19,361 research outputs found
Natural History and Clinical Management of Chronic Hepatitis B Virus Infection in Children
No full textHepatitis B virus (HBV) infection may cause acute, fulminant , or chronic hepatitis, leading to liver cirrhosis or hepatocellular carcinoma. Despite the availability of effective vaccine, HBV infection during infancy or early childhood is common in areas of high endemicity. In these regions, mother-to-infant transmission accounts for approximately 50% of chronic infections. Although the natural history of HBV infection in adults is well characterized, little information is available in the literature regarding the natural history of HBV infection in children. Similar to infection in adults, chronic HBV infection in children can be divided into distinct phases: immune tolerant, immune clearance, and inactive carrier state. However, acute exacerbation, with reactivation of HBV replication and re-elevation of alanine aminotransferase levels after hepatitis B e antigen seroconversion, is relatively rare in children, in comparison to adults. Although several potent antiviral agents are now available for the treatment of chronic hepatitis B, experience with these agents in the pediatric setting is limited. To date, conventional interferon a and lamivudine are the only two antiviral agents approved to treat chronic hepatitis B in children. The rapid emergence of resistant HBV associated with long-term lamivudine therapy, as well as poor tolerability associated with conventional interferon a, are factors that should be considered before initiating antiviral therapy. This article reviews current knowledge regarding the natural history and treatment of chronic hepatitis B in children. Factors that affect the natural history of HBV infection in children are also reviewed
Breakthrough Hbv Infection in Vaccinated Children in Taiwan: Surveillance for Hbv Mutants
No full textThe universal HBV vaccination programme in Taiwan has effectively led to the reduction of acute and chronic hepatitis B, and of hepatocellular carcinoma among vaccinated children. Seropositivity rates for hepatitis B surface antigen (HBsAg) decreased from 10-17% in those born before the start of the vaccination programme to the current 0.5-1.7%. Nonetheless, breakthrough infection continues to be observed. The main causes include high maternal viral load, intrauterine infection, emergence of S gene mutants and immunosuppression. Among vaccinated individuals with breakthrough HBV infection, sG145R & sT126A/S mutations ( which account for 48% of the mutants detected) have become prominent. However, owing to the marked reduction in the HBsAg carrier rate, the prevalence rate of S gene mutants in the total vaccinated population has not increased. With limited evidence of spread, S gene mutants do not need to be incorporated into the HBV vaccine. Further studies are required to design better strategies to prevent breakthrough HBV infection of both wild-type and S gene mutants
Hepatitis B Virus Infection
No full textHepatitis B virus (HBV) infection is a worldwide health problem and may cause acute, fulminant, chronic hepatitis, liver cirrhosis, or hepatocelullar carcinoma (HCC). Infection with HBV, in infancy or early childhood may lead to a high rate of persistent infection (2590%), while the rates are tower if infection occurs during adulthood (5-10%) . In most endemic areas, infection occurs mainly during early childhood and mother- to-infant transmission accounts for approximately 50% of the chronic infection cases. Hepatitis B during pregnancy does not increase maternal mortality or morbidity or the risk of fetal complications. Approximately 90% of the infants of HBsAg carrier mothers with positive hepatitis B e- antigen (HBeAg) wilt become carriers if no immunoprophylaxis is given. Transptacental HBeAg may induce a specific non-responsiveness of helper T cells and HBcAg. Spontaneous HBeAg seroconversion to anti- HBe may develop with time but liver damage may occur during the process of the immune clearance of HBV and HBeAg. Mother -to-infant transmission of HBV from HBeAg negative but HBsAg positive mothers is the most important cause of acute or fulminant hepatitis B in infancy. Although antiviral agents are available to treat and avoid the complications of chronic hepatitis B, prevention of HBV infection is the best way for control. Screening for maternal HBsAg with/without HBeAg, followed by three to four doses of HBV vaccine in infancy and hepatitis B immunoglobutin (HBIG) within 24 h of birth is the most effective way to prevent HBV infection. In areas with,a low prevalence of HBV infection or with limited resources, omitting maternal screening but giving three doses of HBV vaccine universally in infancy can also produce good protective efficacy. The first universal HBV immunisation programme in the world was launched in Taiwan 22 years ago. HBV infection rates, chronicity rates, incidence of HCC and incidence of fulminant hepatitis in children have been effectively reduced. (c) 2007 Elsevier Ltd. All rights reserved
Autoimmune Hepatitis
No full textAutoimmune hepatitis is characterized by inflammatory liver histology, circulating nonorgan-specific autoantibodies, and increased levels of immunoglobulin G, in the absence of a known etiology. Two types of juvenile autoimmune hepatitis ( AIH) are recognized according to seropositivity for smooth muscle and/or anti-nuclear antibody (AIH type 1) or liver kidney microsomal antibody (AIH type 2). There is a female predominance in both. AIH type 2 presents more acutely, at a younger age and commonly with immunoglobulin A deficiency, whereas duration of symptoms before diagnosis, clinical signs, family history of autoimmunity, presence of associated autoimmune disorders, response to treatment, and long-term prognosis are similar in the 2 groups. Immunosuppressive treatment with steroids and azathioprine, which should be instituted promptly to avoid progression to cirrhosis, induces remission in 80% of cases. Relapses are common, often due to non-adherence. Drugs effective in refractory cases include cyclosporine and mycophenolate mofetil. Long- term treatment is usually required, with only some 20% of AM type I patients able to discontinue therapy successfully. In childhood, sclerosing cholangitis with strong autoimmune features, including interface hepatitis and serological features identical to AIH type 1, is as prevalent as AIH, but it affects boys and girls equally. Differential diagnosis relies on cholangiographic studies. In autoimmune sclerosing cholangitis liver parenchymal damage responds satisfactorily to immunosuppressive treatment, whereas bile duct disease tends to progress. In this article we review the state of the art of diagnosis, monitoring, and treatment for children with AIH
超音波圖在小兒科領域之應用－綜論
No full text 小兒科病人因為各個器官構造小，許多在大人使用的儀器，小孩不能適用；又因 年紀小不合作，故各種診斷工具都有其特殊困難處。再加上生長中的孩子，特別需要 注意診斷性Ｘ光的放射線對其身體的不良影響。故小兒科病人很需要一種無侵犯性， 無放射性又正確的診斷工具。超音波圖正符合了這些優點，故最近十年來漸漸地被小 兒科醫師所喜愛，廣泛地使用於小兒科領域中的各個部分。由於其無侵犯性，無痛苦 ，又快速可行，故小孩子較易接受；又由於其簡單，可反覆操作，故很適合疾病的追 蹤檢查。 在國內，本人於民國64年在婦產科陳皙堯教授與蔡偉雄副教授的指導之下，開始 將超音波圖運用於小兒科領域，至今已有十年的時間了。當初只用於腹部與腹膜後腔 之疾病的診斷。隨著超音波儀器的改良創新，真實時間超音波圖及扇形超音波圖被廣 泛使用。如今由頭到腳，超音波圖已被使用來診斷小兒頭部、頸部、胸部、心臟、腹 腔、骨盆腔、及腹膜後腔的各種疾病了。#c258507
Decreasing Incidence of Hepatocellular Carcinoma among Children Following Universal Hepatitis B Immunization
No full textHepatocellular carcinoma (HCC) is one of the 10 most common malignant tumors worldwide. Chronic infection with hepatitis B or C virus is closely related to hepatocarcinogenesis. The outcome of current therapies for HCC is not satisfactory . Prevention is the best way to control HCC. Among the various strategies of HCC prevention, immunization against hepatitis B virus infection is the most effective. Universal hepatitis B immunization has proved to be effective in reducing the incidence of HCC to 1/4-1/3 of that in children born before the hepatitis B vaccination era in Taiwan. The problems we face in achieving global control of hepatitis- related HCC include: (1) no effective vaccine for the prevention of hepatitis C and its related HCC; (2) no immunization program for hepatitis B in areas with inadequate resources; (3) poor compliance to the immunization program as a result of ignorance, anxiety, or poverty; and (4) vaccine failure. Integration of the hepatitis B vaccination program into the expanded program of immunization for all infants throughout the world will be most urgent and important for HCC control. The reduction of the incidence of HCC will be seen in adults 30-40 years of age after the launch of the universal hepatitis B vaccination program. This concept of cancer vaccine can be applied to other infectious agents and their related cancers
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