Diffuse Alveolar Hemorrhage Syndrome
Diffuse alveolar hemorrhage is a syndrome of recurrent or persistent bleeding into the lungs, caused most often by an autoimmune disorder.
Common symptoms are difficulty breathing and coughing, often coughing up blood.
People usually have a chest x-ray, blood tests, and sometimes examination of the breathing passages with a flexible viewing tube (bronchoscopy).
Treatment of autoimmune causes involves suppression of the immune system with corticosteroids and often cyclophosphamide (a chemotherapy drug) or rituximab (a type of immune suppression drug).
Diffuse alveolar hemorrhage is a syndrome, not a particular disorder. It involves damage to the small blood vessels that supply the lungs, causing blood to accumulate in the tiny air sacs (alveoli) of the lungs. Such blood vessel damage can result from several disorders.
Many disorders can cause diffuse alveolar hemorrhage. The most common causes are
Other disorders that can cause diffuse alveolar hemorrhage include
Lung infections (for example, hantavirus infection)
Toxins (for example, isocyanates, crack cocaine, trimellitic anhydride, and certain pesticides)
Drugs (for example, amiodarone, bleomycin, infliximab, methotrexate, montelukast, nitrofurantoin, phenytoin, and propylthiouracil)
Heart disorders (for example, mitral stenosis)
Defective blood clotting caused by disorders or anticoagulant drugs
Transplantation of organs or bone marrow
Isolated pauci-immune pulmonary capillaritis (an immune disorder that affects people between ages 18 and 35 and damages the tiny blood vessels of the lungs, causing blood to leak into the lungs but no other problems)
Idiopathic pulmonary hemosiderosis (a rare disorder that causes only diffuse alveolar hemorrhage and affects children younger than 10 years)
Diffuse alveolar hemorrhage syndrome can cause
When the disorder is severe, breathing may be extremely difficult. People may gasp and have bluish discoloration of the skin (cyanosis). Some people die. At least two thirds of all people with diffuse alveolar hemorrhage cough up blood.
People may also have other symptoms typical of the disorder that caused the diffuse alveolar hemorrhage.
Doctors can often diagnose diffuse alveolar hemorrhage syndrome by a person's symptoms and chest x-ray findings. Chest x-rays typically show abnormal white patches in the lungs caused by lung bleeding. If the diagnosis is not clear based on symptoms and chest x-ray findings (for example, if the person has not coughed up blood), doctors may need to insert a flexible viewing tube into the lungs (bronchoscopy) and wash out the lungs with fluid (bronchoalveolar lavage) to check for small amounts of blood. The level of red cells in the blood is measured to test for anemia.
After diffuse alveolar hemorrhage has been diagnosed, the cause must be determined. A variety of blood tests may be done, depending on what disorders seem to be likely causes. Urinalysis is done to tell whether the person has kidney damage, characteristic of the pulmonary-renal syndrome.
The disorder causing diffuse alveolar hemorrhage is treated.
Autoimmune disorders are commonly treated with corticosteroids (such as prednisone) and sometimes cyclophosphamide (a chemotherapy drug) or other drugs (such as rituximab) that suppress the immune system.
Problems that people with diffuse alveolar hemorrhage also have, such as difficulty breathing and clotting disorders, are also treated. For example, people may be given oxygen or may need to be on a ventilator for a period of time.
Blood transfusions or other measures may also be needed.