CASE 164 (October 2019)
The patient is a 64-year-old woman with a history of chronic HTA and non-insulin-requiring diabetes mellitus, well controlled. It is evaluated by presenting a month of general malaise and progressive edema. Elevation of serum creatinine is documented: 4.8 mg/dL (previous 1.2 mg/dL, 6 months before). She has not received any medications other than those used to treat hypertension and diabetes. She does not describe changes in the urine.
Paraclinics: Hb: 11.3 mg/dL, hematocrit: 31%, platelets: 250,000/mm2. Normal leukogram. ESR: 29 mm/h. BUN; 72 mg/dL ANAs: Negative, C3: 106 mg/dL, C4; 14 mg/dL. ANCA: negative. Uroanalysis: erythrocytes: countless, leukocytes: 8-10/hpf. Proteinuria: 1.2 g/24h. Studies for viruses: negative.
With presumptive diagnosis of rapidly progressive glomerulonephritis, renal biopsy is performed. Look at the images.
Figure 1. Masson's trichrome stain, X100
Figure 2. Methenamine-silver stain, X200.
Figure 3. H&E, X200.
Figure 4. H&E, X400.
Figure 5. Methenamine-silver stain, X400.
Figure 6. Methenamine-silver stain, X400.
Figure 7. Masson's trichrome stain, X400.
Figure 8. Masson's trichrome stain, X400.
Figure 9. Direct immunofluorescence for IgG, X400.
Figure 10. Direct immunofluorescence for C3, X400.
Figure 11. EM, original magnification, X2,500.
Figure 12. EM, original magnification, X2,500.
Direct immunofluorescence for IgA, IgM, and C1q: negative. Kappa, and lambda: immunostaining similar to IgG.
What is your diagnosis?