Neonatal and Childhood Infections Flashcards
Define congenital infections.
Babies are born with congenital infections i.e. transmitted vertically from mother to baby.
Infection can occur at any time during pregnancy, between first trimester and birth.
What is included in current maternal screening?
Hep B
HIV
Syphilis
What is not currently screened but is possible?
CMV
Toxoplasmosis
Hep C
Group B Streptococcus
Rubella
What is the presentation of congenital infections?
Varied presentations and non-specific signs.
Need to be considered in any sick neonate.
What is TORCH?
- Toxoplasmosis
- Other – syphilis; HIV; hepatitis B/C
- Rubella
- Cytomegalovirus (CMV)
- Herpes simplex virus (HSV)
What are common signs of congenital infections?
Common clinical features:
- Mild/no apparent maternal infection
- Wide range of severity in the baby
- Similar clinical presentation
- Serological diagnosis
- Long term sequelae if untreated
Examples:
- Low platelets, rash
- Cerebral abnormalities
- Hepatosplenomegaly/hepatitis/jaundice
What is toxoplasmosis?
The only known definitive hosts for Toxoplasma gondii are members of family Felidae (domestic cats and their relatives).
Unsporulated oocysts are shed in the cat’s feces. Although oocysts are usually only shed for 1-2 weeks, large numbers may be shed. Oocysts take 1-5 days to sporulate in the environment and become infective. Intermediate hosts in nature (including birds and rodents) become infected after ingesting soil, water or plant material contaminated with oocysts.
Oocysts transform into tachyzoites shortly after ingestion. These tachyzoites localize in neural and muscle tissue and develop into tissue cyst bradyzoites. Cats become infected after consuming intermediate hosts harboring tissue cysts. Cats may also become infected directly by ingestion of sporulated oocysts. Animals bred for human consumption and wild game may also become infected with tissue cysts after ingestion of sporulated oocysts in the environment.
How can humans contract toxoplasmosis?
Humans can become infected by any of several routes:
- Eating undercooked meat of animals harboring tissue cysts.
- Consuming food or water contaminated with cat feces or by contaminated environmental samples (such as fecal-contaminated soil or changing the litter box of a pet cat).
- Blood transfusion or organ transplantation.
- Transplacentally from mother to fetus.
In the human host, the parasites form tissue cysts, most commonly in skeletal muscle, myocardium, brain, and eyes; these cysts may remain throughout the life of the host.
How is toxoplasmosis diagnosed?
Diagnosis is usually achieved by serology, although tissue cysts may be observed in stained biopsy specimens. Diagnosis of congenital infections can be achieved by detecting T. gondii DNA in amniotic fluid using molecular methods such as PCR.
How does congenital toxoplasmosis present?
May be asymptomatic at birth – 60% but may still go on to suffer long term sequelae:
- Deafness, low IQ, microcephaly
40% symptomatic at birth:
- Choroidoretinitis
- Microcephaly/hydrocephalus
- Intracranial calcifications
- Seizures
- Hepatosplenomegaly/jaundice
How does congenital rubella syndrome affect children?
Effect on foetus – dependent on time of infection.
Mechanism: Mitotic arrest of cells; angiopathy; growth inhibitor effect.
- Eyes: Cataracts; microphthalmia; glaucoma; retinopathy
- Cardiovascular syndrome: PDA; ASD/VSD
- Ears: Deafness
- Brain: Microcephaly; meningoencephalitis; developmental delay
- Other: Growth retardation; bone disease; hepatosplenomegaly; thrombocytopenia; rash
What are other congenital infections to be aware of?
- Hepatitis B and C
- HIV
- Syphilis
- Listeria monocytogenes
- Group B Streptococcus
- Parvovirus
-
Chlamydia trachomatis
- Infection transmitted during delivery
- Mother may be asymptomatic
- Causes neonatal conjunctivitis, or rarely pneumonia
- Treated with erythromycin
Define neonatal infections.
Definition varies: First 4-6 weeks of life.
If born early (premature), neonatal period longer and is adjusted for expected birth date.
Higher incidence of infections. Can become ill rapidly and seriously. Unlike adults or older children – need to treat with antibiotics when first suspicion of infection.
What is the aetiology/risk factors of neonatal infections?
Immature host defences.
Increased risk with increased prematurity:
- Less maternal IgG
- NICU care
- Exposure to microorganisms; colonisation and infection
What are features of neonatal infections? What are some causative organisms of neonatal infections?
Early and late onset infection.
Early onset – usually within 48 hours of birth: Some definitions 3-5 days.
Organisms:
- Group B streptococci
- E. coli
- Listeria monocytogenes
What is Group B Strep.?
Gram positive coccus, catalase negative.
Beta-haemolytic.
Lancefield Group B.
In neonates:
- Bacteraemia
- Meningitis
- Disseminated infection e.g. joint infections
What is E. Coli?
Gram negative rod
In neonates:
- Bacteraemia
- Meningitis
- UTI
What are maternal risk factors for early onset sepsis?
- PROM/prem. Labour
- Fever
- Foetal distress
- Meconium staining
- Previous history
