Paediatrics Flashcards
What in utero treatment of the foetus is given via the mother?
- Glucocorticoid Therapy - to accelerate lung maturation
- Digoxin or Flecainide - to treat SVT
What in utero treatment of the foetus is given directly to the foetus?
- Rhesus Isoimmunisation - foetal blood transfusion directly into the umbilical vein may be required regularly in severely affected foetuses. Foetuses at risk can be detected by looking at the maternal antibodies.
- Perinatal Isoimmune Thrombocytopenia - when anti-platelet antibodies from the mother cross the placenta and cause thrombocytopenia in the foetus. Can be treated with IVIg.
What obstetric conditions affect the foetus?
- Pre-eclampsia
- May require preterm delivery
- Can cause maternal eclampsia (seizures in mothers with pre-eclampsia) or a cerebrovascular accident due to the high blood pressure
- Associated with placental insufficiency and growth restriction
- Placental insufficiency and intrauterine growth restriction
- Growth-restricted foetuses require close monitoring
- Absence or reversal of blood flow velocity (in the umbilical or middle cerebral artery) during diastole is associated with increased risk of morbidity from hypoxic damage to the gut or brain, or of intrauterine death
- Multiple births are associated with:
- Preterm labour (median gestation for twins is 37 weeks)
- Intrauterine growth restriction (IUGR)
- Congenital abnormalities
- Twin-twin transfusion syndrome (TTTS) in monochorionic twins (share a placenta)
- Complicated deliveries
Describe maternal diabetes mellitus
What is poorly controlled maternal diabetes associated with?
- Women with insulin-dependent diabetes find it harder to maintain good glycaemic control during pregnancy and have higher insulin requirements
- Poorly controlled maternal diabetes is associated with polyhydramnios and pre-eclampsia, increased rate of foetal loss, congenital malformations and late unexplained intrauterine death
What foetal problems are associated with maternal diabetes?
- Congenital malformations (3 x more common than non-diabetics)
- IUGR
- Macrosomia (high birth weight)
- Mechanism: maternal hyperglycaemia causes foetal hyperglycaemia. Insulin does not cross the placenta, so the foetus produces its own insulin, which promotes growth.
- Associated with increased risk of cephalopelvic disproportion, birth asphyxia, shoulder dystocia and brachial plexus injury
What neonatal problems are associated with maternal diabetes?
- Hypoglycaemia (transient due to foetal hyperinsulinaemia)
- Respiratory distress syndrome
- Hypertrophic cardiomyopathy
- Polycythaemia
What is gestational diabetes?
Which demographics is it more common in?
- Gestational diabetes is when carbohydrate intolerance occurs only during pregnancy.
- It is more common in Asian and Afro-Caribbean women
Why are babies hyperthyroid in Mother’s with Graves disease?
How can foetal hyperthryoidism be detected?
- In mothers with Graves disease, 1-2% of babies are hyperthyroid, due to circulating thyroid-stimulating hormone antibody
- Foetal hyperthyroidism may be noticed by
- detecting tachycardia on the CTG trace
- foetal goitre may be seen on ultrasound
What is Maternal SLE (with anti-phospholipid syndrome) associated with?
- Recurrent miscarriage
- IUGR
- Pre-eclampsia
- Placental abruption
- Preterm delivery
- Some infants born to mother with anti-Ro and anti-La antibodies will develop neonatal lupus syndrome (characterised by a self-limiting rash and (rarely) heart block)
What is maternal autoimmune thrombocytopenic purpura?
- Maternal IgG antibodies cross the placenta and damage foetal platelets
- This could increase the risk of intracranial haemorrhage following birth trauma
- Infants with severe thrombocytopaenia or petechiae at birth should be given IVIg
What are clinical features of foetal alcohol syndrome?
- Growth restriction
- Characteristic face
- Developmental delay
- Cardiac defects
Describe drug abuse during pregnancy
- Increases risk of prematurity and growth restriction
- Withdrawal in infants with opiate-abusing mothers (e.g. jitteriness, sneezing, yawning, poor feeding, vomiting, diarrhoea, weight loss, seizures)
- Cocaine abuse —> placental abruption and preterm delivery and it can cause cerebral infarction
- Drug abusing mothers are also at increased risk of contracting Hepatitis B and C, and HIV
What therapeutic drugs used during pregnancy may be harmful?
- Opioid analgesia - may suppress respiration at birth
- Epidural anaesthesia - may cause maternal pyrexia during labour (which can be difficult to distinguish from a fever due to an infective cause)
- Sedatives (e.g. diazepam) - may cause sedation, hypothermia and hypotension in the newborn
- Oxytocin and Prostaglandin F2 - may cause hyperstimulation of the uterus leading to foetal hypoxia
- IV fluids - may cause neonatal hyponatraemia
What main infections can damage a foetus?
- Rubella
- CMV
- Toxoplasma gondii
- Parvovirus
- VZV
- Syphilis
How is maternal rubella infection confirmed?
- Serology
What is the triad of rubella infection in the newborn?
- Cataracts
- Deafness
- Congenital Heart Disease (PDA)
How does the risk and extent of foetal damage depend on gestational age at onset of maternal infection?
- Infection < 8 weeks —> cataracts, deafness and congenital heart disease in 80%
- 30% of foetuses infected at 13-16 weeks have impaired hearing
- No consequences after 20 weeks
What is the management of rubella in pregnancy?
- Notify the Health Protection Unit (HPU)
- HPU may also test for parvovirus B19
- There is NO effective treatment for rubella
- Recommend rest, adequate fluid intake and paracetamol for symptomatic relief
- Stay off work and avoid contact with other pregnant women for 6 days after initial development of the rash
- Once confirmed, refer urgently to obstetrics for risk assessment and counselling
What is CMV infection?
What happens when the infant is infected?
What clinical features do infants with CMV have?
- Most common congenital infection
- When an infant is infected:
- 90% are normal at birth and develop normally
- 5% have clinical features at birth (e.g. hepatosplenomegaly, petechiae) and most of these babies will have neurodevelopmental disabilities such as sensorineural hearing loss, cerebral palsy, epilepsy and cognitive impairment
- 5% develop problems later in life, mainly sensorineural hearing loss
- Infection of the pregnant woman is usually asymptomatic
- Pregnant women are not screened for CMV and there is no vaccine
What is the management of Newborn Infants with CMV? (BMJ Best Practice)
- IV ganciclovir
- Or oral valganciclovir
What microorganism causes toxoplasmosis infection?
Where can it be contracted from?
What are the clinical features?
- Toxoplasma gondii is a protozoan parasite
- Can be contracted from undercooked meat and with contact with faeces of infected cats
- Most infected infants are asymptomatic
- 10% of infants will have clinical features:
- Retinopathy (due to acute fundal chorioretinitis)
- Cerebral calcification
- Hydrocephalus
- These infants usually have long-term neurological disabilities
- Asymptomatic infants are at risk of developing chorioretinitis in adulthood
What is the management of newborns with toxoplasmosis? (BMJ Best Practice)
- 1st Line: Pyrimethamine + Sulfadiazine + Calcium Folinate
- Adjunct: Prednisolone
What happens if mother develops chickenpox in first half of pregnancy and around birth?
- If the mother develops chicken pox in the first half of pregnancy (< 20 weeks) there is a < 2% risk of the foetus developing severe scarring of the skin and also ocular and neurological damage and digital dysplasia
- If the mother develops chicken pox within 5 days before or 2 days after delivery, when the foetus is unprotected by maternal antibodies and the viral dose is high, about 25% will develop a vesicular rash and mortality can be as high as 30%
What is the management of varicella zoster in mothers?
- Exposed susceptible mothers can be protected with VZV immunoglobulin (VZIG) and treated with aciclovir
How do foetus adapt to extrauterine life?
- Before birth, the blood vessels to and from the lungs are constricted, so most of the blood from the right side of the heart will pass through the ductus arteriosus into the aorta, and some will flow across the foramen ovale
- Shortly before and during labour, lung liquid production is reduced
- During descent through the birth canal, the infant’s chest is squeezed and some lung fluid is drained
- Several thermal, tactile and hormonal stimuli (mainly an increase in catecholamine) to initiate breathing
- The first breath takes place an average of 6 seconds after delivery
- Lung expansion occurs due to intrathoracic negative pressure
- Regular breathing is usually established after 30 seconds
- After a the infant gasps, the rest of the lung fluid is absorbed into the lymphatic and pulmonary circulation
- Pulmonary expansion leads to reduced pulmonary resistance and an increase in pulmonary blood flow
- The flow of oxygenated blood through the ductus arteriosus leads to closure of the duct
Why may babies born via C-section take longer for fluid to be drained from the lungs?
- In babies born via an elective Caesarean section, their chest would not have been squeezed so it may take longer for the fluid to be drained from the lungs
Why may some infants not breathe during birth?
- May be due to asphyxia (lack of oxygen during labour or delivery)
What is primary apnoea?
- If a foetus is deprived of oxygen in utero, the foetus will attempt to breathe
- BUT, as they are still in utero, this attempt will be unsuccessful - this is called primary apnoea
- During the primary apnoea, heart rate is maintained
- If oxygen deprivation continues, primary apnoea is followed by irregular gasping and then a second period of apnoea (secondary or terminal apnoea)
- During terminal apnoea, the heart rate and blood pressure will fall
Describe breathing after birth
- If the infant is delivered after the terminal apnoea, they will need help with lung expansion (e.g. positive pressure ventilation or tracheal tube)
- The foetus rarely experiences continuous asphyxia except in the case of placental abruption or complete occlusion of umbilical blood flow in a cord prolapse
- More commonly, asphyxia during labour and delivery is intermittent (e.g. due to frequent uterine contractions)
- The Apgar Score is used to describe a baby’s condition at 1 and 5 mins after delivery - it is also measured at 5 min intervals thereafter, if the infant’s condition remains poor
What is asymmetrical growth restriction?
- Weight or abdominal circumference lies on a lower centile than that of the head
- This occurs when the placenta fails to provide adequate nutrition late in pregnancy but brain growth is relatively spared at the expense of liver glycogen and skin fat
- This type of growth restriction is associated with utero-placental dysfunction secondary to maternal pre-eclampsia, multiple pregnancy and maternal smoking
- These infants tend to put on weight rapidly after birth
What is symmetrical growth restriction?
- Head circumference is equally reduced
- Suggests a prolonged period of poor intrauterine growth starting in early pregnancy
- Usually due to a small but normal foetus
- It could also be due to a foetal chromosomal disorder, congenital infection, maternal drug/alcohol abuse or a chronic medical condition
- These infants are more likely to be permanently small
What are growth-restricted foetuses at an increased risk of?
- Intrauterine hypoxia and ‘unexplained’ intrauterine death
- Asphyxia during labour and delivery
What are growth-restricted foetuses liable to, after birth?
- Hypothermia (because of their large surface area)
- Hypoglycaemia (from poor fat and glycogen stores)
- Hypocalcaemia
- Polycythaemia
What is large for gestational age?
What is macrosomia?
- Above the 90th weight centile for their gestation
- Macrosomia is a feature of infants of mothers with either permanent or gestational diabetes or a baby with a congenital syndrome (e.g. Beckwith-Wiedemann syndrome)
What is being large for gestational age associated?
- Birth asphyxia from a difficult delivery
- Breathing difficulty from an enlarged tongue in Beckwith-Wiedemann syndrome
- Birth trauma (especially shoulder dystocia)
- Hypoglycaemia (due to hyperinsulinism)
- Polycythaemia
What are newborns given to prevent haemorrhagic disease of the newborn?
- Vitamin K
What is developmental dysplasia of the hip?
- An abnormality of the hip joint where the socket portion does not fully cover the ball portion, resulting in an increased risk of joint dislocation
- Also known as congenital dislocation of the hip (CDH)
- DDH is 6 x more common in girls and in breech presentation
- Early recognition is important because splinting in abduction reduces long-term morbidity
How do you test for DDH?
- Infant needs to be relaxed
- The pelvis is stabilised with one hand
- With the other hand, the examiner’s middle finger is placed over the greater trochanter and the thumb around the distal medial femur
- The hip is held flexed and adducted
- The femoral head is gently pushed downwards
- If the hip is dislocatable, the femoral head will push posteriorly out of the acetabulum
- The next part of the test looks at whether the dislocated femoral head can be positioned back into the acetabulum
- The hip is abducted and upward leverage is applied
- If dislocated, the hip will return with a clunk into the acetabulum
What is the management of DDH (BMJ Best Practice)?
- For infants < 2 months with normal physical examination without instability, observation is recommended with serial examinations and ultrasound on a monthly basis
- Hip abduction orthosis (splint) in a Pavlik harness if the dysplasia persists or worsens
- Serial follow up and plain X-ray evaluation is recommended after 6 months of age
- Breech Delivery: if no DDH at neonatal examination, arrange ultrasound scan at 6 weeks
Describe Vitamin K Therapy
- Vitamin K deficiency may result in haemorrhagic disease of the newborn
- In most affected infants, the bleeding is mild (e.g. bruising, haematemesis, melaena), however, some suffer from intracranial haemorrhage which could cause permanent disability
- Breast milk has low vitamin K whereas formula milk has much more vitamin K
- Therefore, haemorrhagic disease of the newborn is less likely in infants fed formula instead of breast milk
- NOTE: infants of mothers taking anticonvulsants (which impair synthesis of vitamin K-dependent clotting factors) are at increased risk of haemorrhagic disease
- Haemorrhagic disease of the newborn can be prevented by giving IM vitamin K injections
What is the Guthrie Test?
What does it screen?
How is cystic fibrosis screened?
- Performed in every baby
- A blood sample is usually taken as a heel prick
- It is taken once feeding has been established on day 5-9 of life
- All infants are screened for
- Phenylketonuria
- Hypothyroidism
- Haemoglobinopathies (sickle cell and thalassemia)
- Cystic fibrosis
- MCAD deficiency
- NOTE: screening for cystic fibrosis is performed by measuring the serum immunoreactive trypsin, which is raised if there is pancreatic duct obstruction
- If raised, DNA analysis is also performed to reduce the false-positive
What is Evoked Otoacoustic Emission (EOAE) Testing?
- An earphone is placed over the ear and a sound is emitted which evokes an echo or emission from the ear if cochlear function is normal
- If a normal result is not achieved with this test, you move on to the next test
What is Automated Auditory Brainstem Response (AABR) Audiometry?
- A computer will analyse the EEG waveforms evoked in response to a series of clicks
What is hypoxic-ischaemic encephalopathy?
- In perinatal asphyxia, gas exchange, either placental or pulmonary, is compromised leading to cardiorespiratory depression
- This leads to hypoxia, hypercapnia and metabolic acidosis
- Reduced cardiac output leads to hypoxic-ischaemic injury to the brain and other organs
What leads to HIE?
- Hypoxic event immediately before or during labour, delivery such as:
- Failure of gas exchange across placenta (excessive or prolonged uterine contractions, placental abruption, ruptured uterus)
- Umbilical blood flow disrupted (e.g. cord compression including shoulder dystocia, cord prolapse)
- Inadequate maternal placental perfusion
- Compromised foetus (anaemia, IUGR)
- Failure of cardiorespiratory adaptation at birth (failure to breathe)
When do clinical manifestations of HIE start?
- Up to 48 hours after asphyxia
How are clinical manifestations of HIE graded?
- MILD - infant is irritable and responds excessively to stimulation, may have staring eyes, hyperventilation and impaired feeding
- MODERATE - abnormalities of tone and movement, cannot feed and may have seizures
- SEVERE - NO normal spontaneous movements or response to pain, limbs fluctuate between hypotonia to hypertonia, seizures are often prolonged and refractory to treatment, multi-organ failure present
NOTE: the neuronal injury in HIE may be immediate from primary neuronal death or may be delayed from reperfusion injury causing secondary neuronal death
What is the prognosis of HIE?
- Mild HIE: a full recovery
- Even infants with moderate HIE, who have recovered fully on neurological examination and are feeding normally by 2 weeks of age have an excellent long-term prognosis
- Severe HIE has a mortality of 30-40%
- Of the survivors of severe HIE, 80% have neurodevelopmental disabilities, particularly cerebral palsy
- If MRI shows significant abnormalities at 4-14 days, there is a very high risk of later cerebral palsy
What are the different types of extracranial haemorrhages that can occur during birth?
- Caput Succedaneum - bruising and oedema of the presenting part extending beyond the margins of the skull bones (resolves within a few days)
- Cephalhaematoma - haematoma from bleeding below the periosteum, confined within the margins of the skull sutures. Usually involves the parietal bone (resolves over several weeks)
What is Chignon?
- Oedema and bruising from Ventouse delivery
- Bruising
- Abrasions
- Forceps marks
- Subaponeurotic haemorrhage
Describe nerve palsies in the newborn during birth
- Brachial nerve palsies result from traction to the brachial plexus nerve roots
- This can occur during breech deliveries or with shoulder dystocia
- Upper nerve root (C5 and C6) injury results in Erb’s Palsy
- NOTE: Erb’s palsy can happen with phrenic nerve palsy which results in an elevated diaphragm
- Most palsies will resolve completely
How do facial palsies occur?
- Compression of the facial nerve against mother’s ischial spine (this is also usually transient)
How do clavicle fractures occur?
- Usually from shoulder dystocia
- A snap may be heard during delivery and the infant may show reduced arm movement on the affected side
- A lump may be noticed due to callous formation
- Prognosis is excellent - no specific treatment needed
How do humerus/femur fractures occur in delivery?
- Humerus fractures tend to occur with shoulder dystocia
- Femoral fractures are more likely with breech deliveries
- Infants might show some deformity, reduced movement of the limb and pain on movement
- Fractures heal rapidly with immobilisation
What is respiratory distress syndrome (RDS)?
- Also known as hyaline membrane disease
- RDS is caused by a deficiency of surfactant (which is responsible for lowering surface tension)
- RDS is more common, the more preterm the baby is
- However, it can occur in term babies especially if they are born to diabetic mothers
What is surfactant?
What does surfactant deficiency lead to?
- Surfactant is a mixture of phospholipids and proteins produced by type II pneumocytes
- A deficiency of surfactant leads to widespread alveolar collapse and inadequate gas exchange
What can be given to mothers to combat RDS?
- Glucocorticoids given if preterm delivery is anticipated
- In babies born with RDS, artificial surfactant can be instilled into the lungs directly or via a tracheal tube
What are the 4 clinical signs of RDS seen at delivery or within 4 hours of birth?
- Tachypnoea (> 60 breaths/min)
- Laboured breathing with chest wall recession (particularly sternal and subcostal indrawing) and nasal flaring
- Expiratory grunting to try create positive airway pressure during expiration and maintain functional residual capacity
- Cyanosis if severe
What is the management of RDS?
- Oxygen and ventilation
- CPAP or artificial ventilation via a tracheal tube may be necessary
- Other options: mechanical ventilation, high-flow humidified oxygen therapy
How does RDS lead to pulmonary interstitial emphysema?
- Air from overly distended alveoli may track into the interstitium, resulting in pulmonary interstitial emphysema (PIE)
- In about 10% of infants ventilated for RDS, air will leak into the pleural cavity and cause a pneumothorax
What are some signs of pneumothorax in infants?
- An increase in oxygen demands
- Breath sounds
- Chest expansion on the affected side will be reduced
- A pneumothorax can be demonstrated by transilllumination
What is the management of pneumothorax in infants? (BMJ Best Practice)
- Immediate decompression + oxygen therapy + chest drain if tension pneumothorax
- To prevent pneumothoraces, infants should be ventilated with the lowest pressures that provide adequate chest movement and blood gasses
What is pneumothorax in term infants secondary to?
- Secondary to:
- Meconium aspiration
- Respiratory distress syndrome
- Complication of ventilation
Describe Apnoea, Bradycardia and Desaturation
- These episodes are very common in very low birthweight infants until they reach about 32 weeks’ gestational age
- It can occur either when an infant stops breathing over 20-30 seconds or when breathing continues against a closed glottis
- It tends to be caused by immaturity of central respiratory control and breathing will usually start again after gentle physical stimulation
- Caffeine can also help stimulate breathing
- CPAP may be needed if apnoeic episodes are frequent
- However, underlying causes of apnoea include hypoxia, infection, anaemia, electrolyte disturbances and hypoglycaemia
What problems do hypothermia lead to?
Why are preterm infants more vulnerable to hypothermia?
- Hypothermia —> increased energy consumption —> hypoxia and hypoglycaemia, failure to gain weight and increased mortality
- Preterm infants are particularly vulnerable to hypothermia, as:
- Large surface area to volume ratio (i.e. relatively little mass to generate heat, and lots of surface area from which you can lose heat)
- Thin skin that is heat permeable (transepidermal water loss)
- Little subcutaneous fat for insulation
- Often nursed naked and cannot conserve heat by curling up or generate heat by shivering
- Preterm babies are kept in incubators to closely control the temperature and humidity
What is a patent ductus arteriosus?
- This is common in many preterm infants
- Shunting of blood across the ductus from the left to the right side of the circulation is most common in infants with RDS
- It is sometimes asymptomatic
- However, it can cause apnoea and bradycardia, increased oxygen requirement and difficulty in weaning the infant from artificial ventilation
- Other signs include a bounding pulse (due to increased pulse pressure), prominent precordial impulse and a systolic murmur
- Echocardiography can be used to assess the infant’s circulation
What is the management of a patent ductus arteriosus?
- The duct can be CLOSED using:
- IV Indomethacin
- Prostacyclin synthetase inhibitor
- Ibuprofen
- IV Indomethacin
- If drugs are unsuccessful, surgical ligation or percutaneous catheter device closure may be used
Describe nutrition in Preterm Infants
- Preterm infants have a high nutritional requirement
- Infants born at 35-36 weeks can suck and swallow milk
- Less mature infants will need feeding via an orogastric or nasogastric tube
- In very preterm infants, breast milk needs to be supplemented with phosphate and may also need supplementation of protein, calories and calcium
- NOTE: there are special formulas made for very preterm infants, however, unlike breast milk, formula does NOT provide protection against infection
- If the infant is very immature or sick, parenteral nutrition may be required - this is usually administered via a central venous catheter (e.g. PICC line)
- IMPORTANT: PICC lines carry a significant risk of septicaemia (and other risk such as thrombosis)
- NOTE: cows’ milk based formula increases the risk of necrotising enterocolitis
- Poor bone mineralisation used to be common in preterm infants, however, it can be prevented by provision of adequate phosphate, calcium and vitamin D
- Iron is usually transferred to the foetus during the last trimester, so preterm babies often have low iron stores and are at risk of iron deficiency
- Iron supplements are usually started at several weeks of age
Why is there a high infection risk in preterm infants?
Infection where is often a reason for preterm labour?
- High risk of infection because IgG is mainly transferred across the placenta in the last trimester
- Furthermore, infection in and around the cervix is often a reason for preterm labour
- Most infections in preterm infants occur after several days and are nosocomial (often associated with indwelling catheters or artificial ventilation)
What percentage of very low birthweight infants do haemorrhages occur in?
- 25%
- Most occur in 72 hours from birth
Where do haemorrhages occur?
- Germinal matrix above the caudate nucleus
Which events are haemorrhages more common after in newborn?
- Following perinatal asphyxia
- In infants with severe RDS
What is a major risk factor for haemorrhage?
- Pneumothorax is a major risk factor for haemorrhage
What is the most severe form of haemorrhage in preterm infants?
- Unilateral haemorrhagic infarction involving the parenchyma of the brain - usually resulting in hemiplegia
Describe preterm brain injury
- A large intraventricular haemorrhage may impair the drainage and reabsorption of CSF, leading to an accumulation of CSF
- This may resolve spontaneously or may progress to hydrocephalus
- Hydrocephalus may lead to separation of cranial sutures, a rapid increase in head circumference and the anterior fontanelle to become tense
- A ventriculoperitoneal shunt may be required, but symptomatic relief by relieving CSF via a lumbar puncture or ventricular tap may be sufficient
- Around 50% of infants with progressive post-haemorrhagic ventricular dilatation have cerebral palsy
- Periventricular white matter brain injury may occur following infarction or inflammation and may occur in the absence of haemorrhage
- This may resolve spontaneously
- However, if cystic lesions become visible on ultrasound 2-4 weeks later, there is definite loss of white matter
What is the presence of multiple bilateral cysts in the brain called?
What is it associated with?
- The presence of multiple bilateral cysts is called periventricular leukomalacia (PVL) - it is associated with an 80-90% risk of spastic diplegia
- NOTE: PVL and intraventricular haemorrhage could both occur in the absence of clinical sign
What is spastic diplegia?
- A form of cerebral palsy causing high tightness or stiffness in the muscles of the lower extremities
What is necrotising enterocolitis?
- Associated with bacterial infection of ischaemic bowel wall
- Preterm infants fed with cows’ milk formula more likely to develop this
- May rapidly develop shock and require artificial ventilation
- May progress to bowel perforation - this can be detected by X-ray or transillumination of the abdomen
- Mainly affects preterm infants in the first few weeks of life
- Long-term consequences include the development of strictures and malabsorption if extensive bowel resection is necessary
What are the clinical features of necrotising enterocolitis?
- Infant stops tolerating feeds
- Milk is aspirated from the stomach
- Vomiting (may be bile-stained)
- Abdominal distension
- Rectal bleeding (sometimes)
What is the management of necrotising enterocolitis?
- Stop oral feeding
- Broad-spectrum antibiotics
- Surgery if bowel perforation/necrosis
- Parenteral nutrition
- Artificial ventilation and circulatory support
What are characteristic x-ray features of necrotising enterocolitis?
- Distended loops of bowel
- Thickening of the bowel wall with intramural gas
- Gas in the portal tract
What is Retinopathy of Prematurity?
What can it lead to?
- Affects developing blood vessels at the junction of the vascular and non-vascularised retina
- This may progress to retinal detachment, fibrosis and blindness
- Uncontrolled use of high concentrations of oxygen
- This is found in about 35% of very low birthweight infants
What is Bronchopulmonary Dysplasia?
What is lung damage a result of?
What does a CXR show?
- Infants who still have an oxygen requirement at a post-menstrual age of 36 weeks are described as having bronchopulmonary dysplasia (or chronic lung disease)
- Lung damage occurs as a result of artificial ventilation, oxygen toxicity and infection
- A chest X-ray may show widespread areas of opacification, sometimes with cystic changes
- Some infants will need prolonged ventilation, but most will be weaned onto CPAP and then additional ambient oxygen
- Corticosteroids may facilitate earlier weaning (although there are concerns about abnormal neurodevelopment)
- Subsequent pertussis or RSV infection could lead to respiratory failure
What should be given to preterm infants after discharge?
What are preterm infants at risk of?
- Additional iron supplementation needs to be given until 6 months corrected age
- They are at increased risk of:
- Poor growth
- Pneumonia/wheezing/asthma
- Bronchiolitis from RSV infection
- Bronchopulmonary dysplasia
- Gastro-oesophageal reflux
- Complex nutritional and gastrointestinal disorders (e.g. following necrotising enterocolitis)
- Inguinal hernia
- NOTE: about 5-10% of very low birthweight infants develop cerebral palsy, but the most common impairments are learning difficulties
Why are newborn infants jaundiced?
Why is it important to take note of neonatal jaundice?
- Over 50% of all new born infants become visibly jaundiced
- This is due to:
- Marked physiological release of haemoglobin from the breakdown of red blood cells because of the high Hb concentration at birth
- Red cell life span of newborn infants (70 days) is considerably shorter than that of adults (120 days)
- Hepatic bilirubin metabolism is less efficient in the first few days of life
- It is important to notice neonatal jaundice because:
- It may be a sign of another disease (e.g. haemolytic anaemia, infection)
- Unconjugated bilirubin can get deposited in the brain, particularly the basal ganglia, causing kernicterus
What is kernicterus?
What feature of bilirubin enables it to happen?
- Encephalopathy due to unconjugated bilirubin in the basal ganglia and brainstem nuclei
- May occur when the level of unconjugated bilirubin exceeds the albumin-binding capacity of bilirubin of the blood
- Free bilirubin is fat-soluble, so it can cross the blood-brain barrier
What are acute manifestations of kernicterus?
- Lethargy
- Poor feeding
What are signs of severe kernicterus?
- Irritability
- Increased muscle tone causing the baby to lie with an arched back (opisthotonos)
- Seizures
- Coma
What conditions may infants who survive from kernicterus develop?
- Choreoathetoid cerebral palsy (due to damage to the basal ganglia)
- Learning difficulties
- Sensorineural deafness
What is jaundice less than 24 hours of age due to?
- Usually due to haemolysis
- Haemolytic Disorders
- Rhesus Haemolytic Disease
- Affected infants are usually identified antenatally
- Severely affected infants will have anaemia, hydrops and hepatosplenomegaly with rapidly developing jaundice
- NOTE: antibodies may develop to rhesus antigens other than D (e.g. Kell and Duffy)
- ABO Incompatibility
- Most ABO antibodies are IgM and do NOT cross the placenta
- However, some group O women have an IgG anti-A-haemolysin in the blood, which can cross the placenta and haemolyse the red cells of a group A infant
- Jaundice doesn’t tend to be as bad as with rhesus disease and hepatosplenomegaly is absent
- Direct antibody test (Coombs’ test) is positive
- G6PD Deficiency
- Parents of affected infants should be given a list of drugs that they should avoid that may precipitate haemolysis
- Spherocytosis
- Rhesus Haemolytic Disease
- Congenital Infection - can cause jaundice < 24 hours after birth
What causes of jaundice at 2 days to 2 weeks of age?
- Physiological Jaundice
- Most babies will become mildly jaundiced with no underlying cause
- Breast Milk Jaundice
- Jaundice is more common and prolonged in breast-fed infants
- Hyperbilirubinaemia is unconjugated
- Dehydration
- Jaundice can be exacerbated if milk intake is poor
- In some infants, IV fluids may be needed
- Infection
- A baby with an infection may develop unconjugated hyperbilirubinaemia from poor fluid intake, haemolysis, reduced hepatic function and an increase in enterohepatic circulation
- Other causes
- Bruising and polycythaemia can exacerbate jaundice
- Crigler-Najjar syndrome (deficient or absent UGT)
What are the causes of jaundice > 2 weeks of age?
What are causes of unconjugated hyperbilirubinaemia?
What are signs of conjugated hyperbilirubinaemia?
- Biliary atresia (disease of the liver with abnormally narrow, blocked or absent bile ducts)
- However, most cases of jaundice are unconjugated
- In prolonged unconjugated hyperbilirubinaemia:
- Breast milk jaundice (MOST COMMON, affected up to 15% of infants)
- Infection (especially of the urinary tract)
- Congenital hypothyroidism
- Conjugated hyperbilirubinaemia will cause pale stools and dark urine
- It may also cause hepatomegaly and poor weight gain
What are causes of conjugated hyperbilirubinaemia?
- Neonatal hepatitis syndrome
- Biliary atresia
How does Jaundice spread?
How is bilirubin checked?
When should bilirubin be checked in babies?
- Jaundice tends to start on the head and face and spread down the trunk and limbs
- Bilirubin checked with a transcutaneous bilirubin meter or blood sample
- It is recommended in the UK that all babies should be checked clinically for jaundice in the first 72 hours of life, and if clinically jaundiced, a transcutaneous measurement should be made
- The rate at which bilirubin rises tends to be linear until it plateaus, so serial measurements can be plotted on a chart and used to anticipate the need for treatment
- Drugs that displace bilirubin from albumin (e.g. sulfonamides and diazepam) should be avoided in newborn infants
How is neonatal jaundice managed? (NICE Guidelines)
- Assessment
- Visually inspect the baby in natural light
- Measure Bilirubin
- Use serum bilirubin - if jaundice developed in the first 24 hours of life or if the gestational age is < 35 weeks
- In babies born > 35 weeks or with jaundice that develops after the first 24 hours - use a transcutaneous bilirubinometer
- If the result is > 250 micromol/L, check the result by measuring serum bilirubin
- Measure Bilirubin
- Assess risk of developing kernicterus
Increased risk if:- Serum bilirubin > 340 micrmol/L in babies > 37 weeks gestation
- Rapidly rising bilirubin of > 8.5 micromol/L per hour
- Clinical features of acute bilirubin encephalopathy
- Serum bilirubin should be measured every 6 hours until it drops below the treatment threshold or becomes stable/falling
- Visually inspect the baby in natural light
- Investigation of Underlying Cause
- Measure haematocrit
- Blood group of mother and baby
- DAT test (Coombs)
- If the mother is Rh-negative, find out whether the mother received prophylactic anti-D immunoglobulin during pregnancy
- Consider the following tests
- FBC and blood film (e.g. looking for hereditary spherocytosis)
- Blood G6PD levels (consider ethnic origin)
- Microbiological cultures of blood, urine and/or CSF (if suspected infection
What is the treatment of neonatal jaundice?
- Use threshold table to determine whether the bilirubin measurement warrants treatment
- 1st line: Phototherapy
- Light (wavelength 450 nm) form the blue-green band of the visible spectrum converts unconjugated bilirubin into a harmless water-soluble pigment that is predominantly excreted in the urine
- Monitor the baby’s temperature whilst having phototherapy and protect the baby’s eyes
- Phototherapy can be stopped once the serum bilirubin level is >50 micromol/L below the threshold for treatment
- Check for rebound hyperbilirubinaemia by measuring serum bilirubin 12-18 hours after stopping phototherapy
- Other treatment options
- Exchange transfusion
- IVIG
What is transient tachypnoea of the newborn?
How is it caused?
- Most common cause of respiratory distress in term infants
- Cause: delayed reabsorption of lung liquid
- More common in birth by C-section
- Usually settles within the first day of life
What is meconium aspiration?
- Meconium = dark green substance forming the first faeces of a newborn infant
- Passed before birth by 8-20% of babies
- It may be passed in response to foetal hypoxia
- Asphyxiated infants may start gasping before delivery and aspirate the meconium
- Meconium is a lung irritant and will cause both mechanical obstruction and chemical pneumonitis, and it predisposes to infection
- The lungs become over-inflated and have patches of collapse and consolidation
- There is a high incidence of air leak, leading to pneumothorax and pneumomediastinum
- Artificial ventilation is often needed
- Infants may develop persistent pulmonary hypertension
What is the management of meconium aspiration? (BMJ Best Practice)
- If normal term infant with meconium-stained amniotic fluid but no history of GBS, observation is recommended
- If there are risk factors or laboratory findings that are suggestive of infection, consider antibiotics
- IV ampicillin AND gentamicin
- Oxygen therapy and non-invasive ventilation (e.g. CPAP) may be used in more severe cases
What predisposes to pneumonia? (Perinatal)
- Prolonged rupture of the membranes, chorioamnionitis and low birthweight predispose to pneumonia
- Broad-spectrum antibiotics are started early until the results of the infection screen are available
- NOTE: milk aspiration can also cause respiratory symptoms in the newborn