Perinatal infections Flashcards
What is the leading cause of neonatal chorioretinitis?
a. CMV
b. Rubella
c. Syphilis
What percentage of pregnant women are IgG+ for HSV-2?
20-30%
What percentage of women HSV seroconvert during pregnancy?
2-4%
What percentage of HSV-2 infected people are not aware of having the infection?
75-90%
Symptoms of newly acquired HSV infection
Asymptomatic in 70% of pregnant women
30% - range from minimal lesions to widespread genital lesions, tender regional lymph node enlargement, fever, malaise, headache
HSV-1 causes what percentage of oral infections? genital?
90% oral
10% genital
HSV-2 causes what percentage of oral infections? genital?
10% oral
90% genital
(but among college-age populations, majority of new cases of genital HSV are HSV-1)
What percentage of neonatal HSV results from women who acquire HSV-1 or -2 near term?
50-80%
What is a “nonprimary first-episode HSV infection”?
HSV-2 confirmed in a person with prior HSV-1, or vice-versa. Symptoms are usually milder than a first-episode primary infection.
What is reactivation (recurrent) genital herpes?
- Caused by reactivation of latent HSV, usually HSV-2.
- Over 90% of HSV episodes in pregnancy are recurrent or non primary 1st
- Symptoms last 7-10 days, with low viral load shedding for 3-5 days.
What is the incidence of neonatal HSV after a vaginal delivery during a first episode primary infection?
25-50%
What is the incidence of neonatal HSV after a vaginal delivery during a recurrent infection?
<1%
Why is the incidence of neonatal HSV after a primary maternal infection higher?
The infant of the mother with primary HSV lacks the protection of transplacental type-specific antibodies. The major sites of intrapartum viral entry are the neonatal eys, nasopharynx, or a break in the skin. Transplacental infection is rare.
What is GBS?
Streptococcus agalactiaeAn encapsulated gram-positive coccus that colonizes the vaginal & GI tract
Manifestations of GBS in the mother
Urinary tract infectionChorioamnionitisEndometritisBacteremiaStillbirth
What are the 2 types of newborn GBS infection?
Early-onset - usually within first 24 hrs of life, up to 6 days after birthLate-onset - Usually at 3-4 weeks of age, can occur any time from 7 days - 3 months
Symptoms of neonatal GBS
Early-onset:Respiratory distressShockPneumoniaMeningitis (occasionally)Late-onset:Bacteremia (common)Meningitis (common)Poor feedingIrritabilityExtreme drowsinessListlessnessLocalized infection: middle ear, sinuses, bones, joints, skin
Prevalence of asymptomatic GBS anovaginal colonization in pregnant women
20%, can be transient or persistentA substantial portion of women colonized in one pregnancy will not have colonization during a subsequent pregnancy
Percentage of neonates born to mothers colonized with GBS that are colonized themselves
40-75%
Risk factors for early-onset GBS disease
Prolonged ROM (>/= 18 hrs)Preterm birth (but >80% GBS are term)Termp >/= 38 deg CMaternal GBS colonization btw 35-37wPrevious infant with invasive GBS diseaseMaternal choioBlack or HispanicGBS bacteriuria during pregnancyDM or GBS colonization in a previous pregnancy are not risk factors
Neonatal mortality due to GBS disease
5%25% if < 33w GA
Is there a vaccine for GBS?
accination against GBS is potentially the most effective method of preventing the morbidity and mortality caused by infection. GBS vaccines have been investigated as a tool to reduce maternal colonization and prevent transmission to the neonate; however, a licensed vaccine is not yet available.
What percentage of neonates with early-onset GBS sepsis are born to women without risk factors?
20.00%
How effective is a screening-based strategy compared to a risk factor-based strategy for GBS?
> 50% more effective for early-onset GBS, but does not affect the incidence of late-onset GBS sepsis
For whom is intrapartum GBS prophylaxis indicated?
Previous infant with invasive GBS diseaseGBS bacteriuria during current pregnancy+GBS screening culture during current pregnancy (unless C/S prior to ROM)Unknown GBS status and: /= 18 hrs Intrapartum temp >38 deg C Intrapartum NAAT GBS+
For whom is intrapartum GBS prophylaxis NOT indicated?
Previous pregnancy with a positive GBS screening culture (unless indication present during current pregnancy)C/S in absence of labor or ROM (regardless of culture status)Negative vaginal & rectal GBS screening culture 35-37w, regardless of intrapartum risk factors
What is the NPV of GBS cultures at 35-37w
95-98%, if prevalence 20%
Recommended regimen for GBS prophylaxis
Penicillin G, 5 million units IV x 1, then 2.5-3 million units IV q 4 hrs until delivery
Alternative GBS regimen
Amp 2 g IV x 1, then 1 g IV q 4 hrs until delivery
GBS prophylaxis - PCN allergic, but not at high risk for anaphylaxis
Cefazolin 2 g IV x 1, then 1 g IV q 8 hrs until delivery
GBS prophylaxis - PCN allergic, at high risk for anaphylaxis, susceptible to clinda & erythro
Clinda 900 mg IV q 8 hrs until delivery
GBS prophylaxis - PCN allergic, but not at high risk for anaphylaxis - resistant to clinda or erythro or susceptibility unknown
Vancomycin 1 g IV q 12 hrs until delivery
How is susceptibility testing for GBS performed?
Resistance to erythromycin is often, but not always, associated with clindamycin resistance. If a strain is resistant to erythromycin, but appears susceptible to clindamycin, it may still have inducible resistance to clindamycin. Treatment with erythromycin is not recommended.
Have current prevention strategies decreased the incidence of late-onset GBS disease.
Nope.
How long is a GBS screening culture valid for?
5 weeks
Parvovirus B19 structure
Single-stranded DNA virus
What percent of women of reproductive age are Parvovirus immune?
50-75% of women are IgG+ (immune)
When is Parvovirus infection more common?
Winter and spring
Among which group does Parvovirus infection occur the most?
Schoolteachers, day care workers, and women with nursery or school-aged children in the home. Around 50% to 80% of susceptible household members and 20% to 30% of individuals exposed in a classroom acquire acute infection from an infected child.
Parvovirus - adverse prognostic factors
Older maternal age
Maternal immunity and seroconversion
Raised maternal serum alpha-fetoprotein
Ultrasound findings
How common are symptoms in adults with Parvovirus? What are the symptoms?
In adults at least half of the infections are asymptomatic.
About 30% may have flulike symptoms, arthralgias, and adenopathy.
What are symptoms of Parvovirus in children?
Parvovirus B19 causes a common exanthematous disease in children 5 to 14 years old, called fifth disease or erythema infectiosum. Children have symptoms such as low- grade fever and ’¢ŠäŒ–slapped-cheeks’¢ŠäŒÎ rash, and are usually diagnosed just based on these symptoms.
Transmission of Parvovirus
Respiratory droplets
Parvovirus incubation period? When is infectivity greatest?
Incubation period 13-18 days
Infectivity greatest 7-10 days before the onset of symptoms
What are the target cells for Parvovirus infection?
Erythroid progenitors bearing the main cellular parvovirus B19 receptor P blood group antigen globoside on their surface
Fetal complications of Parvovirus infection
Of the infected fetuses, about 5% to 20% can develop anemia, of which 30% to 50% develop hydrops fetalis (about 2–6% of all infected fetuses), with some series showing hydrops rates as high as 66% of anemic fetuses.
What percentage of fetuses of mothers with primary Parvovirus infection will become infected themselves?
25-30% of fetuses of mothers with primary parvovirus B19 infection become infected themselves by vertical transmission.
What percentage of Parvovirus-infected fetuses will develop complications?
10%
What percentage of Parvovirus-infected fetuses will develop complications?
10%
Of fetuses infected with Parvovirus, what percentage will develop anemia?
5-20%
Of fetuses that develop anemia from Parvovirus, what percentage will develop hydrops fetalis?
30-50 (2-6% of all infected fetuses)
What is the risk of fetal death from Parvovirus?
1-6%. Fetal death occurs almost exclusively in hydropic cases diagnosed at 20 weeks are treated with timely transfusion (90% survival).
US findings in fetal parvovirus infection
Pericardial or pleural effusion Ascites Abdominal wall/skin edema Bilateral hydroceles Oligohydramnios or hydramnios Increased (>95th percentile) cardiac biventricular outer diameter Rare: Hydrocephalus Microcephaly Intracranial and hepatic calcifications
Treatment of Parvovirus exposure
Intravenous immunoglobulin (IVIG) prophylaxis is reasonable to consider for documented exposures in immunocompromised patients, although it is not currently recommended for prophylaxis in pregnancy.
Diagnosis of maternal Parvovirus infection
Maternal infection is usually diagnosed by IgM+ or by IgG seroconversion. IgM appears by 3 days of an acute infection, peaks at 25 to 30 days, and disappears by 4 months. Serum IgG appears a few days after IgM, and coincides with resolution of maternal symptoms. The detection of viral DNA by PCR is another means of diagnosis.
After maternal Parvovirus infection has been diagnosed, how do you screen for fetal anemia?
- Anemia can be detected by increased PSV of the MCA prior to the appearance hydrous
- With fetal anemia there is an increase of fetal cardiac output to maintain adequate oxygen delivery to tissues, leading to increased blood flow velocities
- MCA PSV using a threshold of >/=1.50 MoM has a high sensitivity (100%) and specificity (100%) for detecting fetal anemia