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 in which people have body swelling, high blood pressure, and red blood cells in the urine).
Pulmonary-renal syndrome can be caused by various disorders. Pulmonary-renal syndrome involves diffuse alveolar hemorrhage, which is widespread damage to the small blood vessels that supply the lungs, causing blood to accumulate in the lung's tiny air sacs (alveoli). People also have glomerulonephritis, a disorder of glomeruli (clusters of microscopic blood vessels in the kidneys with small pores through which blood is filtered). Glomerulonephritis is characterized by body tissue swelling (edema), high blood pressure, and the presence of red blood cells in the urine.
Pulmonary-renal syndrome is almost always caused by an autoimmune disorder, such as Goodpasture syndrome, systemic lupus erythematosus (lupus), granulomatosis with polyangiitis (formerly called Wegener granulomatosis), microscopic polyangiitis, and other disorders that cause inflammation of the blood vessels (vasculitis). Less common causes include rheumatoid arthritis, systemic sclerosis (scleroderma), polymyositis or dermatomyositis, autoimmune kidney disorders, drugs (for example, propylthiouracil), and heart failure.
Typical symptoms include cough (usually coughing up blood), difficulty breathing, fever, and body swelling (edema). Occasionally symptoms are severe enough to cause the lungs to fail and people to have severe difficulty breathing, gasping, and bluish discoloration of the skin (cyanosis). When the lungs fail, the tissues of the body do not receive enough oxygen, and the person may die. Kidney involvement causes blood in the urine, but if the amount is very small, it may not be visible. Kidney involvement also causes blood pressure to increase. The symptoms related to the lungs and the kidneys may not occur at the same time.
Diagnosis of pulmonary-renal syndrome requires the presence of both diffuse alveolar hemorrhage (as in diffuse alveolar hemorrhage syndrome) and glomerulonephritis. Doctors can often diagnose diffuse alveolar hemorrhage 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 blood. The level of red cells in the blood is measured to test for anemia. Glomerulonephritis is diagnosed by symptoms, urinalysis, and blood tests of kidney function.
Once pulmonary-renal syndrome has been diagnosed, doctors try to determine the cause. They order blood tests for antibodies directed against the person's own tissues (called autoantibodies). If test results do not reveal the cause, doctors may need to remove a small piece of lung or kidney tissue for analysis (biopsy).
Most people with pulmonary-renal syndrome have autoimmune disorders, and treatment typically requires high doses of corticosteroids (such as prednisone). If people are very ill, they are often also given cyclophosphamide to further suppress the immune system. Plasma exchange—a procedure in which the unwanted antibodies are removed from the blood (see Controlling Diseases by Purifying the Blood)—is often helpful. Many people need supportive care until an acute flare of the disease lessens in intensity. For example, people may be given oxygen or may need to be on a ventilator for a period of time. Blood transfusions may also be needed. If the kidneys fail, kidney dialysis or a kidney transplant may be required.
Last full review/revision May 2013 by Marvin I. Schwarz, MD