Some causes of coughing up blood are tuberculosis, pneumonia and pulmonary embolism, according to Mayo Clinic and MedicineNet. Tuberculosis is a contagious bacterial infection that most often affects the lungs, according to Mayo Clinic. It can be chronic or acute. Additionally, a parasitic infection, mitral valve stenosis or pneumonia also can lead to coughing up blood.
Tuberculosis can also be latent or active. In latent tuberculosis, the patient harbors the bacteria that causes the disease but does not become ill himself, says Mayo Clinic. He is also not contagious but must still take steps to make sure his tuberculosis does not become active. In active tuberculosis, the patient is ill and contagious.
Pneumonia is also a disease that affects the lungs, but it can be caused by viruses, bacteria and fungi, says Mayo Clinic. With pneumonia, the air sacs in the lungs are inflamed, which in turn causes them to be filled with pus or fluid. Besides coughing up blood, the patient suffers chills and fever and finds it hard to breathe. Very young children, older people and people who are already ill are at the most risk from pneumonia.
A pulmonary embolism is an obstruction in a lung artery that is caused by a blood clot or, less frequently, other bodily debris, that forms elsewhere in the body and travels to the lungs through the bloodstream, says MedicineNet. The patient has chest pain and shortness of breath besides bloody sputum. A pulmonary embolism is a medical emergency that can cause death if not treated promptly.
Blood that comes from the respiratory tract or lungs is referred to as hemoptysis, according to Mayo Clinic. Blood coming from other areas such as the stomach can appear to be coming from a person's lungs. A person who is coughing up blood should call his doctor to determine the cause of bleeding. A person who is coughing up a large amount of blood or experiencing bleeding that cannot be stopped should call 911 immediately.
In some cases, the reason for coughing up blood is not identified and the condition improves within a six-month time frame, states WebMD. Testing that can help to identify the cause of hemoptysis are chest x-ray, computed tomography or CT scan, a bronchoscopy, a complete blood count or CBC, a physical exam and personal history. These tests center on determining the rate of bleeding that is occurring and whether there is a risk to breathing ability.