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CASE 177 (November 2020)

Clinical information

A 17-year-old girl was admitted to the emergency department for diarrhea and weakness. The onset of the disease was five days prior to the admission with anorexia and diarrhea. On physical examination, the girl was dehydrated and ill-appearing, with a normal body temperature, heart rate of 100 beats/min, blood pressure of 90/60 mm Hg, and oxygen saturation of 95%.

Laboratory work-up showed anemia (Hb: 6.8 g/dL), thrombocytopenia (platelet count 48.000/uL), increased serum creatinine: 3,4 mg/dL, BUN: 68 mg/dL; lactate dehydrogenase (LDH) 1250 U/L. Serum complement: normal. Peripheral blood smear showed schizocytes. Tests for viruses: negative.

Due to some doubts about the diagnostic possibilities, and raising some differential diagnoses, the treating team decided to take a kidney biopsy. Look at the photomicrographs.

Figure 1. H&E, X100. Some normal-appearing glomeruli and others altered.

Figure 2. Masson's trichrome stain, X200.

Figure 3. H&E, X400.

Figure 4. Masson's trichrome stain, X400.

Figure 5. Masson's trichrome stain, X400.

Figure 6. PAS, X400.

Figure 7. Methenamine-silver stain, X400.

Figure 8. Methenamine-silver stain, X400. Ischemic changes.

Figure 9. Electron microscopy, original magnification, X4,000. Identify the glomerular basement membrane; Observe the capillary lumen obstructed and occupied by amorphous, granular material, with electron-dense material that may correspond to detritus; loss of endothelial fenestrations.

Figure 10. Electron microscopy, original magnification, X4,000. Again, identify the basement membranes of two capillaries, thin on the left, thick and irregular on the right, with podocyte damage, swollen endothelium; electron-dense granules (like "black balls") that correspond to lysosomes in the cytoplasm of an endothelial cell, due to endocytosis of something that it is not possible to define what it is.

Direct immunofluorescence for IgA, IgG, IgM, C3 and C1q: Negative.

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