RESUMEN
The patient was a 64-year-old man who had been receiving methotrexate (MTX) for rheumatoid arthritis for 8 years. Computed tomography (CT) obtained one month prior to admission revealed numerous enlarged lymph nodes. Lower leg edema appeared two weeks prior to admission. Severe proteinuria was confirmed, and the patient was admitted. A renal biopsy revealed minimal changes in glomeruli. CT on day 14 revealed shrinking lymph nodes, and the patient was diagnosed with Hodgkin lymphoma by a neck lymph node biopsy. This is the first report of secondary minimal change nephrotic syndrome caused by an MTX-associated lymphoproliferative disorder.
RESUMEN
A 75-year-old man with fever was diagnosed with alveolar hemorrhage. Antineutrophil cytoplasmic antibodies for myeloperoxidase and proteinase 3 were absent. He received corticosteroid therapy, which immediately improved his symptoms and chest radiological findings. After the discontinuation of corticosteroids, fever and general fatigue relapsed, and renal function deteriorated with hematuria and proteinuria. A nerve conduction study revealed mononeuritis multiplex. Renal biopsy demonstrated focal necrotizing crescentic glomerulonephritis with endocapillary proliferative lesions, immunofluorescence C3 deposits, and electron-microscopic subepithelial hump-like deposits. Nephritis-associated plasmin receptor (NAPlr) and plasmin activity, biomarkers of infection-related glomerulonephritis, were positive in glomeruli. Although pathological findings suggested infection-related glomerulonephritis (IRGN), clinical manifestations, such as alveolar hemorrhage and mononeuritis multiplex, suggested systemic small vessel vasculitis. After corticosteroid therapy, systemic symptoms disappeared, and the gradual amelioration of hematuria and proteinuria was observed. Based on the clinical symptoms for which steroid therapy was effective, the patient was considered to have systemic small vessel vasculitis, the etiology of which may have been associated with infection.