Neonates Flashcards
At what age is newborn screening (heel prick/guthre test) carried out?
Day 5-7
What conditions are screened for in the UK on the newborn heel prick?
Sickle cell disease Cystic fibrosis Congential hypothyroidism AND 6 inborn errors of metabolism: 1. Phenylketonuria (PKU) 2. Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) 3. Maple syrup urine disease (MSUD) 4. Isovaleric acidaemia (IVA) 5. Glutaric aciduria type 1 (GA1)
- Homocystinuria (pyridoxine unresponsive) (HCU)
Why is neonatal jaundice so common?
Because in the fetus there is a higher concentration of Hb (to maximise O2 exchange).
After delivery there is breakdown of Hb as the raised concentration is no longer needed.
ALSO the liver is immature and is unable to process high Hb concentrations.
What is kernicterus?
Encephalopathy resulting from deposition of unconjugated bilirubin in the basal ganglia and brainstem nuclei.
It can occur when the levels of unconjugated bilirubin exceeds the albumin-binding capacity of bilirubin the blood. The free bilirubin is fat soluble so can cross the blood brain barrier.
What are the neurotoxic effects of kernicterus?
They can vary in severity from acute manifestations - lethargy and poor feeding.
Severe cases - irritability, increased muscle tone causing the baby to lie with an arched back, seizures and coma.
Infants who survive may develop choreoathetoid cerebral palsy (damage to basal ganglia), learning difficulties and sensorineural deafness.
WHO recommends exclusive breast feeding for how long?
6 months
Breast feeding reduces the risk of which conditions in later life? (think cardiovascular type)
Insulin-dependent diabetes
Hypertension
Obesity in later life
What are the benefits of breast feeding with regards to gastro problems?
Reduces risk of gastroenteritis and necrotising enterocolitis (in premature infants)
As well as gastroenteritis breast feeding also reduces the risk of which types of infections?
Otitis media
Respiratory infections
What are the benefits to the mother of breast feeding?
Reduced risk of:
Type 2 diabetes
Ovarian cancer
Breast cancer
In what situations is breast feeding contraindicated?
Chemotherapy (cytotoxic drugs)
HIV
With breast feeding the volume of milk intake is not always known so how can you monitor growth?
Monitor weight gain
How does colostrum differ from milk?
Colostrum is produced for the first few days
Colostrum differs from mature milk in that the content of protein and immunoglobulin (IgA, IgM and IgG) is much higher
What is the histology of breast lobes?
Which 2 hormones are important in milk secretion? Describe each of their roles
Breast tissue lobes are make up of lobules of alveoli, blood vessels and lactiferous ducts. The lactiferous ducts connect the lobules to the tip of the nipple (areola). Myoepithelial cells surround the alveoli and are responsible for milk let down.
PROLACTIN secretion stimulates milk secretion by cuboidal cells in the acini of the breast. It is produced from the anterior pituitary.
OXYTOCIN secretion results in contraction of myoepithelial cells in the alveoli, forcing milk into larger ducts - the so-called ‘let-down’ reflex
Why is unmodified cow’s milk unsuitable for feeding an infant? What can is subsequently result in?
Because it contains a protein called casein. The baby can’t digest this. It can lead to diarrhoea
What is WHO’s code of marketing breast milk substitutes?
What additional modifications are made to formula feeds?
-
The code prohibits advertising of infant formula, bottles and teats and gifts to mothers or inducements to health workers.
Formula fees make their mineral content and renal solute load comparable with that of mature human milk.
They also have polyunsaturated fatty acids, nucleotides, prebiotics and probiotics
What is the advice given with regards to children who are on cow’s milk? (E.g what age/what type)
Should receive full fat milk up to the age of 5 years
After what age does breast milk become increasingly nutritionally inadequate as the sole feed for infants?
When should solid foor be introduced:
A) Not before?
B) No later than?
After 6 months of age, breast milk becomes increasingly nutritionally inadequate as a sole feed, as it does not provide sufficient energy, vitamins or iron.
Solid foods are recommended to be introduced from around 6 months of age, not before 17 weeks and no later than 26 weeks
How do the components of milk change over the first 2 weeks?
What types of food should infants initially be weaned onto?
The milk develops to contain less proteins, more fat and more sugars (energy source)
Weaning should be done gradually, initially with small quantities of pureed fruit, root vegetables or rice.
In women who are pregnant where is group B streptococci commonly present?
What percentage of pregnant women carry group B strep?
Vagina or rectum
25% of women
What can group B strep cause in neonates?
Infection - typically sepsis, pneumonia or meningitis
This is known as early onset GBS disease of the newborn
What is considered to be early-onset neonatal sepsis?
How does early-onset sepsis present?
What are the most likely causative organisms of early-onset sepsis?
Sepsis that presents within 48 hours of birth
Presents with:
It is associated with acquisition of micro-organisms from the mothers birth canal (e.g group B strep)
What is considered to be late-onset neonatal sepsis?
How does late-onset sepsis present?
What are the most likely causative organisms of late-onset sepsis?
Why do they present later?
Late onset = >48 hours from birth
Late-onset sepsis normally occurs due to hospital acquired pathogens such as Staphylococcus epidermidis and Staphylococcus aureus
A high percentage of women are colonised with group B strep but not as many have affected infants. What are some risk factors for infection in the neonate?
UTI caused by GBS during pregnancy Previous baby with GBS infection Pyrexia during labour Prematurity <37 weeks Positive GBS swab during pregnancy Rupture of membranes >24 hours before delivery
What types of swab is used to look for group B strep in pregnancy? What week is this done at?
One swab (the same swab) is used for the vagina and then the rectum
2 individual swabs can be used of preferred
Not all women are screened only if you are high risk.
It is carried out at 33-35 weeks if the woman was found to have GBS colonisation in a previous pregnancy but the fetus was not affected with GBS
What are antibiotics given for prophylaxis of early onset neonatal group B strep?
Who is given them?
High dose IV Penicillins e.g benzylpenicillin OR cefuroxime in pen allergic
Indicated in women who are high risk:
- GBS positive swabs
- A UTI caused by GBS during this pregnancy
- Previous baby with GBS infection.
- Pyrexia during labour
- Labour onset <37 weeks
- Rupture of membranes >18 hours
What is the difference between symmetrical growth restriction and asymmetrical growth restriction a) in terms of presentation? b) in terms of when the restriction occurs?
Asymmetrical:
Weight of abdominal circumference lies on the lower centile than that of the head
Failure of placenta to provide inadequate nutrition in later pregnancy
Symmetrical: head circumference is equally reduced as abdominal circumference. Suggestive of a prolonged period of poor intrauterine growth starting in early pregnancy
What are some underlying causes of asymmetrical growth restriction?
Uteroplacental dysfunction secondary to maternal pre-eclampsia, multiple pregnancies, maternal smoking or can be idiopathic
Infants rapidly put on weight after birth
Associated with an increased risk of obesity and type 2 diabetes in later life.
What are some causes of symmetrical growth restriction?
It is usually due to a small but normal fetus, but may be due to a fetal chromosomal disorder or syndrome, a congenital infection, maternal drug and alcohol abuse, a maternal chronic medical condition or malnutrition. These infants are more likely to remain small permanently.
Need to finish IUGR
