CASE 218 (April 2024)

Clinical information

A 58-year-old man presented trauma from a fall on a bicycle with a fracture of the tibia and fibula, which was treated surgically, presenting weeks later infection of the surgical wound, as well as an increase in serum creatinin: 1.9 mg/dL, with microhematuria and proteinuria of 2.3 g/24 hours. Serum supplement: C3: 52 mg/dL (88-180), C4: 15 mg/dL (12-39). ANA, anti-DNA and ANCA: negative. HIV and liver viruses: negative.

Look at the images of the kidney biopsy.

Figure 1. H&E, X400.

Figure 2. H&E, X400.

Figure 3. H&E, X400.

Figure 4. Masson's trichrome, X400.

Figure 5. Methenamine-silver, X400.

Figure 6. Direct immunofluorescence for IgA, X400. Positivity with "lumpy-bumpy" appearance.

Figure 7. Direct immunofluorescence for C3, X400.

Figure 8. Electron microscopy, original magnification, X4,000. Note subepithelial electron-dense deposits..

Figure 9. Electron microscopy, original magnification, X4,000. Note the large, subepithelial deposit in the central part of the image. Do you remember what this type of deposit is called?

Immunofluorescence for IgG, IgM and C1q: Negative; kappa and lambda: both similar to IgA.

What is your diagnosis?

See diagnosis and discussion

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