CASE 77 (July 2012)

Clinical information

The patient is a 16-year-old man who presented 3 years ago microscopic hematuria. A urological evaluation including a pyelogram and a cystoscopy was negative. His urinalysis showed 1+ proteinuria, but not blood, and a comprehensive metabolic panel was normal with creatinine 0.4 and BUN 14. ANA, ANCA, HIV and hepatitis serologies were negative. His C3 was low: 55 (90-180) and C4 was normal: 16 (10-40). Both kidneys were normal on ultrasound. Plans were underway for a kidney biopsy, but the patient was lost to follow-up.

Since then, he has not noted gross hematuria and denies any other urinary complaints. He has not had swelling. No skin lesions, mouth ulcers, arthritis, or morning stiffness.

He was a full term infant, and had normal development. No previous hospitalizations or childhood illnesses. There is not familial history of kidney or autoimmune diseases.

The physical examination is normal.

Other laboratory tests: HCT 36.1, Hb 12,5, PLT 183.000, Liver tests normal, BUN 18 and creatinine 0,7. CBC: normal, Coomb’s negative. Urinalysis: 3-5 RBC, no WBC, and 2+ proteinuria: 591 mg/24h. CrCl: 82 ml/min.

A renal biopsy was undertaken.

Figure 1. H&E, X400.

Figure 2. H&E, X400.

Figure 3. Methenamine-silver stain, X400.

Figure 4. Methenamine-silver stain, X400.

Figure 5. Methenamine-silver stain, X400.

Figure 6. PAS, X400.

Figure 7. Immunofluorscence for C3, X400.

Figure 8. Electron microscopy. Original magnification, X6000.

Figure 9. Electron microscopy. Original magnification, X6000.

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

What is your diagnosis?

Thanks a lot to Dr. Carlos Jiménez for providing this case

See diagnosis and discussion

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