Coughing up blood is a symptom that causes immediate concern and always warrants prompt medical attention. This occurrence, known medically as hemoptysis, involves the expectoration of blood or blood-streaked sputum originating from the lower respiratory tract, specifically the lungs or bronchial tubes. The amount of blood can vary significantly, ranging from small streaks mixed with mucus to much larger quantities. Understanding the source and potential severity of this bleeding is the first step in determining the necessary medical response.
Defining Hemoptysis and Clarifying the Source
Hemoptysis is defined as bleeding that originates below the voice box, within the airways or lung tissue. The blood often comes from the bronchial arteries, which are under high systemic pressure, or from the lower-pressure pulmonary arteries. It is important to distinguish this true respiratory bleeding from other sources that may appear similar but involve different causes and treatments.
One common confusion is pseudohemoptysis, which is blood originating from the nose, mouth, or throat, such as from a nosebleed, that is then swallowed and coughed up. Another distinct condition is hematemesis, which is the vomiting of blood originating from the gastrointestinal tract, like the stomach or esophagus.
Hemoptysis is typically frothy, bright red, and mixed with sputum due to mixing with air in the lungs. Conversely, hematemesis is usually dark, non-frothy, and has a “coffee-ground” appearance because it has been exposed to stomach acid. The presence of nausea or abdominal discomfort often precedes hematemesis, while coughing is the precursor to hemoptysis. Making this distinction is an important part of the initial medical assessment.
Common Causes Associated with Minor Illnesses
In most cases, hemoptysis is mild and self-limiting, often stemming from common respiratory illnesses. Acute or chronic bronchitis is the most frequent cause in adults, where inflammation and irritation of the bronchial tubes can cause small blood vessels to rupture. This irritation results in blood-streaked sputum, typically a small amount of blood mixed with mucus.
A severe or persistent cough can also lead to minor hemoptysis by physically tearing small blood vessels lining the airways due to the force and pressure. Pneumonia, an infection causing inflammation in the air sacs, can also present with blood-tinged or rust-colored sputum, especially if the infection is severe.
Individuals taking anticoagulant or antiplatelet medications, known as blood thinners, may experience minor bleeding more easily from slight airway irritation. These medications increase the likelihood and duration of bleeding from an existing minor injury or inflammation. While these causes are generally not life-threatening, any instance of coughing up blood requires professional medical evaluation.
Serious Conditions Requiring Immediate Investigation
While most hemoptysis is minor, it can also be a symptom of a serious underlying condition that requires urgent medical intervention. Lung cancer, particularly in smokers, must be considered, as it can cause bleeding by invading and eroding the high-pressure bronchial arteries. Associated symptoms that raise concern for malignancy include unexplained weight loss, fatigue, and a persistent change in a chronic cough.
A pulmonary embolism (PE), a blockage of an artery in the lungs, can cause hemoptysis, often accompanied by a sudden onset of shortness of breath and sharp chest pain that worsens with deep breathing. This condition causes tissue death (infarction) in the lung, which can lead to bleeding.
Tuberculosis (TB), a bacterial infection, remains a frequent cause globally and can cause significant bleeding by damaging lung tissue and blood vessels. TB often presents with night sweats, weight loss, and chronic cough.
Conditions affecting the heart can also lead to hemoptysis through pressure backup in the lungs. Congestive heart failure or mitral stenosis, a narrowing of the heart’s mitral valve, can cause high pressure in the pulmonary circulation, leading to rupture of small capillaries and the expectoration of pink, frothy sputum. Bronchiectasis, a chronic condition where the airways are abnormally widened and damaged, is another common serious cause, as the inflamed airways are prone to recurrent infection and bleeding.
Medical Evaluation and Diagnostic Procedures
Because of the potential for life-threatening causes, any episode of hemoptysis requires a medical assessment. Massive hemoptysis—defined as more than 100 to 200 milliliters of blood in 24 hours—is a medical emergency requiring immediate hospitalization. The initial evaluation involves a detailed patient history and physical examination to gauge the severity of bleeding and assess the patient’s stability.
Diagnostic testing usually begins with a chest X-ray, a readily available test that can provide clues about the location of the bleeding and underlying causes like pneumonia or a mass. However, its sensitivity is limited, and further imaging is often required. A computed tomography (CT) scan of the chest, often performed with intravenous contrast, is the preferred modality for locating the bleeding source and determining the exact cause, such as detecting a tumor or structural lung damage.
Specialized procedures are used when the cause is not identified by imaging or when cancer is suspected. A bronchoscopy involves inserting a thin, flexible tube with a camera down the throat into the airways, allowing a doctor to directly visualize the source of the bleeding and sometimes stop it. Blood tests are also performed to check for infection, clotting factors, and to rule out a bleeding disorder. The goal of this process is to treat the underlying cause to prevent recurrence.