Neonatology 2 Flashcards
How does GBS present in neonates?
• Around 10-30% of pregnant women have faecal or vaginal carriage
0.5-1 in 1000 babies have early-onset infection- respiratory distress and pneumonia. May cause septicaemia and meningitis
Severity depends on duration of infection in utero
Late-onset disease- 3 months of age. Meningitis or focal infection (osteomyelitis or septic arthritis)
What are the risk factors for GBS in colonised mothers?
o Preterm o Prolonged rupture of membranes o Maternal fever during labour (>38oC) o Maternal chorioamnionitis o Previously infected infant
What is the prophylactic management for GBS?
• Prophylactic intrapartum antibiotics given IV to the mother can prevent group B strep infection in the newborn baby
• There are two approaches to the use of intrapartum antibiotics
o Universal screening at 35-38 weeks to identify mothers who carry the organisms
o Risk-based approach, in which mothers with risk factors for infection are offered antibiotics
What is the management for GBS once the baby is born?
CXR and septic screen
FBC is performed to detect a neutropenia as well as blood cultures- CRP is also taken, but takes 12-24hrs to rise
• Antibiotics are started immediately without waiting for cultures and are usually broad spectrum amoxicillin or benzylpenicillin
o If cultures are negative and clinical signs return to normal, then they are stopped after 48hrs
o If cultures are positive, then continue, check for neurological signs, examine and culture the CSF
How does early onset sepsis present?
<48 hrs after birth
Bacteria have ascended from the birth canal and invaded the amniotic fluid
the foetus is secondarily infected because the foetal lungs are in direct contact with infected amniotic fluid- these infants have pneumonia and secondary bacteraemia/septicaemia
Risk of early-onset infection is increased if there has been prolonged or premature rupture of the amniotic membranes and when chorioamnionitis is clinically evident, such as when the mother has fever during labour
What are the features of late onset sepsis?
> 48hrs after birth
Source of infection is often the infant’s environment
• Coagulase negative staphylococcus (Staph epidermis) is the most common pathogen, but the range of organisms is broad and includes Gram +ve bacteria (Staph aureus & Enterococcus faecalis) and Gram –ve (E.coli, Pseudomonas, Klebsiella & Serratia species)
What are the main sources of infection in the NICU?
o Indwelling central venous catheters for parenteral nutrition
o Invasive procedures which break the skin
o Tracheal tubes
How does neonatal meningitis present?
mortality of 20-50%, with 1 in 3 survivors having serious sequelae
Tense or bulging fontanelle and head retraction (opisthotonos) and are late signs and rarely seen in newborn infants-Complications include cerebral abscess, ventriculitis, hydrocephalus, hearing loss and neurodevelopmental impairment
What are the features of CMV?
Most common congenital infection
• About 1% of susceptible women will have a primary infection during pregnancy-and in about 40% of them the infant becomes infected
o 90% are normal at birth and develop normally
o 5% have clinical features at birth - such as hepatosplenomegaly and petechiae- most of whom will have neurodevelopmental disabilities – such as sensorineural hearing loss, cerebral palsy, epilepsy and cognitive impairment
o 5% develop problems later in life- mainly sensorineural hearing loss
How does rubella affect the foetus?
Must be confirmed serologically
• Infection before 8 weeks’ gestation causes deafness, congenital heart disease and cataracts in >80%
• About 30% of foetuses of mothers infected at 13-16 weeks’ gestation have impaired hearing- beyond 18 weeks, the risk to the foetus is minimal
• Viraemia after birth continues to damage the infant
Congenital rubella is preventable- MMR vaccine
What is toxoplasmosis?
Toxoplasma gondii- a protozoan parasite, may result from the consumption of raw or undercooked meat and from contact with the faeces of recently infected cats
• Transplacental infection may occur during the parasitaemia of a primary infection- about 40% of foetuses become infected
1 per 10,000
What are the clinical features of toxoplasmosis?
• Most infected infants are asymptomatic- about 10% have clinical manifestations of which are
o Retinopathy- an acute fundal chorioretinitis which sometimes interferes with vision
o Cerebral calcification
o Hydrocephalus
hese infants usually have long-term neurological disabilities
• Infected newborn infants are treated for 1 year with pyrimethamine and sulfadiazine
• Aysmptomatic infants remain at risk of developing choriorentinitis into adulthood
What are the interventions to prevent vertical transmission of HIV?
Avoid breast-feeding- 25-40% of infants become infected
o Use of maternal antenatal, perinatal and postnatal anti-retroviral drugs to achieve an undetectable maternal viral load at the time of delivery
o Active management of labour & delivery to avoid prolonged rupture of the membranes or unnecessary instrumentation
o Pre-labour C-section if the mother’s viral load is detectable close to the time of delivery
What are the main risk factors for neonatal infection?
- Infection is common in preterm infants- they are at an increased risk of infection because no IgG has been transferred across the placenta until the last trimester and IgA & IgM have not been transferred at all
- Another cause of infection is that there is often infection around the cervix causing preterm labour
- Many other infections occur days after birth and are hospital derived
- There is an increased risk of infection if there is prolonged rupture of membranes (>18hrs)
- Later infections are most likely to be environmental and come from indwelling lines or catheters
What are the symptoms of syphilis in the neonate?
o Failure to thrive o Fever o Irritability o No bridge to nose o Early rash- small blisters o Larger rash o Rash of the mouth, anus and genitalia o Watery discharge from the nose o Splenomegaly & hepatomegaly o Bone inflammation Complications include- blindness, deafness, deformities of the face and neurological problems • Treated with penicillin
