Neonataology Flashcards
When does the CVS start to develop?
End of third week
When does the heart start beating?
End of fourth week
What is the critical period for development of the heart?
20 to 50th day after fertilisation
What is the ductus venosus?
Vein that comes off of the umbilical vein that shunts a portion of oxygenated blood coming from the placenta directly into the IVC (bypassing the liver)
What is the foramen ovale?
Shunt between the R and L atrium - allowing blood to bypass the pulmonary circulation
What is the patent ductus arteriosus?
Connects pulmonary artery to the descending aorta - allowing blood to bypass the pulmonary circulation
What is normal SaO2 in foetal body?
60-70%
What are the functions of the ductus arteriosus?
Protects lungs against circulatory overload
Allows the R ventricle to strengthen
Carries low oxygen saturated blood
How is blood flow regulated in the ductus venosus? What kind of blood is mostly carried in the ductus venosus?
Oxygenated blood regulated via sphincters
What do the foramen ovale and ductus arteriosus become after birth?
Ligamentum arteriosum and fossa ovalis
What is the normal BP of a 1h old?
70/44
What is the normal BP of a 1 day old?
70+/-9/42+/-12
What is the normal BP of a 3 day old?
77+/-12/49+/-10
What is the normal RR of a newborn?
30-60m
Periodical breathing
What is the normal HR of a newborn?
120-160bmp
Tachycardia is over 160
Bradycardia is <100
Why are newborns purely reliant on metabolic production of heat?
Inability to shiver
What does cold stress lead to in babies?
Lipolysis and heat production
Brown fat well innervated by sympathetic neurons
Define radiation of heat
Heat dissipated to colder objects
Define convection of heat
Heat loss by moving air
Why is evaporation of heat important in newborns?
We are born in water
What is conduction?
Heat loss to the surface on which the baby lies
A newborn does not pass urine for 24 hours - what does this mean?
It is normal
Weight loss of up to what is normal in the newborn? What is the weight loss due to?
10%
Due to shift of interstitial fluid to intravascular
Diuresis
When does physiological jaundice occur?
Day 2-3 of life
Disappears within 7-10 days of life in term infants (up to 21 in prem babies)
Where does most bilirubin come from?
Metabolism of Hb
Where is bilirubin conjugated?
Liver
What is the most serious complication of jaundice?
Kernicterus
What type of bilirubin is able to cross the BBB to cause kernicterus?
Unconjugated
How does fluid balance differ in neonates compared with adults?
Neonates have less body fat, increased loss of fluids via kidney (slower GFR, reduce Na absorption, decreased ability to concentrate or dilute urine)
Increased insensible water loss (via immature skin and breathing)
Define IUGR
<10th centile
Severe IUGR - <0.4th centile
What are the groups of causes for small for dates baby?
Maternal
Foetal
Placental
Other
Give an example of a maternal causes of small for dates babies
Maternal pre-eclamptic toxaemia (PET)
Smoking
Give two examples of a foetal cause of small for dates babies
Chromosomal syndromes, e.g. Edwards syndrome
Foetal infection, e.g. CMV
Give an example of a placental cause of small for dates babies
Placental abruption
Give an example of another cause for small for dates babies
Twin pregnancy
What are the common problems small for dates babies face?
Perinatal hypoxia Hypoglycaemia Hypothermia Polycythaemia Thrombocytopenia GI problems (e.g. feeds) Infection
What are some long term problems associated with small for dates babies?
HTN, reduced growth, obesity, ischaemia heart disease
Define pre-term baby
<37w
Define extremely pre-term baby
<28w
Define low birth weight
<2.5kg
Define v. low birth weight
<1.5kg
Define extremely low birth weight
<1kg
Which systems are affected by prematurity?
All of them
What respiratory issue are premature babies more at risk of?
IRDS
How do you prevent IRDS?
Antenatal steroids
How do you treat IRDS?
Surfactant
Early extubation and non-invasive CPAP
Minimal ventilation
What minor respiratory problems are very common in premature babies?
Apnoea, irregular breathing, desaturations
How do we treat the minor respiratory problems in premature babies?
Caffeine
N-CPAP
What brain issue are premature babies more at risk of?
Intraventricular haemorrhage
How can you reduce the risk of intraventricular haemorrhage in premature babies?
Antenatal steroids
Delayed cord clamping
How do you treat intraventricular haemorrhage?
Sympthomatic
Drainage?
Why is intraventricular haemorrhage more common in premature babies?
Unsupported BVs in the ependymal germinal matrix and unstable BP assoc. with birth trauma and respiratory distress
What are signs of an intraventricular haemorrhage?
Seizures
Bulging fontanelle
What is the best investigation for intraventricular haemorrhage?
USS
What is peri-ventricular leukomalacia?
Necrosis of white matter in later ventricles
What is the role of the ductus arteriosus in utero?
It is a diversion for blood from the pulmonary trunk to the foetal aorta to avoid passage through the lungs
Describe the pathophysiology of PDA
Pressure in the aorta is greater than that in the pulmonary artery and so there is a L to R shunt
This means there is additional blood going to the pulmonary circulation –> over-perfusion of the lungs and lung oedema & stealing from the systemic circulation –> systemic ischaemia
What are the consequences of PDA?
Worsening of respiratory symptoms
Retention of fluids (low renal perfusion)
GI problems (e.g. GE ischaemia)
What are the symptoms of PDA?
Symptoms rare unless there is CCF or pulmonary hypertension
What are the signs of PDA?
Continuous machine murmur below L clavicle, thrill, collapsing pulse, FFT, pneumonias, loud S2.
How do you treat PDA?
Ibruprofen
What GI problem are premature babies more at risk of?
Necrotising entero-colitis
What occurs in NEC?
Ischaemic and inflammatory changes
Necrosis of the bowel
How do you manage NEC?
Surgery often req.
Antibiotics and parenteral nutrition may suffice
Why is nutrition so important in prems?
They have huge nutritional requirements
And a lot of growing to do
True or false:
Only 1/2 of all premature babies are entirely normal at 6 years of age
False
Only 1/6 are entirely normal at 6y
What are milia?
Raised bumps on the skin
Thought to be caused by damage to the skin
What is milaria?
Sweat rash
What is erythema toxicum neonatorum?
A benign self-limited maculopapular rash in healthy neonates
Rash fades by end of 1st week
No Rx req.
Cause unknown
What is sebaceous naevus?
Hairless plaque that typically occurs on the scalp
What are capillary haemangiomas?
Benign tumour due to abnormal growth of capillaries
What are Mongolian blue spots?
Pigmented slate grey birth marks
Due to a collection of melanocytes
Usually disappear after 4y
Often found in lower back/buttocks
What are port wine stains?
Birthmark caused by capillary malformation in the skin
What are stork marks?
Flat red or pink patches that appear on the babies forehead, neck or eyelids at birth
Gradually fades w.i. 1st 2y (facial lesions tend to fade more than occipital ones)
Most common type of vascular birth mark
What are giant melanocytic naevi?
Large brown/black moles present from birth
Due to overgrowth of pigment cells in the skin
What are café au lait spots?
Coffee coloured skin patches
>6 before age 5y may indicate neurofibromatosis
What condition affecting pigmentation of the skin affects most newborns?
Physiological jaundice
What causes physiological jaundice?
Increased RBC breakdown
Immaturity of hepatic enzymes
–> unconjugated hyperbilirubinaemia
What can worsen hyperbilirubinaemia in newborns?
Dehydration if feeding is delayed
Onset of jaundice in the first 24 hours of life is always pathological/physiological
Pathological
Why is it very important to treat severe neonatal unconjugated hyperbiilirubinaemia?
To prevent bilirubin encephalopathy or kernicterus
What is kernicterus?
Brain damage due to deposition of bilirubin in the basal ganglia
Early evaluation of conjugated hyperbilirubinaemia (>20mmol/L) is important to allow early diagnosis of what condition?
Biliary atresia
Apart from jaundice in the first 24h, in what other setting would jaundice require further investigation?
If it persists >24h
What is plethora?
Redness of the skin
What may cause plethora in a neonate?
Polycythaemia
Bluing of the skin in a newborn may indicate what?
Central/peripheral cyanosis
In which groups of people are Mongolian blue spots most common?
Races with pigmented skin
What are the causes of jaundice in the first 24h?
Haemolytic (e.g. G6PD, spherocytosis, rhesus incompatibility, ABO incompatibility)
ToRCH (congenital infections)
What are the causes of jaundice from the 2nd day to the 3rd week?
Physiological (gone after 1st week) Breast milk Sepsis Polycythaemia Cephalhaematoma Crigler-Najjar syndrome Haemolytic disorders
What are the causes of jaundice after the 3rd week?
Breast milk
Hypothyroidism
Pyloric stenosis
Cholestasis
How do you treat jaundice in neonates?
Treat underlying cause
Hydrate
Phototherapy or exchange transfusion
Immunoglobulin
What should you use when treating neonatal jaundice?
Phototherapy chart to decide if using phototherapy or exchange transfusion based on bilirubin and age
What babies are at risk of hypoglycaemia?
Those with limited glucose supply (premature babies, perinatal stress)
Hyperinsulinism - infants of diabetic mothers
Increased glucose utilisation - sepsis, hypothermia, small for gestational age
What are symptoms of hypoglycaemia?
Jitteriness Hypothermia Temp instability Lethargy Hypotonia Apnoea, irregular respirations Poor suck/feeding Vomiting High pitched or weak cry Seizures
May be asymptomatic
Define hypoglycaemia in neonates
<2.6mmol/L
When might bedside blood glucose testing be inaccurate?
If poor perfusion/polycythaemia
What babies are most vulnerable to hypothermia?
Low birth weight
Those requiring prolonged resus
What is the energy triangle?
The main energy deficit for neonates is preventing hypoglycaemia, hypothermia and hypoxia
How is heat lost in newborns?
Via conduction, convection, evaporation, radiation
What is evaporation?
Loss of heat when liquid is converted into vapour (e.g. wet skin, wet nappy)
What is conduction?
Loss of heat from the body surface to cooler surface in direct contact
What is convection?
Loss of heat from body surface to cooler air
What is radiation?
Loss of heat from body surface to a cooler solid surface that is not in direct contact but in close proximity to the body
How to do you deal with a baby in cold stress?
Dry quickly Remove wet linens Use warm towels/blankets Provide radiant warmer heat Use heated/humidified oxygen
What are tongue ties?
Short/thickened frenulum attaching anteriorly to the base of the tongue
How do you Rx tongue ties?
Mostly not needed
If restriction of tongue protrusion beyond alveolar margins/heavy grooving of tip of tongue/feeding affected –> frenotomy
What is the commonest reason for admission to NNU?
Respiratory distress
How do you examine a neonate in respiratory distress?
RR
Increased effort - ?grunting, ?retractions, ?nasal flaring
Colour
O2 sats
Where should you assess for retractions in a neonate in respiratory distress?
Substernal
Subcostal
Intercostal
Suprasternal
What is cleft lip associated with?
Cleft palate
What are the types of cleft lip?
Incomplete (small gap in lip)
Complete (continue into nose)
Unilateral (L most common)
Bilateral
What causes cleft lip?
Failure of maxillary and medial nasal processes to merge during 5th week of gestation
What issues are caused by cleft lip?
Feeding issues (need special bottles & teats)
Airway problems
Associated abnormalities
What extra things should you do for a neonate with a cleft lip?
Hearing screen
Cardiac echo
Think about trisomies
What should you always check in the eyes of a neonate?
Red reflexes
What two conditions should you check for in neonates?
Cataracts
Retinoblastoma
What are cataracts?
Lens opacifications
Can lead to blindness
May req. lens removal & artificial lens
What are retinoblastomas?
Rare eye cancer that can be treated easily if picked up early
How do children with retinoblastomas tend to present?
If bilateral tend to present earlier
Leukocoria (white pupillary reflex), strabismus, red eye and reduced vision
How do you treat retinoblastoma?
Laser therapy, chemo, surgical removal of eye
5% of kids with retinoblastoma have what?
Deletions of chromosome 13q14 and present with dysmorphic features and FTT
What may spinal dimples on neonates indicate?
Serious abnormality involving the spine, e.g. spina bifida occulta
May also indicate a kidney problem
Under what circumstances would you do an USS & MRI to rule out a serious diagnosis if there was a spinal dimple?
If dimple is large, red, swollen, off midline, higher than the sacral area, pigmented, tender or accompanied by fluid
What are cephalohaematomas?
Localised swellings over one or birth sides of the head
Maximal at 3rd/4th day of life
Soft, non-translucent and limited by cranial bones
Haemorrhage is underneath pericranium
How do you treat cephalohaematomas?
No Rx required and resolves in 3-4 weeks
What is cephalohaematoma associated with?
Increased haemolysis & therefore prolonged infant jaundice
NOT an intracranial bleed!
What is caput succedaneum?
Serosanginous, s/c fluid collected with poorly defined margins
What causes caput succedaneum?
Pressure of presenting part of the scalp against the dilating cervix during delivery leads to scalp swelling that extends over the mid and suture lines & is assoc with head moulding
Resolves in first few days
What are talipes?
Club foot
Can be medial (varus), lateral (valgus) deviation of the foot or equinus
How do you Rx varus/valgus talipes?
Often just req. physio
What Rx do fixed talipes req?
Vigorous manipulation, strapping, casting, surgery
What are significant talipes related to?
DDH
What is the goal of treating DDH?
Relocate femur head to acetabulum so hip develops normally
How do you Rx DDH?
Pavlik harness
Surgical reduction
What features are characteristic of trisomy 21?
Dysmorphism Hypotonia Cardiac defects Learning problems Haematological problems Thyroid problems
What dysmorphisms are related to trisomy 21?
Low set ears, downward slanting palpebral fissures, epicanthic folds, single palmar creases, wide sandal gap
What are the symptoms of sepsis in neonates?
Baby pyrexia/hypothermia Poor feeding Lethargy Early jaundice Hypoglycaemia Hyperglycaemia Asymptomatic
What things put neonates at higher risks of sepsis?
Maternal pyrexia
Maternal GBS carriage
Premature rupture of the membranes
How do you manage presumed neonatal sepsis?
Admit to NNU
Partial septic screen (FBC, CRP, blood cultures), & blood gas
Consider CXR, LP
Rx: IV penicillin & gentamicin (1st line)
2nd line: IV vancomycin and gentamicin Add metronidazole if surgical/ab concerns Fluid management and treat acidosis Monitor vital signs Support respiratory and CV as req.
What are the commonest causes of neonatal sepsis in order?
- GBS
- E. coli
- Listeria
- CNS
- H. influenzae
What are the potential complications of GBS sepsis?
Meningitis DIC Pneumonia and resp. collapse Hypotension Shock
What things tend to cause congenital infections?
ToRCH Toxoplamosis Rubella CMV Herpes
What are the potential consequences of congenital infection?
IUGR, brain calcifications, neurodevelopmental delay, visual impairment, recurrent infections, bone abnormalities, rashes, hepatosplenomgaly, jaundice, hepatitis…
May cause pregnancy loss/premature delivery
What typical rash can congenital infections cause?
Blueberry muffin rash
What is the characteristic rash of congenital syphilis?
Rash on hands and feet
How might congenital toxoplasmosis present in later years?
Retinitis
What may cause respiratory distress in neonates?
Sepsis
Transient tachypnoea of the newborn
Meconium aspiration
What is transient tachypnoea of the newborn?
Delayed clearance of foetal lung fluids
What does TTN present like?
Presents within 1st hour of life with grunting, tachypnoea, O2 req, normal gases
How do you manage TTN?
Supportive Antibitoics Fluids O2 Airway support
What will a CXR show in TTN?
Fluid in lung dissures
Hyperinflation
Perihilar haziness
What are the risk factors for meconium aspiration?
Post dates (aged placenta), maternal diabetes, maternal hypertension, difficult labour
What are the symptoms of meconium aspiration?
Cyanosis, increased WoB, grunting, apnoea, floppiness
How do you Ix meconium aspiration?
Blood gas, septic screen, CXR
What causes meconium aspiration?
Near term dates the foetal meconium accumulates in the foetal colon during pregnancy and is passed in utero leading to meconium stained amniotic fluid
Aspiration of meconium usually occurs in utero
What are the consequences of meconium aspiration?
Airway obstruction, surfactant dysfunction, pulmonary vasoconstriction, infection and chemical pneumonitis
How do you manage meconium aspiration?
Suction below cords Airway support (intubation/ventilation) Fluids and antibiotics IV Surfactant NO or ECMO (extracorpeal membrane oxygen)
Should you be alarmed at a blue baby?
Yes - req. urgent Rx
Remember sepsis & resp causes more common than cardiac
When does cyanosis occur?
When there is >5g/dL of deoxyhaemoglobin
How do you Ix the blue baby?
Ex and Hx Sepsis screen Blood gas and glucose CXR Pulse oximetry ECG Echo
What are the differential cardiac diagnoses for the blue baby?
Transposition of the great arteries Tetralogy of fallots Total Anomalous Pulmonary Venous Drainage Hypoplastic left heart valve syndrome Tricuspid atresia Truncus arteriosus Pulmonary atresia
How do you Rx hypoglycaemia in the neonate?
Enteral feeds my be ok Monitor BG Start 10% glucose IV Increase fluids Increase glucose concentration (central IV access) Glucagon Hydrocortisone
Why are infants born to mothers with diabetes at risk of neonatal hypoglycaemia?
Maternal hyperglycaemia causes beta cell hyperplasia of pancreas and hyperinsulinaemia in foetus which lasts for up to 48h after birth
How do you manage the hypothermic baby?
If unable to maintain temp on PNW admit to place in incubator
Sepsis screen & antibx
Consider checking thyroid function
Monitor BG
What is birth asphyxia?
Lack of oxygen at or around birth that leads to multiorgan dysfunction
What are the causes of birth asphyxia?
Placental problem Long, difficult delivery Umbilical cord prolapse Infection Neonatal airway problem Neonatal anaemia
What are the stages of birth asphyxia?
1st:
- W/I mins w/o O2
- Cell damage occurs with lack of blood flow and O2
2nd
- Reperfusion injury
- Can last days-wks
- Toxins released from damaged cells
What is HIE?
Hypoxic-ischaemia encephalopathy
Brain injury secondary to hypoxic-ischaemic insult
How do you manage HIE?
Supportive
Therapeutic hypothermia (cooling) improves outcomes
Treat seizures
Cardiac & resp support
Monitor for liver/renal failure
Fluid restriction (to prevent cerebral oedema)
What are causes of failure to pass stool?
Constipation Large bowel atresia Imperforate anus (+/- fistula) Hirschsprungs disease Meconium ileus
What should meconium ileus make you think of?
CF
Diaphragmatic hernia may also be associated with what?
Pulmonary hypoplasia
What is the management of diaphragmatic hernia?
Intubation at birth
Respiratory support
Surgery
ECMO
