Are there any special clinical features of HIVAN that may help in establishing this diagnosis from others?
There are two additional clinical findings (other than race) that are often reported to favor a diagnosis of HIVAN as opposed to the other types of glomerular disease.
The first is the absence of hypertension in the setting of kidney disease and proteinuria. Typically, FSGS and the glomerulopathies related to viral hepatitis (HCV or HBV), HIVICK, or diabetes are associated with moderate to marked hypertension, but not HIVAN.
Patients with HIVAN have unexpectedly normal blood pressure because of the presence of vasodilatory cytokines that are produced in response to the HIV infection, and a salt-losing state in the kidney, which is also related to active HIV infection. More than 80% of patients with HIVAN have normal blood pressures in the setting of significant kidney injury.
Based on these data, the presence of hypertension in a patient with HIV with kidney disease should prompt a reconsideration of the diagnosis of HIVAN to an alternative etiology.
The second suggestive feature that may point to HIVAN is the presence of large echogenic kidneys on ultrasound. Most patients with nephrotic syndrome and progressive CKD will have loss of kidney size and mild echogenicity due to interstitial fibrosis. In HIVAN, the presence of microcystic dilation may result in larger than expected kidney size at any level of kidney function, and the degree of echogenicity is significantly more than that seen in other kidney lesions. Since HIVAN may increase the size and echogenicity of the kidneys and HIVICK will not, many studies that question the predicative reliability of these findings in HIV patients may be biased, because the patient population may be a mixture of these two diagnoses. Therefore the initial evaluation by ultrasound of a patient with HIV with proteinuria may already lead to a tentative diagnosis of HIVAN if these characteristic findings are reported. The ultrasound radiologist may be the first one to suggest a differential diagnosis of HIVAN based on these characteristic findings.
