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Questions and Answers
What is the percentage of infants infected from HBsAg positive and HBeAg positive mothers?
What is the main mode of hepatitis C virus transmission?
Which serological marker indicates low infectivity in hepatitis B infection?
What is the effectiveness rate of administering HBIG and full HBV vaccination to newborns of HBsAg positive mothers?
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Which group is considered at high risk for hepatitis B transmission?
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Which antigen is a marker of viral replication in hepatitis B infection?
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What is the typical incubation period for hepatitis C?
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How many injections of the HBV vaccine typically result in about 94% seroconversion rates?
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What is the primary mode of transmission for Hepatitis A virus?
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Which of the following clinical features is associated with Hepatitis A?
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What is a common symptom that may precede jaundice in acute viral hepatitis?
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What is the typical prognosis for Hepatitis A?
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Which laboratory findings are typically elevated in acute viral hepatitis?
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What differentiates Hepatitis E from Hepatitis A?
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What is the causative agent of Hepatitis E?
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Which of the following symptoms is less commonly associated with Hepatitis A?
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Hepatitis D requires which virus for its replication?
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Which of the following is a method of transmission for Hepatitis E virus?
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What is the primary prevention method for Hepatitis B?
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What is the mechanism by which high doses of acetaminophen can lead to liver damage?
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In cases of drug-induced liver disease from chlorpromazine, which of the following symptoms may occur?
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What is the most effective treatment for acetaminophen overdose if administered within the appropriate time frame?
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What percentage of patients using isoniazid (INH) develop significant liver injury?
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What is a common clinical manifestation of acute acetaminophen toxicity within the first 24 hours?
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Study Notes
Hepatitis: Liver Inflammation
- Etiology: Viral infections, toxins, drugs, immune-mediated mechanisms
Viral Hepatitis
- Acute Viral Hepatitis: Duration less than 6 months
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Clinical Features: Most cases are subclinical. Early symptoms mimic a flu-like illness, preceding jaundice by 1-2 weeks.
- Symptoms: Nausea, vomiting, anorexia, taste/smell disturbance, headaches, fatigue, malaise, myalgias (muscle aches), low-grade fever.
- Signs: Arthralgia (joint pain), urticaria (hives) (especially in hepatitis B), clinical jaundice (yellowing of the skin and eyes), pale stools, dark urine, hepatomegaly (enlarged liver), RUQ pain (right upper quadrant pain), splenomegaly (enlarged spleen), and cervical lymphadenopathy (swollen lymph nodes in the neck).
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Liver Enzymes:
- Elevated AST and ALT (more than 10-20 times normal) due to hepatocellular necrosis (liver cell death).
- Mildly elevated ALP (alkaline phosphatase) and bilirubin (a breakdown product of heme).
- WBC count may be normal or slightly decreased initially.
Hepatitis A Virus (HAV)
- Etiology: Hepatitis A virus (most common viral hepatitis worldwide)
- Pathogenesis: Fecal-oral transmission, 2-6 week incubation period, virus directly damages liver cells (cytopathic) but does not cause cirrhosis.
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Clinical Features:
- Acute symptoms only: no chronic hepatitis.
- Viremia: Fever, malaise, anorexia, nausea, arthralgia.
- Signs: Jaundice (after 1-2 weeks) due to intrahepatic cholestasis (bile buildup in the liver), increased conjugated bilirubin (a type of bilirubin), hepatomegaly, splenomegaly, tender lymphadenopathy.
- Rare Complications: Hepatic encephalopathy (brain dysfunction) and death.
- Investigations: Liver function tests (LFTs) with elevation of all values, hepatitis A serology (blood tests for antibodies), hepatitis A PCR (polymerase chain reaction).
- Prognosis: Usually self-limiting with supportive treatment.
Hepatitis E Virus (HEV)
- Similar to Hepatitis A but High Mortality in Pregnancy: 20% mortality exceeding disseminated intravascular coagulation (DIC) in the third trimester.
- Etiology: Hepatitis E virus (a herpesvirus)
- Pathogenesis: Virus is directly cytopathic to the liver cells.
- Clinical Features: Fecal-oral transmission including vectors like dogs, pigs, and rodents. Clinical picture is similar to hepatitis A.
- Investigations: Liver function tests (LFTs) with elevation of all values, hepatitis E serology, hepatitis E PCR.
- Prognosis: 1-2% mortality from fulminant hepatic failure, 20% mortality in pregnancy from DIC during the third trimester.
Hepatitis B Virus (HBV)
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Transmission: Parenteral route (blood), vertical transmission (mother to child) during the third trimester or early postpartum.
- Mothers with HBsAg and HBeAg: 90% infant infection.
- Mothers with HBsAg and anti-HBe: 10-15% infant infection.
- Newborns of HBsAg+ mothers: Receive Hepatitis B immune globulin (HBIG) and full HBV vaccination (90% effective).
- Incubation Period: 6 weeks to 6 months.
- Infectivity: During HBsAg positivity.
- High Risk Groups: Neonates of carriers, partners of infected individuals (especially male homosexuals), IV drug users, healthcare workers, individuals from endemic countries.
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Serological Markers:
- HBsAg (surface antigen): Present during acute hepatitis B.
- HBeAg (e antigen): Component of HBV core, marker of viral replication, present during acute hepatitis B.
- HBcAg (core antigen): Cannot be measured in serum.
- Anti-HBs: Develops after HBsAg clearance and confers long-term immunity.
- Anti-HBe and Anti-HBc: Appear during the acute and chronic phases, but do not provide immunity. Anti-HBe indicates low infectivity.
- Prevention: HBV vaccine (recombinant HBsAg) with about 94% seroconversion rate after 3 injections. Hepatitis B Immune Globulin (HBIG) (anti-HBs) for needle sticks, sexual contact, and neonates born to infected mothers.
Hepatitis C Virus (HCV)
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Transmission: Primarily parenteral (blood) through transfusions (most common cause of post-transfusion hepatitis), IV drug use.
- Sexual transmission: Occurs but at lower risk than HBV.
- 40% of cases: No identifiable risk factors.
- Incubation Period: 5-10 weeks.
- Liver Enzymes: AST and ALT levels fluctuate unlike hepatitis A or B.
- Progression: More than half progress to chronic liver disease.
- Serological Markers: HCV RNA (detected by PCR assay), anti-HCV develops in 6-8 weeks in 85% of patients, persists in chronic infection and does not confer immunity.
- Prevention: No accepted vaccine for HCV.
Hepatitis D Virus (HDV)
- Infectivity: Only in the presence of HBV. HBV surface antigens required for replication.
- Transmission: Non-parenteral contact in endemic areas (Mediterranean), blood products in non-endemic areas (IV drugs, transfusions).
- Coinfection: Simultaneous HBV and HDV infection.
- Superinfection: Occurs as an exacerbation in chronic HBV patients.
- Complications: Predisposes to severe or fulminant hepatitis.
- Serological Markers: HBsAg, anti-HDV IgM or IgG.
- Prevention: HBV vaccine.
Hepatitis E Virus (HEV)
- Transmission: Fecal-oral, often in epidemics in Asia, Africa, Central America.
- Clinical Course: Most have mild disease, but 10-20% develop fulminant liver failure during the third trimester of pregnancy.
- Serological Markers: Anti-HEV.
- Prevention: No vaccine available.
Drug-Induced Liver Disease (Drug-Induced Hepatitis)
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Specific Drugs:
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Acetaminophen: Metabolized by the hepatic cytochrome P450 system. Can cause fulminant hepatic failure (transaminases > 1,000 U/L). Toxic dose is 10-15g in normal individuals, 4-6g in alcoholics or those taking anticonvulsants.
- Mechanism: High doses saturate the glucuronidation and sulfation elimination pathways, leading to the formation of a reactive metabolite that binds to hepatocyte membranes.
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Presentation:
- First 24 hours: Nausea and vomiting within 4-12 hours of ingestion.
- Next 24-48 hours: Hepatic necrosis (liver cell death) with increased aminotransferases, jaundice, possible hepatic encephalopathy, acute renal failure, and death.
- After 48 hours: Ongoing hepatic necrosis or resolution.
- Note: Potential delay in presentation with sustained-release products.
- Blood Levels: Correlate with the severity of hepatic injury.
- Therapy: Gastric lavage/emesis (within 2 hours of ingestion), oral charcoal, N-acetylcysteine orally or intravenously (within 8-10 hours of ingestion, effective for up to 72 hours) promotes hepatic glutathione synthesis.
- Chlorpromazine: Cholestasis in 1% after 4 weeks, often with fever, rash, jaundice, pruritus (itching), and eosinophilia (an increase in a type of white blood cell).
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INH (Isoniazid): 20% develop elevated transaminases, but less than 1% develop clinically significant disease.
- Susceptibility: Increases with age.
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Acetaminophen: Metabolized by the hepatic cytochrome P450 system. Can cause fulminant hepatic failure (transaminases > 1,000 U/L). Toxic dose is 10-15g in normal individuals, 4-6g in alcoholics or those taking anticonvulsants.
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Description
This quiz explores the causes, symptoms, and clinical features of viral hepatitis, particularly focusing on acute infections. Test your knowledge on how hepatitis affects the liver and the body's response to various viral infections. Ideal for students or healthcare professionals studying hepatology.
