Case 16
With discussion
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Clinical information

The patient is a 19 year old Hispanic male. He first presented having noticed increasing ankle edema over the previous month. On examination BP was 136/85 mmHg. Chest, abdomen, and nervous system exam showed no abnormalities. There was marked pedal and pre-tibial edema.

Urinalysis showed proteinuria: >300 mg/dL; microscopic hematuria; no leucocytes, no casts; 24 hour urine protein was 13.4 g, serum albumin 3.1 g/L, serum creatinine 1.7 mg/dL; HBSAg, HCV, HIV, ANCA all negative; complement: C3: 39 (90-180), C4: 4 (10-40); antistreptolysin O (ASO): 15 Todd units/mL.

One month previous to the beginning of the symptoms he presented pyodermitis in his left leg, without antibiotic treatment; lesions spontaneously resolved one week later (and three weeks previous to the edema was noticed).

A renal biopsy was performed.

See the images.

Figure 1. H&E, X400.

Figure 2. Masson's trichrome stain, X400.

Figure 3. PAS stain, X400.

Figure 4. Methenamine silver stain, X400.

Figure 5. Methenamine silver stain, X400.

Figure 6. Immunofluorescence using antiserum to IgG, x400 (left) and IgA, x400 (right).

Figure 7. Immunofluorescence using antiserum to C3, x400 (left) and C1q, x400 (right).

Immunofluorescence for IgM was also positive (image similar to C1q microphotography).

What is your diagnosis?

See diagnosis and discussion