor Pulmonale
Most common cause of cor pulmonale
COPD
Diagnostic study required for the diagnosis of COPD
Spirometry
Will also do a CBC, BNP, cardiac enzymes, metabolic panel, AAT but spirometry is diagnostic
Other tests: Pulse ox, ABG, EKG, sputum exam, CXR/HRCT
The amount of air forcefully exhaled during maximal forced expiration
Forced Vital Capacity (FVC)
Normal is 80-120%
Compared to Forced Expiratory Volume in 1 second (FEV1)