Common symptoms are difficulty breathing and coughing, often coughing up blood.
People usually have chest imaging, 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 medication).
An important function of the immune system Overview of the Immune System The immune system is designed to defend the body against foreign or dangerous invaders. Such invaders include Microorganisms (commonly called germs, such as bacteria, viruses, and fungi) Parasites... read more is fighting off infections. To do this, the immune system recognizes microorganisms as foreign to the person and produces proteins (antibodies Antibodies One of the body's lines of defense ( immune system) involves white blood cells (leukocytes) that travel through the bloodstream and into tissues, searching for and attacking microorganisms and... read more ) that bind to the microorganisms so they can be removed from the body. In autoimmune disorders Autoimmune Disorders An autoimmune disorder is a malfunction of the body's immune system that causes the body to attack its own tissues. What triggers an autoimmune disorder is not known. Symptoms vary depending... read more , the body mistakenly reacts against a person's own tissues as if they were foreign. In autoimmune disorders that involve the lungs, the immune system attacks and damages lung tissue. Autoimmune disorders that affect the lungs can also affect other organs, like the kidneys.
Diffuse alveolar hemorrhage is a syndrome, not a particular disorder. A syndrome is a group of symptoms and other abnormalities that occur together but may be caused by several different disorders. Diffuse alveolar hemorrhage 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.
Causes of Diffuse Alveolar Hemorrhage
Many disorders can cause diffuse alveolar hemorrhage.
The most common causes are
Autoimmune disorders (for example, vasculitis Overview of Vasculitis Vasculitic disorders are caused by inflammation of the blood vessels (vasculitis). Vasculitis can be triggered by certain infections or drugs or can occur for unknown reasons. People may have... read more and Goodpasture syndrome Goodpasture Syndrome Goodpasture syndrome is an uncommon autoimmune disorder in which bleeding into the lungs and progressive kidney failure occur. People usually have difficulty breathing and may cough up blood... read more )
Other disorders that can cause diffuse alveolar hemorrhage include
Defective blood clotting Overview of Blood Clotting Disorders Blood clots help stop bleeding. Blood clotting (coagulation) disorders are dysfunctions in the body's ability to control the formation of blood clots. These dysfunctions may result in Too little... read more caused by disorders or anticoagulant drugs
Idiopathic pulmonary hemosiderosis Idiopathic Pulmonary Hemosiderosis Idiopathic pulmonary hemosiderosis is a rare disorder that causes repeated episodes of bleeding into the lungs, leading to accumulation of iron (hemosiderosis) in the lungs. Idiopathic pulmonary... read more (a rare disorder, possibly due to autoimmune injury, that causes only diffuse alveolar hemorrhage and typically affects children younger than 10 years)
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)
Medications (for example, amiodarone, bleomycin, infliximab, methotrexate, montelukast, nitrofurantoin, and propylthiouracil)
Toxins (for example, isocyanates, crack cocaine, trimellitic anhydride, certain pesticides, and vaping)
Symptoms of Diffuse Alveolar Hemorrhage
Diffuse alveolar hemorrhage syndrome can cause
At least two thirds of people with diffuse alveolar hemorrhage cough up blood. When the disorder is severe, breathing may be extremely difficult. People may gasp and have bluish or pale and grayish discoloration of the skin (cyanosis). Some people die.
People may also have other symptoms typical of the disorder that caused the diffuse alveolar hemorrhage.
People who have repeated episodes of bleeding into the lungs can develop anemia Overview of Anemia Anemia is a condition in which the number of red blood cells is low. Red blood cells contain hemoglobin, a protein that enables them to carry oxygen from the lungs and deliver it to all parts... read more (low blood count, often causing fatigue) and lung scarring that causes pulmonary fibrosis Idiopathic Pulmonary Fibrosis Idiopathic pulmonary fibrosis is the most common form of idiopathic interstitial pneumonia. Idiopathic pulmonary fibrosis affects mostly people over the age of 50 years, usually people who have... read more .
Diagnosis of Diffuse Alveolar Hemorrhage
Computed tomography scan of chest
Sometimes insertion of a flexible viewing tube into the lungs (bronchoscopy) with fluid wash out (bronchoalveolar lavage)
Doctors can often diagnose diffuse alveolar hemorrhage by a person's symptoms and chest imaging findings. If the diagnosis is not clear based on symptoms and chest imaging findings (for example, if the person has not coughed up blood), doctors may need to insert a flexible viewing tube into the lungs (bronchoscopy Bronchoscopy Bronchoscopy is a direct visual examination of the voice box (larynx) and airways through a viewing tube (a bronchoscope). A bronchoscope, a thin viewing tube with a light, has a camera at the... read more ) and wash out the lungs with fluid (bronchoalveolar lavage Procedures Done With Bronchoscopy Bronchoscopy is a direct visual examination of the voice box (larynx) and airways through a viewing tube (a bronchoscope). A bronchoscope, a thin viewing tube with a light, has a camera at the... read more ) 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 Pulmonary-Renal Syndrome Pulmonary-renal syndrome combines both diffuse alveolar hemorrhage (recurrent or persistent bleeding into the lungs) and glomerulonephritis (damage to the microscopic blood vessels in the kidneys... read more . Sometimes, when a cause remains unclear after these tests or the progression of disease is rapid, biopsy of the lungs or kidneys may be needed.
Treatment of Diffuse Alveolar Hemorrhage
Treat specific cause of disorder
Sometimes corticosteroids, cyclophosphamide, or rituximab
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 medications (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 mechanical ventilator Mechanical Ventilation Mechanical ventilation is use of a machine to aid the movement of air into and out of the lungs. Some people with respiratory failure need a mechanical ventilator (a machine that helps air get... read more for a period of time.
Blood transfusions Overview of Blood Transfusion A blood transfusion is the transfer of blood or a blood component from one healthy person (a donor) to a sick person (a recipient). Transfusions are given to increase the blood's ability to... read more , plasma exchange Plasma exchange In apheresis, blood is removed from a person and then returned after substances are removed from it. Apheresis can be used to Obtain healthy blood components from a donor to transfuse to a person... read more , or other measures may also be needed.