CASE 165 (November 2019)
An 11-year-old boy presented, a year before, nephritic syndrome after an episode of upper respiratory tract infection, at that time creatinine rose to 1.4 mg/dL and serum C3 was decreased: 65 mg/dL, with Normal C4: 14 mg/dL. After a week the edemas and the HTA disappeared. Six weeks later the uroanalysis was normal. Since then, C3 has been persistently low: between 70 and 84 mg/dL, but all renal function studies have been normal and the patient is asymptomatic, without high blood pressure. In the last uroanalysis 4-5 erythrocytes/hpf were reported.
The treating group decides to take renal biopsy, look at the image.
Figure 1. H&E, X400
Figure 2. H&E, X400.
Figure 3. Masson's trichrome stain, X400.
Figure 4. Masson's trichrome stain, X400.
Figure 5. Methenamine-silver stain, X400.
Figure 6. PAS, X400.
Figure 7. Direct immunofluorescence for C3, X400.
Figure 8. EM, original magnification: X2,100.
Figure 9. EM, original magnification: X2,100.
Figure 10. EM, original magnification: X3,000.
Direct immunofluorescence for IgA, IgG, IgM, C1q, kappa, and lambda: Negative.
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