L39: Hepatitis Flashcards
3 types of viral hepatitis
- Acute (main one)
- Chronic (doesn’t resolve after 6 months)
- Fulminant (rapid, severe form that affects brain function – often need liver transplant)
Symptoms of hepatitis
Jaundice, liver inflammation, dark stool, acholic stool (light/clay-colored due to reduced bile production), prodrome preceding jaundice
Importance of bilirubin
Formed when body recycles heme from red blood cells – secreted in bile in liver and excreted – gets into the body fluids (blood and urine) in liver disease
Importance of liver enzymes
ALT and AST are elevated with hepatitis (even in prodrome phase) – usually higher than other causes of liver disease
Chronic viral hepatitis
Does not resolve within 6 months – symptoms become milder but predisposes to hepatocellular carcinoma and cirrhosis due to immune response to infected cells that causes tissue damage – can take 15-40 years to cause other diseases
Fulminant viral hepatitis
Rapid, severe, causes massive hepatic necrosis, encephalopathy (confusion, disorientation, coma), edema, and other complications – liver transplant often necessary
Which types of viral hepatitis are NOT associated with chronic infections?
Hepatitis A and E
Which types of viral hepatitis are transmitted fecal-orally?
Hepatitis A and E
What types of viral hepatitis are transmitted via body fluids?
Hepatitis B, C and D
Hepatitis A characteristics
Picornavirus family, +ssRNA genome, fecal-oral, all age groups susceptible (children usually asymptomatic), incubates for about a month and resolves within 2 months
Diagnosis of Hepatitis A
Acute infection = IgM antibodies against HAV, later stages anti-HAV IgG antibodies for protective immunity
Prevention of Hepatitis A
Inactivated vaccine (HAVRIX and VAQTA), IM injection with 2 doses – infants and high-risk adults – vaccine or anti-HAV IgG antibodies given as prophylaxis
Hepatitis B characteristics
Hepadnavirus family, partially dsDNA, uses reverse transcriptase,
2 types of particles of Hepatitis B
- Noninfectious tubes and spheres – only contain HBsAg but indicate presence of disease
- Infectious (Dane) particle – have HBsAg covering them, HBcAg inside, and HBeAg found in DNA
Hepatitis B general serology
Acute = HBsAg early in infection, goes away as virus cleared; anti-HBs increases when HBsAg goes away; IgG anti-HBc increases and stays high until resolution Chronic = simiar HBsAg early on but is maintained throughout infection, anti-HBc is present (IgG) but IgM goes down
Diagnosis of Hepatitis B
Viral antigens and anti-HBV antibodies, presence of HBsAg is marker of active infection
Serology for acutely infected (Hep B)
HBsAG: +
anti-HBsAg: -
Total anti-HBc: +
IgM anti-HBc: +
Serology for chronically infected (Hep B)
HBsAG: +
anti-HBsAg: -
Total anti-HBc: +
IgM anti-HBc: -
Serology for vaccinated (Hep B)
HBsAG: -
anti-HBsAg: +
Total anti-HBc: -
Serology for previously infected (Hep B)
HBsAG: -
anti-HBsAg: +
Total anti-HBc: +
Serology for susceptible (Hep B)
HBsAG: -
anti-HBsAg: -
Total anti-HBc: -
Transmission of Hepatitis B
Via body fluids (sexual transmission, needle stick, perinatal transmission at birth)
Chronic infection and age
The younger you are when you’re infected, the more likely you are to become chronically infected
Treatment for Hepatitis B
None for acute infections, Lamivudine (reverse transcriptase inhibitor) or Famcylovir/Adefovir dipivoxil (nucleoside inhibitor) combined with interferon-a for chronic infections
Vaccine for Hepatitis B
Composed of purified HBsAg protein (3 dose schedule, IM) – used to be from purified plasma of humans, now recombinant from yeast – recommended for all infants (also used for prophylaxis with HBIG)
Hepatitis C characteristics
Flavivirus family, enveloped, +ssRNA genome – much milder than HAV or HBV
Transmission of Hepatitis C
Bloodborne, through body fluids – INJECTION DRUG USE is a big one, along with tattos, accidental needle stick, perinatal, or sexual
Diagnosis of Hepatitis C
Done when chronic infection suspected – screening test first (Ab-based) then confirmatory test (nucleic acid-based)
What are the detectable lab features of acute Hepatitis C?
HCV RNA followed by ALT and anti-HCV
Treatment for Hepatitis C
Always includes a sofosbuvir (across all genotypes) – very expensive treatments
Prevention of Hepatitis C
No vaccine but can reduce high risk behaviors (drug use or unprotected sex), screening of blood supply
Hepatitis D characteristics
Small circular ssRNA genome, encodes two proteins covering virion (Delta short and long), helper-dependent virus – DEPENDS ON HBV PROTEINS – directly injures hepatocytes
Transmission of Hepatitis D
Body fluids – ONLY can cause disease in people infected with Hepatitis B
Hepatitis D and fulminant hepatitis
More likely in double infection of Hepatitis B and D double infection than any other single infection
Diagnosis of Hepatitis D
ELISA to detect anti-HDV antibodies
Treatment of Hepatitis D
No specific antivirals
Prevention of Hepatitis D
HBV infection is ABSOLUTELY required so HBV vaccine prevents HDV
Hepatitis E
Hepevirus family, +ssRNA genome, fecal-oral transmission, does not cause chronic infection, normally travel-related in US – high risk of death in pregnant women – treatment alleviates symptoms and prevention is clean water/proper food handling
