Characteristics of patients with HIV and biopsy-proven acute interstitial nephritis

The objective of this study was to describe the characteristics of patients with HIV infection and biopsy-proven acute interstitial nephritis (AIN).

Pathology reports were reviewed for patients who had HIV infection and underwent renal biopsy at Johns Hopkins Hospital from January 1, 1995, through January 1, 2008. Patients who received a diagnosis of AIN without evidence of HIV-associated nephropathy were identified, and their clinical course was reviewed up to 18 months after biopsy.

Of 262 biopsies, 29 (11%) patients who had AIN without evidence of HIV-associated nephropathy were identified. The mean age at the time of biopsy was 47.5 years (range 28 to 71 years), 17 (59%) were men, and 23 (79%) were black. The majority (62%) of patients were on antiretroviral therapy, 59% were current or former intravenous drug users, and 62% had hepatitis C co-infection. Drugs were identified as the cause of AIN in the majority (72%) of cases. Nonsteroidal anti-inflammatory drugs were most commonly implicated, followed by sulfamethoxazole/trimethoprim. Antiretroviral therapy was identified as the cause in only three cases. None of the patients presented with the classic triad of fever, rash, and pyuria, and only seven (24%) patients presented with <1 g/d proteinuria.

In our series, AIN was prevalent (11%) and was often drug induced. AIN should not be excluded from the differential diagnosis on the basis of absence of the classic clinical triad of fever, rash, and pyuria.