Abstract
We report a case of poststreptococcal acute glomerulonephritis with an unusual clinical course, showing nephrotic syndrome, prolonged proteinuria, and recurrent gross hematuria. An 11-year-old male patient suffered transient gross hematuria, when three months later, he again developed gross hematuria which was associated with streptococcal pharyngitis. His serum complement levels were normal. This episode of gross hematuria lasted for a few days.About 3 weeks after diagnosis of streptococcal pharyngitis, he developed acute nephritis with gross hematuria, heavy proteinuria, hypoalubminemia, and hypocomplementemia. His first renal biopsy showed diffuse endocapillary proliferation with cellular crescent formation in some glomeruli, and remarkable inflammatory cell infiltration in the tubulointerstitium. Immunofluorescence (IF) showed C3 deposition along capillary walls. Electron microscopy showed intramembranous deposits. Hump was not observed. Staining for nephritis-associated plasmin receptor (NAPlr) and plasmin-like activity were positive in the glomeruli. We diagnosed this case as an acute phase of atypical PSAGN with severe inflammation from these pathological evidences. Serum albumin and complement levels returned to normal after a month. However, his mild proteinuria and microscopic hematuria persisted. He was then treated with intravenous methylpredonisolone pulse therapy (MPT) followed by oral predonisolone, mizoribine, warfarin, and dipyridamole. In spite of this therapy, his hematuria and proteinuria persisted. His second renal biopsy was performed at 5 months after MPT, and this showed diffuse and global mesangial proliferation with several segmental and global sclerosis. Immunofluorescence showed that both IgA and C3 were negative in glomeruli. The second histology indicated recovery phase of PSAGN. His proteinuria and hematuria disappeared 1 year and 9 months following the start of the above therapy respectively, at this point, we discontinued his multidrug therapy, and since, there has been no recurrence.This presentation of gross hematuria simultaneously with respiratory infection may be concluded as a typical presentation of IgA nephritis. However, these pathological findings suggested a severe presentation of PSAGN with an unusual clinical course, since there were no pathological findings suggesting other co-existing nephritides. Although we are currently unable to reach a definitive explanation for his complicated clinical course, we suggest a diagnosis of PSAGN superimposed by IgA nephritis.
