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Maternal Medicine > Hepatitis B > Flashcards

Hepatitis B Flashcards

References: Evidence-Based MFM, Ch 30; Creasy & Resnik

1
Q

What is the vertical transmission rate of HBV in women with HBeAg+?

A

95%

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2
Q

What is the vertical transmission rate of HBV in women who are HBsAg+ but HBeAg-?

A

25%

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3
Q

What is the vertical transmission rate of acute HBV in the third trimester?

A

90%

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4
Q

Without intervention, what percent of newborns infected with HBV develop chronic hepatitis? How many develop complications?

A

90%, with 25% of chronic HBV carriers eventually dying of complications (cirrhosis, hepatocellular cancer)

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5
Q

What vaccines do newborns born to women with HBV receive? Efficacy?

A

HBIg, HB vaccine, within 12 hrs of birth, prevents 90% of neonatal HBV infection

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6
Q

Is breastfeeding contraindicated in HBV+ mothers?

A

Breast-feeding is not contraindicated, as long as the mother is HBeAg- and HIV-, and the newborn receives appropriate immunoprophylaxis.

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7
Q

Labs for serologic diagnosis of acute HBV

A

HBsAg+, HBcAb+, HBcIgM+, HBsAb–

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8
Q

Labs for serologic diagnosis of chronic HBV

A

HBsAg+ >6 months, HBsAb–

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9
Q

Differential diagnosis of hepatitis

A 
Hepatic A, B, or C virus
Cytomegalovirus (CMV)
Epstein–Barr
Varicella (VZV)
Coxsackie B
Herpes (HSV)
Rubella
Autoimmune
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10
Q

Diagnosis of newborn HBV

A

Detection of persistent (e.g., >9 months of age) HBsAg. Only HbsAb is attributable to newborn vaccination: HBcAb arises only as the result of actual HBV infection.

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11
Q

Symptoms of acute HBV

A

Only 30% to 50% of patients acutely infected have symptoms such as loss of appetite, malaise, nausea, and vomiting. About 10% have jaundice. The onset is usually insidious.

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12
Q

Natural history of HBV infection

A

One-third of the world’s population (two billion people) have been infected with HBV: 90% have complete resolution, while about 10% overall develop chronic HBV infection; but this incidence is 90% in children 5 years old. About 25% of HBV chronic infection patients die of liver disease (4000/yr in the United States, >1 million/yr world-wide—0.5% mortality)

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13
Q

HBV vaccine efficacy

A

The vaccine is about 95% effective against HBV.

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14
Q

HBV incubation period

A

60-90 days

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15
Q

HBV antigens

A

“s” surface—infected. If present >6 months = chronic HBV infection
“c”—core
“e”—infectious

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16
Q

HBV antibodies

A

“s”—immune

“c”—covers “window” period, and usually precedes HBsAb conversion

17
Q

Risk of chronic HBV infection

A

About 5% of HBV infections become chronic. This can lead to cirrhosis, hepatocellular carcinoma, and death.

18
Q 
Interpret this HBV panel:
HbsAg -
Anti-HBc -
Anti-HBs -
Vertical transmission rate?
A

Susceptible

0%

19
Q 
Interpret this HBV panel:
HbsAg -
Anti-HBc +
Anti-HBs +
Vertical transmission rate?
A

Immune bc of natural infxn

0%

20
Q 
Interpret this HBV panel:
HbsAg -
Anti-HBc -
Anti-HBs +
Vertical transmission rate?
A

Immune bc of HB vaccine

0%

21
Q 
Interpret this HBV panel:
HbsAg +
Anti-HBc +
Anti-HBc IgM +
Anti-HBs -
Vertical transmission rate?
A 
Acutely infected
First trimester: 10% 
Third trimester: 90% 
HBeAg -: 10–20% 
HBeAg +: 90%
22
Q 
Interpret this HBV panel:
HbsAg +
Anti-HBc +
Anti-HBc IgM -
Anti-HBs -
Vertical transmission rate?
A

Chronically infected
HBeAg -: 2–10%
HBeAg +: 90%

23
Q

Interpret this HBV panel:
HbsAg -
Anti-HBc +
Anti-HBs -

A

Four interpretations possible:

  1. May be recovering from acute HBV infection
  2. May be distantly immune and test is not sensitive enough to detect very low level of anti-HBs in serum
  3. May be susceptible with false-positive anti-HBc
  4. May be an undetectable level of HBsAg present in the serum and the person is actually a carrier
24
Q

Blood transfusion HBV transmission risk

A

1/137,000 transfused units of screened blood

25
Q

HBV risk factors

A 
Intravenous drug abuse
Sexually transmitted diseases
Multiple sex partners
House contacts
Metal institution/prison
Acupuncture are other risk factors
HBV-infected patients are at higher risk of HIV and HCV infections.
26
Q

Complications of HBV

A
  • Ninety percent of patients resolve the infection (clear the s and e Ag) and develop HBsAb
  • 10% develop chronic HB (maintain HBsAg). Of these, most are asymptomatic with normal liver function tests (LFTs), and no HBV detectable by PCR.
  • The other 15% to 30% of chronic HB has persistent viral replication: these patients can develop cirrhosis and hepatocellular cancer. Mortality is 0.5% to 1%. This is more common in pts coinfected with HCV or HIV.
27
Q

Lamivudine for HBV - efficacy, dosing

A

-FDA category B
- >95% efficacy to achieve <150,000 HBV DNA, 167% HbeAg negativity
-Can reverse cirrhosis of the liver.
Given usually as 100 mg from 28 weeks to one month after birth in HBV carrier mothers, has been associated with a significant decrease in the HBV mother-to- child transmission

28
Q

How to treat HBV exposure in pregnancy

A

Check serologies, LFTs. If HBsAg- and sAb-, give HBIg and begin the HB vaccine series (preferably within 24 hours of exposure): this combination will prevent 75% of transmission. Must give HBIg within 14 days of sexual contact. Repeat HBIg within one month if blood or mucous membrane exposure.

29
Q

What is HDV?

A

Incomplete RNA virus, which can super- infect 20% to 25% of chronic HBV-infected patients. HDV infection worsens chronic HBV infection, so that 25% may die from disease. If HBV is prevented, HDV infection is prevented too. HDV has no effect on pregnancy or fetus/ neonate.

30
Q

Presence of HBeAg indicates:

A

Active viral replication and a high level of infectivity.

31
Q

When should you start lamivudine treatment for HBV in pregnancy, if the pt has had a previous perinatal transmission?

A

28 weeks

HBV DNA >/= 200,000 IU/mL or >10^6 copies/mL

32
Q

When should you start lamivudine treatment for HBV in pregnancy, if the pt has NOT had a previous perinatal transmission?

A

28 weeks

HBV DNA >/= 2,000,000 IU/mL or >10^7 copies/mL

33
Q

In clinical trials, effect of lamivudine prophylaxis on perinatal HBV transmission with lamivudine prophylaxis decreases by?

A

The overall effect favored lamivudine prophylaxis when these studies were combined (RR 0.31, 95% CI 0.15-0.63).

Maternal Medicine (20 decks)

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