Glomerulonephritis Quiz

The answer is - MPGN - C.
The patient has a low C3, azotemia and a nephritic urine and a normal ASLO titer and a normal ANA, anti-GBM and ANCA.

17-year old female comes to your office complaining of an episode of gross hematuria. For the past 5 days she has had pharyngitis, nasal discharge, and flu-like symptoms. Over the past two days has taken 8 Bactrim tablets left over from a previous episode of bronchitis. She reports no change in her urine output.

On examination her key findings: her weight is 55 kg, Pulse-76 bpm, BP 130/80 mmHg. Heart, lungs, abdomen are normal. There is no rash or edema.

Laboratory Studies

Hb-14 g/dL, WBC-5400 (normal diff), BUN-25, creat-1.7, C3 88 (100-233), C4-28 (14-48), ASLO-200  (normal is less than 200), ANA, GBM, ANCA negative. Urine protein2.4g/24h, UA-2+ protein, 20-30 RBCs, 4-6 WBC, occasional rbc casts 

During close outpatient monitoring, blood pressure and creat remain unchanged. On follow-up 12 weeks later, laboratory studies reveal;

Bun-24, creat-1.9, C3-70, C4-20, UA- 2+protein,  3-8 RBCs, 0-4 wbcs, no casts

A renal biopsy is performed:

Which of the following is the most likely diagnosis?

A. Allergic interstitial nephritis

B. Post-strep glomerulonephritis

C. Membranoproliferative glomerulonephritis

D. IgA Nephropathy 

(Source: Dr. Brad Denker, Renal Division, Beth Israel Deaconess Medical Center/Harvard Medical School)