Problems of Low Birthweight Infant Flashcards
What is the median UK birthweight at term?
3.480kg
Below what weight is low birth weight
<2500g
Below what weight is very low birth weight
<1500g
Define prematurity
Birth before 37 weeks gestation
Define small for gestational age
Birth weight below 10th centile
What is fetal growth restriction
Failure of achieve normal rate of foetal growth
What are the consequences of a small for gestational age baby
Complications of foetal growth restriction
Very long term health problems
What are the consequences of a premature baby
Neurodevelopmental disorder
Name 5 acquired causes of SGA baby
- Utero-placental insufficiency
- Congenital infection
- Smoking
- Maternal chronic illness
- Multiple pregnancy
What are the consequences of congenital CMV on the brain
Hydrocephalus and calcification
What is genetic basis of Edwards syndrome
Trisomy 18
What does Edwards syndrome baby look like
Small with congenital abnormalities (clenched fist)
In which 2 ways can utero-placental insufficiency lead to untrauterine growth restriction
- Failure of syncytiotrophoblast invasion of high resistance spiral arteries
- Poor placental development with raised resistance in placental vascular bed
How can hypoxic placenta be detected
Doppler ultrasound in uterine arteries and foetal circulation
What is meant by brain sparing circulatory redistribution
When there is limited oxygen, baby’s circulation prioritises blood floow to deliver oxygen to brain and heart at expense of other parts of body
Where does SGA baby have problems with temperature control
Increased SA:V ratio
Reduced adipose tissue insulation
Reduced capacity for thermogenesis
How is hypoglycaemia treated in SGA baby
IV dextrose
What does symptomatic hypooglycaemia look like, and what does it suggest
Lethargy and fits
Risk of adverse neuro-developmental outcome
What is necrotising enterocolitis
Acute bacterial invasion/ inflammation/ necrosis of bowel with gas formation in bowel wall
Why is SGA baby at risk of hypoglycaemia
Low glycogen reserves
What adult diseases is low birth weight associated with
Diabetes HT Coronary heart disease Stroke Chronic bronchitis
What can cause spontaneous preterm labour
Infection/ ruptured membranes
Cervical incompetence
Polyhydramnios
Name 6 systems that may be affected by prematurity
Temp control Resp Cardiovascular Nutritional Infection Neurological
Why is preterm baby at high risk of heat loss?
Large SA: body mass ratio Thin skin Less adipose tissue Wet at birth Can't shiver Poor metabolic reserve
Why is temperature set as it is in modern incubators
Set to help baby maintain temperature but at minimal metabolic cost- neutral thermal environment
What respiratory structural immaturity can be seen in premature infants
Primitive alveolar development
Susceptibility to oxygen toxicity and barotrauma
What respiratory functional immaturities can be seen in premature infants
Surfactant deficiency
Lack of resp drive
Why are premature babies more susceptible to infection
Immature immune system
Instrumentation of airway
3 short term respiratory clinical problems of premature babies
Respiratory distress syndrome
Pneumonia
Apnoea of prematurity
Long term respiratory clinical problem of premature baby
Chronic lung disease of infancy
What is found at the air-liquid interface in alveoli and what does it consist of
Surfactant- monolayer of phospholipid molecules
Consists of DPPC and phosphatidylglycerol
What stabilises surfactant
Surfactant protein B
What is the function of surfactant
Reduces surface tension at air-fluid interface
What is RDS
Respiratory distress syndrome
Lack of surfactant in premature baby
Tachypnoea, expiratory grunting, recession
4 ways to prevent RDS
Ante-natal steroids
Avoidance of intrauterine hypoxia
Prophylactic surfactant treatment
Keep warm, avoid acidosis
What causes chronic lung disease of infancy
Lung injury in preterm infant
Inflammation, fibrosis, emphysema
What is PPHN
Persistent pulmonary hypertension of the newborn
How many caloiries does preterm baby need to grow a day
110-135
How does the baby receive nutrition in utero
Foetus swallows amniotic fluid
Nutrition is provided continuously across placenta
What are the challenges in feeding a preterm baby
Immature suckling
Poor gut motility
May not tolerate enteral feeds
What happens if baby is not fed
Gut mucosa atrophies
What is pneumotosis
Gas formation in bowel wall
Risk factors for necrotising enterocolitis
Prematurity, hypoxia, infection, enteral feeding
Clinical presentation of nectorising enterocolitis
Abdo distention
Tenderness
Discolouration
Blood in stools
Treatment of necrotising enterocolitis
Stop feeds
Give antibiotics
Sometimes surgery
What bacterias most commonly cause infections within 48 hours of birth
Group B beta haemolytic strep
E coli
What bacterias most commonly cause infections >48 hours after birth (hospital acquried)
Coagulase negative straphylococci
Gram negative organisms that colonise intestine
What immune protection is present in full term baby but not preterm
Transplacental IgG in 3rd trimester
IgA and immunlogically active cell in colostrum
Skin barrier
Acquisition of normal flora from mother
Why is preterm baby immunocompromised?
No usual full term benefits
Nursed in bacterially hostile environment
Given broad spectrum antibiotics
Invasive procedures breach host defeces
Why are preterm babies susceptible to Periventricular haemorrhage
Germinal matrix in floor of lateral ventricles is vascular due to active glial and neuronal proliferation
Poor control of brain perfusion
What is periventricular leucomalacia
Ischaemia of periventricular white matter
What are the risk factors for periventricular haemorrhage
Prematurity RDS Pneumothorax Hypercapnia Acidosis Hypotension
What % of babies <1500g develop cerebral palsy
10
What long term problems in the brain result from prematurity
Cognitive and behavioural problems
Sensory impairment
Minor hearing and vidual impairment
