PBL 1 Flashcards
What is the pathophysiology of neonatal respiratory distress syndrome?
surfactant deficiency so there is increased surface tension and the lungs are more likely to collapse
what is atelectasis?
a complete or partial collapse of the entire lung or area (lobe) of the lung.
what are some causes of surfactant deficiency?
congenital absence where proteins dont produce it being prematurely born having an infection metabolic acidosis hypothermia meconium aspiration
when do babies begin producing surfactant?
between 24-28 weeks in utero
what are some risk factors for NRDS?
premature baby <28 weeks maternal diabetes C-section multiple births asphyxia precipitous delivery maternal history of NRDS in previous infant
at what week in utero should there be enough surfactant produced to keep alveoli from collapsing?
34 weeks
why can maternal diabetes cause NRDS?
Glucose passes across the placenta to the baby causing hyperplasia of pancreatic beta cells causing hyper insulinism and therefore hypoglycaemia -
this disrupts normal surfactant production
why can a C-section cause NRDS?
vaginal birth causes more stress so more cortisol is produced which helps push fluid out the lungs and produce surfactant
what lecithin to sphingomyelin ratio is characteristic of mature foetal lungs?
> 2:1
what is the lecithin - sphingomyelin ratio usually before 28 weeks?
1:1
what are symptoms of respiratory depression
shortness of breath, tachypnoea, audible prominent grunting, intercostal muscle restrictions, nasal flaring, resp failure, cyanosis, crackles due to oedema in lungs, harsh tubular breath sounds, hypotension
what do alveoli look like microscopically in NRDS?
as alveoli collapse, damaged cells (hyaline cells) build up in the lungs and you would be able to see this
how can you prevent NRDS?
avoid unnecessary C-sections before 39th week
antenatal steroid prophylaxis to increase surfactant production before 34 weeks
postnatal surfactant administration
prevention of complications like maternal diabetes
how do we diagnose NRDS?
- a physical examination
- blood tests to measure oxygen sats and check for an infection
- a pulse oximetry test to measure oxygen sats
- a chest X-ray to look for the distinctive cloudy appearance of the lungs in NRDS
what are some complications of NRDS?
death
respiratory alkalosis or acidosis
oxygen toxicity due to free radical damage of lungs, retina and bronchioles
patent ductus arteriousus due to lack of ventilation
necrotising enterocolitis due to intestinal ischaemia
bronchopulmonary dysplasia
developmental disabilities
haemorrhage
interstitial emphysema
pneumothorax
foetal hypoglycaemia can lead to seizures or neuronal damage
how do we treat NRDS?
supportive care for breathing - supplemental oxygen or mechanical ventilation
continuous monitoring for grunting and breathing - if grunting disappeared and cyanosis appears then the syndrome is worsening
artificial surfactant administration
incubator
how many neonates experience some degree of jaundice in the first week of life?
60%
what’s the difference between jaundice and hyperbilirubinaemia
jaundice is the yellowing of skin and sclera
hyperbilirubinemia refers to the total serum bilirubin being >95th percentile for their age
what are the symptoms of hyperbilirubinemia?
yellowing of skin and sclera dark yellow urine pale coloured stool increased sleepiness increased feeding difficulties
what is physiologic jaundice?
Babies typically have high haematocrit and RBCs with shorter lifespans which both increase potential for RBC turnover. they are also slower to metabolise unconjugated bilirubin as they are just starting to upregulate the UGT1A1 enzyme in the developing liver. As baby is learning to feed, excretion of bilirubin in the stool may be decreased
This jaundice often peaks by day 5 and resolved by 1-2 weeks of life
what is breastfeeding failure jaundice?
some babies dont breastfeed well at first which causes dehydration and less urination causing bilirubin to buildup in the body
what is breastmilk jaundice?
when newborns being breastfed get jaundice- it is thought to be due to beta glucoronidase within breast milk that increases enterohepatic circulation. it may also be due to it contaiing factors to help absorb more bilirubin from the intestine or factors that inhibit liver proteins to break down bilirubin
what can cause jaundice from haemolysis?
Rh disease
polycythaemia
or excessive destruction of RBCs
what proportion of preterm babies get jaundice?
80%
what is bilirubin-induced neuralgic dysfunction?
when unconjugated bilirubin levels go >25mg/dL
this is when kernicteru occurs due to bilirubin crossing the blood brain barrier and binding to tissue
what is kernicterus?
a type of brain damage that can result from high levels of bilirubin in a baby’s blood.