Differential Diagnosis of Renal Dysfunction and HIV

Tubular Microcyst with Proteinaceous cast

This week we had an interesting patient that present several months ago with HIV/AIDS with very low CD4 count off HAART for the last several years. The patient presents with nephrotic syndrome with lower extremity edema, normal renal function, and 13 grams proteinuria/day. Renal biopsy was done and showed membranoproliferative pattern with “full house” of immune complexes with IgA, IgG, and IgM, as well as C1q. We decided that this was HIV associated MPGN and referred to ID for initation of HAART therapy. The patient present to clinic for f/u one several months later with viral load in the 50s and CD4 of 250. So we decided to re-evaluate our diagnosis as patient still has 3 grams of proteinuria despite a decreased viral load with therapy. So here is a review of the differential diagnosis or renal dysfunction in patients with HIV, to help you not fall into the trap of HIV + kidney disease = HIVAN (FSGS, collapsing variant). Of course we see collapsing variant of FSGS in patients of African descent, nephrotic proteinuria, high viral load and CD4 count < 200. If HIV RNA is less 400 copies/ml another diagnosis is likely, see below.

Glomerular

Collapsing FSGS glomerulopathy
Immune complex GN
Thrombotic microangiopathy (TMA)
Membranoproliferative GN
Membranous nephropathy
Fibrallary and immunotactoid glomerulopathies
Amyloid (AA) nephropathy
Minimal change disease

Tubular

ATN
Proximal tubule injury (Fanconi syndrome)
Diabetes insipidus
Chronic tubular injury
Crystalluria with nephropathy
- Seen with indinavir, atazanavir;sulfadiazine, cipro, and rapidly infused IV acyyclovir

Interstitial

Interstitial nephritis

As seen above antiviral therapy can nephrotoxic itself. Specifically the classes of Protease Inhibitors , Reverse Transcriptase Inhibitors, and cidofovir/adefovir.

Adrian

Differential Diagnosis of Renal Dysfunction and HIV