Hepatitis Viruses Flashcards
What is hepatitis
Inflammation of the liver without pinpointing a specific cause
What disorders may a patient present with when they have hepatitis
- Have a liver injury caused by a toxin
- Have liver damage caused by interruption of the organ’s normal blood supply
- Be experiencing an attack by his or her own immune system through an autoimmune disorder
- Have experienced trauma to the abdomen in the area of the liver
- Viral or bacterial infection of the liver
What do the hepatitis viruses do in acute infectious fevers
They infect the Kuppfer cells of the reticuloendothelial system, so avoiding liver damage
What are the characteristics of hepatitis carriers
- Evolve from acute infections that are mild and anicteric
- May be asymptomatic but detectable by blood testing
- Are frequently the source of infection for others
- Suffer long term sequelae of persistent infection
What types of hepatitis are common to form hepatitis carriers
Hepatitis C and B
What kind of virus is hepatitis A and how is it spread most frequently
- Enterovirus
- Fecal oral contamination - shellfish, children, group homes, water food
- Oral anal sexual activity contamination
What are the clinical features of Hepatitis A
Jaundice - chances increase as you get older
What complications are associated with hepatitis A
Fulminant hepatitis
Cholestatic hepatitis
Relapsing hepatitis
How serious is hepatitis A
Tests show 40% of urban americans have had Hep A but only 5% recall being sick
Hep A can cause prolonged illness but usually only short term and doesn’t cause chronic liver disease
Describe the pathogenesis of hepatitis A
- Virus replicates primarily in the hepatocytes
- Passes through the bile duct into the intestine where it is shed in large quantities
- Damage to liver function results in raised liver enzymes
- Jaundice lasts ~ 1 month, no carrier state, no tendency to chronicity or malignancy
What passive protection methods for Hep A are there
Human normal immunoglobulin - 3-6 months coverage, post exposure prophylaxis for health care workers
How is Hep A managed
- Vaccine - formalin inactivated vaccine prepared from HAV grown in human diploid cells
- Very high hygiene standards required
What is the incubation period for Hepatitis A
15-50 days
How does Hep B contamination occur
Skin/mucus membrane contamination with blood or serous fluid, most likely transmission is through blood - low concs of virus in saliva, semen and vaginal fluid
What is the incubation period for Hepatitis B
48-180 days
What are the complications hepatitis B
Chronic hepatitis
Cirrhosis
Liver cancer
How does replication occur for hepatitis B
- RNA intermediate and use of reverse transcriptase
- High mutation rates, however small genome prevents a large degree of genetic variability
What are the clinical features of hepatitis
Jaundice
Acute case-fatality rate - 0.5-1%
Chronic Infection
Premature mortality from chronic liver disease - 15-25%
What are the modes of transmission of Hep B
- Parenteral - transfer in blood
- Sexual - via genital fluids, sex workers and homosexuals
- Perinatal - at/during birth
What chronic hep B diseases are there from bad to the worst
- chronic persistent hepatitis asymptomatic
- chronic active hepatitis - symptomatic exacerbations of hepatitis
- Cirrhosis of Liver
- Hepatocellular carcinoma
What in the blood indicates the patient’s blood is infective for others
Presence of HBeAg and Dane Particles
NB the core antigen is not detectable
What antigens are serological markers of Hepatitis B
HBsAg: present in acute and chronic infections
HBeAg: present in acute and chronic infections (indicates infectivity when present)
What enzyme is present in acute and chronic Hep B infections
Viral DNA polymerase
What antibodies are serological markers for Hepatitis B
- Anti-HBs indicate recovery, present in convalescence
- Anti-HBe indicates little or no infectivity
- Anti-HBc indicates recent infection if present in IgM form
