A: travelers to regions with high rates of Hep A, sex contacts, MSM, household members or caregivers of infected person, illegal drug users (injection and non injection), pt with clotting factor disorders
B: infants of infected mothers, sex partners (or those with multiple partners or MSM), those with STDs, IVDUs, household contacts of infected person, healthcare workers exposed to blood on the job, hemodialysis patients, residents and staff of facilities for developmentally disabled persons, travelers to endemic regions
C: Current or former IVDUs, recipients of clotting factors prior to 1987 or of blood transfusions or organ donations before 1992, long-term hemodialysis pts, persons with known exposures to HCV, HIV pts, infants of infected mothers
What are the 3 types of acute hepatitis? Describe each.
Asymptomatic - Rise in LFTs and serologic markers present
Fulminant - severe liver failure that develops w/in 8 weeks of sx onset. Liver cell destruction leading to coagulopathy and hepatic encephalopathy
Describe each of the phases of symptomatic hepatitis
1. incubation period - time from infx to onset of sx
2. pericteric phase - lasts days to 3 weeks - nonspecific influenza like sx - malaise, aches, fever - conjugated bilirubin rises, dark urine
3. icteric phase - lasts 7-30 d - jaundice in sclera, pale stools, pruritis reported in 40% of pts
4. convalescent phase - may take up to 6 mo - fatigue and weakness
What is the incubation period for HAV, B, C?
A: 28 d
B: 120 d
C: 45 d
Describe chronic viral hepatitis
hepatocellular necrosis and inflammation, often with fibrosis, lasting 6+ months
not caused by HAV
mild to severe
can result in cirrhosis, portal HTN, hepatocellular carcinoma
liver injury is d/t cytolytic t-cell response to virus-infected hepatocytes (not from the virus itself being cytopathic)
Which Hepatitis viruses are transmitted enterally, which are transmitted parenterally?
Enterally - A, E (not in chronic carrier state)
Parenterally - B, C, D (exist in chronic carrier state)
Serologic test results for HBV
HBc (core particle) - indicates replicating HBV
HBsAg (surface antigen) - the immunogenic component of the vaccine
If pt is negative for HBsAg, anti-HBc, and anti-HBs they are susceptible
If pt is negative for HBsAg, but positive for anti-HBc and anti-HBs, they are immune d/t natural infection (have cleared the infx)
If pt is negative for HBsAg and anti-HBc, but positive for anti-HBs, they're immune d/t HBV vaccine
If pt is positive for HBsAg, anti-HBc, IgM anti-HBc, and negative for anti-HBs, they are acutely infected (can tell b/c IgM goes up first)
If pt is positive for HBsAg and anti-HBc, and negative for IgM anti-HBc and anti-HBs, they are chronically infected
If the HBsAg is negative, the anti-HBc is positive, and the anti-HBs is negative, the interpretation is unclear. Most likely a resolved infection, but could be susceptible, low level chronic infx, or resolving acute infx.
How is chronic infection defined? What does the timeline look like graphically?
Defined as presence of detectable HBsAg, HBeAg, and HBV DNA for > 6 months.
The HBsAg peaks around 2 weeks post exposure and then levels out and stays high.
The total anti-HBc and IgM anti-HBc begin to rise around 6 weeks and peak around 16 weeks. The IgM then drops off while the total anti-HBc remains high and levels off.
What are the phases of chronic hepatitis infection? Describe each.
Immune tolerant (4-10 weeks) - viral replication is active, but little or no evidence of disease. HBsAg are produced and IgM anti-HBc are produced before sx onset
Immune active - symptomatic - flares of hepatitis and increased ALT. Presence of HBeAg. Development of cirrhosis and hepatocellular carcinoma occurs in this phase. Repetitive cycle of inflammation, damage, healing, inflammation, damage, healing, etc.
Inactive carrier - levels of HBV DNA are present in liver, but undetectable. Seroconversion - anti-HBe develop and clear HBeAg.
Treatment of HBA
No drugs therapies
Supportive tx only - bed rest, anti-nausea meds (avoid chlorpromazine d/t cholestasis), correct fluid imbalance, pain control with APAP, cholestyramine for pruritis