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Pulmonary-Renal Syndrome

By

Joyce Lee

, MD, MAS, University of Colorado Denver

Last full review/revision Apr 2020| Content last modified Apr 2020
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Pulmonary-renal syndrome is diffuse alveolar hemorrhage plus glomerulonephritis, often occurring simultaneously. Cause is almost always an autoimmune disorder. Diagnosis is by serologic tests and sometimes lung and renal biopsy. Treatment typically includes immunosuppression with corticosteroids and cytotoxic drugs.

Pulmonary-renal syndrome is not a specific entity but is a syndrome that has a specific differential diagnosis and a specific sequence of testing.

Pulmonary pathology is small-vessel vasculitis involving arterioles, venules, and, frequently, alveolar capillaries.

Renal pathology is small-vessel vasculitis resulting in a form of focal segmental proliferative glomerulonephritis.

Etiology

Pulmonary-renal syndrome is almost always a manifestation of an underlying autoimmune disorder. Goodpasture syndrome is the prototype cause, but pulmonary-renal syndrome can also be caused by systemic lupus erythematosus, granulomatosis with polyangiitis, microscopic polyangiitis, and, less commonly, by other vasculitides, connective tissue disorders, and drug-induced vasculitides (eg, propylthiouracil—see table Causes of Pulmonary-Renal Syndrome).

Pulmonary-renal syndrome is less commonly a manifestation of immunoglobulin A (IgA)-mediated disorders, such as IgA nephropathy or IgA–associated vasculitis, and of immune complex–mediated renal disease, such as essential mixed cryoglobulinemia. Rarely, rapidly progressive glomerulonephritis alone can cause the syndrome through a mechanism involving renal failure, volume overload, and pulmonary edema with hemoptysis.

Table
icon

Causes of Pulmonary-Renal Syndrome

Disorder

Examples

Connective tissue disorders

Progressive systemic sclerosis

Goodpasture syndrome

Renal disorders

Idiopathic immune complex glomerulonephritis

Systemic vasculitis

Other

Drugs (eg, propylthiouracil)

Symptoms and Signs

Symptoms and signs typically include

  • Dyspnea

  • Cough

  • Fever

  • Hemoptysis

  • Peripheral edema

  • Hematuria

Patients may also have other signs of glomerulonephritis. Pulmonary and renal manifestations can occur weeks to months apart.

Pearls & Pitfalls

  • Consider pulmonary-renal syndrome in patients with findings compatible with alveolar hemorrhage and glomerulonephritis even when pulmonary and renal findings occur at different times.

Diagnosis

  • Serologic testing

  • Sometimes lung and kidney biopsies

Pulmonary-renal syndrome is suspected in patients with hemoptysis not obviously attributable to other causes (eg, pneumonia, carcinoma, bronchiectasis), particularly when hemoptysis is accompanied by diffuse parenchymal infiltrates and findings suggesting renal disease.

Initial testing includes urinalysis for evidence of hematuria and red cell casts (suggesting glomerulonephritis), serum creatinine for renal function assessment, and CBC for evidence of anemia. Chest x-ray is done if not yet obtained.

Serum antibody testing may help distinguish some causes, as in the following:

Definitive diagnosis requires lung biopsy with findings of small-vessel vasculitis or renal biopsy with findings of glomerulonephritis with or without antibody deposition.

Pulmonary function tests and bronchoalveolar lavage are not diagnostic but can be used to help confirm diffuse alveolar hemorrhage in patients with glomerulonephritis and pulmonary infiltrates but without hemoptysis. Lavage fluid that remains hemorrhagic after sequential sampling establishes diffuse alveolar hemorrhage, especially when hematocrit is falling.

Treatment

  • Corticosteroids

  • Sometimes cyclophosphamide

  • Plasma exchange

Immunosuppression is the cornerstone of treatment of pulmonary-renal syndrome. Standard induction-remission regimens include pulse IV methylprednisolone (500 to 1000 mg IV once a day for 3 to 5 days). As life-threatening features subside, the corticosteroid dose can be reduced; 1 mg/kg prednisone (or equivalent) orally once a day is given for the first month, then tapered over the next 3 to 4 months.

Cyclophosphamide should be added to corticosteroid therapy in critically ill patients with generalized disease, at a dose of 0.5 to 1 g/m2 IV given as a pulse once a month or orally (1 to 2 mg/kg once a day). Rituximab may be used instead of cyclophosphamide; it is non-inferior and causes fewer adverse effects.

Plasma exchange is also often used, particularly in Goodpasture syndrome and certain vasculitides.

Transition to maintenance therapy may occur 6 to 12 months after the initiation of induction therapy or after clinical remission. Maintenance therapy includes low-dose corticosteroids coupled with cytotoxic agents. However, relapse may occur despite ongoing therapy.

Key Points

  • The most suggestive clue to pulmonary-renal syndrome is often that patients have both unexplained pulmonary and renal symptoms, even when such symptoms occur at different times.

  • Do routine laboratory tests (including urinalysis and chest x-ray) as well as autoantibody testing.

  • Confirm the diagnosis when necessary with lung or kidney biopsy.

  • Treat underlying autoimmune disorders.

Click here for Patient Education
NOTE: This is the Professional Version. CONSUMERS: Click here for the Consumer Version
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