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Thursday, December 4, 2014

Acute and Chronic Hepatitis B Treatment

What is hepatitis B


Hepatitis B (formerly serum hepatitis) is an infection of the liver with hepatitis B virus (HBV), often acute (90%), occasionally also extends chronic. With about 350 million people, in whose blood the virus is detectable and thus where the virus is present as a permanent source of infection, the hepatitis B worldwide one of the most common viral infections. Approximately one-third of the world population as a sign of a healed HBV-specific antibodies detected. On the basis of chronic inflammation of the liver can result in a liver cirrhosis and hepatocellular carcinoma. The treatment of chronic hepatitis B is difficult, therefore, preventive vaccination is the most important measure to prevent infection and reduce viral carrier number.

Transmission


HBV infection is parenteral and sexual, ie. With blood or other body fluids of an infected HBsAg-positive patients The infectivity of a virus carrier is dependent on the concentration of virus in the blood; in so-called highly viremic carriers (107 to 1,010 HBV genomes / ml), there are also infectious virus in urine, saliva, semen, tears secretion, bile and breast milk.

The entrance doors are usually minor injuries of the skin or mucous membrane. Therefore considered a risk factor also remains unprotected sex. Among young children, the infection can also be passed by scratching or biting. Even everyday objects such as razors or nail scissors with which one often slightly injured, HBV can be transmitted. In countries where the barber shaving is still widely used, is usually found an increased incidence of HBV infection. Other major transmission facilities are also a major injury to blood contact eg. As in intravenous drug use, tattooing and piercing. In the medical field HBV can be transmitted through invasive, surgical procedures and injuries, as of unrecognized HBsAg carriers on patients or non-tested patients on medical or dental staff. The transmission of HBV through blood and blood products for transfusion is on anti-HBc, HBsAg and HBV DNA has become very rare in Germany since the testing of blood donations.

In endemic areas, the most important is the vertical transmission of infection from an HBsAg-positive mother during birth (perinatal) on the child. Perinatal infection has 90% of the child a chronic infection result.

The risk of infection from a needle stick injury with known HBsAg-positive index patient is about 10-30%. This risk is very dependent on the virus concentration below 105 HBV genomes / ml such transfer has not been proven in the medical field. This, for example, in the UK already stated limit is of great importance in the employment of HBsAg carriers in the medical field.

Clinical course


Acute hepatitis B
About 2/3 of all infections are without clinical signs (asymptomatic), ie only about a third of those infected show after an incubation period of one to six months, the classical hepatitis characters such as yellowing of the skin and sclera (jaundice), dark urine, body aches, pain in the upper abdomen, nausea, vomiting and diarrhea. Often after asymptomatic forms a slight malaise is given or an increase in liver enzymes (transaminases) is discovered by chance; such an infection can usually be detected only by serology.

In general, an uncomplicated acute hepatitis B heals within two to six weeks clinically, the detection of antibodies against HBsAg (anti-HBs) indicates this. With the disappearance of HBsAg and the appearance of anti-HBs (seroconversion) the risk of infection than overcome applies.

Rarely can become severe acute hepatitis B, which is leading to impaired blood clotting, and brain damage (encephalopathy); Here therapy with a nucleoside analog (eg. as lamivudine) is recommended. In the worst case occurs in about 1% of symptomatic courses to life-threatening course (in hours to a few days), the so-called fulminant hepatitis. In this case, the rapid disappearance of HBsAg and shrinkage of the liver as unfavorable marks are considered; drug therapy and intensive medical care with the possibility of liver transplantation should be considered. The administration of interferon is contraindicated in any form of acute hepatitis B.

Chronic Hepatitis B
In many cases, the infection is unnoticed and without symptoms. By definition, it is called chronic hepatitis B when the symptoms of hepatitis caused by HBV and corresponding viral markers exist for more than six months (persist). Chronic this disease is in 5-10% of cases. You can develop either following an acute hepatitis B or run primarily chronic. The chronicity rate decreases with decreasing steadily age and is highest in neonates. These are in an infection, as described above in about 90% of cases of chronic virus carriers. Even at four years old patient half of all infections are chronic. In about one-quarter of all chronic hepatitis B disease in a severity-enhancing disease (progressive) is observed, which often leads then to significant consequential damages such as a hepatocellular carcinoma or liver cirrhosis. At the latest on the occurrence of changes in consciousness (so-called hepatic encephalopathy) laying in a center for liver diseases is appropriate.

In a malignant course form after hepatitis B infection, there is a case fatality rate of 0.5-1%. In 5-10% of infected it comes to the development of chronic hepatitis.

Approximately 5% of HBV-infected are also infected with hepatitis D.

HBV belongs together with the Epstein-Barr virus (EBV), hepatitis C virus (HCV), human papilloma virus (HPV), human T-lymphotropic virus 1 (HTLV-1), and human herpes virus 8 (HHV-8, and Kaposi's sarcoma herpesvirus, KSHV) to a group of human viruses that are responsible for 10 to 15 percent of all cancers worldwide.

reactivation
With new therapies in the treatment of leukemia and for immunosuppression after organ transplantation, a reactivation of an old, clinically healed HBV infection has been observed in recent years in some cases. Also reactivation of HBV in advanced AIDS (C3) have been described. The HBV infection was in some cases the Reactivation of decades back, and the patient had before the classic serological pattern of an old infection (anti-HBc and anti-HBs positive, see Diagnostics). Such reactivation often runs very difficult, especially if after reactivation immunosuppression is reduced and the immune system occurs then the liver is quickly destroyed as a fulminant hepatitis. The emergence of such symptoms after reduction of immunosuppression (eg. As at the completion of chemotherapy or with successful HIV therapy) is also called immune reconstitution syndrome.

Particularly vulnerable to reactivation are patients after kidney transplantation, bone marrow transplantation, and patients with acute myeloid leukemia. Treatment with a nucleoside analogue for several weeks to months is advised when a proven reactivation.

The phenomenon of reactivation once again indicates the fact that the HBV like a real retro virus can enter a sleep state and is not eliminated from all cells. Overall, however, the reactivation is a very rare event.

Treatment for hepatitis B


In the acute stage (ie in the first months after infection) Hepatitis B is usually treated only symptomatically, as the disease in 90-95% of cases heals by itself.

For chronic hepatitis B are two classes of drugs are available:

-Pegylated interferon, which is injected once a week. Interferons stimulate the immune system so this effectively fights against the virus.
-Nucleoside and nucleotide analogues that are taken daily in tablet form. These include lamivudine, adefovir, entecavir, telbivudine and tenofovir. These drugs inhibiting the virus from multiplying.

Other drugs are tested in trials. However, these therapies are not curative, so there is no complete cure expected. The therapeutic goal is rather to mitigate the progression of chronic hepatitis B and to reduce the risk of late complications. Rare (up to 3%) may disappear during therapy with (PEG) interferon or other drugs also the HBsAg from the blood and act as immune response anti-HBs antibody, which is equivalent to a cure.

Which patient must be treated when and with what medication from case to case. For very mild course of chronic hepatitis B is usually only observed. If there is evidence of harm to the liver or other risk factors, however, a therapy is very important (as of August 2008). This should be assessed by specialist doctors in a particular case.

Vaccination


Hepatitis B can be active and passive vaccination. The active vaccination consists of a replica of part of the viral envelope, the HBs antigen. Active the body forming against foreign substances defensive molecules (immunoglobulins) in order to destroy it is. After 3 vaccinations, the immune cells know the virus component and can it in a real fight infection. Contrary to other opinions no real viruses to be administered in hepatitis B vaccination. The number of non-responders is significantly below 10%. Vaccination is done three times:

-Vaccination (week 0)
-Vaccination (approximately 1 month later)
-Vaccination (six months to 1 year after first vaccination)

Two weeks after the third vaccine is vaccine for at least ten years. According to the vaccination titer, the number of active hepatitis immune molecules, a booster dose should be made now. A blood test can be determined after completion of the vaccination, whether a sufficient vaccination reaction occurred.

Hyper immune globulins are injected with passive vaccination; finished immunoglobulins, which help the immune system fight off the viruses. This is along with the active vaccine after contact with infected material (medical post exposure prophylaxis, ESP. in the hospital: needle injuries, mucous membrane contact, etc.) and administered in newborns of hepatitis-B positive mothers until 12 hours after contact or birth. This vaccine is completed in newborns after the normal vaccination schedule (0 - 1 - 6 months). This ensures an immune response in more than 95% of the Impflinge.

Because it can infect D is only with hepatitis, if there is already a hepatitis B, the hepatitis B vaccine also protects against hepatitis D virus. In addition, there is a combination vaccine that protects against hepatitis A. Generally, the vaccine is well tolerated. Occasionally there is redness at the injection point. Fever, headache, fatigue and joint complaints are rare. Vaccine damage or severe allergic reactions are very rare. A causal link with neurological diseases (E.g. Guillain-Barre Syndrome) is so far unclear; There are individual case reports, with a random coincidence is suspected. If acute diseases or other contraindications exist, such as a vaccine component is not tolerated or a febrile illness, you should forgo vaccination.

Whether a unsymptomatische Multiple Sclerosis can be triggered by the HBV vaccine, has been discussed repeatedly in studies and anecdotal reports. It is so far but not scientifically proven. A study in 2004 allegedly observed a triple increased MS risk by the HBV vaccine; She was criticized because of methodological errors as misleading and not meaningful but (inter alia by the World Health Organization): the study, only MS patients were asked how many of them were vaccinated during the three years preceding their MS diagnosis against hepatitis B (this was only on 11 originally 713 MS patients). It was not investigated how many healthy against hepatitis B had been vaccinated and not MS became ill, to make a comparison framework.

The World Health Organization called on all Member States 1992 to be the hepatitis B vaccination in national routine immunization programs. In Taiwan, the universal HBV immunization has significantly reduced the incidence of liver cancer.

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