My Clinical Notes

Infections associated with congenital abnormality

 

• Specific infections that can adversely affect the fetus, neonate or mother – STORCH
• S          Syphilis
• T          Toxoplasmosis

Other

BV

Trichomoniasis vaginalis

Group B strep 

E.coli

Varicella

Listeria monocytogenes

• R         Rubella
• C         Cytomegalovirus
• H         HIV

Herpes

Hep B 

Human papillomavirus

Human parvovirus

 

Syphilis

• 70% of fetuses become infected if mother has primary or secondary syphilis during pregnancy.
• With later infection the risk is less
• Features of early congenital syphilis
  • Intrauterine death
  • Early congenital syphilis
  • Maculopapular rash
  • Hepatitis splenomegaly
  • Lymphadenopathy
  • Bone abnormalities
  • Anaemia
  • Neurosyphilis
• Late congenital syphilis – occurring after the age of 2
  • Blunted upper incisor teeth known as Hutchinson’s teeth
  • Inflammation of the cornea known as interstitial keratitis
  • Deafness from auditory nerve disease
  • Clutton’s joints – painless, symmetrical hydrarthrosis of the knee
• Treatment
  • Penicillin – the later the stage the longer the dose
  • A Jarish-Herxheimer reaction may occur as a result of release of proinflammatory cytokines in response to dying bacteria. This can be associated with pre-term labour
  • Women allergic to penicillin are problematic.
  • Tetracylin is second line but is contraindicated in pregnancy
  • Erythromycin is less reliable and resistance has been reported

 

 

Toxoplasmosis

 

• Mostly asymptomatic
• Not a problem if mother has been infected prior to pregnancy and has developed cell mediated immunity
• Infection in the first trimester most potentially damaging
• Only 25% of infections are transmitted to the fetus
• Those where infection has been transmitted late in gestation are at less risk of fetal damage
• Symptoms of severely infected infants
  • Hydrocephalus
  • Microcephaly
  • Chorioretinitis
  • Convulsions
  • Cerebral calcifications
• Treatment
  • Sulphadiazine and pyrimethamine in symptomatic adults
  • Pyrimethamine is teratogenic and shouldn’t be used in first trimester
  • Use spiramycin instead

 

Cytomegalovirus

 

• Herpes virus and therefore able to establish latency
• Of the mothers infected during pregnancy, only about 40% pass the infection to the fetus
• Of those infected 90% are asymptomatic
• Principle features
  • Microcephaly
  • Blindness
  • Deafness
  • Pneumonitis
  • Chorioretinitis
  • Cerebral calcification
  • Developmental delay
• Because initial infection of the mother is generally asymptomatic, the diagnosis isn’t made until late in pregnancy or birth
• Diagnosis
  • Definitively made by isolating virus in cell culture from throat swabs, urine, blood or CSF in the first three weeks of life
  • Also serological testing looking for rising IgG or virus spp IgM
  • In utero by amniocentesis and PCR
• Treatment
  • Ganciclovir and forscarnet – not used in pregnancy or for infected infants

 

 

Rubella

 

• Togovirus, causes insignificant infection in adults and adolescents but can have major congenital effects
• Features of congenital infection
  • Gregg’s triad – Cardiovascular defects

 Eye defects

 Deafness

• • Hepatitis
  • Thrombocytopenia
  • Bone involvement
  • Microcephaly
  • Mental retardation
  • Miscarriage
  • Stillbirth
  • Preterm birth
• Syndrome is more likely if mother has been infected early in pregnancy
• Diagnosis
  • At booking maternal antibody levels are measured, if low a booster vaccination should be given.
  • Virus specific IgM indicates recent infection

 

 

Varicella Zoster

 

• Pregnant women are more susceptible to chicken pox and may develop pneumonitis which can be fatal
• If infection occurs prior to 20 weeks gestation there is a 1% risk of a congenital varicella syndrome
• Consists of
• Hypoplastic limbs
• Scarring
• CNS anomalies
• If infection occurs late and the fetus is exposed to virus in the absence of maternal antibody, then infection is severe and there is a significant mortality rate
• Varicella zoster immune globulin should be given and perhaps also aciclovir

 

 

Infections associated with pregnancy loss and preterm birth

 

Parvovirus B19

 

• In 15% of infections occurring during pregnancy, the fetus becomes chronically infected
• This leads to persistant anaemia in utero which may develop into non-immune hydrops fetalis. This may spontaneously resolves or require intrauterine blood transfusion
• Diagnosis made by detection of materal viral specific IgM or seroconversion
• No treatment for infection

 

 

Listeria monocytogenes

 

• In the mother may present as a ‘glandular fever’ type illness with malaise, fever, headache, backache and diarrhoea
• Listeria infection of the new born occurs in two forms
• Early onset results from in utero infection and manifests as septicaemia within 2 days of birth.
• 30% of babies with early onset disease are still born
• Late onset form presents are menigo-encephalitis after the 5^th day
• For diagnosis, specimens from infected sites are taken for culture
• Treatment is with antibiotics – ampicillin is treatment of choice
• Without diagnosis the mortality for infected babies is 90%. With early treatment this figure is 50%

 

Malaria

 

• Pregnant women are at increased risk of the severe manifestations of malaria
• Infection may cause miscarriage or trigger premature labour
• Congenital malaria has been described
• Chloroquine is probably the lest toxic prophylactic for a pregnant women to take

 

 

UTI

 

Bacterial Vaginosis

 

• May be the most important cause of preterm birth
• Also associated with chorioamnionitis which can progress to deciduitis or amniotic fluid infection
• This may then lead to fetal pneumonitis and fetal death due to sepsis
• The inflammatory cytokines that are produced duing chorioamnionitis can lead to production of prostaglandins which can cause cervical ripening and the onset of labour
• Treatment
  • Metronidazole – was thought to be teratogenics but studies suggest this isn’t the case

 

Infections affecting the neonate at birth

 

Herpes simplex virus

 

• In pregnancy recurrent herpes may be more severe than normal and resemble primary herpes
• HSV2 is more likely than HSV1 to cause symptomatic recurrences
• Herpes infection in pregnancy can resulting in neonatal abnormalities of the skin, liver and CNS
• Neonatal mortality is 75% however if acyclovir is administered quickly this can be reduced to 40%
• Outcome is worse if the mother has been infected late in gestation when the baby has no protective antibodies and is vulnerable to disseminated infection or encephalitis
• If primary herpes presents around the time of delivery caesarean section may provide some protection as long as no more than 4 hours have elapsed since the rupture of the membranes
• I.V. acyclovir should be administered to the neonate
• Risk to the neonate is very small with recurrent herpes
• Infection during first trimester may cause miscarriage
• A congenital syndrome has been described involving;
  • Micro-ophthalmia
  • Chorioretinitis
  • Microcephaly

 

 

Group B Streptococcus

 

• Commensal in the gut and genital tract of 20-40% of women
• Associated with severe neonatal infection that can result in neonatal death
• The infants most at risk are premature, have undergone delivery following a prolonged rupture of membranes and growth restricted or have birth asphyxia
• Early disease presents as septicaemia and pneumonia
• Secondary disease can present a 1 to 4 weeks of age with meningitis
• Some units screen mothers at high risk at 28 weeks and offer then prophylactic penicillin

 

 

Chlamydia trachomatis

 

• Serotypes D-K cause genital infection
• Serotypes A-C cause trachoma
• Causes neonatal eye infections (ophthalmia neonatorum) and neonatal pneumonitis
• 50% of babies born to infected mothers develop ophthalmia neonatorum – presents about 1 week after birth as bilateral sticky eyes
• Treatment of choice is tetracycline or erythromycin however tetracycline should be avoided in pregnancy
• Neonates with ophthalmia neonatorum should be treated with tetracycline eye drops
• Erythromycin syrup should also be given to prevent pneumonitis
• Many women with Chlamydia trachomatis have subclinical endometritis which may predispose to  early pregnancy loss, chorioamnionitis, preterm birth and clinical post partum endometritis.
• High risk women and their partners should therefore be screened

 

Gonorrhoea

 

• Can lead to a neonatal eye infection that, if untreated, can lead to corneal scarring and blindness
• Neonates present a few days after birth
• Requires systemic antibiotic treatment according to sensitivities
• Gonorrhoea is also associated with chorioamnionitis and preterm birth

 

Trachomoniasis

 

• Newborn girls have a stratified squamous vaginal epithelium as an adult due to the effect of maternal oestrogen in utero
• They are therefore susceptible to trichomonas vaginalis infection from the mother
• Causes purulent vaginal discharge
• As the effects of maternal oestrogen wanes after the first few weeks, infection normally spontaneously resolves

 

 

 

 

 

 

 

 

 

 

 

HIV Infection

 

• Vertical transmission occurs in 25-40% of pregnancies if there are no interventions to reduce the risk
• The minority occur during gestation with the majority occurring at during parturition and breast feeding
• The risk of vertical transmission is higher if there is an increased viral load or a preterm delivery
• Vertical transmission is avoided by;
  • Avoiding breast feeding
  • Elective Caesarean section
  • Antiviral treatment prescribed during the latter half of pregnancy and to the neonate for 6 weeks after delivery
• If all three of these interventions are taken the risk of transmission in reduced to 1%

 

 

 

 

 

This entry was posted on Sunday, September 30th, 2007 at 1:30 pm and is filed under Gynaecology/Obstetrics. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.