Know hepatitis 認識肝炎

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肝炎即是指肝臟細胞發炎,通常由感染肝炎病毒引起的。肝炎病毒共有五個主要種類,分別為甲、乙、丙 、丁、戊型(又稱A, B, C, D, E)。另外,肝炎亦可由酒精、藥物、化學物或遺傳病等因素而引發。

急性病毒性肝炎的病徵

急性病毒性肝炎患者不一定會有病徵,若出現病徵,典型的臨床表現可包括:

  • 不明顯病徵如發燒、疲倦、肌肉疼痛、頭痛、噁心及腹瀉
  • 食慾不振
  • 厭惡吸煙 (吸煙者)
  • 皮膚及眼白變黃
  • 小便顏色加深,呈茶色
  • 大便呈泥土色或變淺色

慢性病毒性肝炎的病情發展

感染乙、丙 、丁、戊型肝炎病毒後可引致慢性肝炎。若沒有適當治療,慢性肝炎可發展為嚴重的肝病,如肝硬化及肝癌。沒有治療過的慢性肝炎的典型病情發展如下:

Hepatitis is the state of inflammation of cells in liver, an important organ. It is commonly caused by viral infection. There are five main hepatitis viruses, namely hepatitis A, B, C, D and E viruses. In addition, hepatitis can be caused by alcohol, drugs, chemicals or genetic diseases.

Clinical features of acute viral hepatitis

Acute hepatitis can be asymptomatic. If symptoms develop, typical clinical presentation may include:

  • Non-specific symptoms, such as mild fever, fatigue, muscle pain, headache, nausea and diarrhea
  • Loss of appetite
  • Distaste for cigarette (in smokers)
  • Yellowing of skin and the whites of the eyes (jaundice)
  • Dark urine, almost like tea
  • Clay or light colored stools

Progression of chronic viral hepatitis

Chronic hepatitis can be caused by infection with hepatitis B, C, D or E viruses. If left untreated, chronic hepatitis could lead to serious liver diseases, including cirrhosis and liver cancer. Typical prognosis of untreated chronic hepatitis would be as follows:

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HEPATITIS A

Transmission

  • Hepatitis A spreads commonly in all parts of the world
  • Hepatitis A virus is primarily transmitted by faecal-oral route when an uninfected person consumes contaminated food or water.
  • Hepatitis A virus can also be transmitted through close physical or sexual contact with an infectious person.

Prevention

  • Hepatitis A vaccine is safe and effective to prevent the infection.
  • Risk of infection with hepatitis A virus can be reduced by observing personal, food and environmental hygiene.

Management

  • There is no specific treatment for hepatitis A.
  • Infected adults usually have symptoms compatible with acute viral hepatitis, while most children have asymptomatic infection.
  • The disease is self-limiting, and most symptoms usually resolve within a couple of months.
  • Hepatitis A infection is rarely fatal, but life-threatening debilitating symptoms and fulminant hepatitis may occur occasionally, leading to acute liver failure.
  • Hepatitis A virus infection does not cause chronic liver disease.
  • Most people recover fully from hepatitis A with lifelong immunity.

甲型肝炎

傳播途徑

  • 甲型肝炎在世界各地普遍流行
  • 甲型肝炎病毒主要是通過糞口途徑傳播,如進食受污染的食物或食水
  • 與甲型肝炎患者有緊密接觸或性接觸都有可能傳播甲型肝炎病毒

預防方法

  • 甲型肝炎疫苗既安全,亦能有效預防感染甲型肝炎病毒
  • 注意個人、食物及環境衛生能降低感染甲型肝炎病毒的風險

治理方法

  • 目前沒有藥物醫治甲型肝炎
  • 成年感染者多數會出現與急性肝炎相似的病徵,而小童則沒有明顯病徵
  • 甲型肝炎患者一般能自行痊癒,大部分感染症狀能於一兩個月內消除
  • 感染甲型肝炎病毒很少會致命,但亦有機會出現危及性命的併發症及暴發性肝炎,可以引致急性肝衰竭
  • 感染甲型肝炎病毒不會導致慢性肝病
  • 大部分甲型肝炎患者康復後終身免疫

HEPATITIS B

Transmission

  • Hepatitis is highly prevalent in Hong Kong and other Asian countries
  • Hepatitis B virus can be found in blood and body fluids of an infected person.
  • The main routes of transmission include mother-to-child transmission, blood contact and sexual contact.

Prevention

  • Hepatitis B vaccination is the most effective way to prevent infection.
  • A complete course of hepatitis B vaccination normally takes 3 injections. The injections are given 1 month and 6 months, respectively, after the first shot.
  • Risk of hepatitis B virus infection can also be reduced by avoiding sharing razors, toothbrushes or needles with other people, handling wound properly, disinfecting objects contaminated with blood and practising safer sex.

Management

  • There is no specific treatment for acute hepatitis B.
  • Acute infection can be asymptomatic, though rare cases of fulminant hepatitis may also occur.
  • Over 90% of adults can recover completely from hepatitis B virus infection and do not become chronically infected, but infected children are more likely to become chronic carriers.
  • Chronic hepatitis B infection can be treated, but not cured, with medicines, which suppresses the replication of hepatitis B virus for slowing the progression of cirrhosis, reducing incidence of liver cancer and improving long-term survival
  • Most people who start hepatitis B treatment must continue it for life.

乙型肝炎

傳播途徑

  • 乙型肝炎在香港和亞洲地區非常普遍
  • 乙型肝炎病毒大量存在於受感染者的血液及體液
  • 乙型肝炎病毒的主要傳播途徑包括母嬰接觸、血液接觸及性接觸

預防方法

  • 接種乙型肝炎疫苗是現時最有效預防感染的方法
  • 乙型肝炎疫苗一般需要三次注射,第二和第三針疫苗通常於第一針注射後的一個月及六個月接種
  • 其他可降低乙型肝炎毒感染風險的方法包括避免與他人共用剃刀、牙刷或針具,妥善處理傷口,消毒受血液污染的物品,與及進行安全性行為

治理方法

  • 目前沒有藥物醫治急性乙型肝炎
  • 由乙型肝炎病毒引起的急性感染者可以全無病徵,但偶然會發生罕見的暴發性肝炎
  • 九成以上的成年人感染乙型肝炎毒後可完全痊癒,並不會引致慢性肝炎,但小童若受感染則很大機會成為慢性乙型肝炎感染者
  • 現時透過藥物可控制但不能根治慢性乙型肝炎,藥物主要的作用是抑制乙型肝炎病毒的複製,從而減慢肝硬化的進程、降低肝癌的發病率及延長壽命
  • 乙型肝炎的藥物治療一旦開始,大部分患者需要終身服藥
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HEPATITIS C

Transmission

  • Hepatitis C virus is mainly transmitted through blood contact, such as sharing injection equipment, reusing inadequately sterilised medical equipment and transfusion of unscreened blood products
  • Other possible but less common routes of transmission include mother-to-child transmission and sexual transmission

Prevention

  • There is no vaccine available against hepatitis C
  • In health care settings, prevention of hepatitis C virus transmission depends largely on the protection of blood safety and upholding infection control standards
  • Individuals should not share needles, syringes and other personal care items that can potentially be contaminated with blood

Management

  • Hepatitis C does not always require treatment as the immune response in some people may clear the infection
  • When treatment is necessary, therapy with direct acting antivirals can cure most persons with hepatitis C virus infection
  • Chronic hepatitis C virus infection can result in serious long-term health problems, such as liver fibrosis, cirrhosis and liver cancer
  • Hepatitis C virus infection does not confer protective immunity and reinfection can happen in individuals with ongoing risk behaviour

丙型肝炎

傳播途徑

  • 丙型肝炎病毒主要是透過接觸患者的血液而傳染,如共用注射器具、重複使用未被徹底消毒的醫療器材及輸入未經篩查的血液製品
  • 丙型肝炎病毒亦可從母親傳給嬰兒或經性接觸而傳染,但並不常見

預防方法

  • 現時沒有可有效預防丙型肝炎病毒感染的疫苗
  • 確保血液安全及實行有效的感染控制措施可預防丙型肝炎病毒在醫護環境中的傳播
  • 避免共用針筒、針具或其他易受血液污染的個人衛生用品能預防感染丙型肝炎病毒

治理方法

  • 部份人的免疫反應能自行清除體內丙型肝炎病毒,故此感染後並不一定需要藥物治療
  • 當患者需要接受藥物治療時,大部分能透過服用直接作用抗病毒藥物根治丙型肝炎
  • 慢性丙型肝炎可引致嚴重的長期健康問題,如肝臟纖維化、肝硬化及肝癌
  • 感染丙型肝炎病毒後身體並不能產生具保護性的免疫力,若風險行為持續,痊癒者有重新感染丙型肝炎病毒的風險

HEPATITIS D

Transmission

  • Hepatitis D virus is transmitted through contact with blood or other body fluids of an infected person
  • Hepatitis D infection is more prevalent in some Mediterranean countries, Africa and Asia, but rare in Hong Kong
  • Vertical transmission from mother to child is possible but rare
  • Hepatitis D virus exists like a parasite of hepatitis B virus. Infection can only occur in the presence of hepatitis B virus

Prevention

  • Getting vaccinated against hepatitis B can prevent hepatitis D virus infection, but hepatitis B immunization does not provide protection against hepatitis D virus for carriers of hepatitis B virus.
  • Avoiding sharing of syringes, razors, toothbrushes and other objects that may be contaminated with blood and practising safe sex might reduce possible exposure to hepatitis D virus.

Management

  • Persistent hepatitis D virus replication is the most important predictor of mortality and the need for antiviral therapy.
  • There is currently no effective antiviral therapy for curing hepatitis D. The optimal duration of therapy is not well defined, but most patients relapse after discontinuation of therapy.
  • Liver transplantation may be required for cases of fulminant hepatitis and end-stage liver disease.

丁型肝炎

傳播途徑

  • 丁型肝炎病毒主要是透過接觸患者的血液或體液而傳染
  • 丁型肝炎在一些地中海、非洲和亞洲國家比較普遍,在香港則極為罕見
  • 母嬰傳染亦可傳播丁型肝炎病毒,但相對罕見
  • 丁型肝炎病毒就像寄生在乙型肝炎病毒一般,只會在已感染乙型肝炎病毒的患者中發生

預防方法

  • 接種乙型肝炎疫苗能預防丁型肝炎病毒的感染,但對已感染乙型肝炎病毒的帶菌者則不能起保護作用
  • 避免共用針筒、剃刀、牙刷等易受血液污染的物品及進行安全性行為能減低接觸到丁型肝炎病毒的機會

治理方法

  • 丁型肝炎病毒的持續複製可以導致死亡,患者需要接受抗病毒藥物治療
  • 現時沒有抗病毒藥物能根治丁型肝炎,而療程尚未明確界定,且大多數患者在停止治療後復發
  • 暴發性肝炎患者及末期肝病患者或需要接受肝臟移植
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HEPATITIS E

Transmission

  • Hepatitis E is found worldwide
  • Hepatitis E virus is mainly transmitted by faecal-oral route, principally via consumption of contaminated water
  • Foodborne transmission by eating raw or undercooked meat or meat products derived from infected animals may occur
  • Other identified, but uncommon, transmission routes include transfusion of infected blood products and mother-to-child transmission

Prevention

  • Effective vaccine for hepatitis E virus infection is not available in Hong Kong.
  • Risk of infection with hepatitis E virus can be reduced by maintaining good personal hygiene, avoiding consumption of water or ice of unknown purity and adhering to food safety

Management

  • There is no specific treatment for hepatitis E.
  • Symptomatic infection commonly occurs in young adults, while the disease is mostly asymptomatic or causes mild illness without jaundice in children
  • The disease is usually self-limiting, and people with hepatitis E will recover completely in 4-6 weeks.
  • The overall case-fatality rate of hepatitis E virus infection is about 1-2%, but clinical disease can be severe in pregnant women in their third trimester, with a case-fatality rate of 20%.
  • Cases of chronic hepatitis E infection have been reported in immunosuppressed people, who may require antiviral drugs for viral clearance.

戊型肝炎

傳播途徑

  • 戊型肝炎病毒在全球各地傳播
  • 戊型肝炎病毒主要是通過糞口途徑傳播,如飲用受污染的食水
  • 食用來自受感染動物而未被徹底煮熟的肉類或肉製品可感染戊型肝炎病毒
  • 輸入受感染的血液製品及母嬰傳染亦可傳播戊型肝炎病毒,但並不常見

預防方法

  • 香港現時沒有可有效預防戊型肝炎病毒感染的疫苗
  • 保持良好的個人衛生、避免飲用潔淨度不明的水或冰及注要食物安全都能降低感染戊型肝炎病毒的風險

治理方法

  • 目前沒有藥物醫治戊型肝炎
  • 年青的成年感染者多數會出現肝炎病徵,而小童則沒有明顯病徵或只出現輕微病徵
  • 戊型肝炎患者一般能於四至六星期內自行痊癒
  • 感染戊型肝炎病毒後的整體死亡率大概只有百分之一至二,但處於妊娠晚期的孕婦於感染後出現嚴重併發症的機會較高, 死亡率可高達百分之二十
  • 免疫力較弱的人群感染戊型肝炎病毒後,可引致慢性戊型肝炎,或需服用抗病毒藥物清除體內的戊型肝炎病毒