Goodpasture Syndrome Flashcards
A 24-year-old male presents with hemoptysis, dyspnea, and fatigue. He reports a recent upper respiratory tract infection. On examination, he has bilateral crackles in the lung bases and lower extremity edema. Urinalysis shows hematuria and proteinuria. Chest X-ray reveals diffuse pulmonary infiltrates. Renal biopsy demonstrates crescentic glomerulonephritis with linear IgG deposits along the glomerular basement membrane on immunofluorescence. Which of the following is the most likely underlying mechanism of this condition?
A) Immune complex deposition in the glomerular basement membrane
B) Anti-glomerular basement membrane (anti-GBM) antibody-mediated damage
C) T-cell mediated destruction of the glomerular basement membrane
D) Deposition of amyloid fibrils in the glomeruli
E) Activation of complement via alternative pathway
Answer: Anti-glomerular basement membrane (anti-GBM) antibody-mediated damage
Explanation: Goodpasture syndrome is a type II hypersensitivity disorder caused by autoantibodies directed against type IV collagen in the glomerular and alveolar basement membranes. This leads to rapid glomerular damage (crescentic glomerulonephritis) and pulmonary hemorrhage. Immunofluorescence reveals linear IgG deposits along the glomerular basement membrane, confirming the diagnosis. Hemoptysis, hematuria, and acute kidney injury are hallmark features.
Incorrect Answers:
A) Immune complex deposition is seen in lupus nephritis or post-infectious glomerulonephritis, not Goodpasture syndrome.
C) T-cell mediated damage occurs in conditions like minimal change disease.
D) Amyloidosis involves amyloid fibril deposition and does not cause linear IgG staining.
E) Complement activation via the alternative pathway is characteristic of C3 glomerulopathy.
What is the underlying pathophysiology of Goodpasture syndrome?
Formation of anti-glomerular basement membrane (anti-GBM) antibodies targeting type IV collagen in the basement membranes of the kidneys and lungs
What organs are primarily affected in Goodpasture syndrome?
Kidneys (glomerulonephritis) and lungs (pulmonary hemorrhage)
What type of hypersensitivity reaction is Goodpasture syndrome?
Type II hypersensitivity reaction
What are the hallmark clinical features of Goodpasture syndrome?
- Hemoptysis
- Dyspnea
- Pulmonary hemorrhage
- Hematuria
- Proteinuria
- Rapidly progressive glomerulonephritis
What is the characteristic finding on immunofluorescence microscopy following a kidney biopsy in Goodpasture syndrome?
Linear IgG deposits along the glomerular basement membrane on immunofluorescence microscopy
What laboratory test confirms the diagnosis of Goodpasture syndrome?
Detection of circulating anti-GBM antibodies in the serum
What are the treatment options for Goodpasture syndrome?
Plasmapheresis, corticosteroids, and immunosuppressive therapy (e.g., cyclophosphamide)
What are the complications of untreated Goodpasture syndrome?
End-stage renal disease (ESRD) and life-threatening pulmonary hemorrhage
