5.18
Hepatite viral I: Introdução
A hepatite viral é uma condição inflamatória do fígado causada pela infecção por vírus hepatotrópicos, mais comumente os vírus das hepatites A, B, C,…
Hepatite viral é uma inflamação hepática causada por uma infecção viral que tem como alvo o tecido hepático. As causas mais comuns são vírus da família da hepatite, A-E.
O vírus da hepatite A se espalha por alimentos contaminados ou água pela via fecal-oral.
A hepatite B é um vírus de DNA transmitido por sangue e fluidos corporais infectados. As rotas comuns incluem contato sexual, exposição ocupacional, especialmente lesões por agulhada e transmissão perinatal de mãe para filho.
A hepatite C é um vírus de RNA transmitido principalmente por exposição ao sangue. Caminhos comuns incluem compartilhar agulhas de drogas e práticas inseguras de tatuagem.
O vírus da hepatite D é um vírus de RNA defeituoso que requer o VHB para infectar. Pode ocorrer como uma coinfecção, ou seja, quando o VHB e o VHD entram juntos nos hepatócitos, ou como superinfecção, quando o VHD infecta alguém que já está portador de VHB.
O vírus da hepatite E é um vírus de RNA transmitido pela via fecal-oral, comumente por meio de água contaminada.
Além disso, outros vírus, como o vírus Epstein–Barr, citomegalovírus e vírus da febre amarela, também podem causar hepatite.
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Q1: How does hepatitis A virus spread from person to person?
Hepatitis A virus spreads through the fecal-oral route, typically when a person ingests food or water contaminated with fecal material from an infected individual. After entering the gastrointestinal tract, the virus reaches the liver and infects hepatocytes, causing an acute, self-limiting illness that resolves without chronic infection.
Q2: What are the main transmission routes for hepatitis B virus?
Hepatitis B virus spreads through infected blood and body fluids via sexual contact, sharing needles, occupational exposures such as needlestick injuries, and vertical transmission from mother to infant during childbirth. HBV infection may be acute or progress to chronic disease, making transmission prevention critical in healthcare settings.
Q3: Why is hepatitis D virus dependent on hepatitis B virus?
Hepatitis D virus is a defective RNA virus that requires hepatitis B virus for replication and cannot infect hepatocytes independently. HDV infection occurs as coinfection when HBV and HDV enter hepatocytes simultaneously, or as superinfection in individuals already chronically infected with HBV, typically worsening disease severity.
Q4: How does hepatitis C virus primarily transmit between individuals?
Hepatitis C virus is an RNA virus transmitted primarily through blood exposure, including sharing drug-injection equipment and unsafe tattooing or piercing practices. Sexual contact involving blood exposure is a less common transmission route. HCV infection can lead to chronic hepatitis and requires careful prevention strategies.
Q5: What distinguishes hepatitis E virus transmission and clinical course?
Hepatitis E virus is an RNA virus spread via the fecal-oral route, most commonly through contaminated water. While HEV generally causes acute hepatitis, infection can be especially severe in pregnant individuals, particularly during the third trimester, distinguishing it from other hepatitis viruses in terms of pregnancy-related complications.
Q6: Can viruses other than hepatitis A-E cause liver inflammation?
Yes, additional viruses such as Epstein-Barr virus, cytomegalovirus, and yellow fever virus can cause hepatitis as part of systemic infections. These non-hepatotropic viruses infect hepatocytes and provoke immune responses that can hinder liver function, though they are less common causes of viral hepatitis than the hepatitis family viruses.
Q7: What is the fundamental mechanism by which viral hepatitis damages the liver?
Viral hepatitis causes liver inflammation when hepatotropic viruses infect hepatocytes and provoke immune responses that can hinder liver function. Despite variations in viral structure and transmission routes, all hepatitis viruses target hepatic tissue, resulting in inflammation that ranges from acute, self-limiting illness to chronic disease with potential complications.