Infections Flashcards
For women with toxoplasmosis, is there an association between the risk of infection and gestation age?
Yes.
- The risk of fetus acquiring infection INCREASES with advancing gestational age.
- the risk of fetus being affected/damaged DECREASES with increasing GA.
In other words a younger/less developed fetus is less likely to contract toxo, but if it does it is likely to be more severely affected.
Fetal risks associated with toxo?
Spontaneous T1 losses
IUGR
Microcephaly
Hydrocephalus
Intracranial calcification
Chorioretinitis
What is the most common congenital viral infection in pregnancy?
CMV
T/F. Neonatal CMV can be detected from a urine culture?
True, as CMV is excreted in urine
Can CMV occur if the mother is immune prior to pregnancy?
Yes, because both primary and reactivated infection can infect the neonate
A patient has a negative VDRL and a positive FTA-Abs, interpret these results.
- Consistent with treated syphilis or newly contracted syphilis
- when syphilis is contacted, the FTA-Abs becomes positive before the VDRL, hence it could indicate early infection.
- after the patient is treated, the VDRL becomes negative, but the FTA-Abs remains positive.
- so VDRL will be positive in untreated secondary/latent/tertiary syphilis
- TPHA (Treponema Pallidum Haemagglutination) tests also remain positive after treatment.
VDRL/RPR= rapid plasma reagin
FTA-Abs= fluorescent treponemal antibody- absorption test
Which tests for syphilis remain positive after adequate treatment?
- TPHA (Treponema Pallidum Haemagglutination) tests and
- FTA-Abs (fluorescent treponemal antibody- absorption) tests
Is a boy with Fifth’s disease contagious?
Assuming he has the slapped cheek rash, then NO.
—-because the virus disappears from the serum and respiratory droplets about 5 days prior to onset of the rash.
- Rash occurs approx 17-18 days after infection.
T/F. A patient with clinical signs of Fifths disease is no longer contagious?
True
How long does it take for IgM to be detectable after parvovirus exposure? How long does it persist? When should testing be repeated if pt was initially IgG neg?
3 days
- usually persists up to 6 mths
- repeat testing in 2-3wks, depending on time of exposure
Management of parvovirus positive mother?
Serial u/s scans for early identification of hydrops
Pt presents in TI with fever and vesicular, generalised rash for 3 days. No respiratory/neurological signs. What is ur advice?
- This patient has likely contracted a Varicella infection
-Oral acyclovir 800mg po five times daily for 7 days.
—to prevent development of severe complications (hepatitis, encephalitis, pneumonia) - acetaminophen for the fever
- advise to self isolate and stay away from patients at high risk of getting the infection (babies, other pregnant women, known immunocompromised persons).
- I would not administered Varicella immunoglobulin, as she presented after the rash appeared and it has no therapeutic benefit at this point.
- as the infection is contracted early in pregnancy (<28weeks), the risk of fetal infection (fetal Varicella syndrome) is very low.
- infection in the first trimester does NOT increase her risk of miscarriage.
- she would be referred to a maternal fetal medicine/MFM specialist at 5 weeks post infection or between 16-20 weeks gestation.
—-they will perform a detailed u/s to assess for evidence of fetal anomalies and they will also counsel her about the risks to the fetus.
-Her delivery would be vaginal unless there is an obstetric indication. - the paediatricians would be informed of this patient and any fetalncomplications that developed due to the infection [Fetal Varicella syndrome which may require nursery admission].
Give a brief overview of Hep C
- Hepatitis C is an RNA- viral infection that causes acute and chronic hepatitis.
- 80% develop chronic HCV, of which 20% develop progressive cirrhosis over 1-3decades (10-30yrs).
- Risk of progressive liver disease is LOWER when:
—- age <40yrs
—- non-alcohol drinkers - Prevalence 0.3%-0.5%
-Transmission is via blood mainly seen with IV drug users but also with blood transfusion.
It is the commonest cause of post transfusion hepatitis and it is not commonly transmitted via intercourse.
- <5% of long term sexual partners become infected.
- there is no vaccine to prevent transmission
- Risk of vertical transmission is 3%-5% (uncommon) but risk increases if viruses contracted in T3.
—-increases to 20% with HIV confection
-Vertical transmission is dependent on the viral RNA load. - chronic HCV does not affect the the rates of transmission.
- treatment with interferon alpha and ribavirin are Contraindicated in pregnancy.
- other newer antivirals (Sofosbuvir, ledipasvir) show no evidence of harm in animal models.
—both are taken orally, are well tolerated and highly effective.
Intrapartum - reduce transmission:
No fetal scalp electrode/fetal blood sampling
No AROM until delivery of Presenting part
Timing of delivery and mode of delivery impacted by hiv co-infection - will be dependent on HIV viral load at 36 weeks
—otherwise, vaginal delivery at term if no obstetric contraindications
- breastfeed postpartum as transmission in breast milk is uncommon.
-Test neonate for infection - look for HCV RNA in 2 serum samples taken at least 3 months apart w/in the first year Or a positive test for antibodies at 18mths
What does detection of HCV antibodies in the mother imply?
Persistent infection, NOT immunity
What are the s/es of interferon therapy for HCV? What percentage are asymptomatic?
Nonspecific symptoms:
Flu-like illness 80%
Fatigue 50%
Depression 25%
Haematological 10%
15% - asymptomatic
What are the maternal risks of Varicella infection?
HEP-D:
Hepatitis
Encephalopathy
Pneumonia
Death
T/F. Acute hepatitis is a rare event in pregnancy?
True
VZIG can be given for how many days post exposure?
10 days
What is the postmortem protocol for maternal sepsis (as per the Saving lives and improving mother’s care report 2014)?
- Thorough examination and histological sampling of all organs, including bone marrow.
- Examine and sample placenta if available.
- Information on the status of the fetus
- Blood cultures as soon as possible after death
—- taken from heart/neck veins, NOT from below the umbilicus and BEFORE the body is opened.
——-if not possible, take a sample of spleen parenchyma for culture.
T/F. Parvovirus infection is self-limiting?
True
What is the treatment for hydrops due to fetal paroviral infection?
- Intrauterine fetal blood transfusion
—– to correct the fetal anaemia and resolve the hydrops
Neonatal mortality rate of Listeria infection in pregnancy?
22%
How is MTCT of Hepatitis B prevented?
- hep-B specific Immunoglobulin
—provides immediate protection - hep-B vaccine
—–to develop lifelong immunity
- These reduce vertical transmission by 90%