Sunday, December 4, 2011

Renal disease and HIV

Perhaps the most renowned renal disease associated with HIV infection is the collapsing variant of FSGS. This typically presents with the nephrotic syndrome and has been associated with relatively advanced HIV infection, with low CD4 counts and higher viral loads. HIV infection of tubular cells may play a direct role in the pathogenesis, with some supporting evidence from animals studies in which transgenic mice were created with HIV constructs in their genome – they developed proteinuria and similar histological findings of collapsing glomerular tufts and interstitial disease. Hypertension appears to be less common, possibly due to an association with salt wasting.

In addition there are many other renal diseases that can be associated with HIV infection, its treatment or associated conditions. An interesting review can be found here.

Below are some of the differentials on that long list:

Many of the anti-retrovirals have been associated with nephrotoxicity in various forms. Further information can be found on previous posts.

Similarly, various antibiotics and other anti-microbials used to treat or prophylaxis this population must be kept in mind (e.g. Bactrim, amphotericin, pentamidine etc.). Another potential problem over the longer term is the diabetogenic potential from various protease inhibitors.

Co-infection with other diseases, particularly HBV and HCV should be investigated. This opens a whole other list of differentials in terms of renal disease – e.g. membranous associated with HBV and syphilis; cryoglogulin and membranoproliferative disease associated with HCV. An immune complex mediated disease with predominance of IgA has also been described, as have various forms of lupus like clinical cases.

One other rare consideration is thrombotic thrombocytopaenic purpura, which may result from HIV induced endothelial injury.

Just some of the differentials to keep in mind when asked to see a patient with kidney disease and HIV infection.

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