Coughing up blood

Coughing up blood, medically called haemoptysis, means blood coming up from the lungs or airways, ranging from a few streaks in the phlegm to larger amounts. It first needs to be distinguished from blood from the nose or mouth, or vomited blood from the stomach, which are different problems. Once it is clear the blood is from the chest, the causes span a wide range. The most common and usually least serious is a chest infection — bronchitis or pneumonia — where inflamed airways bleed a little; bronchiectasis (damaged, widened airways) is another infective cause. More serious causes are important to exclude: a blood clot in the lung (pulmonary embolism), which classically comes with sudden breathlessness and chest pain; tuberculosis, especially with weight loss, fever and night sweats; and lung cancer, particularly in smokers or with persistent haemoptysis and weight loss. Occasionally it comes from the heart (a very congested heart in mitral valve disease) or a clotting or blood-vessel disorder. Because the possible causes include several that need prompt treatment, coughing up blood is a symptom that always warrants medical assessment, even when it seems minor.

• Chest infection — bronchitis or pneumonia; the commonest and usually mildest cause.
• Bronchiectasis — damaged, widened airways that bleed and produce infected phlegm.
• Pulmonary embolism — a blood clot in the lung; often with sudden breathlessness and chest pain.
• Tuberculosis — especially with weight loss, fever and night sweats.
• Lung cancer — particularly in smokers, or with persistent haemoptysis and weight loss.
• A severe nosebleed or bleeding from the mouth — mimicking blood from the chest.
• Clotting problems or blood thinners — increased bleeding tendency.

Coughing up blood is assessed clinically first, and the tests depend on the likely cause and how unwell the person is. A chest X-ray is usually arranged, and often a CT scan of the chest. Blood tests support this: a full blood count and haemoglobin (to gauge blood loss and look for infection), CRP for infection, clotting tests and a review of any blood thinners, and a D-dimer with imaging if a clot in the lung is suspected. Sputum tests can look for infection or tuberculosis. Mediora.AI can surface an infection or clotting-related pattern from your results, but coughing up blood needs proper clinical assessment and usually chest imaging — the cause is worked out by your doctor, not blood tests alone.