Body Fluid Exposures 

Occupational transmission of blood-borne infections may occur through parenteral, mucous membrane, and nonintact skin exposure. The greatest risk for transdermal transmission is via a skin penetration injury sustained with a sharp hollow-bore needle that was recently removed from a blood-contaminated source. Although many infections may be transmitted by such contact, the most consequential are hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). In addition, skin and soft tissue infection at the site of the inoculation, through introduction of staphylococcal species, is an issue of concern and must not be neglected. Tetanus prophylaxis is also an important issue of concern. Another important concept is the fact that many clinical pathways adopt plans for management primarily of health care personnel but are woefully lacking when faced with the outside individual at risk for significant exposure.

A flowsheet for management of body fluid exposure is shown below.

When intact, the integumentary system serves as an effective physical barrier to the entry of infectious elements into the body. However, a special situation exists in terms of mucous membranes. Across these membranes, lies a layer of mucus secreted by specialized columnar cells that are closely associated with each other through gap junctions, which are little more than specialized cell surface projections that allow intercellular communication. The presence of a moist mucous layer tends to prolong the viability of fragile viruses, such as HIV and HBV, which cannot survive long in drier environments. However, HBV has been demonstrated to survive on countertops for 7 days and remain capable of causing infection,^[1] while HCV has been shown to be able to survive on environmental surfaces for a minimum of 16 hours but not for 4 days.^[2]

Higher vascularity coupled with a relatively permeable cellular layer gives rise to a presumed heightened risk of transmission of HBV, HCV, and HIV across this organ system and into the bloodstream. Still, at least for occupational HIV exposures, transmission rarely occurs. Intact, keratinized skin does not possess these characteristics and is virtually impermeable unless disrupted. After initial exposure, animal models have shown that HIV replicates within dendritic cells of the skin and mucosa within the first 48 hours before spreading through lymphatic vessels and becoming a systemic infection. This time lapse from initial introduction of the virus to systemic spread allows an opportunity to inhibit the replication of the virus using postexposure prophylaxis.^[3]

In terms of blood and body fluids, semen and vaginal secretions with visible blood should be considered potentially infectious vehicles. Similarly, cerebrospinal fluid, amniotic fluid, pleural fluid, synovial fluid, and peritoneal and pericardial fluids carry a high suspicion of risk for transmission. In addition, unless blood is present, saliva, sputum, sweat, tears, feces, nasal secretions, urine, and vomitus carry a low risk of transmission of HBV, HCV, and HIV.

Frequency

United States

Sharps injuries occur at a rate of 1.8 per year per physician and 0.98 per year per nurse while working on the same medical ward. Statistically, twice as many nurses as doctors have been reported with occupationally acquired HIV infection. Whether this is a functionality of the significance of the exposure (ie, severity of the stick) or the route of exposure remains to be studied.

The risk for developing HIV after a needlestick injury involving an HIV-infected patient is around 0.3%. Factors that increase the odds of HIV transmission after percutaneous exposure are depth of injury, visibility of blood on device, exposure from a needle that was in an artery or vein, and terminal illness in source patient.^[4] Note that the risk of HIV transmission from exposure of HIV-infected fluids on the mucosa of health care workers was extremely low (0.09%) and that no cases HIV conversion after exposure of intact skin to HIV-contaminated fluids were reported.^[5]

Following a needlestick, the risk of HCV is 3 times higher than that of HIV, while that of HBV ranges from 6-30%, depending on the presence of hepatitis B e antigen (HBeAg).^[6]

In a retrospective study of first responders presenting to an ED for body fluid or blood exposure, the incidence was 23.29 ED visits per 100,000 ambulance runs.^[7]

Mortality/Morbidity

Health care workers who have a significant exposure to HBV (ie, inoculation with an open-bore needle from a source known to have active HBV disease) but have not previously received hepatitis B vaccine and do not receive postexposure prophylaxis have a 6-30% risk of becoming infected.

The risk of HCV transmission from a known HCV-positive source by a sharps injury is 0-7%. Approximately 80% of those infected with HCV will develop active liver disease, 10-20% will develop cirrhosis, and 1-5% of cirrhosis cases will develop liver cancer over a period of years.^[8]

The rate of HIV transmission from a known infected individual via a sharps injury is 0.3%, whereas that for exposure to mucous membrane is 0.09%.^[9] The rate is higher if the injury was sustained by a hollow-bore needle, if the injury was deeply penetrating, or if blood was injected during injury. Risk to the injured health care worker is greater if the source patient has a high HIV viral load, lower CD4 count, or both.