Hepatitis
Viral hepatitis may result from infection with any of several
different pathogens. Of greatest interest to the
TABLE 88-1 -- Recommended HIV postexposure prophylaxis for percutaneous injuries
|
Infection Status of Source |
|
Exposure Type |
HIV Positive Class 1
*
|
HIV Positive Class 2
*
|
Source of Unknown HIV Status
†
|
Unknown Source
‡
|
HIV Negative |
|
Less severe
§
|
Recommend basic 2-drug PEP |
Recommend expanded 3-drug PEP |
Generally, no PEP warranted; however, consider basic 2-drug PEP
‖
for source with HIV risk factors
¶
|
Generally, no PEP warranted; however, consider basic 2-drug PEP
‖
in settings where exposure to HIV-infected persons is likely |
No PEP warranted |
|
More severe
£
|
Recommend expanded 3-drug PEP |
Recommend expanded 3-drug PEP |
Generally, no PEP warranted; however, consider basic 2-drug PEP
‖
for source with HIV risk factors
¶
|
Generally, no PEP warranted; however, consider basic 2-drug PEP
‖
in settings where exposure to HIV-infected persons is likely |
No PEP warranted |
|
From U.S. Public Health Service: Updated U.S. Public
Health Service guidelines for the management of occupational exposures to HBV, HCV,
and HIV and recommendations for postexposure prophylaxis. MMWR Recomm Rep 50(RR-11):1–42,
2001. |
*HIV
positive, class 1—asymptomatic HIV infection or known low viral load (e.g.,
<1500 RNA copies/mL). HIV positive, class 2—symptomatic HIV infection,
AIDS, acute seroconversion, or known high viral load. If drug resistance is a concern,
obtain expert consultation. Initiation of postexposure prophylaxis (PEP) should
not be delayed pending expert consultation, and because expert consultation alone
cannot substitute for face-to-face counseling, resources should be available to provide
immediate evaluation and follow-up care for all exposures.
†Source
of unknown HIV status (e.g., deceased source person with no samples available for
HIV testing).
‡Unknown
source (e.g., a needle from a sharps disposal container).
§Less
severe (e.g., solid needle and superficial injury).
‖The
designation "consider PEP" indicates that PEP is optional and should be based on
an individualized decision between the exposed person and the treating clinician.
¶If
PEP is offered and taken and the source is later determined to be HIV negative, PEP
should be discontinued.
£More
severe (e.g., large-bore hollow needle, deep puncture, blood visible on device, or
needle used in patient's artery or vein).
anesthesiologist are hepatitis B virus (HBV) and hepatitis C virus (HCV), the major
cause of non-A, non-B (NANB) hepatitis. In contrast to these hazardous pathogens,
hepatitis A is normally transmitted by the fecal-oral route and almost never by contact
with blood. It is usually self-limited and rarely produces significant long-term
sequelae. The appearance of antibodies to the virus several weeks after exposure
confirms the diagnosis. Treatment is limited to one dose of gamma globulin.[53]
Hepatitis B
Hepatitis B is a serious disease that may be life threatening,
but it can be prevented. In the 1970s the prevalence of HBV infection in health
care workers was 10 times higher than that in the general population. In the 1980s,
it was estimated that 200 to 300 health care workers would die annually from the
effects of hepatitis B. Fortunately, the introduction of an effective vaccine for
hepatitis B has dramatically decreased the incidence, morbidity, and mortality of
the disease.[47]
Infection may be documented serologically
by the appearance of HBV surface antigen (HBsAg), HBV surface antibody (anti-HBs),
or HBV core antibody (anti-HBc) in serum. Before routine vaccination, the development
of covert seropositivity for hepatitis B during residency was common. In a multicenter
study involving hospitals in both rural and metropolitan areas, the overall prevalence
of serologic indicators for hepatitis B in anesthesiology residents who had received
neither hepatitis vaccine nor hepatitis B immune globulin (HBIG) was 17.8% in 267
tested. Most seropositive residents were unaware of having been exposed to hepatitis.
No correlation was found between the incidence and geographic location, but the
incidence of seropositivity increased in parallel with clinical experience. Thirty
percent of residents with more than 11 total years of experience, including their
current residency and previous work in other specialties, were seropositive for HBV.
Routine use of gloves and attention to obtaining detailed histories from patients
did not appear to decrease the incidence of infection.[54]
An estimated 200,000 new cases of HBV infection occur each year.
Of these cases, jaundice will develop in 50,000, and 10,000 will require hospitalization.
As many as 12,000 to 20,000 annually become asymptomatic carriers of HBsAg, with
the total number of carriers in the United States estimated to be nearly 800,000.
[55]
It is this group that threatens nonimmunized
anesthesiologists. The epidemiologic features of HBV and AIDS have much
in common, although intravenous drug abuse has surpassed homosexual activity as the
most common risk factor associated with HBV infection.[56]
The likelihood of hepatitis developing in nonimmunized health care workers from
contact with infected body fluids is much higher than that for AIDS. The incidence
of seroconversion after parenteral inoculation with HBV can be as high as 40%, depending
on the infectivity of the host and the magnitude of contact with the blood.[57]
In comparison to HIV, HBV is much more robust. Neither treatment at 60°C for
4 hours nor the use of disinfectants containing phenol or chlorine is sufficient
to inactivate the hepatitis B particle with certainty. It remains viable on needles,
environmental surfaces, and gloves for longer than 14 days.[30]
Because gloves do not guarantee protection from accidental needlestick and because
HBV is relatively resistant, accidental contact with live virus may occur in the
course of patient management and also during cleaning of equipment.
Active immunization of seronegative health care workers with hepatitis
B vaccine is imperative for prophylaxis against infection. The first vaccine was
composed of inactivated particles of surface antigen prepared from the sera of HBsAg
carriers. Ninety percent of recipients of the vaccine became seropositive and thus
were protected against infection.[55]
Despite the
efficacy and the safety of the early vaccine, in the mid-1980s, substantial numbers
of anesthesia personnel refused to be immunized for unspecified reasons.[54]
Some were concerned that because the vaccine
TABLE 88-2 -- Recommended postexposure prophylaxis for exposure to hepatitis B virus
|
Treatment |
|
Vaccination and Antibody Response Status
of Exposed Workers
*
|
Source HBsAg Positive |
Source HBsAg Negative |
Source Unknown or Not Available for Testing |
|
Unvaccinated |
HBIG
†
× 1 and initiate vaccine
series |
Initiate HB vaccine series |
Initiate HB vaccine series |
|
Previously vaccinated |
|
|
|
|
Known responder
‡
|
No treatment |
No treatment |
No treatment |
|
Known nonresponder
§
|
HBIG × 1 and initiate revaccination or HBIG × 2
‖
|
No treatment |
If known high-risk source, treat as though source were HBsAg
positive |
|
Antibody response unknown |
Test exposed person for anti-HBs |
No treatment |
Test exposed person for anti-HBs |
|
1. If adequate,
‡
no treatment is
necessary |
|
1. If adequate,
‡
no treatment is
necessary |
|
2. If inadequate,
§
administer HBIG
× 1 and vaccine booster |
|
2. If inadequate,
§
administer vaccine
booster and recheck titer in 1–2 mo |
|
Anti-HBs, HBV surface antibody; HBIG, hepatitis B immune globulin;
HBsAg, hepatitis B surface antigen. |
|
From U.S. Public Health Service: Updated U.S. Public
Health Service guidelines for the management of occupational exposures to HBV, HCV,
and HIV and recommendations for postexposure prophylaxis. MMWR Recomm Rep 50(RR-11):1–42,
2001. |
*Persons
who have previously been infected with hepatitis B virus (HBV) are immune to reinfection
and do not require postexposure prophylaxis.
†Hepatitis
immune globulin, 0.06 mL/kg intramuscularly.
‡A
responder is a person with adequate levels of serum antibody to HBsAg (e.g., anti-HBs
≥10 mIU/mL).
§A
nonresponder is a person with an inadequate response to vaccination (i.e., serum
anti-HBs <10 mIU/mL).
‖The
option of giving one dose of HBIG and reinitiating the vaccine series is preferred
for nonresponders who have not completed a second three-dose vaccine series. For
persons who previously completed a second vaccine series but failed to respond, two
doses of HBIG are preferred.
for hepatitis B was prepared from sera obtained from patients at high risk for HIV
infection, it might also transmit HIV. In the late 1980s, a vaccine was developed
in yeast by the use of recombinant DNA methods. Although there is no possibility
that HIV could be present in this vaccine, it is less effective than vaccine prepared
from plasma in producing antibodies to HBV.[58]
The OSHA standard on blood-borne pathogens mandates that employers make vaccine
against HBV available at no cost to all employees who have a reasonable chance of
exposure to the virus.[31]
In spite of its proven
safety and economic appeal, a substantial number of health care workers have continued
to refuse the immunity conferred by this vaccine.[59]
Anesthesiologists in whom no antibodies are present in serum and
who suspect that contact with HBV has occurred should be passively immunized with
HBIG and should also receive a series of three injections of hepatitis B vaccine
[47]
( Table
88-2
). Previous vaccination and seroconversion eliminate the need for
HBIG, whose acronym is an appropriate description of the discomfort that it produces
after injection.
Hepatitis C
HCV is now recognized as one of the major causes of NANB hepatitis.
This disease, whose symptoms and signs are nonspecific, is the predominant source
of hepatitis from transfusion. Chronic hepatitis develops in more than 85% of hepatitis
C infections, with 20% progressing
to cirrhosis and 3% to hepatocellular carcinoma. It may also result in the development
of a chronic carrier state.[60]
Important discoveries in the diagnosis of HCV were reported in
1989 when a segment of the genome of an NANB virus was isolated, cloned, and designated
hepatitis C virus and when an assay for circulating
anti-HCV antibodies was developed.[61]
[62]
Like HBV, HCV appears to be transmitted principally by infected blood. Studies
using the anti-HCV assay have shown that HCV is responsible for up to 90% of transfusion-related
NANB hepatitis.[63]
With this assay, some have
reported only a 1% to 2% incidence of antibody to HCV in health care workers (similar
to that seen in volunteer donors), thus suggesting that HCV is not easily transmitted.
[63]
[64]
Reports
based on the same assay indicate that transmission of HCV by contaminated needles
occurs in less than 4% of these injuries.[65]
More
sensitive assays for HCV are currently under investigation. One of these assays,
detection of HCV RNA by polymerase chain reaction, documented a 10% incidence of
HCV infection in health care workers.[66]
This
method is limited to laboratory investigation, it is not licensed for clinical use,
and its accuracy is widely variable.[67]
However,
with further refinement, it may become an important method for precisely determining
the incidence of occupationally acquired HCV infection.
At present, no effective postexposure treatment is available for
HCV exposure. Instead, the recommendations for postexposure management are geared
toward early recognition and intervention in chronic disease. Health care workers
who are exposed to HCV should undergo baseline testing for anti-HCV and alanine aminotransferase
activity as soon as possible after the injury, with follow-up testing 3 and 6 months
after exposure.[67]
Some institutions offer immune
serum globulin to these persons as prophylaxis against infection. However, such
prophylaxis is of little value because anti-HCV antibodies are not consistently found
in production lots of immune globulin.[47]
