Lung Disease: unexplained worsening of COPD

Patients with COPD (chronic obstructive pulmonary disease and/or emphysema) with unexplained worsening of COPD have a roughly 30% chance of having a pulmonary embolism - a blood clot lodged in the lungs. Most flare-ups of COPD are caused by infection, with cough, sputum, fever, and shortness of breath. If you have a flare-up of COPD and you don't have most of these symptoms, you should be evaluated for a pulmonary embolism, a potentially fatal condition.