Goodpasture Syndrome

Goodpasture syndrome, or anti-GBM disease, is a rare autoimmune disease characterized by antibodies that attack the basement membrane of the glomeruli in the kidneys and the alveoli in the lungs. This autoimmune attack results in nephritis and pulmonary hemorrhage, leading to severe complications if not promptly diagnosed and treated.

The epidemiology of Goodpasture syndrome shows that it is a rare disease with an estimated incidence of about 1 case per million population annually. The disease occurs more frequently in young men aged 20-30 and in older adults aged 60-70. There is also a slight male predominance.

The pathophysiology of Goodpasture syndrome involves the development of antibodies targeting the α3 chain of type IV collagen, which is found in the basement membrane of the glomeruli and alveoli. These autoantibodies induce an inflammatory response, leading to tissue damage and necrosis.

The causes of the disease are mainly genetic and environmental. Genetic predisposition may exist due to specific alleles of complement and HLA genes. Environmental factors such as smoking, viral infections, and exposure to organic solvents may also play a role.

Symptoms include hematuria, proteinuria, and renal failure, as well as hemoptysis, dyspnea, and cough. Patients may also present with weakness, fatigue, and weight loss. In advanced cases, renal failure can be so severe that dialysis is required.

Differential diagnosis includes other causes of glomerulonephritis and pulmonary hemorrhage, such as systemic lupus erythematosus, granulomatosis with polyangiitis, and microscopic polyangiitis. It is crucial to differentiate Goodpasture syndrome from these conditions due to the differing therapeutic approaches.

Complications of the disease include chronic kidney disease, pulmonary fibrosis, and respiratory failure. These complications can significantly reduce the quality of life and survival of patients.

Treatment involves immunosuppressive drugs such as corticosteroids, cyclophosphamide, and plasmapheresis to remove the autoantibodies from the blood. Early treatment initiation is critical to preventing permanent damage to the kidneys and lungs.

Laboratory tests and monitoring are vital for diagnosing and managing Goodpasture syndrome. Detection of anti-glomerular basement membrane (anti-GBM) antibodies is central to the diagnosis. Patients should undergo blood tests for these antibodies, tests to assess kidney function, such as creatinine and urea levels, and urine tests for hematuria and proteinuria.

A variety of nonspecific tests may be helpful in Goodpasture syndrome. A CBC frequently reveals anemia in patients with Goodpasture syndrome. Creatinine and blood urea will likely be elevated in response to kidney damage. Urinalysis may also show red blood cells (RBCs), hemoglobin, and protein. C-reactive protein (CRP) is generally the preferred marker of inflammation and is usually elevated in Goodpasture syndrome. Anti-GBM antibody concentrations decline with effective treatment, and increased antibody concentrations following remission may indicate relapse.

Up to 30% of patients with Goodpasture syndrome are also antineutrophil cytoplasmic antibody (ANCA) positive. ΑNCA testing should be performed concurrently with anti-GBM testing. Patients with Goodpasture syndrome who are ANCA positive are more susceptible to relapse than patients positive only for anti-GBM antibodies. Although this susceptibility has not been established, patients positive for ANCA may warrant additional monitoring. ANCA test results may also support diagnosing another form of vasculitis or rule out other causes of rapidly progressive glomerulonephritis.

A kidney biopsy can confirm the diagnosis by revealing characteristic histological features, such as crescentic formations. Additional laboratory tests may include immunofluorescence to detect antibody deposits on the basement membrane.

Monitoring patients with Goodpasture syndrome involves regular checks of kidney and lung function and monitoring levels of autoantibodies. The frequency of tests depends on the severity of the disease and response to treatment.

This article belongs to a new series on our blog that covers all fields of health! We present information on the most frequent pathological conditions in a comprehensive, clear, understandable, but always scientifically documented way so you can know and protect the most crucial good: your health!

Ioannis Sideris, Medical Doctor