HIV Infection: Recognition, Risk Stratification, and Post-Exposure Prophylaxis in Emergency Medicine - Part Two
HIV Infection: Recognition, Risk Stratification, and Post-Exposure Prophylaxis in Emergency Medicine
Part II: Drug Therapy, Assessment, and Prophylaxis
Authors: Dawn Demangone, MD, FAAEM, Assistant Professor of Medicine, Assistant Residency Director, Co-Director, Graduate Medical Education, Temple University Hospital and School of Medicine, Philadelphia, PA; and Betsy Schrader, MD, Division of Emergency Medicine, Temple University Hospital, Philadelphia, PA.
Peer Reviewer: Sid M. Shah, MD, FACEP, Assistant Residency Director of Research, Sparrow/Michigan State University Emergency Medicine Residency Program, Ingham Regional Medical Center, Lansing, MI.
The risk of occupational exposure to human immunodeficiency virus (HIV) remains a concern among health care workers. Despite the risks, a significant percentage of health care workers fail to comply with universal precautions. To minimize transmission of HIV in occupational settings, evaluation and treatment protocols have been established according to size of inoculum and titers. A careful consideration of these and other factors will determine the potential usefulness of antiretroviral therapy. Non-occuptational exposures may be more difficult to evaluate, and there is less consensus about the effectiveness of post-exposure prophylaxis.
This second part of a two-part series will present a systematic approach for evaluating exposures to HIV and risk-stratifying patients according to their need for pharmaco-propylaxis. In this issue, specific regimens are discussed and potential complications, drug toxicities, and interactions are highlighted.
— The Editor
Pharmacotherapy for HIV: Protocols, Side Effects, and Adverse Events
Nucleoside Reverse Transcriptase Inhibitors (NRTIs). Medications in this drug class inhibit viral reverse transcriptase, thus preventing or interfering with the production of a DNA copy of the viral RNA, therefore, preventing its replication and/or ultimate insertion into the host cell genome following infection.4 Intracellular activation is required for nucleoside reverse transcriptase inhibitor (NRTI) effectiveness. Medications in this class primarily are metabolized through renal mechanisms.2,5 Current regimens frequently include one or two medications from this class; however, stavudine and zidovudine (ZDV) should not be used concurrently because of antagonistic activities.6 Some side effects are common to all medications in this group, and drug-specific side effects can occur. (See Table 1.)1-4
| Table 1. Side Effects of NRTIs1-4 | |
| Medication | Side Effects |
| Zidovudine (AZT, ZDV, Retrovir) | |
| Headache, Insomnia, Asthenia, Bone Marrow Suppression (anemia +/- neutropenia), Lactic acidosis with hepatic steatosis, Myopathy | |
| Didanosine (DDI, Videx) | |
| Peripheral neuropathy, Pancreatitis, Nausea, Diarrhea, Lactic acidosis with hepatic steatosis, Retinal depigmentation | |
| Zalcitabine (DDC, Hivid) | |
| Peripheral neuropathy, Pancreatitis, Stomatitis, Rash, Lactic acidosis with hepatic steatosis, Esophageal ulceration, Fever | |
| Stavudine (D4T, Zerit) | |
| Peripheral neuropathy, Pancreatitis, Transaminitis, Agitation | |
| Lamivudine (3TC, Epivir) | |
| Peripheral neuropathy, Pancreatitis, Nausea | |
| Abacavir (Ziagen) | |
| Nausea, Headache, Hypersensitivity syndrome | |
Peripheral neuropathy can occur with some of the NRTIs. Interestingly, there is a correlation with disease stage and development of peripheral neuropathy (i.e,. those with more advanced disease have a greater likelihood of developing this side effect).6 Symptoms begin as distal extremity numbness or burning, which can progress to a constant, severe burning sensation, or intermittent, sharp shooting pains.6 Hepatic steatosis and lactic acidosis also can occur with this group of medications.2
Of special note is that abacavir has been associated with a drug-specific side effect that must be recognized by the emergency physician. Two percent of patients treated with abacavir develop a potentially fatal hypersensitivity reaction.7 Misdiagnosis or delaying diagnosis can allow continuation or re-introduction of this medication in the patient’s treatment regimen, which can have life-threatening implications. Patients can develop more severe symptoms within hours that may include life-threatening hypotension and death.2,7 Presentations can vary, but any patient on abacavir with fever, rash, fatigue, respiratory symptoms, or gastrointestinal (GI) symptoms (nausea, vomiting, diarrhea, abdominal pain) should discontinue the drug as soon as hypersensitivity reaction is considered. Such cases should be reported to the ABC Hypersensitivity Registry at 1-800-270-0425.2,3,6,7
Respiratory symptoms recently have been recognized as a presentation of hypersensitivity reaction. Approximately 20% of patients with a hypersensitivity reaction to abacavir experience cough, dyspnea, or pharyngitis.7 It should be noted that patients have died after being initially diagnosed with an acute respiratory illness, such as bronchitis, pneumonia, or flu-like illness, rather than hypersensitivity reaction to abacavir.7 (See Table 2.)4,7-9
| Table 2. Symptoms Associated with Abacavir Hypersensitivity Reaction |
|
• Fever • Skin rash • Fatigue • Gastrointestinal symptoms Nausea Vomiting Diarrhea Abdominal pain • Respiratory symptoms Pharyngitis Dyspnea Cough |
Non-Nucleoside Reverse Transcriptase Inhibitors (NNRTIs). Medications in this class directly bind viral reverse transcriptase, preventing transcription of viral RNA into DNA copies.6 Metabolism of NNRTIs is largely via the cytochrome p450 system, which must be considered when prescribing other medications metabolized in the same manner. Resistance quickly develops to the NNRTIs through viral mutations; consequently, they are only recommended as part of combination therapy, and never in combination with each other.3,6 The most common side effect of the NNRTIs is a maculopapular rash that typically is self-limited.3 Between 1.7% and 7% of patients taking NNRTIs discontinue the medication due to the rash. Stevens-Johnson syndrome has been associated with NNRTI use on rare occasions.2 (See Table 3.)
| Table 3. Side Effects and Contraindicated Drug Interactions of NNRTIs2,3 | ||
| Side Effects | Drug Interactions | |
| Nevirapine (Viramune) | ||
| Rash | Protease inhibitors | |
| Nausea | Rifampin rifabutin | |
| Transaminitis | Oral contraceptives | |
| Hepatitis | Triazolam, midazolam | |
| Delavirdine (Rescriptor) | ||
| Rash | Terfenadine, astemizole | |
| Nausea | Alprazolam, midazolam, triazolam | |
| Transaminitis | Rifampin, rifabutin, Ergot derivatives, Amphetamines, Nifedipine, Anticonvulsants, Cisapride | |
| Efavirenz (Sustiva) | ||
| Altered dreams | Astemizole, cisapride | |
| Dizziness | Midazolam, triazolam | |
| Somnolence | Ergot derivatives | |
| Insomnia Transaminitis Impaired concentration Confusion Hallucinations Amnesia |
||
Protease Inhibitors. Protease inhibitors (PIs) appear to be the most potent anti-retroviral medications.3 These drugs prevent precursors of viral proteins from being activated into mature, potentially infective viral proteins.4,6 Metabolism is via the cytochrome p450 system, and again, care must be taken when prescribing other medications metabolized by this mechanism. Carefully following dosing schedules for these medications is especially important, as resistant mutations have been associated with low trough levels.3
Fat redistribution and abnormal metabolism of lipids and glucose are side effects common to all PIs.2,6 Fat may accumulate at the base of the neck, or in the abdomen or mesentery. Terms such as "protease paunch" or "crix belly" have been coined to describe this side effect. Women may experience an increase in breast size. Losses of fat occur in the arms, legs, and face. It is unclear whether these effects are reversible with discontinuation.3 Additionally, all PIs can increase bleeding in hemophiliacs.2
Indinavir is associated with nephrolithiasis in 3-5% of patients. Typically, the symptoms develop after taking indinavir for approximately 18 weeks. Patients may present with dysuria and urgency or with symptoms suggestive of renal colic, although they may or may not have evidence of stones. Drinking 1.5-2.0 liters of water daily is encouraged to prevent crystallization of indinavir in the urine.3
Drug Interactions. Drug interactions frequently occur with the anti-retroviral medications. Although absolute contraindications for drug interactions are listed in Table 4, many other interactions also exist. Before adding any medications to the regimen of patients on anti-retroviral therapies, consultation with their primary care physician or a pharmacist is prudent.
| Table 4. Side Effects and Contraindicated Drug Interactions of Protease Inhibitors2-4,32 | |||
| Side Effects | Use Contraindicated With | ||
| Saquinavir (Fortovase) | Headache | Rifampin, rifabutin | |
| Transaminitis | Terfenadine, astemizole | ||
| Hyperglycemia | Cisapride | ||
| Fat redistribution | Ergot alkaloids | ||
| Lipid abnormalities | Triazolam, midazolam | ||
| Diarrhea | |||
| Abdominal Pain | |||
| Dyspepsia | |||
| Nausea | |||
| Ritonavir (Norvir) | Nausea, vomiting | Amiodarone, encainide, flecainide | |
| Diarrhea | Propafenone, quinidine | ||
| Peri-oral paresthesias | Astemizole, terfenadine | ||
| Extremity paresthesias | Bepridil | ||
| Hypertriglyceridemia | Bupropion | ||
| Taste changes | Cisapride | ||
| Fat redistribution | Clozapine, clorazepate | ||
| Transaminitis | |||
| Hepatitis | Triazolam, flurazepam, zolpidem | ||
| Hyperglycemia | Meperidine, piroxicam | ||
| Asthenia | Propoxyphene | ||
| Indinavir (Crixivan) | Nausea | Astemizole, terfenadine | |
| Hyperbilirubinemia | Cisapride | ||
| Nephrolithiasis | Triazolam, midazolam | ||
| Fat redistribution | Ergot alkaloids | ||
| Hyperglycemia | |||
| Headache | |||
| Dizziness | |||
| Rash | |||
| Metallic taste | |||
| Thrombocytopenia | |||
| Blurred vision | |||
| Nelfinavir (Viracept) | Nausea | Astemizole, terfenadine | |
| Diarrhea | Cisapride | ||
| Hyperglycemia | Triazolam, midazolam | ||
| Ergot alkaloids | |||
| Amprenavir(Agenerase) | Nausea | Astemizole, terfenadine, Cisapride, Triazolam, midazolam, Ergot alkaloids | |
Evaluating and Managing Exposures to HIV
Occupational Exposure. Health care workers are at risk for exposure to HIV. Standard (universal) precautions for all health care workers are strongly encouraged to prevent acquisition of HIV and other blood-borne pathogens. However, not all health care workers may be fully aware of or regularly comply with standard precautions. One Level-1 trauma center presented a questionnaire to its emergency department (ED) staff (physicians, nurses, and technicians) and found personnel were not knowledgeable of risks for blood-borne pathogen infection, did not report all exposures, and were not compliant with universal precautions.11 Other studies have shown similar findings, with rates of physician compliance with universal precautions ranging between 54% and 94%, with 44% of physicians reporting that they do recap needles contaminated with blood.9
Among surveyed emergency medicine residents, only 36.6% always followed standard precautions, 54% frequently followed them, and 9.4% sometimes, rarely, or never followed them.12 One group has suggested barrier precautions for all but the most uncomplicated procedures performed in the ED. Face protection should be considered during invasive procedures, such as lumbar puncture or examination of the bleeding patient, since face splashes are not uncommon.13
Risk Factors for Occupational Transmission. Needle stick injuries can occur any time a needle is used or exposed, and in fact, needle stick injuries account for 80% of reported occupational exposures.14 One group studied the effect of time into shift on exposure rate and found higher exposure rates during the first hour and last two hours of a shift among the workers in their hospital.15 Following standard precautions and infection control recommendations could prevent a significant number of exposures.
Some activities that appear to be particularly dangerous for injury include recapping needles, improper disposal of used needles, and transferring body fluids between different containers.16 Of 326 needle stick injuries in one study, 17% occurred during device use and 13% during disposal or after disposal. The great majority (70%) occurred after use, but before disposal. Recapping needles accounted for 17.8% of injuries. Contact of a used needle that had penetrated through the cap accounted for another 12.3% of injuries. Exposed needles left on working surfaces were contacted after use for 10.7% of injuries, and 8.9% contacts occurred with used needles protruding from trash.17 In addition, one group found that the risk of injury was further influenced by the type of device being used. Particularly, devices that required disassembly had increased risks. It appears that special care should be taken when disassembling and disposing of equipment.17
Institution of needles with safety devices has been shown to lower the number of percutaneous injuries.17-20 One group reported that 83% of needle sticks from hollow bore needles could be prevented by using protective devices.21 Safer needle devices have been created in an attempt to minimize potential health care worker contact with the needle. These devices should provide a permanent barrier between the health care worker and the needle, keep workers hands behind the needle at all times, remain in effect after disposal, and be simple to use. Other devices, such as blunt needles and pre-penetrated intravenous catheter tips, also are useful for diminishing risk of injury.22
Compliance with these measures, in addition to following standard precautions, can reduce the health care worker’s risk of injury, but cannot eliminate risk completely. Other factors that are not always the health care worker’s control can contribute to exposures to blood and body fluids. One study found that latex gloves can leak, exposing health care workers’ skin to blood or other body fluids. They also found increased glove perforations when gloves were worn for longer periods, used during critical care procedures, or worn during more than one procedure.23
After an exposure, health care workers should report the contact to the employee health service. Studies have found frequent underreporting. One study found that 70% of surgeons never or rarely reported their needle stick injuries, despite an average of 11 needle sticks every three years.24 Among surveyed emergency medicine residents, 56.1% had at least one significant exposure during their training, and only 46.7% of the most recent exposures had been reported.12
According to the Centers for Disease Control and Prevention (CDC) HIV/AIDS surveillance report that was published in 1997, there were 52 documented cases of HIV seroconversion after occupational exposure to the virus, with an additional 114 cases of seroconversion possibly due to an occupational exposure.25 Again, the most effective way to prevent transmission of HIV is by primary prevention or avoiding percutaneous, mucous membranes, or non-intact skin exposure by using standard precautions.26
It has been estimated that the average risk of HIV seroconversion after a percutaneous exposure is 0.3%, and average risk after a mucous membrane exposure is 0.09%.21,27 The actual risk of seroconversion after an exposure, however, is dependent on many factors. An increased risk of transmission was noted with exposures that involve deep injuries, injuries with a device contaminated with visible blood, or injuries involving a procedure in which a device is placed directly into an artery or vein of the source patient.28 It also has been shown that exposures involving blood from a patient with terminal AIDS carries an increased risk of transmission.29
Post-Exposure Management. After an exposure has occurred, the use of medications for post-exposure prophylaxis (PEP) may reduce the risk of seroconversion. Although there have been no prospective, randomized studies proving the effectiveness of PEP in reducing the rate of seroconversion, use is based on animal and human studies. Some animal studies have shown the use of ZDV as PEP was successful in preventing infection.29 In addition, a prospective trial has proven that the use of ZDV during pregnancy, labor, and delivery decreases the risk of maternal-fetal transmission by 67%.30 A retrospective case-control study reviewing seroconversion in health care workers after an exposure showed an 81% reduction in the odds of HIV infection by those who took ZDV as PEP.28
In 1996, the Public Health Service (PHS) interagency, comprised of representatives from the CDC, FDA, and National Institutes of Health, published recommendations for PEP for health care workers with occupational exposures to HIV.31 In 1998, the PHS revised the recommendations in light of emerging data and new medications.26 The following is a summary of the recommendations.
Step 1. The first step is evaluating the exposure incident for risk of transmission. There is a risk of transmission if the health care worker is exposed to blood, body fluids containing visible blood, semen, vaginal secretions, cerebrospinal fluid, synovial fluid, pleural fluid, peritoneal fluid, pericardial fluid, or amniotic fluid.26 If the exposure occurred to intact skin, no PEP may be required. Exposures that occur to mucous membranes or non-intact skin that involve a small amount of body fluid or a short duration of exposure are considered small inoculums exposures. Those involving a large amount of body fluid or a long duration of exposure to mucous membranes or non-intact skin are considered moderate inoculums exposures. Percutaneous injuries with solid needles or those resulting in superficial scratches are moderate inoculums exposures, and those involving hollow-bore needles and deep injuries are large inoculums exposures.29 (See Figure 1.)
Step 2. The second step in evaluating an occupational exposure to HIV is determining the status of the source patient. If the source patient is known, laboratory data, medical records, clinical symptoms, or history may determine HIV status. If consent can be obtained, the patient can be tested for HIV, but if consent cannot be obtained, further HIV testing depends upon state and local laws. If the source patient is unknown, risk of transmission should be determined by the prevalence of HIV among the population.29 If the source patient is HIV negative with no signs or symptoms of the disease, no further testing is required and PEP is not necessary. It has not yet been determined whether further testing should be performed on source patients with recent potential exposures to HIV. If the source patient is HIV positive, patients with high CD4 + T cell counts who are asymptomatic are considered low titer exposures. Exposures to patients with end-stage AIDS, low CD4+ T cell counts, and high viral loads are considered high titer exposures.29 (See Figure 2.)
Step 3. The third step in determining an appropriate PEP regimen involves comparing the exposure risk with the HIV status of the source patient. Exposures that are considered small inoculums, low-titer exposures are not associated with a risk of transmission and may not require PEP. Small inoculums, high-titer exposures are associated with a relatively low risk of transmission.In these cases, a basic PEP regimen should be considered. The basic regimen for adults consists of four weeks of ZDV 600 mg daily in divided doses and lamivudine 150 mg twice a day. Most commonly, health care workers experience moderate inoculums, low-titer exposure. This type of exposure requires the basic PEP regimen. Injuries associated with a higher risk of transmission, which include moderate inoculums, high-titer exposures, and large inoculums with either low- or high-titer exposures require an expanded PEP regimen. The expanded regimen consists of the basic regimen plus either indinavir 800 mg every eight hours or nelfinavir 750 mg three times a day. Indinavir should be taken on an empty stomach with increased fluid intake, and nelfinavir should be taken with meals.29
Initiation of Therapy: Timing and Special Considerations. PEP medications should be started immediately after an exposure. This recommendation is based on information suggesting that there is a short period between exposure to the virus and replication within its target cells. Animal studies have shown a decrease in transmission of HIV when PEP was given within 24 hours of exposure, but no difference was seen when given after 72 hours. Since no data are available on humans, PEP should still be given even up to two weeks following an exposure with a high risk of transmission.29 (See Table 5.)
Certain situations require special consideration when choosing a PEP regimen. Exposure to drug-resistant HIV may effect which medications are chosen. Avoid medications to which the virus may have developed resistance. If the virus is resistant to one class of medications, the use of a medication in another class may be warranted. Also, consider using a third or fourth drug until expert consultation can be obtained.67
Another group requiring special consideration is the pregnant health care worker. The pregnant health care worker should make an informed decision about PEP based on information about what is known and not known about the risks and benefits of PEP, the potential risks to the fetus, and the risk of transmission of HIV. Information on the medications and their usage in pregnancy should be relayed to the health care worker. ZDV has been used in pregnancy, and data suggest that there are no short-term risks associated with its use.
Data on long-term risk, as well as short- and long-term risks of lamivudine are limited. The dosages for ZDV and 3TC are the same in pregnancy. The use of protease inhibitors in pregnancy has not yet been studied, but many HIV-positive pregnant women on aggressive antiretroviral therapy continue on these drugs or resume them during pregnancy, so data should be forthcoming.29
HIV testing for all health care workers with an exposure should occur at the time of exposure and at six weeks, 12 weeks, and six months post exposure. There is no clear recommendation as to whether 12-month follow-up is beneficial, but it may considered in health care worker’s who receive highly potent PEP regimens or who also were exposed to Hepatitis C. If the health care worker experiences symptoms consistent with acute retroviral syndrome (ARS), repeat testing should be performed. Although no prospective, randomized trials have proven the effectiveness of PEP, its benefits often outweigh the risks when used after an occupational exposure to HIV. If the clinician is unsure which PEP medications to give, it is recommended to start ZDV and 3TC immediately rather than to delay treatment. For questions regarding medications or special situations, consultation may be obtained through the National Clinicians Post-Exposure Prophylaxis Hotline at 1-888-448-4911.29
Non-Occupational Exposure
Emergency physicians are likely to encounter patients inquiring about PEP following non-occupational exposures, particularly as the public becomes more aware of its existence. Probably the most effective manner to prevent acquisition of HIV is to abstain from the behaviors at risk for transmission. Obviously, this message must continue to be emphasized as the primary means to prevent acquisition, and should never be replaced by post-exposure antiretroviral therapy.
Occupational exposures actually account for very few HIV infections; the majority of infections occur through needle sharing and sexual activity. Certain high-risk behaviors, such as sharing needles and receptive anal or vaginal intercourse, carry similar or higher risks of transmission to that of occupational exposures. Many believe that since PEP has been found to be effective in preventing infection in occupational contacts,29,30,33 it also should be offered to other potential victims of similar transmission risk.34-36 Indeed, physicians do prescribe PEP for non-occupational exposures, even though no data exist on its efficacy.37 Some recommend PEP after unprotected receptive and insertive anal and vaginal intercourse with HIV+ or high-risk partners, or after receptive fellatio with ejaculation.34,35,38 However, the CDC recommends only considering therapy, not necessarily providing therapy, after unprotected receptive anal and vaginal intercourse with an HIV+ partner.37
Most advocates of PEP for non-occupational exposures support using the same medication combinations as those recommended for occupational exposures by the CDC.35,36,38,39 However, the potential risks of medication toxicity, lowered compliance with protective behaviors, and resistance development must be considered prior to beginning therapy.37,38 In addition, the same behaviors that put patients at risk for acquiring HIV also include risk for other transmissible diseases. Evaluation for hepatitis B and C (as well as other sexually transmissible diseases) and pregnancy also should be pursued.37,38,40 Behavioral modification also should be considered part of non-occupational PEP.41
The prescribing physician must carefully consider several issues, which make the decision to provide PEP for non-occupational exposures more complex than for occupational exposures. As stated above, the efficacy of PEP for non-occupational exposures has not yet been proven. Failures are known to occur with occupational exposures, and have now been reported with non-occupational exposures.8,42 It is unlikely that PEP for non-occupational exposures will ever be investigated through clinical trials because an extremely large number of participants would be required, and some argue that it is not ethical to use a placebo when treatments are known to be effective.34,35 Patients must be made aware of the unknown efficacy, and the possible risks and benefits of PEP prior to beginning treatment.38
Several questions must be considered before beginning PEP treatment. As with the health care worker with occupational exposures, perhaps the first item to address is evaluation for the risk of the exposure. The specific activity and circumstances of the contact must be elicited from the patient. Some activities actually have higher estimated risks of HIV transmission than occupational exposures. Beside the specific activity, characteristics of both the source and exposed individuals can influence the risk for transmission and should be examined.
The HIV status of the exposure source should be estimated. This information frequently is available or can be obtained in the occupational environment. Some patients with non-occupational exposures may know the status of the source, such as couples who may have experienced an isolated exposure event, but most probably will not. The local seroprevalence rates can be helpful in estimating the likelihood of a HIV-positive source.
The time from exposure also should be determined. Current occupational exposure recommendations support starting PEP for occupational exposures up to two weeks after contact but are believed to be most effective within 72 hours based on PEP efficacy animal studies.29 Several physicians currently prescribing non-occupational PEP recommend limiting the time limit to 72 hours.34,37,43 The likelihood of repeated or continued exposures should be evaluated. Occupational exposure usually is not repeated willingly, however, needle sharing and high-risk sexual contacts frequently are. Most agree that PEP has no role in the treatment of individuals likely to continue in their high-risk behaviors.34,36 Perhaps these patients would be better served by participating in educational programs that discourage high-risk exposures. Individuals with episodic exposures, such as condom slippage, sexual assault, or relapsing intravenous drug use, can be considered for PEP according to non-occupational PEP advocates.34-36
Patient compliance should be estimated. In a study of occupational exposures, 31% of individuals receiving PEP discontinued therapy due to side effects of AZT alone.44 One group reported that 75% of health care workers receiving PEP with combination therapy experienced one or more side effects. Of those health care workers with sources of unknown or HIV+ status, 47% discontinued medications due to side effects.45 The benefits of taking the medications in an otherwise healthy population may not justify the risks of the potential toxicities.36,37 Additionally, poor or sporadic compliance could lead to the development of resistance to current standard therapies. Even if taken properly, therapy can be ineffective and may select out resistant strains.37 Based on the aforementioned criteria, one study found that only one of 42 patients (or 2%) with non-occupationally acquired primary HIV infection would have qualified for receiving PEP, and in that one case, only if the patient had presented in a timely manner.43 The majority of these participants were not aware of the HIV exposure, and did not seek medical care until symptomatic. Of those infected through sexual contact, only one knew of his partner’s HIV positive status. Whether the patients were aware of the existence of PEP was not reported, but may not have made much of a difference, as few identified the specific event that allowed for disease transmission.
These authors concluded that PEP probably would not prevent significant numbers of new, non-occupationally acquired infections.43 However, as public awareness of PEP increases, more patients are likely to present for evaluation. A legitimate concern of making PEP available for non-occupational exposures is a potential increase in high-risk activities. More people may increase their high-risk activities if they are already receiving PEP, or if it is easily available and they perceive it as a "cure."35 And, since PEP is not 100% effective in preventing infection, the number of infections could actually increase.35 One study found that the recent successes in the treatment of HIV infections negatively have influenced compliance with protection during high-risk activities. Of 54 studied men who had sex with men, 15% reported they had "taken a chance of getting infected when having sex" because of the effectiveness of new treatments. Whether their attitudes were influenced by availability of PEP or the recent improvement in HIV treatment is unclear.46
Despite these findings, some believe that this is not an adequate reason to withhold therapy.36 In summary, before offering PEP, several issues must be considered. Risks and benefits of treatment must be considered. The probability that the source is HIV positive, the time from exposure, the risk of transmission via the particular exposure, and patient compliance must all be estimated.37 Additionally, baseline HIV testing, evaluation for other transmissible diseases, pregnancy evaluation, prevention counseling, and arranging follow-up care are crucial.
Rape. Offering PEP following sexual assault has been recommended by the CDC; however, no specific protocols were offered.47 Treating the victim of sexual assault poses multiple complexities. Frequently, the HIV status of the aggressor is not known. The victim may present within 72 hours of exposure, and rape typically is not a repeated behavior by the victim.40 In addition to attending to other needs of the sexual assault patient, circumstances that influence HIV transmission should be addressed. The emergency physician must assess the amount of trauma to the patient, the probability of blood and body fluid exposure, and the presence of any sexually transmitted diseases or other ulcerations. Guidelines for occupational and non-occupational exposures should be followed when evaluating and treating the victim of sexual assault for HIV transmission.40
Summary
As current anti-retroviral therapies are proving effective in prolonging lives of those infected with HIV, and as the number of HIV cases continues to increase, the likelihood of encountering HIV-positive patients in the ED is high. Recognizing the signs and symptoms associated with primary HIV infection (i.e., ARS) is important for improving patient disease course and to prevent further disease transmission. Emergency physicians must be aware of the contraindications and side effects of the currently recommended medications when evaluating patients on antiretroviral regimens. Familiarity with transmission risks is imperative for evaluating both health care workers and the general public, for potential exposure to HIV, and for potentially prescribing PEP.
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