Hepatite crônica B

Abstract

Hepatitis B virus infection is an important public health issue with significant morbidity and mortality. Patients with chronic HBV infection may develop immune mediated hepatic injury due to a tentative of the immune system to eliminate the virus. Nevertheless the cccDNA persistis in the infected cell; therefore, there is no cure from the viral infection even when there is serologic evidence of "viral clearance" and viremia is undetectable. Hepatitis B e antigen (HBeAg) positive chronic hepatitis is characterized by the presence of HBsAg in serum for more than 6 months, HBeAg positivity, increased HBVDNA serum levels usually greater than 20.000 IU/ml (100.000 copies/ml) and presistenly or intermittently increased ALT. Quantitative HBV DNA (viral load) is essential to determine the therapy management and asntiviral choice. The HBVDNA arbitrary cutoff level of ≥ 20.000IU/ml is considered to be diagnostic criteria. HbeAg-Negative chronic hepatitis is characterized by the absence of HBeAg, the presence of anti-HBe antibody, detectable levels of HBV DNA (greater than 2.000 IU/ml), elevated levels of serum ALT, and histological findings of continued necroinflammation of the liver. Patients usually have a more severe disease than HBeAg positive chronic hepatitis. Quantitative HBV DNA is essential to differentiate HBeAg-Negative chronic hepatitis from the state of inactive HBsAg carrier. Frequently HBV DNA monitoring should be considered due to the possibility of fluctuating HBV DNA levels. Patients become infected with mutant strains that do not express HBeAg due to mutations in the "precore" or "core-promoter" regions of the HBV genome. HBeAg-Negative Chronic Hepatitis represents a potentially progressive and severe hepatic disease. The annual incidence of cirrhosis is 8% to 10% compared to 2% to 5% among those who are HBeAg positive. The aim of the treatment is to prevent the progression to cirrhosis and the development of hepatocelular carcinoma. In chronic HBeAg positive hepatitis the seroconversion to anti-HBe as well as the sustained reduction for more than 6 months of the HBV DNA levels, the ALT normalization and the HBsAg clearance contribute to the clinical benefits. Patients who should be treated are the ones with persistently increased ALT at least twice the upper limit of normal and HBV DNA > 20.000IU/ml. Recently the european consensus recommended the treatment of HBeAg positive chronic hepatitis with no evidence of cirrhosis and HBVDNA levels ≥ 2.000IU/ml (10.000cps/mL) since the patient had one of the following findings: elevated ALT levels greater than the upper limit of normal, liver biopsy showing necro-inflammatory activity or significant fibrosis. In HBeAg-Negative Chronic Hepatitis it is recommended to treat patients with HBVDNA ≥ 2.000 IU/mL and ALT levels greater > 1-fold the upper limit of normal. The choice of the antiviral, standard or pepylated interferon and the nucleotides/nucleosides analogs adefovir, entecavir, tenofovir and telbivudine should be based on the efficacy, safety, incidence of resistance development, via of administration, cost, presence or absence of cirrhosis. After seroconversion, most patients remain negative for HBeAg and positive for anti-HBe antibody. Seroconversion is usually accompanied by stabilization of hepatitis, characterized by normalization of ALT levels and condition is commonly referred to as the "inactive carrier state". Histologically, minimal to mild hepatitis may be observed, although the degree of fibrosis maybe variable. Most patients remain in this phase for many years, if not indefinitely. Their prognosis is generally favorable, particularly if this phase is reached early in the disease course. There is no need of anti-viral therapy. Of note, HBV replication may be reactivated when inactive carriers are subjected to immune suppression or chemotherapy. © Copyright Morelra Jr. Editera.