INTRODUCTION — Exposure to blood or other bodily fluids can cause many serious infections, including the human immunodeficiency virus (HIV, the virus that causes AIDS). While most people are not exposed to these fluids, a number of situations can arise where exposures may occur, such as finding a syringe with needle, helping an injured person, or being the victim of an assault or rape.
Experts have worked to determine the best advice for these situations. It is important to note that the guidelines are based on studies of exposures within the healthcare system, from needlestick and other exposures of healthcare workers.
Although more than 200 different diseases can be transmitted from exposure to blood, the most serious infections are hepatitis B virus (HBV), hepatitis C virus (HCV), and HIV. Fortunately, the risk of acquiring any of these infections is low. This topic review discusses the definition of exposure, the risk of infection, and treatment and follow up recommendations for non-healthcare workers.
DEFINITION OF EXPOSURE — In order to be exposed to a bloodborne pathogen, an individual must have contact with blood, a visibly bloody fluid (eg, phlegm or urine containing blood), or another bodily fluid (eg, semen or vaginal secretions) that contain a virus. The blood or fluid must come in direct contact with some part of the person's body. A virus can enter the body through the bloodstream or mucous membranes, which include the eye, mouth, or genitals. Contact with skin that is intact (without new cuts, scraps, or rashes) poses little to no risk of infection.
Thus, exposure to a bloodborne pathogen is possible after: A percutaneous (through the skin) injury such as a needlestick or cut with a sharp object Contact with a mucous membrane (including exposure through sexual intercourse, especially if an ulcer is present or trauma to vaginal tissues occurs) or non-intact skin
INFECTION AFTER EXPOSURE
Needlestick — Of the viruses that may be transmitted through the blood or bodily fluids, hepatitis B virus (HBV) is the most infectious. A healthcare worker who sustains a needlestick with blood from a known HBV-infected patient has between a 6 and 30 percent chance of developing HBV. The risk of HCV and HIV in the same situation is 1.8 and 0.3, respectively. Other factors influence the risk of becoming infected, including the amount of blood or bodily fluid involved, the depth of penetration, and the amount of virus in the source's blood or body fluid.
Mucous membrane — The risk of becoming infected from a mucous membrane exposure is more difficult to define. When healthcare workers were followed after mucous membrane exposure to HIV, no cases of HIV were identified among those who had been exposed. However, no other explanation for HIV has been found in a few cases where mucous membrane exposure occurred in a work setting. This has led most experts to believe that the risk of acquiring HIV following a mucous membrane exposure is far less than 0.3 percent, but the risk is not zero.
One versus multiple exposures — There is also a difference in terms of risk if the individual has a one-time exposure or has multiple exposures. Thus, the risk of infection for the victim of a single sexual assault is far less than that of a regular sexual partner of an infected person.
POST-EXPOSURE RECOMMENDATIONS — The first and most important measure to take following exposure to blood or bodily fluids is to wash the area well with soap and water. Crime victims are exceptions to this rule since washing may destroy important evidence for criminal prosecution. Recommendations to prevent infection after exposure depend upon the risk of a specific virus being present:
Hepatitis B — The risk of becoming infected with hepatitis B is greater than the risk of other infections. Fortunately, there is an effective vaccine that can help to prevent infection.
Hepatitis B vaccine — The vaccine may be administered to individuals who are exposed to blood, even if the blood is not known to carry HBV. The vaccine should be given at the time of exposure, and repeated one month and six months later to achieve full protection. (See "Patient information: Hepatitis B").
Many people have previously been given the series of three HBV vaccines. In this case, some experts recommend a single booster dose of the vaccine.
Hepatitis B immune globulin — If the source of the blood is known to be positive for HBV, treatment with hepatitis B immune globulin (HBIG) is recommended. HBIG contains antibodies that provide temporary protection against the infection. HBIG is an injection, which should be given as soon as possible after exposure, preferably within 24 hours. The first dose of hepatitis B vaccine should be given at the same time. HBIG is not needed if a person was previously vaccinated with HBV vaccine.
Hepatitis C — HCV can cause a form of hepatitis that leads to chronic liver disease. There is no known way to prevent this infection following exposure. Blood tests should be done immediately after exposure to measure liver function and test for the presence of hepatitis C; the tests should be repeated after four to six weeks and again after four to six months, or sooner if symptoms of hepatitis develop. Symptoms of hepatitis C include loss of appetite, nausea, abdominal pain, darkening of urine, light stools, or jaundice (yellowing of the skin or whites of the eye). (See "Patient information: Hepatitis C").
Human immunodeficiency virus (HIV) — Treatments are available to reduce the risk of becoming infected with HIV after exposure. One retrospective study suggested that the use of an anti-HIV medication, zidovudine (ZDV), reduced the already low risk of healthcare workers becoming infected with HIV by about 81 percent. The risk of becoming infected with HIV as a result of other types of exposure (eg, trauma, rape) is probably even lower than that of a healthcare worker.
However, unlike in healthcare settings, it is often difficult after a rape or trauma if the blood or bodily fluid contains HIV. If the source of the exposure is known, an attempt can be made to test the person for HIV. However, treatment is available even if the source's HIV status cannot be determined.
The benefits of post-exposure treatment (eg, reduced risk of infection) must be weighed against the risks (eg, side effects of treatment, interactions with other medications, cost of treatment). All women of childbearing age should be tested for pregnancy before beginning treatment. Anyone who was exposed to potentially infected blood or bodily fluids should be tested for HIV at the time of exposure (baseline) and at six weeks, three months, and six months postexposure (show table 1).
Recommendations — Experts from the United States Center for Disease Control recommend use of medications to reduce the risk of HIV infection if all of the following criteria are met: Exposure occurred less than 72 hours previously One or more of the following areas were exposed: the vagina, rectum, eye, mouth, or other mucous membrane, open skin, through the skin (eg, from a sharp or needle) One or more of the following bodily fluids was involved in the exposure: blood, semen, vaginal secretions, rectal secretions, breast milk, or any body fluid that is visibly contaminated with blood
However, the CDC also recommends that each situation be considered on an individual basis; preventive treatment may be recommended to people who do not meet these criteria in some situations. In all situations, regardless of whether treatment is used, it is important to follow strategies to prevent further spread of the potential infection (see "Protecting others after exposure" below).
The CDC recommends NOT using preventive treatment when: the exposure occurred more than 72 hours prior; when the exposure is to intact skin; or when the exposure fluid is urine, nasal secretions, saliva, sweat, or tears, and is not visibly contaminated with blood.
Anyone who is exposed to blood or bodily fluids should consult with a healthcare provider if symptoms of fever, swollen lymph nodes (glands), sore throat, skin lesions, muscle or joint pain, diarrhea, headache, nausea/vomiting, or weight loss develop. The usual time from HIV exposure to the first symptoms of HIV is two to four weeks. (See "Patient information: Symptoms of HIV infection").
Treatment regimen — Postexposure prevention treatment should be started as soon as possible after exposure, within a few hours rather than days. Animal studies suggest that the longer treatment is delayed, the less effective it is. Preventive treatment should not be given if more than 72 hours have elapsed since exposure.
The Centers for Disease Control and Prevention (CDC) recommends a combination of two or three medications to prevent developing HIV after exposure; the best regimen should be determined by a healthcare provider who is experienced with HIV prevention and treatment regimens (show table 2). The optimal length of preventive treatment is unknown, although four weeks is generally recommended.
It is important to be aware of the potential side effects of these drugs, possible interactions with other medications, and the proper timing of doses. Because there are a variety of medications and combinations, it is best to discuss these issues with the person who prescribes them. In all cases, it is crucial to take all of the medication exactly as directed.
FOLLOW-UP
Testing — Follow-up testing for HBV, HCV, and HIV should be performed after possible exposure (see above for specific recommendations on frequency of testing). For people receiving HBV vaccine, return appointments to complete the vaccine series are crucial.
People exposed to a bloodborne pathogen via sexual intercourse are often tested for other sexually transmitted diseases (STDs). In particular, blood tests for syphilis and cultures for gonorrhea and chlamydia are usually performed immediately after exposure and four to six weeks later (show table 1).
Anxiety — It is common to feel anxious or scared after being exposed to blood or bodily fluids.
These fears are normal but may interfere with a person's ability to concentrate on normal day to day responsibilities.
However, the risk of becoming infected with hepatitis B, C, and HIV is small in most cases. Following the steps outlined here and the advice provided by healthcare personnel can further decrease this risk. Counseling may be helpful for people who have difficulty coping, especially during the first few weeks and months after exposure.
PROTECTING OTHERS AFTER EXPOSURE — Anyone exposed to a bloodborne pathogen should understand how to prevent spreading their potential infection to others (for example, family, sexual partner or breastfeeding child) during the follow-up period, especially during the first six months after exposure; this is when most people who are infected with HIV become antibody positive.
Precautions should include abstaining from sexual intercourse or using condoms every time. Condoms reduce, but do not completely eliminate, the chances of transmitting HBV, HCV, or HIV infection to others. Women who have been exposed to blood or body fluids from a person known to be infected should avoid becoming pregnant during this time. In addition, individuals who have been exposed to HIV-infected fluids should not donate blood, plasma, organs, tissue, or semen during the follow-up period. Women who are breastfeeding may consider stopping temporarily. To maintain a supply of breastmilk, it is acceptable to pump milk and then dump it.
WHERE TO GET MORE INFORMATION — Your healthcare provider is the best source of information for questions and concerns related to your medical problem. Because no two patients are exactly alike and recommendations can vary from one person to another, it is important to seek guidance from a provider who is familiar with your individual situation.
This discussion will be updated as needed every four months on our web site (www.patients.uptodate.com). Additional topics as well as selected discussions written for healthcare professionals are also available for those who would like more detailed information.
A number of web sites have information about medical problems and treatments, although it can be difficult to know which sites are reputable. Information provided by the National Institutes of Health, national medical societies and some other well-established organizations are often reliable sources of information, although the frequency with which they are updated is variable. National Library of Medicine
(www.nlm.nih.gov/medlineplus/healthtopics.html)
Centers for Disease Control and Prevention (CDC)
Toll-free: (800) 311-3435
(www.cdc.gov)
[1-8]
Use of UpToDate is subject to the Subscription and License Agreement. REFERENCES 1. Bamberger, JD, Waldo, CR, Gerberding, JL, Katz, MH. Postexposure prophylaxis for human immunodeficiency virus (HIV) infection following sexual assault. Am J Med 1999; 106:323.
2. Beck-Sague, CM, Solomon, F. Sexually transmitted diseases in abused children and adolescent and adult victims of rape: review of selected literature. Clin Infect Dis 1999; 28 Suppl 1:S74.
3. Fong, C. Post-exposure prophylaxis for HIV infection after sexual assault: when is it indicated?. Emerg Med J 2001; 18:242.
4. Lurie, P, Miller, S, Hecht, F, Chesney, M. Postexposure prophylaxis after nonoccupational HIV exposure: clinical, ethical, and policy considerations. JAMA 1998; 280:1769.
5. Tokars, JI, Marcus, R, Culver, DH, et al. Surveillance of HIV infection and zidovudine use among health care workers after occupational exposure to HIV-infected blood: The CDC Cooperative Needlestick Surveillance Group. Ann Intern Med 1993; 118:913.
6. Wiebe, ER, Comay, SE, McGregor, M, Ducceschi, S. Offering HIV prophylaxis to people who have been sexually assaulted: 16 months' experience in a sexual assault service. CMAJ 2000; 162:641.
7. Workowski, KA, Berman, SM. Sexually transmitted diseases treatment guidelines, 2006. MMWR Recomm Rep 2006; 55:1.
8. Smith, DK, Grohskopf, LA, Black, RJ, et al. Antiretroviral postexposure prophylaxis after sexual, injection-drug use, or other nonoccupational exposure to HIV in the United States: recommendations from the U.S. Department of Health and Human Services. MMWR Recomm Rep 2005; 54:1.
No comments:
Post a Comment