hemoptysis
Hemoptysis is coughing up blood that comes from the lungs or lower airways. It can range from a faint pink streak in the phlegm to frank red blood, and it understandably alarms people, because the airway is meant to carry air, not blood.
The first task is to confirm the blood truly comes from below the voice box and not from the nose, mouth or stomach. True hemoptysis tends to be bright red and frothy, mixed with sputum, and brought up by coughing; vomited blood from the stomach is usually darker, may contain food, and is acidic. This distinction changes the entire workup.
Most bleeding comes from the bronchial arteries, a small high-pressure circulation that supplies the airway walls. Common causes include infection such as bronchitis, bronchiectasis or tuberculosis, lung cancer, and pulmonary embolism; the trigger varies greatly with age, smoking history and region. Even small-volume hemoptysis warrants explanation, since it can be the first sign of a serious condition.
Massive hemoptysis — large volumes over a short time — is a medical emergency, not because of blood loss but because blood flooding the airways can drown the air spaces and cause suffocation. Such cases need urgent airway protection and source control.
A long-term smoker reports two weeks of blood-streaked sputum each morning; a chest scan and bronchoscopy are arranged to look for a tumor or infection as the source.
Even small, recurrent hemoptysis deserves imaging, because it may mark an early cancer or active infection.
Telling hemoptysis (from the lungs) apart from hematemesis (vomited blood from the gut) and pseudohemoptysis (blood from the nose or mouth) is the crucial first step, because each leads to a completely different investigation.