" / would have everie man write what he knowes and no more."—MONTAIGNE
BRITISH JOURNAL OF ANAESTHESIA OCTOBER 1979
VOLUME 51, No. 10
Whilst every effort is made by the publishers and editorial committee to see that no inaccurate or misleading data, opinion or statement appears in this Journal, they wish to make it clear that the data and opinions appearing in the articles and advertisements herein are the responsibility of the contributor or advertiser concerned. Accordingly, the publishers and the editorial committee and their respective employees, officers and agents accept no liability whatsoever for the consequences of any such inaccurate or misleading data, opinion or statement. •
VIRAL HEPATITIS
Hepatitis may result from infection with a number of viruses, most commonly either virus hepatitis A (HAV) or virus hepatitis B (HBV); less commonly cytomegalovirus, herpes simplex virus or EpsteinBarr virus (infectious mononucleosis) may be responsible. These last infections may be encountered in patients receiving immunosuppressive therapy. Hepatitis A is endemic in all parts of the world. The infection is not normally transmitted by blood transfusion; although severe and sometimes fatal hepatitis may result, in most cases recovery is complete and there is no evidence of progression to chronic liver disease. In contrast, hepatitis B is commonly transmitted parenterally, and, in addition to occasionally causing fulminant hepatic failure, may be associated with the development of chronic liver disease. Some of those who survive infection with hepatitis B may become symptomless chronic carriers. Certain groups of patients are more likely to develop the chronic carrier state (Waterson, 1976) and these include patients with liver and kidney disease, a history of drug abuse, after tattooing, following acupuncture (Editorial, 1977) and persons coming from countries with a high endemic rate of infection. The carrier state may be quantified by the detection of various antigens in the serum (Zuckerman, 1979), and is characterized serologically by the finding of hepatitis B surface antigen (HBsAg, Australia antigen) and the absence of surface antibody. In some carriers hepatitis B DNA polymerase activity is present and another antigen, the e antigen, may also be detected. If both HBsAg and e antigens are present |in the serum, this usually indicates a highly infectious individual. The use of serological testing has now made possible the specific diagnosis of both hepatitis A and B. The application of such testing to the Blood
Transfusion Service has dramatically reduced the risk of transfusion hepatitis. Indeed, it was assumed that such hepatitis could be almost entirely avoided. It has become clear, however, that transfusion hepatitis still occurs even in the absence of detectable infection with either virus A or B or other viruses which on occasion may cause hepatitis. The description non-A non-B hepatitis is now used for such occurrences, which are the major cause of transfusion hepatitis in North America. Non-A non-B hepatitis has been transmitted to chimpanzees (Alter et al., 1978); there is evidence that a carrier state exists and that in some patients chronic liver disease may occur. However, no specific laboratory tests are available for identifying non-A non-B hepatitis (Zuckerman, 1979). The ability to diagnose virus hepatitis specifically in many instances is of relevance to anaesthetic practice in a number of respects. The risk of infection to anaesthetic personnel is obvious. There is epidemiological evidence of an increased frequency of liver dysfunction among anaesthetists (Spence and Knill-Jones, 1978) which may be partially, at least, accounted for by viral hepatitis. Simple measures are effective in preventing infection being transmitted from patients to staff (Waterson, 1976; Strunin, 1977). The first and obvious factor is awareness of the problem and this implies that patients should be screened for the presence of HBsAg and if possible e antigen; but even if these facilities are not available, patients in the high-risk categories should be regarded as antigen positive until it is proved otherwise. Since many cases of hepatitis follow accidental inoculation, present casual attitudes to the spillage of blood should be tempered with restraint. The wearing of gloves, a disposable gown and a mask, the use of disposable anaesthetic equipment where appropriate and safe disposal of such equipment afterwards, are obvious
Downloaded from http://bja.oxfordjournals.org/ at Indiana University Library on July 13, 2015
EDITORIAL
914
Anxiety is often expressed by anaesthetists that, should they become chronic carriers of HBV, they may be at risk with regard to employment. This is not the case. There is, of course, a risk of chronic liver disease and incapacity. However, this is a rare event and, in most instances, the carrier state may be associated with only minimal evidence of liver dysfunction or may persist for only a relatively short period of time. The only bar to employment of HBsAg positive individuals is in the handling of blood products or employment in renal dialysis units. Indeed, an antigen-positive anaesthetist may be in great demand as the obvious choice to anaesthetize antigen-positive patients without risk. Apart from personal hazard, what is the risk to the patient who either is incubating viral hepatitis or is a chronic carrier of hepatitis B when subjected to anaesthesia and surgery ? The few studies of liver function in patients subjected to anaesthesia and surgery while incubating viral hepatitis or in the acute stages of the disease have suggested that liver function deteriorates subsequently (Harville and Summerskill, 1963; Hardy and Hughes, 1968; Marx et al., 1968). All anaesthetic techniques and many operative procedures will reduce liver blood flow. It seems sensible not to add additional problems to an already compromised liver. Therefore, where there is doubt, surgery should be delayed if possible. Such patients, however, are the minority and a far larger group are those who have already been diagnosed as chronic carriers of hepatitis B. Personal experience and the observations of others (Dykes, 1977) suggest that patients are not likely to undergo any "activation" of their virus infection as a result of anaesthesia and surgery and that any ill effects on the liver will be determined by the patient's state before operation. Clearly those with severe chronic liver disease are at risk if subjected to anaesthesia and major surgery. The advent of specific serological diagnosis of viral hepatitis (Zuckerman, 1979) means that there is now additional help in determining the cause of jaundice after operation. Although, in most instances the cause of such jaundice is clear, on occasion liver dysfunction is unexplained and suspicion may fall on the anaesthetic used. The ability to determine if viral infection is involved may be an important factor if the patient requires further anaesthesia and surgery. In the majority of patients with unexplained postoperative jaundice or hepatitis it is now possible to eliminate viral hepatitis as the cause. Leo Strunin REFERENCES ON PAGE 9 2 6
Downloaded from http://bja.oxfordjournals.org/ at Indiana University Library on July 13, 2015
precautions. Hepatitis B virus is susceptible to heat, ethylene oxide and proprietary bleach solutions, such as Diversol BX (Diversey Ltd) which is a crystalline blend of chlorinated trisodium phosphate, admixed with a bromine salt. In solution, sodium hypochloride is formed, which reacts with the bromine to produce sodium hypobromite. This disinfectant is an example of the dual halogen type (chlorine and bromine). Despite precautions the anaesthetist may find that he has inadvertantly inoculated himself with potentially infective material. What steps should be taken ? First, it should be clearly established that the material was indeed infected. Second, the subject should have standard liver function tests performed and a test for the presence of hepatitis B surface antibodies. If these are present this implies that the individual has had a previous infection with hepatitis B and is now immune, and there is no risk of subsequent infection. In the event that such antibodies are not present and it is clear that infective material was inoculated, a dose of specific anti-HBs immunoglobulin should be administered. It should be noted that this form of immunoglobulin is recommended for the treatment of hepatitis B infection. Human normal immunoglobulin ( gammaglobulin) is effective in preventing hepatitis A infection and is normally administered before visiting parts of the world where such infection is endemic. Human normal immunoglobulin is not effective in the treatment of hepatitis B infection, but it does appear to have a beneficial effect in preventing non-A non-B hepatitis (Editorial, 1978). Although specific anti-HBs immunoglobulin gives protection after inoculation accidents, clinical infection may be delayed beyond the normal incubation period of hepatitis B and individuals should be followed up for at least a year to be sure that they do not develop hepatitis. A more unusual use of specific anti-HBs immunoglobulin is during the anhepatic phase of liver transplantation in patients with hepatoma and who are antigen-positive. Four such patients have occurred in Britain and all remained free from the virus after surgery and one patient was still alive after 3 years (Johnson et al., 1978). Immunoglobulin confers only passive immunity and, except in the rare event of transplantation when the source of infection is removed, does not confer any long-term effect. Active immunity has been hampered by the inability to culture hepatitis B virus. Nevertheless, work is progressing toward the development of a vaccine which may be available soon.
BRITISH JOURNAL OF ANAESTHESIA
BRITISH JOURNAL OF ANAESTHESIA OCTOBER 1979
VOLUME 51, No. 10
Whilst every effort is made by the publishers and editorial committee to see that no inaccurate or misleading data, opinion or statement appears in this Journal, they wish to make it clear that the data and opinions appearing in the articles and advertisements herein are the responsibility of the contributor or advertiser concerned. Accordingly, the publishers and the editorial committee and their respective employees, officers and agents accept no liability whatsoever for the consequences of any such inaccurate or misleading data, opinion or statement. •
VIRAL HEPATITIS
Hepatitis may result from infection with a number of viruses, most commonly either virus hepatitis A (HAV) or virus hepatitis B (HBV); less commonly cytomegalovirus, herpes simplex virus or EpsteinBarr virus (infectious mononucleosis) may be responsible. These last infections may be encountered in patients receiving immunosuppressive therapy. Hepatitis A is endemic in all parts of the world. The infection is not normally transmitted by blood transfusion; although severe and sometimes fatal hepatitis may result, in most cases recovery is complete and there is no evidence of progression to chronic liver disease. In contrast, hepatitis B is commonly transmitted parenterally, and, in addition to occasionally causing fulminant hepatic failure, may be associated with the development of chronic liver disease. Some of those who survive infection with hepatitis B may become symptomless chronic carriers. Certain groups of patients are more likely to develop the chronic carrier state (Waterson, 1976) and these include patients with liver and kidney disease, a history of drug abuse, after tattooing, following acupuncture (Editorial, 1977) and persons coming from countries with a high endemic rate of infection. The carrier state may be quantified by the detection of various antigens in the serum (Zuckerman, 1979), and is characterized serologically by the finding of hepatitis B surface antigen (HBsAg, Australia antigen) and the absence of surface antibody. In some carriers hepatitis B DNA polymerase activity is present and another antigen, the e antigen, may also be detected. If both HBsAg and e antigens are present |in the serum, this usually indicates a highly infectious individual. The use of serological testing has now made possible the specific diagnosis of both hepatitis A and B. The application of such testing to the Blood
Transfusion Service has dramatically reduced the risk of transfusion hepatitis. Indeed, it was assumed that such hepatitis could be almost entirely avoided. It has become clear, however, that transfusion hepatitis still occurs even in the absence of detectable infection with either virus A or B or other viruses which on occasion may cause hepatitis. The description non-A non-B hepatitis is now used for such occurrences, which are the major cause of transfusion hepatitis in North America. Non-A non-B hepatitis has been transmitted to chimpanzees (Alter et al., 1978); there is evidence that a carrier state exists and that in some patients chronic liver disease may occur. However, no specific laboratory tests are available for identifying non-A non-B hepatitis (Zuckerman, 1979). The ability to diagnose virus hepatitis specifically in many instances is of relevance to anaesthetic practice in a number of respects. The risk of infection to anaesthetic personnel is obvious. There is epidemiological evidence of an increased frequency of liver dysfunction among anaesthetists (Spence and Knill-Jones, 1978) which may be partially, at least, accounted for by viral hepatitis. Simple measures are effective in preventing infection being transmitted from patients to staff (Waterson, 1976; Strunin, 1977). The first and obvious factor is awareness of the problem and this implies that patients should be screened for the presence of HBsAg and if possible e antigen; but even if these facilities are not available, patients in the high-risk categories should be regarded as antigen positive until it is proved otherwise. Since many cases of hepatitis follow accidental inoculation, present casual attitudes to the spillage of blood should be tempered with restraint. The wearing of gloves, a disposable gown and a mask, the use of disposable anaesthetic equipment where appropriate and safe disposal of such equipment afterwards, are obvious
Downloaded from http://bja.oxfordjournals.org/ at Indiana University Library on July 13, 2015
EDITORIAL
914
Anxiety is often expressed by anaesthetists that, should they become chronic carriers of HBV, they may be at risk with regard to employment. This is not the case. There is, of course, a risk of chronic liver disease and incapacity. However, this is a rare event and, in most instances, the carrier state may be associated with only minimal evidence of liver dysfunction or may persist for only a relatively short period of time. The only bar to employment of HBsAg positive individuals is in the handling of blood products or employment in renal dialysis units. Indeed, an antigen-positive anaesthetist may be in great demand as the obvious choice to anaesthetize antigen-positive patients without risk. Apart from personal hazard, what is the risk to the patient who either is incubating viral hepatitis or is a chronic carrier of hepatitis B when subjected to anaesthesia and surgery ? The few studies of liver function in patients subjected to anaesthesia and surgery while incubating viral hepatitis or in the acute stages of the disease have suggested that liver function deteriorates subsequently (Harville and Summerskill, 1963; Hardy and Hughes, 1968; Marx et al., 1968). All anaesthetic techniques and many operative procedures will reduce liver blood flow. It seems sensible not to add additional problems to an already compromised liver. Therefore, where there is doubt, surgery should be delayed if possible. Such patients, however, are the minority and a far larger group are those who have already been diagnosed as chronic carriers of hepatitis B. Personal experience and the observations of others (Dykes, 1977) suggest that patients are not likely to undergo any "activation" of their virus infection as a result of anaesthesia and surgery and that any ill effects on the liver will be determined by the patient's state before operation. Clearly those with severe chronic liver disease are at risk if subjected to anaesthesia and major surgery. The advent of specific serological diagnosis of viral hepatitis (Zuckerman, 1979) means that there is now additional help in determining the cause of jaundice after operation. Although, in most instances the cause of such jaundice is clear, on occasion liver dysfunction is unexplained and suspicion may fall on the anaesthetic used. The ability to determine if viral infection is involved may be an important factor if the patient requires further anaesthesia and surgery. In the majority of patients with unexplained postoperative jaundice or hepatitis it is now possible to eliminate viral hepatitis as the cause. Leo Strunin REFERENCES ON PAGE 9 2 6
Downloaded from http://bja.oxfordjournals.org/ at Indiana University Library on July 13, 2015
precautions. Hepatitis B virus is susceptible to heat, ethylene oxide and proprietary bleach solutions, such as Diversol BX (Diversey Ltd) which is a crystalline blend of chlorinated trisodium phosphate, admixed with a bromine salt. In solution, sodium hypochloride is formed, which reacts with the bromine to produce sodium hypobromite. This disinfectant is an example of the dual halogen type (chlorine and bromine). Despite precautions the anaesthetist may find that he has inadvertantly inoculated himself with potentially infective material. What steps should be taken ? First, it should be clearly established that the material was indeed infected. Second, the subject should have standard liver function tests performed and a test for the presence of hepatitis B surface antibodies. If these are present this implies that the individual has had a previous infection with hepatitis B and is now immune, and there is no risk of subsequent infection. In the event that such antibodies are not present and it is clear that infective material was inoculated, a dose of specific anti-HBs immunoglobulin should be administered. It should be noted that this form of immunoglobulin is recommended for the treatment of hepatitis B infection. Human normal immunoglobulin ( gammaglobulin) is effective in preventing hepatitis A infection and is normally administered before visiting parts of the world where such infection is endemic. Human normal immunoglobulin is not effective in the treatment of hepatitis B infection, but it does appear to have a beneficial effect in preventing non-A non-B hepatitis (Editorial, 1978). Although specific anti-HBs immunoglobulin gives protection after inoculation accidents, clinical infection may be delayed beyond the normal incubation period of hepatitis B and individuals should be followed up for at least a year to be sure that they do not develop hepatitis. A more unusual use of specific anti-HBs immunoglobulin is during the anhepatic phase of liver transplantation in patients with hepatoma and who are antigen-positive. Four such patients have occurred in Britain and all remained free from the virus after surgery and one patient was still alive after 3 years (Johnson et al., 1978). Immunoglobulin confers only passive immunity and, except in the rare event of transplantation when the source of infection is removed, does not confer any long-term effect. Active immunity has been hampered by the inability to culture hepatitis B virus. Nevertheless, work is progressing toward the development of a vaccine which may be available soon.
BRITISH JOURNAL OF ANAESTHESIA
