Infections

Question 1

Main risk factors for neonatal infection

Answer 1

• EARLY ONSET INFECTION RFs
  
  • ​prolonged ROM
  • premature ROM
  • chorioamniocitis (maternal fever during labour)
  • persistent fetal tachycardia during labour
  • maternal GBS +ve
• LATE ONSET INFECTION RFs
  
  • ​hospital inpatient
  • indwelling catheters, invasive procedures, lines, tracheal tubes

Question 2

What is late-onset infection in the newborn?

Answer 2

• >48hrs after birth- 3m of age
• tranmission
  
  • infants environment (generally at risk if in hospital- nosocomially acquired infection)
    
    • indwelling catheters- PEN
    • invasive procedures
    • tracheal tube

Question 3

What is early-onset infection in the newborn?

Answer 3

• < 48 h after birth
• transmission
  
  • amniotic fluid
    
    • ​pathogen from birth canal invades amniotic fluid
    • fetal lungs in direct contact with amniotic fluid
  • placenta
    
    • ​congenital viral infections
    • Listeria monocytogenes
• pneumonia
• 2” bacteraemia/ septicaemia

Question 4

List the common bacteria/ viruses causing infection in newborn

Answer 4

• Bacteria
  
  • GBS
  • Listeria monocytogenes
  • Staph. epidermidis
  • Staph. aureus
  • Enterococcus faecalis
  • Escherichia coli
  • Pseudomonas
  • Klebsiella
  • Serriata species
• Virus
  
  • ​CMV
  • Rubella
  • Toxoplasmosis

Question 5

Presenting symptoms and signs of neonatal infection

Answer 5

• Symptoms:
  
  • Poor feeding
  • Vomiting
  • Apnoea
  • Jaundice
  • Lethargy
  • Seizures
  • irritability
• Signs
  
  • Bradycardia
  • Respiratory distress
  • Abdominal distension
  • Neutropenia
  • Hypo/ hyoer glycaemia
  • Shock
• Meningitis
  
  • ​tense/ bulging fontanella
  • Head retraction (opisthotonos)

Question 6

Infection screen in newborn infants

Answer 6

• CXR
• Septic screen
  
  • LP- blood cultures +ve/ neuro signs esp.
  • Urine
• FBC
• U&Es
• Glucose
• CRP (0-10 mg/L)
• Blood cultures

Question 7

Treatment of neonatal bacterial infections

Answer 7

• Early onset neonatal infection
  
  • ​Antibiotics started immediately (before culture result back)
  • IV benzylpenicillin/ amoxicillin
    
    • GBS, Listeria monocytogenes, other gram +ves
  • IV gentamicin
    
    • gram -ves
  • ABx can be stopped if cultures and CRP negative and clinical recovery
• Late onset neonatal infection
  
  • ​Flucloxacillin* and *gentamicin
    
    • staphylococci, gram -ve
  • Then (if condition deteriorates or resistance shown)
    
    • vancomycin
      
      • staph. epidermis, enterococci
    • broad-spectrum ABx- meropenem
• Meningitis
  
  • ​Ampicilliin
  • Penicillin
  • Cefotaxime (CSF penetration)

Question 8

List the risk factors for neonatal invasive Group B streptococcus infection

Answer 8

• Colonised mothers (10-30% prgenant women have vaginal or faecal carriage)
  
  • ​Preterm
  • Prolonged rupture of membranes
  • Maternal fever (>38”C) during labour
  • maternal chorioamniocitis
  • previous baby with GBS

Question 9

Antenatal/ postnatal management of GBS positive mothers/ babies

Answer 9

• Consequences of GBS infection:
  
  • _​_early onset infection
    
    • respiratory distress
    • pneumonia
    • may cause septicaemia/ meningitis
  • late onset infection (up to 3m of age)
    
    • meningitis
    • focal infection- osteomyelitis/ septic arthritis
• Prevention:
  
  • prophylactic intrapartum IV ABx
  • in U.K. have to get privately screened, risk factor based
  • in USA/ Austrailia screen at 35-38 weeks

Question 10

List key features of CMV

Answer 10

• most common congenital infection
• 90% normal at birth/ develop normal
• 5% hepatospelnomegaly, petechiae, neurodevelopmental disabilities (sensorineural hearing loss, cerebral palsy, epilepsy and cognitive impairment)
• 5% develop problems later in life (sensorineural hearing loss)

Question 11

List key features of toxoplasmosis

Answer 11

• Toxoplasma gondii = protazoan parasite
  
  • raw/ undercooked meats
  • faeces of recently infected cats
• clinical features:
  
  • _​_retinopathy- acute fundal chorioretinitis
  • cerebral calcification
  • hydrocephalus
  • long term neurological deficits

Question 12

List key features of rubella

Answer 12

• Infection < 8 weeks gestation
  
  • _​_Deafness
  • CHD
  • Cataracts (80%)
• 13-16 weeks gestation infection
  
  • _​_impaired hearing
• >18 weeks gestation infection
  
  • _​_minimal risk to fetus
• Viraemia continues after birth to damage infant

Question 13

Key management steps in the care of HIV- positive mothers and baby

Answer 13

• Transmission
  
  • ​Mother to baby
    
    • Intrauterine
    • Intrapartum
    • Breast feeding
  • Infected blood products
  • Contaminated needles
  • Child sexual abuse- uncommon
• Reduction methods
  
  • ​Avoidance of breast feeding
  • use of maternal antenatal, perinatal and postnatal ARV drugs –> undetectable maternal viral load at delivery
  • active management of labour
    
    • avoid prolonged ROM
    • avoid instrumentation
  • pre-labour C-section if mothers viral load is detectable close to time of delivery
• All above management can reduce HIV transmission from M to B to <1%

Question 14

List common causes of billious vomiting in the newborn

Answer 14

• Intestinal obstruction
  
  • intususscetion
  • malrotation
  • strangulated inguinal hernia

Question 15

Hepatitis B transmission risk and preventative measures

Answer 15

• Without prophylaxis, the risk of HBV vertical transmission is high
  
  • ​highest in HBsAg- and HBeAg-positive mothers (transmission rate: 70%–90%)
  • low for HBsAg-positive HBeAg-negative mothers (transmission rate: 10%–40%)
• In Hep. B surface antigen (HBsAg) +ve mothers infants should receive hepatitis B vaccination shortly after birth
• vaccination course should be completed in infancy and AB levels monitored
• High risk of being chronic carriers if maternal e Ag +ve but no eAB
  
  • should also be given hepatitis B Ig within 24hrs birth