Diagnosis and Treatment of COPD for the Physician Assistant Exam
Chronic obstructive pulmonary disease (COPD) is a serious condition and the Physician Assistant Exam (PANCE) will expect that you know the basics. COPD is an inflammatory disease of the lungs caused by one of two medical conditions:
Chronic bronchitis: A productive cough for at least 3 months per year for 2 consecutive years
Emphysema: A lung disease characterized by airway inflammation and loss of elasticity of the alveoli over time, secondary to destruction of the walls of the alveoli; continued smoking makes this process worse
How to diagnose COPD
Here are the key points concerning COPD:
The biggest risk for developing COPD is cigarette smoking. Environmental exposures, such as long-term exposure to second-hand smoke, are also important predisposing factors. Other risk factors include occupational exposures to chemicals and other pulmonary irritants. Alpha-1 antitrypsin (ATT) deficiency is a genetic cause of emphysema.
Clinical presentations of an acute COPD exacerbation include shortness of breath and productive cough.
Physical examination can show tachypnea, a decreased pulse oximetry, and cyanosis if hypoxemia is present.
COPD isn’t diagnosed by chest radiograph findings. However, radiography can be suggestive, especially if you see hyperinflation of both lung fields. Emphysematous bullae may or may not be present on a chest radiograph.
CT scan findings can show two patterns of emphysemas: centrilobular or panacinar. Centrilobular emphysema, which is due to chronic tobacco use, causes changes that predominantly affect the upper lobes as seen on CT scan. Panacinar emphysema causes changes in the lower lobes as seen on CT scan and commonly occurs with alpha-1 antitrypsin deficiency.
Alpha-1 antitrypsin deficiency is characterized by elevated liver function tests and worsening emphysema. The condition, which is autosomally inherited, can be either homozygous or heterozygous, and it usually affects people at a very young age. You diagnose it by checking an alpha-1 antitrypsin level.
For people with lung involvement, treatment can involve administering alpha-1 antitrypsin protein. This condition can also cause liver failure in a young person, especially if the affected person is homozygous for this condition. In cases of fulminant liver failure, the patient may need a liver transplant.
Physiologic characteristics in a question can help tip you off that COPD is present. For example, the classic description of someone with chronic bronchitis is an obese individual with cyanosis, often termed the blue bloater.
This is also known as the Pickwickian syndrome, named after the character Samuel Pickwick, the main character in Charles Dickens’s novel The Pickwick Papers. Joe, a fat boy, eats lots of food and constantly falls asleep. Joe and others with chronic bronchitis often have alveolar hypoventilation and suffer from obstructive sleep apnea also. Indications of obstructive sleep apnea syndrome include being overweight and falling asleep at any time of day.
The diagnosis of COPD is confirmed via a pulmonary function test (PFT). Changes from baseline can be followed by spirometry in a pulmonologist’s office. To determine the severity of COPD, look at three basic parameters:
FEV1 (forced expiratory volume in 1 second): The FEV1 is how much air can be forced out in 1 second. You look at the FEV1 level to see how far from the predicted value it lies. If the FEV1 is < 50 percent of what the predicted value should be, then the patient has severe COPD. After establishing the FEV1, see whether the FEV1 improves after administering a bronchodilator.
FVC (forced vital capacity): The FVC is how much air can be forced out during a forced exhalation, like when doing a PFT.
FEV1/FVC ratio: A normal value for many people is > 0.7, or 70 percent. If the FEV1/FVC ratio is less than 70 percent, then there’s likely some degree of airflow obstruction.
Knowing someone’s FEV1 level and FEV1/FVC ratio and how far off they are from their predicted values is important because you may see significant decreases in these levels before a person becomes symptomatic.
Treatment of COPD
The treatment for an acute COPD exacerbation consists of intravenous steroids and a combination of short-acting beta-2 agonists and anticholinergic agents, usually given via a nebulizer. If there’s evidence of an acute infection, antibiotics are administered as well.
Other agents used to treat COPD include theophylline, which increases the contractility of the diaphragm. Oxygen is given if hypoxemia is present. The long-term treatment is for the patient to stop smoking.
If you see a question in which a patient has an acute COPD exacerbation with a change in mental status and an acute respiratory acidosis, the treatment is either BiPAP or intubation. A person has to be able to take a deep breath for BiPAP to work.
Which one of the following statements concerning the management of COPD is true?
(A) Intravenous steroids and beta-2 agonists are given for an acute exacerbation.
(B) Oxygen administration is avoided because it can elevate CO2 levels.
(C) Theophylline (Theo-Dur) decreases diaphragmatic contractility.
(D) Common causes of infection include anaerobic organisms.
(E) The influenza vaccine should be given every ten years.
The answer is Choice (A). Choice (A), intravenous steroids and beta-2 agonists, are the standards of treatment for a COPD exacerbation. Oxygen, Choice (B), actually is one of the treatments for COPD, although it’s usually titrated slowly to achieve an oxygen saturation of 92 percent. Concerning Choice (C), theophylline actually increases, not decreases, diaphragmatic contractility. It also can function as a bronchodilator.
Anaerobic organisms, Choice (D), are common causes of aspiration pneumonia, particularly in someone with very bad oral dentition. Haemophilus influenzae and Branhamella catarrhalis are common causes of COPD exacerbations. Influenza can also cause a COPD exacerbation. The influenza vaccine, Choice (E), is given annually, not every 10 years. Patients with both COPD and asthma should be vaccinated for influenza yearly.