AE  stands for acute exacerbation and is usually written AE-COPD referring to an acute exacerbation in a patient with COPD. PE is the medical shorthand for pulmonary embolism, blood clot found in the lungs. What do these two terms have in common? About 70% of all acute exacerbations for COPD have a definable cause. Most are due to infection, and treatments such as antibiotics are needed. About 30% of acute exacerbations do not seem to have a recognizable cause.

However, a recent observational study found that about 16% of acute exacerbations of COPD are associated with pulmonary embolism. More importantly, the blood clots found in the lungs of these patients were substantial and could explain their acute symptoms. In this group, empiric antibiotic therapy and steroids does not usually get the results we want, mostly because we are treating the wrong problem. 16% of all exacerbations of COPD is not a very significant percentage.

However, it is an important percentage if the patient is not responding to usual therapy and should prompt getting the proper diagnostic tests to look for a PE. Now, it does not seem prudent to subject every COPD patient with an exacerbation to a CT scan looking for PE. Radiation exposure and cost are two very good reasons not to get advanced studies routinely, especially when the patient’s history would suggest an infectious cause for their trouble. However, if the hospitalization is more prolonged and the patient is not responding, PE should be a consideration.