Coughing up blood, or hemoptysis can be a complication of a chronic cough. Some patients with cystic fibrosis only cough up a small about of blood at a time, while in others the blood coughed up is massive. Massive hemoptysis means that the patient has coughed up more than 240 milliliters of blood in a 24 hour period or over 100 mL of blood a day over the course of a few days. It can be severe enough to threaten the patient’s life by causing their blood pressure to crash or causing them to choke on the blood. Doctors do not know why CF patients suffer from hemoptysis, though some believe that blood vessels in the lungs weakened by persistent inflammation are a cause.Next