Testing for Viral Hepatitis Flashcards
What is the DDx for acute hepatocellular injury?
- Viral hepatitis (A, B, C, D, E, EBV, CMV, Parvovirus)
- Acetaminophen toxicity
- Other toxins
- Ischemia
- Autoimmune liver disease
- Wilson’s disease (can present with fulminant acute hepatitis)
- Alpha 1 anti-trypsin deficiency
Hep A,B,C,D,E…RNA or DNA?
RNA, DNA alternating
CMV EBV HSV… RNA or DNA?
DNA
Self‐limited illness (<2 months)
Jaundice, fatigue, fever, anorexia, diarrhea, dark
urine, pale stools, abdominal pain
Younger age: fewer (if any) symptoms
Spread is fecal‐oral
Poor sanitation, contaminated food and water
Hep A
Dark urine and pale stools: not able to excrete conjugated bile normally, so some is excreted in the urine (making the urine darker)
Incubation is 2-6 weeks compared to 2-6 mos for B!
hep A
Most recent outbreak associated with frozen
strawberries in smoothies from “Tropical Smoothie Cafés”. 135 infections reported.
Hep A
Hep A vaccine became available?
1995
What are the two general tests for HepA?
Total anti-HAV:
- IgM, IgG, IgA
- looks at all antibodies, so if positive, can be from an acute infection, a previous infection, or has been immunized (cannot differentiate)
- IgM anti-HAV: acute infection only
To be diagnosed for Hep A you must meet both clinical and lab criteria which are…
Clinical case definition: An acute illness with
a) discrete onset of symptoms and
b) jaundice or elevated serum aminotransferase levels
And laboratory criteria for diagnosis:
Immunoglobulin M (IgM) antibody to hepatitis A
virus (anti‐HAV) positive
Who should be vaccinated for Hep A?
All children at 1 year (12‐23 mo)
Children and adolescents ages 2‐18 years where
routine vaccination is implemented because of
high prevalence
Travelers to high/intermediate prevalence
countries
Men who have sex with men
High risk: drug users, occupational exposure
Chronic liver disease patients
Pts. receiving clotting factors
RNA virus, flaviviridae family
Estimated that only 25‐50% of infected U.S.
patients are diagnosed
High rate (75‐85%) of chronic infection
because of low spontaneous clearance
Leading indication for liver TRANSPLANT in U.S.
Hep C
What is hte natural outcome of an HCV infection?
Of every 100 persons infected with HCV, approximately
75–85 will go on to develop chronic infection
60–70 will go on to develop chronic liver disease
5–20 will go on to develop cirrhosis over a period of 20–30 years
1–5 will die from the consequences of chronic
infection (liver cancer or cirrhosis)
when is acute hep C detectable?
viral RNA: 1-3 weeks post exposure
Abs: 20-150 days (average 50)
sxs of acute hep C? who is more likely to seroconvert?
Jaundice in <20%
preceded by malaise, lethargy, myalgias, low‐grade fever, nausea, vomiting, RUQ pain
symptoms can persist from 2‐12 weeks
symptomatic patients
Three modes of transmission for Hep C?
- exposure to infected blood (IV, needle stick, dialysis)
- Sexual transmission (C MUCH less than B)
- mother to child (4% risk during pregnancy, depend on level of viremia)
What lab tests are done for HCV?
- EIA/CIA immunoassays to look for antibodies
- oraquick (fingerstick)
- RIBA (NO MORE)
- molecular assays (quantitative and genotyping)
- liver bx (not usually needed)
- routine liver fxn tests
What is the signal to cut off ratio (s/co)?
Positive antibody screens should be confirmed by another method, most commonly RNA detection
Confirmatory testing may not always be needed if the s/co ratio (the ratio of a sample’s OD to the OD of the assay cut‐off for that run) EXCEEDS specified values, which vary by test system
** Confirmatory test should be run after positive screen, especially if positive test was “weak zone”!
what HCV genotypes are MC in the us?
1a and 1 b
unfortunately 1 has been most difficult to tx w/ interferon
How long does it take to detect anti-HCV abs?
Anti‐HCV
- Usually by 4‐10 weeks post infection
- By 6 months, >97% are positive
PCR
- 1‐3 weeks
what are reasons for false negative HCV results?
Immunosuppression
Low level of antibodies
Absence of antibodies against antigens in test
*Test has antibodies derived from specific molecule components, may not align with the antibodies formed within the patient
Testing in the “window period” (~11 weeks)
what are reasons for false + HCV results?
Usually unexplained
Aged serum samples
Hypergammaglobulinemia, rheumatoid
factor
Antibodies against vector or fusion proteins
Recent immunizations (influenza vaccine)
What does a positive screening assay indicate?
How do you confirm it?
Indicates current or past infection
No differentiation between acute, chronic, or
resolved infection
Positive results should be confirmed by
supplemental test
RNA
(RIBA test is no longer available) ▪ A different screening test
How many genotypes are there?
What type is the MC in the US?
Which genotypes require alplha interferon +/- ribavarin for 24 weeks vs 48 weeks?
Six genotypes (1‐6) and ~50 subtypes
Genotype 1 is most common in U.S.
Genotypes 2, 3 have a 3x better rate of
response to alpha‐interferon ± ribavarin than genotype 1
Need only 24 weeks of above conventional therapy vs. 48 weeks for genotype 1
who should be screened for HCV?
Persons born from 1945 through 1965 (BABY BOOMERS)
Persons who have ever injected illegal drugs,
including those who injected only once many
years ago
Recipients of clotting factor concentrates made
before 1987
Recipients of blood transfusions or solid organ
transplants before July 1992
Patients who have ever received long‐term
hemodialysis treatment
Persons with known exposures to HCV, such as
health care workers after needlesticks involving HCV‐
positive blood
recipients of blood or organs from a donor who later
tested HCV‐positive
All persons with HIV infection
Patients with signs or symptoms of liver disease (e.g.,
abnormal liver enzyme tests)
Children born to HCV‐positive mothers (to avoid
detecting maternal antibody, these children should not be tested before age 18 months)
baby boomers have an HCV prevalence ____xhigher than other age groups
5x (75% of known HCV infected people)
All should be screened at least ONCE for HCV
What is hte goal for treating HCV?
sustained virologic response (undetectable viral RNA 24 wks after tx completed)
what is used to tx HCV?
Until recently, treatment was combined
Peginterferon‐alpha‐2a OR ‐2b (s.c.)
Ribavarin (oral)
what are SE of PEG/RBV?
Nausea, diarrhea
Skin rash/itch
Insomnia
Severe depression
What is interferon lambda-3 SNLP?
essentially its better to have a C/C genotype
A SNP upstream of the interferon‐lambda‐3 gene (IL28B) influences rate of seroconversion
Subjects with rs12979860 C/C genotype have 2‐ 3 fold higher spontaneous clearance of HCV and 2‐fold higher treatment SVR vs. C/T or T/T
C/C genotype is more common among European‐Americans than African‐Americans
how does tx for geno 1 differ from geno 2?
weekly PEG for 1
Genotype 1: treatment‐naïve patients OR previously treated with PEG/RBV but relapsed
- Daily sofosbuvir and RBV, weekly PEG, for 12 weeks
Genotype 2: treatment‐naïve patients
- Daily sofosbuvir and RBV for 12 weeks
what is a new tx for HCV that has expected SVR 90-94%?
harvoni (ledipsair-sofosbuvir)
what should be done if Q8ok mutation is found associated with genotype 1a?
simeprevir is less efficient in these pts so other tx should be found
what is the cost of Sovaldi vs Harvoni?
Sovaldi: $1,000 per pill or $84,000 for a 12‐ week course
Harvoni: $1,125 per pill or $94,500 for a 12‐ week course
What is the POC method for HCV testing?
oraquick
DNA virus
Worldwide distribution
Parts of Asia have 20% prevalence rate
Age affects acute severity and chronicity
2/3 are asymptomatic
1⁄4 develop symptomatic acute hepatitis 1/10 become chronic carriers
HBV!!
the earlier you get the virus the more likely you are going to be a chronic carrier
who should be vaccinated for HBV?
All persons under 18 years
All persons over 18 years at increased risk
Vaccine is recombinant form of HBsAg
how is HBV spread?
Contact with infected blood or mucosal membranes
Sex with an infected partner
Injection drug use that involves sharing needles,
syringes, or drug‐preparation equipment
Birth to an infected mother
Contact with blood or open sores of an infected person
Needle sticks or sharp instrument exposures
Sharing items such as razors or toothbrushes with an infected person
how does acute HBV present?
(Incubation is 60‐150 days)
Low grade fever, malaise
GI symptoms (nausea, vomiting, diarrhea) Anorexia, altered taste perception
Hepatic tenderness
Dark urine, pale stools
Jaundice
Fatal in 0.5%‐1.0% (higher in over 60’s)
what is the fisrt serologic marker to apper with HBV and when does it disappear?
HBsAg
First serologic marker to appear
Disappears 1‐3 months after jaundice
Coincident with development of anti‐HBs
if HBsAg fails to clear it is evidence of ….
chronic infection
What is anti-HBs?
Appears after HBsAg has disappeared
Persists indefinitely
Indicates sero‐conversion (pt has cleared HBsAg!!!)
Positive in immunized persons
What is anti-HBc present? how long can it last?
Positive during the window when HBsAg is declining and anti‐HBs is appearing
YEARS!
IgM of HBV indicates…
recent infection
IgG of HGB indicates…
past infection
WHat does HBeAg indicate?
ACTIVE VIRAL REPLICATION (means there are intact virons present that are actively replicating and dividing)
HBeAg appears with, or soon after HBsAg
Indicates presence of intact virions, DNA
polymerase, and HBV DNA (i.e. active viral
replication)
Appearance of anti‐HBe is coincident with
disappearance of HBeAg and cessation of replication
What is a good marker for an acute infection during the window period?
anti-HBc IgM (core)
What makes a pt a chronic carrier?
HBsAg still present
Never formed anti- HBs but still has Abs to core antigens (IgM)
HBsAg Negative
Anti-HBc Negative
Anti-HBs Negative
Hep B naive (no exposure or vaccination)
HBsAg Negative
Anti-HBc Negative or
Positive
Anti-HBs Positive
Seroconversion or vaccinated (if anti-HBc is positive, seroconverted and cleared infection, if anti-HBc is negative, represents vaccination)
HBsAg Negative
Anti-HBc Positive
Anti-HBs Negative
Window period!
- Cleared surface antigen, but can’t detect antibody against antigen
- Shows how HBc (IgM) is good marker for window period
- Recheck in 3 months
HBsAg Positive
Anti-HBc (IgM) Positive
Anti-HBs Negative
acute HBV infection
HBsAg positive
Anti-HBc (IgM) Negative
Anti- HBc (total) positive
Anti- HBs negative
chronic infection
what type of virus is hep D and how is it spread?
Cannot get Hep D on its own, must be in conjunction with B!
Spread by percutaneous exposure
Defective RNA virus
- Nucleocapsid contains RNA and delta antigen
what is hte diff between a coinfection and superinfection?
Coinfection: B and D at the same time, more severe disease, but more likely to seroconvert and clear
Superinfection: already had chronic hep B but then infected with D later, much higher rate of cirrhosis
what % of pts with HDV cause a superinfection in chronic HBV ccarriers?
70‐80% cirrhosis vs. 15‐30% without HBD
how do you test for HDV?
Assays for total (IgG and IgM) anti‐delta
IgM is a marker of acute infection
Molecular analysis to detect RNA
what happens to anti-HDV whil anti-HBS goes up?
it goes down
W/ HBV-HDV superinfection what rises first before you can detect anti-HDV?
ALT
women who get Hep E while pregannt ahve…
high maternal mortality
Found in Asia, India, Middle East, Mexico
Travelers in U.S., but increasingly recognized
as being acquired in U.S.
2‐8 week incubation period
High maternal mortality (20‐30%)
Acute, self‐limited hepatitis in most patients,
but can be more serious
CDC offers serologic testing
Hep E
what is the typical serological course for HEV?
IgM first then replaced by IgG
what is the basic work up for acute viral hepatitis?
1 marker for A, 2 for B, 1 for C for first line Viral Hep Testing
- IgM anti-HAV
- HBsAg
- IgM anti-HBc
- Anti-HCV
thinkn about D if especially flulminant disease or known B carrier
Anti‐HAV or anti‐HCV indicates …
acute or previous exposure
does a negative anti-HCV exculde acute infection?
no!
HbsAg without IgM anti‐HBc suggests…
chronic HBV infection
basic panel for chronic hepatitis?
HBsAg
▪ If positive, do HBeAg and anti‐HDV
Anti‐HCV
▪ If positive, confirm with RIBA or PCR
Markers for autoimmune hepatitis
anti-smooth muscle
anti0liver kideny microsme type 1
PBC: anti0mitochrondrial
hemochromatosis
elevated ferritin and iron saturations
alpha 1 antitrypsin
liver and lung
wilsons disease
low serum ceruloplasmin, high urine copper
- Presents with neuropsych manifestations
