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Pulmonary-Renal Syndrome

By

Joyce Lee

, MD, MAS, University of Colorado School of Medicine

Reviewed/Revised Oct 2023
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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).

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 Antibodies ) 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 often affect other organs, such as 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)

  • Difficulty breathing

  • Fever

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

  • Chest imaging

  • 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)

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 Bronchoscopy ) 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 Procedures Done With Bronchoscopy ) 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) or other medications that suppress the immune system, such as rituximab

  • 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.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Cyclophosphamide, Cytoxan, Neosar
RIABNI, Rituxan, RUXIENCE, truxima
Deltasone, Predone, RAYOS, Sterapred, Sterapred DS
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