Flashcards in Neonatology ||| Deck (259):
What is the pathophysiology of hypoxic-ischaemic encephalopathy (3)?
1. Perinatal asphyxia occurs, as gas exchange (placental or pulmonary) are compromised or ceases, resulting in cardiorespiratory depression
2. Hypoxia, hypercarbia (CO2 retention) and metabolic acidosis follow
3. Compromised cardiac output diminishes tissue perfusion causing hypoxic-ischaemic injury to the brain and other organs
What are the 5 most common causes of HIE?
HIE usually follows a significant hypoxic event immediately before or during labour or delivery
1. Failure of gas exchange across the placenta - excessive or prolonged uterine contractions, placental abruption, ruptured uterus
2. Interruption of umbilical blood flow - cord compression including shoulder dystocia, cord prolapse
3. Inadequate maternal placental perfusion, maternal hypotension or hypertension
4. Compromised fetus - intrauterine growth restriction, anaemia
5. Failure of cardiorespiratory adaptation at birth - failure to breathe
What are the 3 grades of the clinical manifestations of HIE?
Mild - infant is irritable, responds excessively to stimulation, may have staring of the eyes, hyperventilation, hypertonia and has impaired feeding
Moderate - marked abnormalities of movement, is hypotonic, cannot feed and may have seizures
Severe - No normal spontaneous movements or response to pain, tone in the limbs fluctuate between hypotonia and hypertonia, seizures are prolonged and often refractory to treatment, multi-organ failure is present
Under what principle does mild therapeutic hypothermia work?
Neuronal damage may be immediate from primary neuronal death or may be delayed from reperfusion injury causing secondary neuronal death from secondary energy failure. This delay offers the opportunity for neuroprotection with mild therapeutic hypothermia
What is the immediate management of HIE (5)?
1. Respiratory support
2. Treatment of clinical seizures with anticonvulsants
3. Fluid restriction because of transient renal impairment
4. Treatment of hypotension by volume and inotrope support
5. Monitoring and treatment of hypoglycaemia and electrolyte imbalance, especially hypocalcaemia
How does therapeutic hypothermia work?
Infant wrapped in a cooling blanket to rectal temperature of 33 degrees for 72 hours, started within 6 hours of birth. Reduces brain damage
In what infants are therapeutic hypothermia used for?
Infants 36 weeks gestation and over with moderate or severe HIE
What are the long-term neurodevelopment risks of HIE (2)?
1. Brain damage resulting in disability or death
2. Cerebral palsy
What is the pathophysiology of RDS?
1. Deficiency of surfactant, which lowers surface tension
2. Leads to widespread alveolar collapse and inadequate gas exchange
What forms surfactant?
Type 2 pneumocytes of the alveolar epithelium
What is surfactant made of and what is its role?
Mixture of phospholipids and proteins
Lowers surface tension
Before what weeks gestation is RDS particularly common in?
Before 28 weeks gestation
What is the given to the mother if preterm delivery is anticipated to prevent RDS?
What are 4 signs of RDS at delivery or within 4 hours of birth in babies?
1. Tachypnoea over 60 breaths/min
2. Laboured breathing with chest wall recession (especially sternal and subcostal indrawing) and nasal flaring
3. Expiratory grunting to try to create positive airway pressure during expiration and maintain functional residual capacity
4. Cyanosis if severe
What is the management of RDS after birth (3)?
1. Raised ambient O2
2. Surfactant therapy may be given by instilling surfactant directly into the lungs via a tracheal tube or catheter
3. Additional respiratory support
-Non-invasive CPAP/high-flow nasal cannula (non-invasive preferred if possible)
-or invasively with mechanical ventilation
What 3 things are mechanical ventilation adjusted according to?
1. Infants oxygenation
2. Chest wall movements
3. Blood gas analysis
What medical problems are preterm infants more likely to get (16)?
1. Need for resus and stabilisation at birth
2. Respiratory problems
-apnoea and bradycardia
4. Patent ductus arteriosus
5. Temperature control
-osteopenia of prematurity
10. Intraventricular haemorrhage/periventricular leukomalacia
11. Necrotising enterocolitis
12. Retinopathy of prematurity
13. Anaemia of prematurity
15. Bronchopulmonary dysplasia (BPD)
16. Inguinal hernias
What weeks gestation are considered preterm?
What weeks gestation are considered term?
What is the clinical presentation of bradycardia and apnoea in preterm infants?
Bradycardia may occur when the infant stops breathing for over 20-30 seconds
When breathing but against a closed glottis
What is the most usual cause of apnoea and bradycardia in a preterm infant?
Immaturity of central respiratory control
What is the treatment of apnoea and bradycardia in a preterm infant (3)?
1. Breathing usually starts again after gentle physical stimulation
2. Respiratory stimulant caffeine
3. CPAP or mechanical ventilation if apnoeic episodes are frequent
What are the consequences of hypothermia in a preterm infant (3)?
1. Hypothermia causes increased energy consumption
2. This can result in hypoxia and hypoglycaemia, failure to gain weight
3. It is an independent risk factor for mortality soon after birth
What are 4 reasons that preterm infants are particularly vulnerable to hypothermia?
1. Large surface area relative to their mass so there is greater heat loss than heat generation
2. Skin is thin and heat permeable, so transepidermal water loss is important in the 1st week of life
3. They have little subcutaneous fat for insulation
4. Often nursed naked and cannot conserve heat by curling up or generate heat by shivering
What is the management/prevention of hypothermia in preterm infants (2)?
2. Overhead radiant heaters
Why is it important to provide adequate nutrition to preterm infants (3)?
1. They have a high nutritional requirement because of their rapid growth
2. Avoid poor bone mineralisation (osteopenia of prematurity) as a result of inadequate phosphate, calcium and vitamin D - treated with supplementation of milk
3. Avoid low iron stores and iron deficiency as iron is transferred to fetus during the last trimester - treated with iron supplements
At how many weeks gestation are infants mature enough to suck and swallow milk?
35-36 weeks gestation
How are less mature infants fed?
Via an orogastric or nasogastric tube
What are preterm infants fed to ensure adequate nutrition (2)?
1. Breast milk supplemented with phosphate and sometimes protein and calories and calcium
2. Special infant formulas designed to meet the increased nutritional requirements of preterm infants (if formula feeding required)
What are some extremely preterm infants initially fed on if maternal breast milk is not available?
Donor breast milk
How are very immature or sick infants (typically <1kg birthweight) fed?
Paraenteral nutrition via a peripherally inserted central line (PIC or long line) or an umbilical venous catheter
Why is breast milk better than formula milk?
1. Infants (2)
2. Mother (1)
3. Both (1)
1. Protection against infection
2. Lowers risk of SIDS, diabetes, obesity etc in future
1. Lowers risk of ovarian/breast cancer, CVD disease, obesity etc
1. Promotes bonding
Why are preterm infants at an increased risk of infection?
IgG is mostly transferred across the placenta in the last trimester and no IgA or M is transferred
What are 3 causes of infection in preterm infants?
1. Infection in or around cervix which causes preterm labour and can cause infection shortly after birth
2. Associated with indwelling catheters
3. Associated with mechanical ventilation
When does the infection usually present in a preterm infant?
After several days of age
What are consequences of infection (3)?
2. Bronchopulmonary dysplasia
3. Brain injury -> disability
What is necrotising enterocolitis?
A serious illness occurring in preterm infants, where the bowel becomes inflamed and necrosed
At what age does NE usually present?
First few weeks of life
What are the 3 key risk factors for NE in preterm infants?
1. Bowel of preterm infant is vulnerable to ischaemic injury
2. Bowel of preterm infant is vulnerable to bacterial invasion
3. More likely if fed cows milk than only breast milk
What are early (4) and late (3) signs of NE?
1. Feed intolerance
2. Vomiting -> may be bile stained
3. Distended abdomen
4. Fresh blood in stools
1. Infant goes into shock
2. Requires mechanical ventilation due to abdominal distension and pain
3. Bowel perforation
What are the characteristic X-ray features of NE (2)?
1. Distended loops of bowel
2. Thickening of bowel wall with intramural gas
How would you confirm a bowel perforation (2)?
2. Transillumination of the abdomen
What is the treatment of NE (6)?
1. Stop oral feeding
2. Give broad-spectrum Abx for aerobic and anaerobic
3. Parenteral nutrition always needed
4. Mechanical ventilation may be needed
5. Circulatory support may be needed
6. Surgery for bowel perforation
What is the long-term sequelae of NE (2)?
2. Malabsorption in extensive bowel resection
What % of very low birthweight infants develop a haemorrhage?
What scan is best used to detect a brain haemorrhage in a preterm infant?
Cranial ultrasound scans
Where do the brain haemorrhages in the preterm infant usually occur?
The germinal matrix above the caudate nucleus, which contains a fragile network of blood vessels
-Small haemorrhages in the germinal matrix
-Larger haemorrhages extend into the ventricles
How many hours after birth does an intraventricular haemorrhage (IVH) occur in a preterm infant?
What are 3 risk factors for IVH in preterm infants (3)?
1. Perinatal asphyxia
2. Severe RDS
What is the most severe type of haemorrhage in preterm infants?
Unilateral haemorrhagic infarction involving the parenchyma of the brain, usually resulting in CP hemiplegia
What are the consequences of brain haemorrhages in preterm infants (2)?
1. Unilateral haemorrhagic infarction involving parenchyma of brain -> hemiplegia
2. A large IVH can impair drainage and reabsorption of CSF, causing build-up under pressure.This can resolve spontaneously or lead to hydrocephalus
What are the clinical features of hydrocephalus (3)?
1. Cranial sutures separate
2. Head circumference increases rapidly
3. Anterior fontanelle becomes tense
How is hydrocephalus managed (2)?
1. Symptomatic relief by removal of CSF by LP or ventricular tap
2. Some may require a VP shunt
What is retinopathy of prematurity?
Vascular proliferation of the bv at the junction of the vascularised and non-vascularised retina
May progress to retinal detachment, fibrosis and blindness
What is a risk factor for retinopathy of prematurity?
Uncontrolled use of high concentrations of O2
What are the 2 treatment options for retinopathy of prematurity to reduce visual impairment?
1. Laser therapy
2. Intravitreal anti-VEGF therapy
What is bronchopulmonary dysplasia?
Chronic lung disease - infants who still have an oxygen requirement at a post gestational age of 36 weeks
What is the pathophysiology of bronchopulmonary dysplasia?
Lung damage due to delay in lung maturation, also from pressure and volume trauma from artificial ventilation, oxygen toxicity and infection
What does the chest x-ray show for bronchopulmonary dysplasia?
Widespread areas of opacification, sometimes with cystic changes
What is the course of bronchopulmonary dysplasia (3)?
1. Some infants need prolonged artificial ventilation
2. Most are weaned onto CPAP or high-flow nasal cannula therapy followed by additional ambient oxygen
3. Some with severe disease may die of itnercurrent infection or pulmonary hypertension
What are the neurodevelopmental complications of prematurity (4)?
1. 5-10% of very low birthweight infants develop CP
2. Most have learning difficulties
3. A small proportion have hearing impairment
4. A small proportion have visual impairment (1% blind in both eyes)
Why is hypoglycaemia common in the first 24 hours of life in a preterm infant?
They have poor glycogen stores
What are 6 symptoms of hypoglycaemia in a neonate?
What is the suggested adequate level of blood glucose level for optimal neurodevelopmental outcome in a neonate?
Glucose levels above 2.6 mmol/l
What is the consequence of prolonged, symptomatic hypoglycaemia in a neonate?
Permanent neurological disability
How can hypoglycaemia be prevented in a neonate (2)?
1. Early and frequent milk feeding
2. Blood glucose regularly monitored at the bedside
In an infant with 2 low glucose values (2.6mmol/l)in spite of adequate feeding, or one very low value (<1.6mmol/l), or becomes symptomatic, what is given?
Glucose by iv infusion aiming to maintain glucose level over 2.6 mmol/l via a central venous catheter
If there is difficulty or delay in starting an infusion, or a satisfactory response is not achieved in a neonate with hypoglycaemia, what can be given?
What area the 4 signs of respiratory distress in an infant?
1. Tachypnoea (>60 breaths/min)
2. Laboured breathing, with chest wall recession (particularly sternal and subcostal indrawing) and nasal flaring
3. Expiratory grunting
4. Cyanosis if severe
What is the general management of an infant with respiratory distress (4)?
1. Admitted to neonatal unit for monitoring of heart and respiratory rates, oxygenation and circulation
2. Chest x-ray will be needed to identify cause
3. Additional ambient oxygen
4. Respiratory support that may be non-invasive e.g. CPAP or high-flow cannula therapy
What are the causes of respiratory distress in an infant?
-Less common (4)
1. Transient tachypnoea of the newborn
1. Meconium aspiration
4. Persistent pulmonary hypertension of the newborn
1. Diaphragmatic hernia
2. Tracheo-oesophageal fistula
3. Pulmonary hypoplasia
1. Congenital heart diseaes
2. Hypoxic-ischaemic/neonatal encephalopathy
3. Severe anaemia
4. Metabolic acidosis
What is the pathophysiology of transient tachypnoea of the newborn? What is its course?
Caused by a delay in resorption of lung liquid causing respiratory distress. It usually settles within 1st day of life but can take several days to resolve completely
What is a risk factor for transient tachypnoea of the newborn?
What would chest x-ray show for transient tachypnoea of the newborn?
Fluid in the horizontal fissure
How is transient tachypnoea of the newborn managed?
Additional ambient oxygen
How is transient tachypnoea of the newborn diagnosed?
Diagnosis of exclusion
What % of babies pass meconium before birth?
Why may it be passed?
8-20% - increasingly occurs with greater gestational age
May be in response to asphyxia
What are the consequences of meconium aspiration (3)?
1. Meconium is a lung irritant and results in both mechanical obstruction and a chemical pneumonitis, as well as predisposing to infection
2. May lead to persistent pulmonary hypertension of the newborn
3. There is high incidence of air leak, which can lead to pneumothorax and pneumomediastinum
What does the chest x-ray show for meconium aspiration (3)?
1. Lungs overinflated
2. Areas of collapse
3. Patches of colsolidation
What is the management of meconium aspiration?
Some may need mechanical ventilation
What is persistent pulmonary hypertension of the newborn?
A life-threatening condition usually associated with birth asphyxia, meconium aspiration, septicaemia or RDS
What is the pathophysiology of persistent pulmonary hypertension of the newborn?
High pulmonary vascular resistance means there is right-to-left shunting within the lungs and at atrial and ductal levels.
What signs are absent in persistent pulmonary hypertension of the newborn (2)?
1. Signs of heart failure
2. Heart murmurs
What signs occur with persistent pulmonary hypertension of the newborn (2)?
2. Pulmonary oligaemia
What investigations are done for persistent pulmonary hypertension of the newborn and what do they show/what are they for (2)?
1. Chest x-ray
-heart is of normal size
2. Urgent echocardiogram
-exclude congenital heart disease
-signs of pulmonary hypertension such as raised pulmonary pressures and tricuspid regurgitation
What is the management of persistent pulmonary hypertension of the newborn (3)?
1. Mechanical ventilation
2. Circulatory support
3. Inhaled nitric oxide, a potent vasodilator is often beneficial
What is a diaphragmatic hernia?
When there is a hole in the diaphragm as it is not formed properly so bowel contents can enter the chest
How are diaphragmatic hernias diagnosed?
On antenatal ultrasound screening
How do diaphragmatic hernias present in the newborn period?
Failure to respond to resuscitation or respiratory distress
Where does the hole in the diaphragm usually occur in a diaphragmatic hernia?
Left side through the posterolateral foramen of the diaphragm
What are the signs of diaphragmatic hernias in a newborn (2)?
1. Apex beat and heart sounds are displaced to the right side of the chest
2. Poor air entry in left chest
How is the diagnosis of diaphragmatic hernia confirmed?
X-ray of chest and abdomen
What is the immediate and then management following stabilisation of a diaphragmatic hernia?
- Once diagnosis is suspected, a large nasogastric tube is passed and suction applied to prevent distension of the intrathoracic bowel
- Diaphragmatic hernia is repaired surgically
What is the main problem of diaphragmatic hernias?
-compression by the herniated viscera throughout pregnancy has prevented development of the lung in the fetus
-mortality is high in this case
What 3 things predispose to pneumonia?
1. Prolonged rupture of the membranes
3. Low birthweight
How is congenital pneumonia managed?
Broad-spectrum abx started early until the results of the infection screen are available
What is early-onset infection?
Early-onset sepsis (<48 hours after birth)
How do bacteria and viruses infect the fetus in early-onset infection (2)?
1. Bacteria have ascended from the birth canal and invaded the amniotic fluid, which is in direct contact with the fetal lungs. This leads to pneumonia and secondary bacteraemia/septicaemia
2. Congenital viral infections and early-onset infection with Listeria monocytogenes, is acquired via the placenta following maternal infection
What is the presentation of neonatal septicaemia (9)?
1. Respiratory distress
2. Temperature instability
3. Poor feeding
5. Apnoea and bradycardia
6. Abdominal distension
What are the investigations done for neonatal septicaemia (5)?
1. Chest x-ray
2. Septic screen
3. FBC -> detect neutropenia
4. Blood cultures
5. CRP (but takes 12-24 hours to rise)
What is the treatment of neonatal septicaemia?
Abx started immediately without waiting for culture results
-iv abx given to cover group B strep, L. monocytogenes and other gram-positive organisms (usually benzylpenicillin or amoxicillin)
-cover for gram-negative organisms (usually aminoglycoside such as gentamicin)
What is late-onset infection in a neonate?
>48 hours after birth
What is the source of infection in late-onset infection in a neonate (3)?
-Indwelling central venous catheters for parenteral nutrition
-invasive procedures that break the protective barrier of the skin
What is the presentation of late-onset infection in a neonate?
The same as early onset - neonatal septicaemia
What are the most common organisms responsible for late-onset infection in neonates (3)?
1. Coagulase-negative staphylococcus - most common
2. Gram-positive bacteria (Staph. aureus and enterococcus faecalis)
3. Gram-negative bacteria (E.coli and pseudomonas, klebisella)
What is the treatment of late-onset infection in neonates?
Initial therapy e.g. with flucloxacillin and gentamicin
-aims to cover most staphylococci and Gram-negative bacilli
What is a danger of treating neonates with abx?
Predisposes to invasive fungal infections e.g. candida albicans
Where can group B streptococci be found in women (2)?
What problems do group B streptococci cause in neonates (2)?
Early and late onset sepsis
Where do infants born to mothers who carry group B strep colonise the bacteria (2)?
Mucous membranes or skin
How does early onset infection usually present in a neonate (2)?
1. Respiratory distress
How does late onset infection usually present in a neonate (2)?
2. Occasionally with focal infection e.g. osteomyelitis or septic arthritis
What are risk factors for infection with group B strep (GBS) in a neonate (5)?
2. Prolonged rupture of membranes
3. Maternal fever during labour (38oC)
4. Maternal chorioamnionitis
5. Previously infected infant
What is the antenatal management of GBS as a prophylaxis?
Prophylactic intrapartum Abx given IV to mother to prevent infection in baby
-in the UK it is offered to mothers with risk factor for infection
What is the postnatal treatment of GBS in a neonate?
IV Abx to cover GBS:
benzylpenicillin or amoxicillin
What is a useful marker to measure response of neonate to Abx treatment for septicaemia?
Serial measurements of CRP
How does neonatal meningitis present (2)?
1. Tense or bulging fontanelle
2. Head retraction (hyperextension of neck and back)
These are late signs and rarely seen in newborns
How common is neonatal meningitis? What is the mortality of it?
Mortality is 20-50%
If blood cultures are positive in a neonate for infection, or there are neurological/generalised signs, what investigation needs to be done?
CSF needs to be examined and cultured?
What is given to infants of mothers who are hepatitis B surface antigen (HBsAG)-positive to prevent vertical transmission?
At what months is it given?
Hepatitis B vaccination
-course needs to be completed during infancy and Ab response checked
-0 months, 1 month, 2 months and 12 months
What is the risk to neonates when their mothers are 'e'-antigen-positive but have no 'e' antibodies?
What is given to these babies to prevent vertical transmission?
Babies are at highest risk of becoming chronic carriers
Given passive immunisation with hepatitis B Ig soon after birth and definitely within 24 hours of birth
What investigations are included in a septic screen of a neonate?
Consider if indicated (5)
1. Blood culture
2. FBC inc differential white cell count
3. acute phase reactant e.g. CRP
4. Urine sample
Consider if indicated:
1. Chest X-ray
3. Rapid antigen screen on blood/CSF/urine
4. Meningococcal and pneumococcal PCR on blood/CSF samples
5. PCR for viruses in CSP (esp herpes simplex virus and enterovirus)
What are the risk factors for neonatal infection (7)?
2. Prolonged rupture of membranes
3. Maternal fever during labour (38oC)
4. Maternal chorioamnionitis
5. Previously infected infant
6. Indwelling central venous catheters
7. Mechanical ventilation
What are 2 risk factors that make vertical transmission of HIV from mother to child more likely?
1. High HIV viral load
2. More advanced disease
What are 5 measures to avoid vertical transmission of HIV from mother to neonate?
1. Use of effective ART during pregnancy and intrapartum to achieve an undetectable maternal viral load at time of delivery
2. Post-exposure prophylaxis given to infant right after birth
3. Avoidance of breastfeeding
4. Active management of labour and delivery, to avoid PROM and unnecessary instrumentation
5. Prelabour C-section if mother's viral load is detectable close to expected date of delivery
What are the common bacteria causing infection in the newborn?
Less common (3)
1. Group B strep
2. Coagulase-negative staphylococcus (Staphylococcus epidermis
3. Listeria monocytogenes
4. Gram positive bacteria:
5. Gram negative bacteria:
What are the key clinical features of congenital rubella, CMV and toxoplasmosis (12)?
1. Growth restriction
2. Eye defects:
4. Liver problems:
5. Virus excreted in urine
6. Bone abnormalities
7. Brain problems:
9. Heart defects:
-Patent ductus arteriosus
-Blueberry muffin or petechial
12. Blood problems:
What are 3 most common viruses affecting neonates?
How does a neonate become infected with Listeria?
Organism transmitted to the mother in food, such as unpasteurized milk, soft cheeses and undercooked poultry
How does a mother present with a Listeria infection?
It causes a bacteraemia, often with mild, influenza-like illness in the mother
How does a fetus become infected with Listeria?
Mother is infected and it passes to the fetus via the placenta
What are the 3 consequences of a Listeria infection in a pregnant woman?
1. Spontaneous abortion
2. Preterm delivery
3. Fetal/neonatal sepsis
What are some characteristic features of a Listeria infection in a neonate (5)?
1. Meconium staining of liquor
2. Widespread rash
What does purulent discharge with conjunctival injection and swelling of the eyelids within the first 48 hours of life indicate?
What does a troublesome discharge with redness of the eye in a neonate indicate?
Staphylococcal or streptococcal infection
How does chlamydia trachomatis eye infections present in neonates?
Purulent discharge with swelling of eyelids at 1-2 weeks of age, but may present shortly after birth
How can HSV infection be transmitted to a neonate?
Usually during passage through an infected birth canal or occasionally by ascending infection
How does HSV infection present in a neonate (4)?
1. Presents anytime up to 4 weeks of age
2. Localised herpetic lesions on the skin or eye
3. May have encephalitis
4. May have disseminated disease
What are causes of bilious vomiting in neonates (5)?
1. Intestinal obstruction
2. Malrotation with volvulus
3. Duodenal/jejunal/ileal atresia
4. Hirschsprung disease
5. Imperforate anus
What is the definition of a baby that is small for gestational age (SGA)?
Babies with a birthweight below the 10th centile
-the majority are normal, but small
What is the definition of intrauterine growth restriction/retardation?
Failure to reach their full genetically determined growth potential
-appear thin and malnourished
What are the 2 classifications of growth restriction?
2. Asymmetrical -> more common
What is asymmetrical growth restriction?
Weight or abdominal circumference lies on a lower centile than that of the head
What is the principle of the cause of asymmetrical growth restriction?
When the placenta fails to provide adequate nutrition late in pregnancy but brain growth is relatively spared at the expense of lover glycogen and skin fat
What are the causes of asymmetrical IUGR (4)?
Uteroplacental dysfunction secondary to:
1. Maternal pre-eclampsia
2. Multiple pregnancies
3. Maternal smoking
What is symmetrical growth restriction?
The head circumference is equally reduced with abdominal circumference and weight.
It suggests a prolonged period of poor intrauterine growth starting in early pregnancy
What are the causes of symmetrical growth restriction (5)?
1. Fetal chromosomal disorder or syndrome
2. A congenital infection
3. Maternal drug and alcohol abuse
4. Maternal chronic medical condition
What are the short-term complications of IUGR after birth (4)?
1. Hypothermia because of their relatively large surface area
2. Hypoglycaemia from poor fat and glycogen stores
What are the short term complications of IUGR in a fetus (2)?
1. Intrauterine hypoxia and 'unexplained' intrauterine death
2. Asphyxia during labour and delivery
What are the long-term complications of IUGR (2)?
1. Increased risk of obesity
2. Increased risk of T2DM
What are the respiratory and cardiovascular circulations like in the fetus?
In the fetus the lungs are filled with fluid. The blood vessels that supply and drain the lungs are constricted (high pulmonary vascular resistance), so blood from the right side of the heart bypasses the lungs and flows through the ductus arteriosus into the aorta.
Some blood flows from the RA through the foramen ovale to the LA.
What are the respiratory changes that occur during the transition from fetus to newborn (7)?
1. Shortly before and during labour, lung liquid production is reduced
2. During descent through the birth canal, the infant's chest is squeezed and some lung liquid drained.
3. Multiple stimuli, including thermal (cold), tactile and hormonal (mainly huge increases in catecholamine levels) initiate breathing
4. High catecholamine levels also stimulate reabsorption of alveolar fluid
5. Lung expansion is generated by intrathoracic negative pressure and a functional residual capacity is established
6. Once the infant breathes, the majority of the remaining lung fluid is absorbed into the lymphatic and pulmonary circulation
7. Pulmonary expansion at birth is associated with a rise in oxygen tension and with falling pulmonary vascular resistance, the pulmonary blood flow increases
What are the cardiovascular changes that occur during the transition from fetus to newborn (2)?
1. Increased left atrial filling results in a rise in the left atrial pressure with clsoure of the foramen ovale
2. The flow of oxygenated blood through the ductus arteriosus causes physiological and eventual anatomical ductal closure
Why is Vitamin K prophylaxis given to a newborn?
How does it present (6)?
To prevent haemorrhagic disease of the newborn.
1. Occurs early in 1st week of life, or late, from 1-8 weeks of age
5. Prolonged bleeding of umbilical stump or after circumcision
6. Some may get intracranial haemorrhage and become permanently disabled or die.
What is the quick immediate assessment of the newborn right after they are born (3)?
1. Baby is pink
2. Breathing normally
3. Has no major abnormalities
Where do preterm, small, or ill babies need to be taken?
To neonatal unit
Within how long of birth do babies need a full and thorough newborn check?
What is the purpose of a newborn baby check (3)?
1. Detect congenital abnormalities
2. Check for potential problems arising from maternal disease or familial disorders
3. Provide an opportunity for parents to discuss qs about baby
What are the steps of a routine examination of a newborn infant (18)?
1. Birthweight, gestational age, and birthweight centile
2. General observation of the baby's appearance, posture, and movements
3. The head circumference
4. Palpation of the fontanelle and sutures
5. Observation of the face
-check for syndromes
6. Check if its plethoric or pale
-central cyanosis in tongue
8. The eyes -Red reflex
9. Inspect and palpate the palate
10. Breathing or chest wall movement
11. Ausultate the heart
12. Palpate the abdomen
13. Palpate femoral pulses
14. Inspect the genitalia and anus (patent)
15. Check muscle tone by observing limb movements
16. Observe the whole of the back and spine
17. Check primitive reflexes including the grasp and moro reflexes for asymmetric or reduced movements
18. Check the hips for DDH
In the newborn baby check, how is the head circumference measured?
Paper tape measure and its centile noted
What could a tense fontanelle when the baby is not crying indicate?
What investigation should be done to check?
Raised ICP or a late sign of meningitis
Cranial ultrasound to check for hydrocephalus
If the baby is plethoric or pale what should you check for?
Haematocrit should be checked to identify polycythaemia or anaemia
What does an absent red reflex in a newborn indicate (3)?
1. Congenital cataracts
3. Corneal opacity
What does the palate need to be checked for in a newborn baby check (2)?
1. Visually inspected - exclude a posterior cleft palate
2. Palpate to detect an indentation of the posterior palate from a submucous cleft
What is the normal heart rate for term neonates during wake and sleep?
110-160 beats/min in term babies but may drop to 85 beats/min during sleep
What organs can be palpated in the abdomen in the newborn baby check (3)?
What pathology are you usually checking for?
1. Liver - normally extends 1cm to 2cm below the costal margin
2. Spleen tip may be palpable
3. Kidney on the left side
What causes a reduction and increase in pulse pressure in the femoral pulse?
Reduction - coarctation of the aorta. Confirm by measuring the blood pressure in the arms and legs
Increased if there is patent ductus arteriosus
What are the aims of newborn hearing screening?
Early detection and intervention to improve speech and language
What is the usual test for newborn hearing screening?
How does it work (2)?
Otoacoustic emission (OAE) testing
1. Earphone placed over the ear and sound emitted
2. Evokes an echo or emission from the ear if cochlear function is normal
If an abnormal result is generated from the newborn hearing screening, what is done?
Neonate is referred to a aediatric audiologist. Testing with auditory brainstem response (ABR) audiometry is done. This uses computer analysis of electroencephalogram waveforms evoked in response to a series of clicks
What does the Guthrie test/biochemical newborn screening screen for (4)?
1. Congenital hypothyroidism
2. Haemoglbinopathies (sickle cell and thalassaemia)
3. Cystic fibrosis
4. Six inherited metabolic diseases:
-MCAD (medium-chain acyl-coenzyme A dehydrogenase deficiency)
-Maple syrup urine disease
-Glutaric acideuria type 1
On what day of life is the Guthrie test performed?
How is the blood sample for the Guthrie test done?
What are the main diagnostic techniques for antenatal diagnosis (2)?
1. Maternal serum screening
2. Detailed USS
What are some antenatal maternal serum screening tests (7)?
1. Blood group and antibodies - for rhesus and other red cell incompatibilities
2. Hep B
5. HIV infection
6. Risk of chromosomal syndromes calculated from maternal age and maternal and fetoplacental hormones. This is combined with USS for nuchal translucency and confirmed with amniocentesis or CVS
7. Neural tube defects - raised maternal serum alphafetoprotein with spina bifida or anencephaly, but USS alone increasingly used
What are some antenatal ultrasound screening tests (5)?
1. Gestational age
2. Multiple pregnancies
3. Structural malformation
4. Fetal growth - abdo circumference, head circumference and femur length. Supplemented with Doppler US umbilical and fetal flow velocity waveform measurements if indicated
5. Amniotic fluid volume - polyhydramnios vs oligohydramnio
What are some causes of polyhydramnios (2)?
1. Associated with maternal diabetes
2. Associated with structural gastrointestinal abnormalities
What are some causes of oligohydramnios (3)?
1. Result from reduced fetal urine production (due to dysplastic or absent kidneys or obstructive uropathy)
2. Prolonged rupture of membranes
3. Associated with severe intrauterine growth restriction
What are some consequences of oligohydramnios (2)?
1. Pulmonary hypoplasia
2. Potter syndrome (limb and facial deformities from pressure on the fetus)
What % of newborns are jaundiced?
Why is jaundice very common in newborns (3)?
1. Marked physiological release of haemoglobin from the breakdown of RBC because of the high haemoglobin concentration at birth
2. The RBC lifespan of newborn infants (70 days) is markedly shorter than that of adults (120 days)
3. Hepatic bilirubin metabolism is less efficient in the first few days of lif
What is kernicterus and its pathophysiology (4)?
1. Encephalopathy resulting from the deposition of unconjugated bilirubin in the basal ganglia and brainstem nuclei
2. Occurs when the level of unconjugated bilirubin exceeds the albumin-binding capacity of bilirubin in the blood
3. As the free bilirubin is fat soluble, it can cross the blood-brain barrier
4. The neurotoxic effects vary in severity from transient disturbance to severe damage and death
What are the acute manifestations of kernicterus (2)?
2. Poor feeding
What are the clinical features of severe cases of kernicterus (4)?
2. Increased muscle tone causing baby to lie with an arched back (opisthotonos)
What are 3 long-term consequences of kernicterus in infants that survive?
1. Choreoathetoid cerebral palsy (due to damage to the basal ganglia)
2. Learning difficulties
3. Sensorineural deafness
Why has the incidence of kernicterus reduced?
The introduction of prophylactic anti-D immunoglobulin for rhesus-negative mothers has been introduced, reducing incidence of rhesus haemolytic disease
Anti-D neutralises any blood cells from RhD-positive baby before the mother has a chance to make antibodies against it
Which 2 groups of infants should you be extra wary of in the detection of kernicterus?
1. Slightly preterm infants (35-37 weeks)
2. Dark-skin toned infants in whom jaundice is more difficult to detect
At what level of bilirubin does the baby become clinically jaundiced?
What are 2 causes of jaundice within <24 hours of age? Which is most common
1. Haemolysis (most common)
2. Congenital infection
What type of bilirubin is present with haemolysis
What is the danger of unconjugated haemolysis?
It can rise very rapidly and reach extremely high levels
What are 4 haemolytic disorders?
1. Rhesus haemolytic disease
2. ABO incompatibility
What is Rhesus haemolytic disease?
Mother is Rhesus D negative, and baby is rhesus D positive. The mother must have also been previously sensitised to RhD positive blood (usually during delivery of a previous RhD positive baby).
The mother has antibodies to the RhD antigen in the baby and attacks it, causing rhesus haemolytic disease in the baby
How does an infant severely affected by Rhesus haemolytic disease present (5)?
4. Rapidly developing severe jaundice
How are infants at risk of rhesus haemolytic disease usually identified?
Maternal antibody screening during pregnancy
How is a fetus at risk of rhesus haemolytic disease usually monitored?
Regular US of the fetus to detect fetal anaemia non-invasively using Doppler velocimetry of the fetal middle cerebral artery
How is a fetus at risk of rhesus haemolytic disease usually managed (2)?
1. Anti-D immunisation of mothers
2. If necessary, fetal blood transfusion via the umbilical vein may be required regularly from about 20 weeks gestation
What is ABO incompatibility?
Most ABO antibodies are IgM and do not cross the placenta but some group O women have an IgG anti-A-haemolysin in their blood, which can cross the placenta and haemolyse the red cells of a group A infant. Occasionally, group B infants are affected by anti-B haemolysins
What are the clinical features of ABO incompatibility (3)? How does it differ from rhesus disease?
1. Severe jaundice, but not as bad as rhesus disease.
2. Infants haemoglobin level is usually normal or only slightly reduced
3. Hepatosplenomegaly is absent, unlike in rhesus disease
What test detects ABO incompatibility?
Coombs' test - demonstrates antibody on surface of red cells is positive
How long after birth does jaundice usually peak in ABO incompatibility?
first 12-72 hours
What are 3 options of therapy available for an infant born with jaundice due to rehsus disease/ABO incompatibility?
2. Ig therapy
3. Exchange transfusion
In infants with jaundice <24 hours after birth due to congenital infection, what type of bilirubin is it?
What are other abnormal clinical features (3)?
1. Growth restriction
3. Thrombicytopenic purpura
What are 5 causes of jaundice that occur at 2 days - 2 weeks of age?
1. Physiological jaundice
2. Breast milk jaundice
5. Haemolysis - can occur during the 1st week
What is physiological jaundice?
Mild-moderate jaundice with no underlying cause, and the bilirubin has risen as the infant is adapting to transition from fetal life
What is breast milk jaundice? What type of bilirubin is involved?
Jaundice is more common and more prolonged in breastfed infants, cause is multifactorial.
The bilirubin is unconjugated
How does dehydration affect jaundice?
In some infants, the jaundice is exacerbated if milk intake is poor from a delay in establishing breastfeeding and infant becomes dehyrated
In a baby with jaundice that occurs 2 days - 2 weeks of age due to infection, what type of bilirubin is it and how does it cause jaundice (4)?
1. From poor fluid intake
3. Reduced hepatic function
4. An increase in eneterohepatic circulation
How can jaundice be observed most easily in an infant?
Blanching the skin with your finger
If an infant is clinically jaundice, what should be used to check the bilirubin?
Transcutaneous bilirubin meter or blood sample
What are the 2 treatments for jaundice in a neonate?
1. Phototherapy - most widely used
2. Exchange transfusion for severe cases
How does phototherapy work?
Light (wavelength 450 nm) from the blue-green band of the visible spectrum converts unconjugated bilirubin into a harmless water-soluble pigment excreted predominantly in the urine
How does exchange transfusion work?
Blood is removed from baby in small aliquots (usually from an arterial line or the umbilical vein) and replaced with donor blood (via peripheral or umbilical vein). Usually, twice the infant's blood volume is exchanged.
Donor blood must be as fresh as possible and screened to exclude CMV, hep B/C and HIV
What is the pattern of spread of jaundice in an infants body?
Starts on head and face then spreads down the trunk and limbs
What is the overall assessment protocol of neonatal jaundice (6)?
-Clinical assessment and check bilirubin with transcutaneous meter or blood sample
-Lower treatment threshold if preterm
-if <24 hours, likely to be haemolysis and potentially serious
-if > 2weeks (3 weeks if preterm) - persistent neonatal jaundice. Need to check if un/conjugated
4. Well or unwell
-check for clinical evidence of sepsis and if dehydrated
5. Risk factors?
-Check for antenatal antibodies, if mother is blood group O (ABO incompatibility), if Mediterranean, Far-Eastern or African origin (G6PD deficiency)
6. Need treatment?
-Plot bilirubin on gestation specific chart according to age since birth
-Plot rate of change of bilirubin to identify potentially high levels
What is jaundice in babies >2weeks old or 3 weeks if preterm, called?
Persistent or prolonged neonatal jaundice
What are you most worried about with persistent/prolonged neonatal jaundice?
What is biliary atresia?
Bile ducts on the inside and outside of the liver are inflamed/obstructed, eventually leading to a complete blockage of bile flow from the liver. This in turn causes scarring (fibrosis) in the liver
In persistent/prolonged neonatal jaundice, what are the 3 causes of unconjugated hyperbilirubinaemia?
1. Breast milk jaundice
2. Infection, particularly of the urinary tract
3. Congenital hypothyroidism - jaundice may be before other clinical features of coarse facies, dry skin, hypotonia and constipation
What are the 2 main causes of prolonged conjugated hyperbilirubinaemia?
1. Neonatal hepatitis syndrome
2. Biliary atresia
What are the clinical features suggesting prolonged conjugated hyperbilirubinaemia (5)?
1. Baby passing dark urine
2. Unpigmented pale stools
4. Poor weight gain
What is neonatal urticaria (erythema toxicum) (4)?
1. A common rash appearing at 2-3 days of age
2. Consist of white pinpoint papules at the centre of an erythematous base
3. Fluid contains eosinophils
4. Lesions concentrated on trunk, they come and go at different sites
What are capillary haemangiomas (3)?
1. Pink macules on the upper eyelids, midforehead and nape of the neck are common
2. Arise from distension of the dermal capillaries
3. Those on eyelids fade over the 1st year, those on neck become covered with hair
What are mongolian blue spots (4)?
1. Blue/black macular discolouration at the base of the spine and on buttocks
2. Usually but not invariably in Afro-caribbean or Asian infants
3. Fade slowly over first few years
4. Of no significance unless misdiagnosed as bruises
What are 6 soft-tissue injuries you can get during delivery?
1. Caput succedaneum
4. Abrasions to the sin from scalp electrodes applied during labour or from accidental scalpel incision at C-section
5. Forceps marks to face from pressure of blades - transient
6. Subaponeurotic haemorrhage - very uncommon
What is a caput succedaneum?
Bruising and oedema of presenting part extending beyond the margins of the skull bones, which resolves in a few days
What is a cephalhaematoma?
Haematoma from bleeding below the periosteum, confined within the margins of the skull sutures. It usually involves the parietal bone. The centre of the haematoma feels soft. It resolves over several weeks
What is a chignon?
Oedema and bruising from Ventouse delivery
What are the causes of brachial nerve palsy during birth (2)?
Traction to the brachial plexus nerve roots by:
1. Breech delivery
2. Shoulder dystocia
What is Erb palsy? What is its course?
A type of brachial nerve palsy where there is upper nerve root (C5 and C6) injury
It usually resolves spontaneously
How may a facial nerve palsy occur during birth?
How does it present (2)?
Compression of the facial nerve against the mother's ischial spine or pressure from forceps
2. Facial weakness on crying but eye remains open
What feeding difficulties can newborns, especially preterm infants get (2)?
1. No coordinated sucking
2. Usually needs paraenteral nutrition and tube feeding
What are risk factors for fetal abnormality in pregnancy (6)?
1. Older mother (>35 years old)
2. Previous congenital abnormality
3. FH of inherited disorder
4. Parents are identified as carriers of autosomal recessive disorder e.g. thalassaemia
5. A parent carries a chromosomal rearrangement
6. Parents are close blood relatives (consanguinity)
What is maternal obesity associated with in pregnancy?
1. Gestational diabetes
2. Pregnancy-induced hypertension
1. Increased risk of miscarriage
3. Congenital abnormalities
5. Neonatal mortality
What are 7 clinical features of Down syndrome (Trisomy 21) at birth?
1. Characteristic facial features
3. Flat ociput
4. Single palmar creases
5. Incurved 5th finger
6. Wide 'sandal' gap between the big and 2nd toes
7. Short neck
What is the VACTERL association?
A group of malformations that occur together more often than expected by chance, but in different combinations from case to case
V - Vertebral anomalies
A - Anorectal malformations
C - Cardiovascular anomalies
T - Tracheoesophageal fistula
E - Esophageal atresia
R - Renal (Kidney) and/or radial anomalies
L - Limb defects
What is CHARGE syndrome?
A rare syndrome caused by a genetic disorder
C - Coloboma of the eye, central nervous system anomalies
H - Heart defects
A - Atresia of the choanae
R - Retardation of growth and/or development
G - Genital and/or urinary defects (Hypogonadism, undescended testicles, besides hypospadias.)
E - Ear anomalies and/or deafness and abnormally bowl-shaped and concave ears, known as "loop ears"
Be aware of 7 clinical features of Edwards syndrome (Trisomy 18)?
1. Low birthweight
2. Prominent occiput
3. Small mouth and chin
4. Short sternum
5. Flexed, overlapping fingers
6. 'Rocker-bottom' feet
7. Cardiac and renal malformations
Be aware of 6 clinical features of Patau syndrome (Trisomy 13)?
1. Structural defect of brain
2. Scalp defects
3. Small eyes (microphthalmia) and other eye defects
4. Cleft lip and palate
6. Cardiac and renal malformations
Be aware of 4 clinical features of fetal alcohol syndrome?
1. Growth restriction
2. Characteristic face
-thin upper lip
3. Developmental delay
4. Cardiac defects (70%)
What is the pathophysiology of cleft lip?
Results from failure of fusion of the frontonasal and maxiallary processes
What is the pathophysiology of cleft palate?
Results from failure of fusion of the palatine processes and the nasal septum
How does a neural tube defect occur?
What can prevent it?
Failure of normal fusion of the neural plate to form the neural tube during the first 28 days following conception. Folic acid supplementation reduces the risk
What is exomphalos?
Abdominal contents protrude through the umbilical ring, covered with a transparent sac formed by amniotic membrane and peritoneum. It is associated with other major congenital abnormalities
What is gastroschisis?
What is the risk of gastroschisis?
The bowel protrudes through a defect in the anterior abdominal wall adjacent to the umbilicus and there is no covering sac. It is not associated with other congenital abnormalities
Risk of dehydration and protein loss
What are the 5 main causes of small bowel obstruction in a neonate?
1. Atresia or stenosis of the duodenum
2. Atresia or stenosis of the jejunum or ileum
3. Malrotation with volvulus
4. Meconium ileus
5. Meconium plug
What are 3 clinical features of bowel atresia causing small bowel obstruction?
1. Persistent vomiting, which is bile stained
2. Meconium may still be passed but subsequently its passage is usually delayed or absent with no transition to normal stool
3. Abdominal distension
If a newborn has ambiguous genitalia, what needs to be done (5)?
1. Do not guess
2. Urgent medical assessments for other syndromes e.g. congenital adrenal hyperplasia
3. Further genetic tests - karyotype
4. Ultrasound of internal organs
5. Counselling for parents
What is the pathophysiology of congenital adrenal hyperplasia (CAH) (3)?
1. Deficiency of enzyme 21-hydroxylase, which is needed for cortisol biosynthesis
2. Unable to produce aldosterone leading to salt loss (low sodium and high potassium)
3. Cortisol deficiency stimulates the pituitary to produce ACTH, which drives overproduction of adrenal androgens
How does CAH present (3)?
1. Virilisation of external genitalia in female infants, with clitoral hypertrophy and variable fusion of the labia
2. In the infant male, penis may be enlarged and scrotum pigmented
3. Salt-losing adrenal crisis occuring at 1-3 weeks of age
What groups of disorders can be associated with ambiguous genitalia (2)?
1. Endocrine e.g. CAH
2. Inborn errors of metabolism
What is the main impact of renal abnormalities such as bilateral renal agenesis/multicystic dysplastic kidney antenatally?
How do renal abnormalities antenatally lead to Potter syndrome?
What are the clinical features of Potter syndrome (4)?
Renal abnormalities lead to lack of fetal urine, causing oligohydramnios.
This leads to intrauterine compression of the fetus causing:
1. A characteristic facies
2. Lung hypoplasia
3. Postural deformities including severe talipes
4. Infant may be stillborn or die soon after birth from respiratory failure
What are symptoms of acute viral hepatitis (5)?
3. Abdominal pain
5. Jaundice (but 30-50% don't)
What are signs of acute viral hepatitis (4)?
1. Large tender liver
2. 30% have splenomegaly
3. Liver transaminases markedly elevated
4. Coagulation normal
Which areas of the world have the highest prevalence of Hep B infection (2)?
1. Sub-Saharan Africa
2. Far East
How is HBV transmitted (3)?
1. Perinatal transmission from carrier mothers or horizontal spread within families
2. Inoculation with infected blood via blood transfusion, needlestick injuries or renal dialysis
3. Among adults, can be transmitted sexually
How is a diagnosis of HBV made (2)?
1. Detection of IgM antibodies to core antigen (anti-HBc) are positive in acute infection
2. Hepatitis B surface antigen (HBsAg) indicates ongoing infectivity