Pulmonary-renal syndromes are almost always caused by an autoimmune disorder 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 .
Diagnostic testing involves urinalysis, blood tests for certain proteins (antibodies) that indicate the body is reacting to its own tissues, and sometimes analysis of tissue from a lung or a kidney.
Treatment requires corticosteroids and often cyclophosphamide (a chemotherapy drug) or rituximab and other drugs that suppress the body's immune system.
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 join with 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 also often affect other organs, particularly the kidneys.
Pulmonary-renal syndrome is a syndrome, rather than a specific disorder. A syndrome is a group of symptoms and other abnormalities that occur together but may be caused by several different disorders or even other syndromes. Pulmonary-renal syndrome involves a lung disorder called diffuse alveolar hemorrhage Diffuse Alveolar Hemorrhage 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... read more , 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 a type of kidney problem called glomerulonephritis Glomerulonephritis Glomerulonephritis is a disorder of glomeruli (clusters of microscopic blood vessels in the kidneys with small pores through which blood is filtered). It is characterized by body tissue swelling... read more , 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.
Causes of Pulmonary-Renal Syndrome
Pulmonary-renal syndrome can be caused by various disorders.
The most common causes of pulmonary-renal syndrome are autoimmune disorders such as
Less common autoimmune causes include
Symptoms of Pulmonary-Renal Syndrome
Symptoms can include
Blood in the urine
Body swelling (edema)
Cough (usually coughing up blood)
Occasionally symptoms are severe enough to cause the lungs to fail (respiratory failure Respiratory Failure Respiratory failure is a condition in which the level of oxygen in the blood becomes dangerously low or the level of carbon dioxide in the blood becomes dangerously high. Conditions that block... read more ), and people have severe difficulty breathing and bluish discoloration of the skin (cyanosis Cyanosis Cyanosis is a bluish discoloration of the skin resulting from an inadequate amount of oxygen in the blood. Cyanosis occurs when oxygen-depleted (deoxygenated) blood, which is bluish rather than... read more ). 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, blood 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.
Sometimes the disease may have sudden flare-ups.
Diagnosis of Pulmonary-Renal Syndrome
Blood and urine tests
Insertion of a flexible viewing tube into the lungs (bronchoscopy) with fluid wash out (bronchoalveolar lavage)
Sometimes a procedure to remove a small piece of lung or kidney tissue for analysis (biopsy)
Diagnosis of a pulmonary-renal syndrome requires the presence of both diffuse alveolar hemorrhage (as in diffuse alveolar hemorrhage Diffuse Alveolar Hemorrhage 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... read more ) and kidney damage (glomerulonephritis Glomerulonephritis Glomerulonephritis is a disorder of glomeruli (clusters of microscopic blood vessels in the kidneys with small pores through which blood is filtered). It is characterized by body tissue swelling... read more ).
Doctors can often diagnose diffuse alveolar hemorrhage by a person's symptoms and chest imaging findings. Chest imaging typically show abnormal white patches in the lungs caused by lung bleeding. 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 has a camera at the end that allows a doctor to look... 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 has a camera at the end that allows a doctor to look... read more ) 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 a 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).
Treatment of Pulmonary-Renal Syndrome
Corticosteroids (such as prednisone)
Sometimes cyclophosphamide (a chemotherapy drug)
Procedure to remove unwanted antibodies from the blood (called plasma exchange)
In most people, pulmonary-renal syndrome is caused by an autoimmune disorder, so treatment typically requires high doses of corticosteroids (such as prednisone) to suppress the immune system. If people are very ill, they are often also given cyclophosphamide to further suppress the immune system. Rituximab may be used instead of cyclophosphamide.
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 —a procedure in which the unwanted antibodies are removed from the blood—may be helpful.
Many people need supportive care until the disease lessens in intensity. For example, people may be given oxygen or may need to be on a 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 may also be needed. If the kidneys fail, kidney dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more or kidney transplantation Kidney Transplantation Kidney transplantation is the removal of a healthy kidney from a living or recently deceased person and then its transfer into a person with end-stage kidney failure. (See also Overview of Transplantation... read more may be required.