COPD Flashcards
Chronic obstructive pulmonary disease, or COPD
A common preventable and treatable lung disease. It is characterised by persistent airflow limitation that is usually progressive. COPD is associated with an enhanced chronic inflammatory response in the airways and the lung to noxious particles or gases especially cigarette smoke. Exacerbations and comorbidities (additional diseases that coexist) contribute to the overall severity in individual patients.
symptoms of COPD
Reduction in the size of a patient’s airways (chronic obstructive bronchitis)
Degradation of the airway wall (emphysema)
COPD increasing?
Unlike many other diseases, COPD is on the increase 1965. CVD stands for cardiovascular disease.
When should the diagnosis of COPD be considered?
If the patient has dyspnea (difficult or labored breathing or shortness of breath), chronic cough or sputum production and a history of exposure to risk factors for the disease (such as smoking).
Why is Spirometry important for COPD?
It is required to make the diagnosis, which measures how much air a patient can breathe out in one forced breath.
How is spirometry done?
Spirometry is a method of assessing lung function by measuring the volume of air that the patient can expel from the lungs after a maximal inspiration. The indices derived from this forced exhaled maneuver have become the most accurate and reliable way of supporting a diagnosis of COPD.
When these values are compared with predicted normal values determined on the basis of age, height, sex, and ethnicity, a measure of the severity of airway obstruction can be determined. It is on these values that COPD guidelines around the world base the assessment of mild, moderate, and severe disease levels.
FVC
Forced Vital Capacity – the total volume of air that the patient can forcibly exhale in one breath.
FEV1
Forced Expiratory Volume in One Second – the volume of air that the patient is able to exhale in the first second of forced expiration.
FEV1 /FVC
The ratio of FEV1 to FVC expressed as a fraction (previously this was expressed as a percentage).
Values of FEV1 and FVC are measured in liters and are also expressed as a percentage of the predicted values for that individual.
The ratio of FEV1/FVC is normally between?
0.7 and 0.8. Values below 0.7 are a marker of airway obstruction, except in older adults where values 0.65–0.7 may be normal. Predicted values are calculated from thousands of normal people and vary with sex, height, age, and ethnicity.
Tiffeneau-Pinelli index:
Tiffeneau-Pinelli index = FEV1FVC
= FEV1%
An FEV1FVC
< 0.70 confirms the presence of persistent airflow limitation and thus of COPD.
FEV1% predicted (also known as mean FEV1) is the patient’s FEV1% divided by the average FEV1% for the patient’s demographic.
Asthmas v COPD, onset?
Asthmas- Childhood
COPD- midlife
Asthmas v COPD, usual etiology?
Asthmas- immunological stimuli, family history
COPD- risk factors such as cigarette smoke
Asthmas v COPD, course?
Asthmas- intermediate and variable
COPD- chronic and progressive
Asthmas v COPD, airflow limitation?
Asthmas- largely reversible
COPD- partially reversible
Asthmas v COPD, clinical features?
Asthmas- wheeze, chest tightness, cough
COPD- cough, sputum
Asthmas v COPD, inflammatory mediator?
Asthmas- eosinophils
COPD- neutrophils
COPD in lungs
Fibrosis: Damaged and scarred lung tissue.
Alveolar disruption: Disrupting the ability of the alveolar to stretch when inhaling and shrink when exhaling.
Neutrophils, T lymphocytes and epithelium cells are all elevated in COPD patients
How do COPD therapies work? 2 main types?
They do not act upon the biological mechanism directly, but treat the symptoms. The two main therapies, bronchodilators and steroids relax the smooth muscle of the airways and reduce inflammation respectively.
How are Anti-inflammatory drugs best used?
They are often used in combination with bronchodilators for best effect.
There are two classes of drugs that act as bronchodilators:
Beta2 agonists and cholinergic antagonists.
How are bronchodilators prescribed?
The choice of treatment depends on the availability of medications and each patient’s individual response in terms of symptom relief and side effects.
The principal bronchodilator treatments are beta2-agonists, cholinergic antagonists, theophylline or combination therapy.
What bronchodilators do COPD patients bests respond to?
cholinergic antagonists.
How do bronchodilators, Beta2 agonists work?
They bind to the β2 adrenergic receptor; a protein that spans cell membranes. The endogenous ligand of β2 adrenergic receptors is adrenaline or epinephrine. Note how similar salbutamol is to the endogenous ligand.
β2 adrenergic receptors are involved in the dilation of smooth muscle, including bronchial passages. Thus a synthetic drug such as salbutamol can amplify the function of β2 adrenergic receptors causing airways to increase.