Viral Hepatitis Flashcards
What are the types of liver diseases?
Alcohol
Toxic
Autoimmune
Infectious (viral, bacterial, parasite)
What are the types of hepatitis infection?
Acute
Chronic
How long does acute hepatitis last?
0-6 months
How long for chronic hepatitis?
> 6 months
What are the features of acute hepatitis?
Short term duration
Presents with clinical symptoms
Patient recovery
Infection resolves
What are the features of chronic hepatitis?
Delayed clinical presentation
Inflammation and fibrosis signs of progressive disease
Persistent
Higher risk of developing hepatic encephalopathy and liver carcinoma
What is the pathogenesis of hepatitis?
Infected hepatocytes Antigen presentation MHC class I CD8 cytotoxic T cells Inflammation Liver damage Symptoms ALT/ATP level rise Jaundice
What are the symptoms of hepatitis?
Jaundice Fever Pain Dark urine Itching Pale stools Sickness Anorexia Myalgia Arthralgia Malaise Hepatomegaly
What does AST stand for?
Aspartate aminotransferase
What does ALT stand for?
Alanine aminotransferase
What is jaundice?
Yellowing of the skin, eyes, mucous membranes, pale stool and dark urine due to accumulation of bilirubin in blood and tissues
What are the types of jaundice?
Pre-hepatic jaundice
Intra-hepatic jaundice
Post-hepatic jaundice
What is pre-hepatic jaundice?
Increased breakdown of RBCs caused by extrinsic disease
What extrinsic disease can cause pre-hepatic jaundice?
Malaria
Sickle cell anaemia
Thalassaemia
What is intra-hepatic jaundice?
Damage to hepatocytes causes loss of liver function therefore altered metabolism of bilirubin
What is intra-hepatic jaundice caused by?
Infectious disease (hepatitis A-E, CMV/EBV) Alcohol abuse
What is post-hepatic jaundice?
Damage or blockage of the bile duct system
What is post-hepatic jaundice caused by?
Gallstones
Pancreatic cancer
Gallbladder cancer
What is liver cirrhosis?
Loss of function through excessive damage and scarring
What are the symptoms of liver cirrhosis?
Weight loss
Ascites
Peripheral oedema
Irregular coagulation
What is hepatitis A?
Small single stranded RNA virus
One serotype, 7 genotypes
What is the structure of HAV?
30nm Naked viron ssRNA in protein shell No envelope 4 viral proteins
What are the 4 viral proteins of HAV?
VP1
VP2
VP3
VP4
How is HAV transmitted?
Faecal oral route
Contaminated food, water, close personal contact
What is the infectious period of HAV?
2 weeks prior to and 1 week after onset of jaundice
What is the incubation period of HAV?
15-45 days
Is HAV chronic?
No
Is there a vaccine available for HAV?
Yes for selected populations
How is HAV diagnosed?
Clinical presentation
Serological analysis
Total anti-HAV Ab
HAV IgM raised during acute phase (drops at 6 months)
What is the structure of HBV?
42nm Inner icosahedral core 27nm Spherical Enveloped viron Surface antigens and glycoproteins Circular dsDNA
How long is the incubation period for HBV?
6-26 weeks
How is HBV transmitted?
Blood borne Sex Perenteral Direct Horizontal transfer from mother to foetus
Who is at risk of HBV infection?
IVDA
Tattoos
Transfusions and blood products
Unprotected sex
What percentage of HBV are asymptomatic?
90%
How many people become chronic carriers of HBV?
350-400 million
