The Preterm Infant + Neonatal Problems Flashcards
How is preterm birth defined?
Delivery before 37 weeks gestation
What are the definitions of extremely preterm, very preterm and moderate/late preterm?
Extremely preterm = < 28 weeks
Very preterm = 28 - 32 weeks
Moderate to late preterm = 32 - 37 weeks
What are some of the causes of preterm birth?
Spontaneous preterm labour Multiple pregnancy Preterm prelabour rupture of membranes Pregnancy associated hypertension Cervical incompetence/uterine malformation Antepartum haemorrhage Intrauterine growth restriction
What are the risk factors for preterm delivery?
Previous preterm deliveries Abnormally shaped uterus Multiple pregnancies Interval of < 6 months between pregnancies IVF Smoking, alcohol + illicit drugs Poor nutrition High BP Diabetes Multiple miscarriages or abortions Infection
What are some of the common problems in a premature infant?
Temperature control Feeding/nutrition Sepsis System immaturity/dysfunction: - respiratory distress syndrome - patent ductus arteriosus - intraventricular haemorrhage - necrotising enterocolitis Others e.g. metabolic, retinopathy of prematurity
Why is it so important to regulate temperature in preterm infants?
Hypothermis is independent risk factor for neonatal death
Increases severity of all preterm morbidities
More susceptible than term infants due to:
- low BMR
- minimal muscular activity
- minimal subcutaneous fat
- high ratio of surface area to body mass
How is hypothermia treated/prevented?
Wrap or bags
Skin to skin
Transwarmer mattress
Prewarmed incubator
Which organisms are likely to be causative in early onset neonatal sepsis?
Bacteria acquired before + during delivery:
- group B strep
- gram negatives
Which organisms are likely to be causative in late onset neonatal sepsis?
Acquired after delivery:
- coagulase negative staph
- gram negatives
- staph aureus
Why are premature babies particularly at risk of infection?
Immature immune system
Intensive care environment
Indwelling tubes and lines
What are the respiratory complications of prematurity?
Respiratory distress syndrome (RDS)
Apnoea of prematurity
Bronchopulmonary dysplasia
What causes RDS?
Surfactant deficiency
What are the clinical features of RDS?
Within minutes-hours from birth Respiratory distress, RR >60 Grunting Intercostal recessions Nasal flaring Cyanosis
How can RDS be prevented?
Maternal IM corticosteroids for deliveries < 36 weeks –> increases fetal surfactant production
What does RDS look like on CXR?
Widespread atelectasis with ground glass appearance
Air bronchogram = air filled trachea + bronchi stand out black against ground glass appearance
How is RDS managed?
Nasal CPAP
–> if remains distressed, intubate and give surfactant via ET tube
Apart from RDS, what are the other causes of neonatal respiratory distress?
Transient tachypnoea of the newborn Meconium aspiration syndrome (MAS) Bronchopulmonary dysplasia Milk aspiration Apnoea of prematurity PPHN Pneumonia (GBS) Pneumothorax
What is bronchopulmonary dysplasia?
Chronic lung disease resulting from disruption of normal lung development in preterm infants with respiratory problems
How is bronchopulmonary dysplasia clinically defined?
Need for supplementary oxygen beyond 28 days postnatal or 36 weeks postmenstrual age in absence of other diagnosis requiring oxygen
How can bronchopulmonary dysplasia be prevented?
Prevent and treat RDS
Minimise ventilation
Caffeine IV if born < 30 weeks
Consider dexamethasone if premature and still ventilated at 8 days (although risk of neurodevelopmental problems)
What causes transient tachypnoea of the newborn (TTN)?
Delay in resorption of lung liquid
–> C-section and maternal DM are risk factors
What are the clinical features of TTN and how is it managed?
Respiratory distress at birth
Usually resolves in 24-48 hours
Give oxygen if needed
What is meconium aspiration syndrome (MAS)?
Occurs when meconium is passed in utero (meconium in liquor) or during birth and is inhaled
- can happen due to fetal maturation (post term baby) or in response to acute hypoxia
Can lead to pneumonitis and obstruction –> collapse or pneumothorax
What might be seen on CXR in MAS?
Patchy atelectasis or consolidation
What is the management and complication of MAS?
Intubate for suction
Can be complex and lead to pulmonary hypertension
How is apnoea of prematurity treated?
IV caffeine
What are the risk factors for intraventricular haemorrhage?
Premature or low birth weight
Associated trauma or asphyxia e.g. RDS
What are the signs of intraventricular haemorrhage?
Lethargy Seizures Apnoea Bulging fontanelle (signs may be minimal)
Which investigation should be done to look for intraventricular haemorrhage?
Premature + very low birth weight infants:
–> cranial USS monitoring in week 1 and week 6
What is necrotising enterocolitis (NEC)?
Bowel necrosis from unknown cause, typically in premature or low birth weight infants
What are the clinical features of NEC?
Abdominal distension or mass Bloody mucous stool Bilious vomit Reduced bowel sounds Shock DIC
What might be seen on x-ray of a baby with NEC?
Pneumatosis intestinalis (gas in bowel wall)
Gas filled bowel loops
“Football sign”
Or pneumoperitoneum
How is NEC managed?
Stop feeds
Insert NG tube for decompression
Give IV antibiotics
What is retinopathy of prematurity (ROP)?
Abnormal vascular growth in retina due to arrest of normal vascular growth
–> can lead to retinal detachment and blindness
What are the causes or ROP?
Premature birth (<32 weeks) Oxygen therapy
How is ROP treated?
Laser therapy
Which metabolic complications might be seen in prematurity?
Early: - Hypoglycaemia - Hypocalcaemia - Hyponatraemia Late: - osteopenia of prematurity
How is neonatal hypoglycaemia defined?
Normal to have slightly low glucose due to drop off of maternal glucose
< 2.6 is pathological
What are the causes of neonatal hypoglycaemia?
Maternal diabetes Premature or SGA Infection --> increased glucose use Hypothyroidism Congenital hyperinsuliniam: maternal diabetes, pancreatic islet cell hyperplasia
Why does maternal diabetes cause neonatal hypoglycaemia?
Raised glucose during pregnancy –> compensatory fetal raised insulin
Raised insulin remains postpartum while maternal glucose stops
What are the clinical features of neonatal hypoglycaemia?
Lethargy and altered consciousness Seizures Vomiting Respiratory distress Cyanosis
How is neonatal hypoglycaemia managed?
Prevent through adequate feeding soon after birth and then 3 hourly
If asymptomatic: ensure adequate feeding, consider NG tube if problems
If symptomatic or severe (<1): IV glucose (bolus then infusion)
When is jaundice considered pathological?
< 24 hours
> 2 weeks
At what level is jaundice visible?
> 85 bilirubin
What are the causes of early (<24 hours) neonatal jaundice?
Haemolytic disease
Congenital infection
What causes of haemolytic disease might be the cause of neonatal jaundice?
Rh incompatibility
ABO incompatibility
G6PD deficiency
Spherocytosis
Which congenital infections might cause neonatal jaundice?
Group B strep TORCH: TOxoplasmosis Rubella CMV HSV
What are the possible causes of high or prolonged (>2 weeks) jaundice?
Breast feeding (failure) jaundice
Breast milk jaundice
Sepsis (most commonly from UTI)
Cephalohaematoma (haemolysis of blood pool)
Biliary atresia
Specific diseases e.g. hypothyroidism, CF, galactosaemia
What is breast feeding failure jaundice and when does it present?
Poor feeding –> reduced gut motility, allowing more conjugated bilirubin to revert to unconjugated and re-enter the blood as part of the enterohepatic circulation
Presents in the first few days
What is breast milk jaundice and when does it present?
An enzyme in breast milk unconjugates the bilirubin, thus increasing enterohepatic circulation
Presents as prolonged jaundice
How does biliary atresia present and what are the complications?
Elevated CONJUGATED bilirubin
Presents with pale stool and dark urine
–> liver failure and death if not treated surgically (phototherapy no use)
What are the signs of neonatal jaundice?
Starts at head and spread down
- Spread below the umbilicus suggests non-physiological jaundice
Which investigations should be done for neonatal jaundice?
Serum bilirubin + conjugated fraction FBC Blood film (haemolysis) Reticulocyte count (haemolysis) Blood group Direct antiglobulin (Coombs') test --> +ve in Rh or ABO haemolytic anaemia
LFTs (increased in infection)
Urine culture
TFTs
When should phototherapy be given?
Onset < 24 hours or lasts > 2 weeks
OR bilirubin above treatment line
What is the goal of phototherapy?
To prevent kernicterus
How long should phototherapy continue?
Until bilirubin >50 below the treatment line (because of rebound after stopping treatment)
What is kernicterus?
Unconjugated bilirubin > 360 which deposits in the brain
- sleepiness
- reduced feeding
- irritability
- seizure
- coma
Long term complications: cerebral palsy + deafness
