HIV-associated nephropathy

HIV-associated nephropathy (HIVAN) is commonly seen in patients with HIV/AIDS, and leads to end stage renal disease (ESRD). The diagnosis is not imaging based and must be confirmed by renal biopsy.

Epidemiology

HIVAN is seen in patients at advanced stages of HIV and AIDS, but it can also be seen in those with less advanced disease. There is a strong association between HIVAN and black race pointing to host genetic factors ¹. 

Clinical presentation

• advanced HIV disease (although it is seen in patients with less advanced disease and acute HIV infections)
• heavy proteinuria
• rapid decline in renal function
• other manifestations include haematuria, hypertension and oedema

Pathology

Infection of kidney epithelial cells with HIV, and expression of HIV genes within those cells. Characterised by collapsing focal sclerosing glomerulosclerosis  accompanied by microcystic tubular dilatation and interstitial inflammation. Diagnosis is made by renal biopsy.

Histology

Basement membrane collapse with obliteration of glomerular capillary lumina. There is hypertrophy and hyperplasia of overlying glomerular epithelial cells.

Radiographic features

Imaging is only suggestive of HIVAN, diagnosis is based on histology sample from renal biopsy.

USUltrasound

Longitudinal renal size is increased. There is increased parenchymal echogenicity and decrease in the amount of renal sinus fat. Findings reflect renal oedema.

CT

CT findings are not well described but as with US are a reflection of renal oedema and include:

• enlarged kidneys
• hyperattenuation of medulla on the unenhanced scan
• striated nephrogram

Treatment and prognosis

Patients should be offered highly active antiretroviral therapy (HAART).

Prognosis is poor with patients (even those on HAART) developing ESRD. ESRD can be managed with renal dialysis.

Transplantation is an option for patients but there is  risk of HIVAN recurring in the transplanted kidney. 

Differential diagnosis

Multiple differential diagnosis are available for the imaging findings of renal oedema. The striated nephrographic appearance can also be seen in mycobacterium avium-intracellulare infection.