Diagnosing the etiology of a rapidly progressive
glomerulonephritis is of vital importance to guide appropriate therapeutic management. This case highlights the complexity involved in establishing diagnosis when presentation is atypical. In certain cases diagnosis cannot be established based on clinical presentation or biopsy findings alone, and critical analysis of biopsy findings in context of clinical presentation is crucial to guide the clinical decision-making process.
CASE PRESENTATION: CONCLUSION: This case presented conflicting serologic and histopathologic findings. The presence of anti-proteinase-3 antibody supported diagnosis of recurrence of GPA. However, linear staining of
immunoglobulin G (
IgG) on immunofluorescence (IF) staining of renal biopsy supported anti-glomerular basement membrane (GBM) disease. The treatment of
anti-GBM disease and GPA both involve immunosuppression with
prednisone and
cyclophosphamide. However, patients with
anti-GBM disease are also treated with
plasmapheresis early in the disease presentation to prevent further damage. The patient with GPA, on the other hand, was shown to benefit from
plasmapheresis only in the case of severe renal disease (serum
creatinine level more than 5 mg/dL) or pulmonary
hemorrhage. In this case, since the patient did not have detectable circulating
anti-GBM antibody, the decision was made not to proceed with
plasmapheresis. The patient was treated with a standard immunosuppressive regimen consisting of
prednisone and
cyclophosphamide with partial renal recovery at 2 months.