Infectious disease Flashcards
What type of virus is Hep B virus?
Enveloped DNA virus
What is the definition of chronic hepatitis B?
HBsAg positive for > 6 mo AND absence of anti-HBs antibody
What is the most common route of transmission of HBV?
What are the other routes?
Vertical is the MOST common route of transmission
High prevalence areas –> perinatal transmission
Intermediate prevalence –> horizontal (child to child) in early childhood
Low prevalence –> Unprotected sex, IDU
Is breastfeeding contra-indicated in HBV?
No, HBV is not spread through breast milk
What is the significance of HBeAg?
Active replication of the virus
(CAUTION: 30 % have mutation that prevent HBeAg expression)
What is the rate of neonatal transmission of hep B with and without PEP?
With: 2 %
Without:
- 90 % (mother HbeAg+)
- 15 % (mother HbeAg-)
Name factors that increase perinatal transmission of Hep B (5)?
HbeAg +
High viral load (DNA)
Genotype
Resistant virus
Altered timing of PEP
What is the single strongest factor driving perinatal transmission of Hep B?
HBV DNA viral load
(Often in viral load > 200 000 ≈106)
Even in the presence of appropriate neonatal PE
Does Hep B increase adverse pregnancy outcomes?
Chronic: None (no increase in SAB, PTB etc)
Acute:
Low birth rate
Prematurity
Increased perinatal transmission:
- 10 % if maternal infection in early pregnancy
- 60 % if maternal infection at or near the time of delivery
In cases of pre-natal serologies positive for HBsAg, what other test should you order?
HBeAg
HbeAb (anti-HBe)
HbcAb (anti-HBc)
Hbc IgM (Anti-HBc IgM)
HBV DNA levels
Liver enzymes, bili, coags, CBC
Ultrasound of the liver
Hepatology/ ID consult
What the indications for HBV treatment in pregnancy?
1- Maternal reasons
2- Prevent transmission
HBV viral load > 200 000 (>106)→ start treatment at 28+32 weeks
What is the PEP regimen to prevent Hep B transmission to newborn
HBIG 0.5 mL IM
+
Hep B vaccine 0.5 mL IM (1st of 3 doses)
Given within 12h of birth
**f baby is preterm or wt < 2000g, needs 4 doses of vaccination (vs 3)**
What additional testing does complicated VVC warrant?
Testing for HIV and DM
What is the definition of complicated VVC?
Recurrent (> 4 episodes in 12 month)
Associated with severe symptoms
Non-albicans species
Present in immunocompromised host
Laboratory findings in Candida infections (3)
pH < 4.5
Wet mount: Budding yeast and pseudohyphae
Gram stain: polymorphonuclear cells, budding yeast, pseudohyphae
What are the RF for yeast infection (4)?
Sexual activity
Recent abx use
Pregnancy
Immunosuppression (HIV, poorly controlled DM)
What are the options to treat non albicans VVC?
Boric acid insert
Flucytosine cream
Amphotericin B suppository
Nystatis suppository
What is the other name for strawberry cervix and what is it associated to?
Colpitis macularis
Associated to trichomonas
Describe the Amsel criteria (4)
3 out of 4 for BV diagnosis
- Adherent and homogenous vaginal discharge
- Vaginal pH > 4.5
- Detection of clue cells on saline wet mount
- Positive wiff test (amine odour after addition of K hydroxide)
Name the reasons to prescribe supressive treatment for HSV (5)?
At least 6 recurrences per year
Less than 6 recurrences but significant complications with recurrences
Need to lower risk of transmission to partner, fetus, neonate
Problem with QoL
Social or sexual dysfunction
What are the treatment schemes for herpes ?
1- Episodic treatment
2- Supressive treatment (only effective during treatment)
What is the classic triad of NEONATAL HSV infection
Skin lesions
Chroniretinitis
CNS abnormalities (seizures, lethargy etc)
What is the risk of neonatal HSV infection in :
1- Primary infection
2- Recurrence
What is the risk of post-natal infection without prevention?
1- Primary infection: 30 - 50 %
2- Recurrence: < 1 %
Post-natal infection without prevention: 15 %
Describe CONGENITAL neonatal HSV
Microcephaly, hydrocephaly, ventriculomegaly
Hepatosplenomegaly
Echogenic bowel
Spasticity, flexed extremities
IUGR
IUFD
What is the treatment of maternal primary HSV infection?
Non severe maternal disease
Acyclovir 400 mg po tid × 7–10 days
Valacyclovir (Valtrex) 1 g po bid × 7–10 days
Severe maternal disease
Acyclovir 5-10 mg/ kg q 8h until clinical improvement then PO tx x 10 days
Prophylactic regimen at 36 weeks