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Case 3: Discussion

Needlestick injuries often involve a source patient whose HIV serostatus is not known. Initial management of a potential exposure to HIV should include immediate decontamination of the region involved in the exposure and immediate evaluation for possible postexposure prophylaxis (PEP)[1]. In the circumstance when the HIV serostatus of the source patient is not known, the important decision of whether or not to initiate PEP can be very difficult. The new rapid and accurate OraQuick fingerstick HIV-1 antibody test[2] can provide results within 30 minutes and thus play an important role in these situations. The Single Use Diagnostic System (SUDS) HIV-1 antibody test is considered moderately complex and results generally take about 30 minutes. Positive results from either the Oraquick or SUDS test should be confirmed with conventional HIV antibody testing.

Initial Approach When Source HIV Status Unknown

If the source patient agrees to undergo HIV antibody testing (and rapid HIV antibody testing can be performed immediately), the result of this rapid test can guide initial decision-making regarding PEP. If, however, rapid HIV testing cannot be performed immediately, decision-making regarding PEP should proceed in the absence of results, because any delay in starting PEP could compromise its efficacy. Testing of the needle or other sharp involved in the injury for the presence of HIV is not recommended because the accuracy of such testing has not been established. If the source patient is not present for immediate HIV antibody testing, he or she should undergo HIV testing as soon as possible. Similarly, if the source patient is present, but a rapid HIV test is not available, a standard HIV antibody test should be performed. Even when results are not immediately available, they can subsequently help to determine whether or not to continue PEP.

In situations where the HIV serostatus of the source patient cannot be ascertained rapidly, decision-making regarding PEP hinges largely on whether the source patient has any known HIV risk factor, such as a history of injection drug use or high-risk sexual activity. Most experts would recommend starting PEP if the source patient has any known HIV risk factor. If the source patient is perceived to be unreliable or is not able to provide a history, then the initial decision on whether or not to offer PEP may depend in part on the prevalence of HIV in that region. In some instances, a needlestick injury may occur and the source patient is not known. For example, this scenario may occur when a health care worker reaches up to a needle disposal and is stuck by a needle protruding from the box, or a needlestick occurs with a needle left sitting out in a procedure room. In these situations, recommendations may also depend on the local prevalence of HIV. Expert consultation is recommended for exposures in which the source patient is not known[1].

Selection of a PEP Regimen

Details regarding the initial management of the exposure, the timing of PEP, resources for expert consultation, and the follow-up of the health care worker, including counseling, serologic testing, and monitoring for medication-related toxicity are outlined in Case 2 in this Postexposure Prophylaxis section. The 2005 U.S. Public Health Service guidelines for the management of occupational exposures to HIV classify PEP regimens as either "basic" or "expanded" (Figure 1Preferred Basic Regimens, Alternative Basic RegimensPreferred Expanded Regimen, Alternative Expanded RegimensRegimens Not Recommended, Regimens Recommended Only with Expert ConsultationAcknowledgments). These guidelines recommend considering a basic, 2-drug PEP regimen for percutaneous exposures involving a source patient whose serostatus is not known, but who is perceived to be at risk for HIV infection (Figure 2)[1]. Since the serostatus of the source patient should become available within 24-48 hours, many experts would recommend initiating therapy with a 3-drug expanded regimen and then discontinuing therapy if the source patient's HIV test is negative.

Duration of PEP

Postexposure prophylaxis is typically administered for 28 days[1], based on previous experience with zidovudine PEP as well as animal studies that have shown better efficacy with 28 days compared with shorter duration of therapy[3,4]. If, however, the health care worker initiates PEP shortly after the exposure, but subsequent testing reveals that the source patient is not infected with HIV, the 2001 U.S. Public Health Service guidelines recommend the health care worker promptly discontinue PEP[1].

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    Figure 1: Recommended Postexposure Prophylaxis Regimens<br /> Image 1. Preferred Basic Regimens, Alternative Basic Regimens.
    Figure 1

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    Figure 2. 2005 U.S. Public Health Service HIV Postexposure Prophylaxis Recommendations for Percutaneous Injuries with Unknown Source Infection Status

    This figure was adapted from Panlilio AL, Cardo DM, Grohskopf LA, Heneine W, Ross CS; U.S. Public Health Service. Updated U.S. Public Health Service guidelines for the management of occupational exposures to HIV and recommendations for postexposure prophylaxis. MMWR Recomm Rep. 2005;54(RR-9):1-17.

    Figure 2