Flashcards in Neonatology Deck (146):
what is a neonate?
infant of 4 weeks (28 days) or less
what is preterm?
gestation less than 37 weeks of pregnancy
define low birth weight?
less than 2.5kg
what monitoring is required for a growth restricted fetus?
monitoring essential to determine optimal time for delivery.
growth parameters-symphysis fundal height (SFH), US measurement of fetal size-will be needed if SFH inaccurate e.g. BMI more than 35, hydramnios, large fibroids.
biophysical profile: amniotic fluid volume
fetal breathing movements
fetal heart activity
and Doppler blood flow velocity-umbilical and middle cerebral artery-if this is absent or reversed during diastole then increased risk of morbidity from hypoxic damage to gut or brain, or of intrauterine death.
umbilical doppler artery scan should be primary surveillence tool in small for gestational age fetus-rpted every 2 wks if indices normal.
patterns of intrauterine growth restriction?
symmetrical and asymmetrical
asymmetrical=more common-weight or abdominal circumference lies on lower centile than that of the head
symmetrical=head circumference equally reduced
aetiology of asymmetrical intrauterine growth restriction?
late in pregnancy, placenta fails to provide adequate nutrition, but brain growth relatively spared receiving preferential nutrition at expense of liver glycogen and skin fat-lack fo storage
assoc. with utero-placental dysfunction secondary to:
after birth, infants rapidly put on weight-*note normal infants lose weight over 1st 7-10 days due to water weight loss, but should lose no more than 12.5% of their birth weight, and this should be regained by 2 weeks, a rapid increase in weight initially therefore highlights some baby abnormality e.g. asymmetrical IUGR.
aetiology of symmetrical intrauterine growth restriction?
prolonged period of poor intrauterine growth, starting in early pregnancy, OR gestational age is incorrect
usually due to small but normal fetus
other causes: fetal chromosomal disorder or syndrome
maternal drug and alcohol abuse
chronic medical condition
more likely to remain small permanently
risks to fetus of intrauterine growth restriction?
intrauterine hypoxia and 'unexplained' intrauterine death
asphyxia during labour and delivery
complications to infant of IUGR?
hypoglycaemia-poor fat and glycogen stores
polycythaemia-venous haematocrit more than 0.65
possibly type 2 DM and HTN in adult life
define small for gestational age
birthweight is below the 10th centile for gestational age
major RFs for IUGR?
maternal age greater than 40 years
smoker of 11 cigarettes or more/day
daily vigorous exercise
chronic HTN, DM, vascular disease, renal impairment, antiphospholipid syndrome
previous SGA baby, previous stillbirth-born at 24 or greater weeks of pregnancy with no signs of life
pre-eclampsia-AP agents should be commenced at or before 16wks of pregnancy if high risk of pre-eclampsia
low maternal weight
fetal echogenic bowel
low level of 1st trimester marker pregnancy-associated plasma protein A (PAPP-A)
minor RFs for IUGR?
maternal age 35 years or older
BMI less than 20, BMI 25-29.9
smokes 1-10 cigarettes/day
low fruit intake pre-pregnancy
pregnancy interval less than 6 months pregnancy interval 30 months or greater
how does presence of RFs at booking assessment influence re-assessment of pt for IUGR in pregnancy?
if 1 major RF or 3 or more minor, then re-assess at 20 wks for abnormal Down's syndrome markers and fetal echogenic bowel.
US criteria for IUGR?
elevated ratio of femoral length to abdominal circumference (AC)
elevated ratio of head circumference (HC) to AC
possible intervention for fetuses with IUGR when considering delivery with fetus between 24+0 and 35+6 wks gestation?
single course of antenatal corticosteroids
when is delivery recommended in preterm SGA fetus with umbilical artery absent or reversed end diastolic velocity detected prior to 32 wks gestation?
when ductus venosus doppler scan becomes abnormal or umbilical vein pulsations appear, provided fetus considered viable and after completed course of steroids.
C section recommended
what is the initial screening check of baby in delivery room?
Apgar score-assesses HR, RR, colour, muscle tone, reflex irritability, max score of 10=good.
this is checked at 1 and 5 mins
note any life threatening conditions
obvious dysmorphic features
gross congenital anomalies e.g. NTDs
umbilical cord vessel count-ensure 2 UAs and 1 UV
causes of depressed fontanelles?
features of dehydration in neonate?
dry mucous membranes e.g. mouth
poor skin turgor
effect of prematurity on baby's muscle tone?
very premature (less than 30wks) normally have minimal flexor tone, like a rag doll
should appear in LLs by 34 wks, and 36wks in ULs.
when do the fontanelles close?
fontanelles=large membranous unossified gaps that exist between skull bones in early infant life.
anterior=where coronal and sagittal sutures will meet between frontal and parietal bones, closes within 2 years
posterior=where sagittal and lambdoid sutures will meet, between parietal and occipital bones, closes within 6-9 mnths.
what is included in examination of the neonatal head?
initial inspection: dysmorphic features
head examination: fontanelles-assess size, may be widened with raised ICP e.g. hydrocephalus, or narrowed or undetectable and immobile with craniosynostosis. traumatic injuries-abrasions, depressed fractures, haematoma or lacerations. swellings.
measure head circumference-normally 32-37cm at term, average estimation-height/2 + 10.
eyes-red reflex-absence-?congenital cataract, retinoblastoma, enlarged and very hazy corneas-glaucoma.
nose-symmetry, nasal patency.
mouth-lips, tongue-adequate protusion so no tongue tie-tight frenulum, and size-macroglossia may indicate hypothyrodism gums, palate-?cleft, oropharynx.
ears-skin lesions-cysts and skin tags common, symmetry and positioning-low set ears-1/3 of ear should lie above horizontal line from eye, seen in down's syndrome, noonan syndrome, edward's syndrome (trisomy 18), patau syndrome (trisomy 13), turner's syndrome.
neck inspection-? web neck-turner's and noonan's syndrome, and palpation-masses or fistulae e.g. branchial-A. to SCM, asymmetry and range of movement-torticollis from SCM fibrosis/tumour.
what are hands inspected for in newborn examination?
single palmar crease-simian line-fusion of 2 palmar creases-down's syndrome and edward's syndrome.
extra or missing digits
what are we examining for in heart auscultation during newborn examination?
HR-normal between 120 and 160bpm
S1 and S2-S2 may be loud and single or closely split with pulm HTN
note day 1 murmur may be due to closing DA
coarctation murmur will be present on day 1-look also for RF delay-may be better feeling brachial pulses?
after a few days, VSDs and ASDs become audible as pressures in L heart increase, VSD-pansystolic murmur, ASD*
why is nappy removed during newborn examination?
examine genitalia-ensure in male babies scrotum contains both testes which should be of similar size, may be hydrocele, not urethral orifice position-epi or hypospadias*, females-look for imperforate hymen or vaginal wall cysts, ambiguous genitalia e.g. CAH
anus-patency and position?
groin swelling?-?indirect inguinal hernia
stools-meconium-very dark green
indications in newborn of hip USS at 6 weeks?
following normal hip examination but hx of:
breech presentation OR
FH of DDH (1st degree relative) OR
difference between ortolani's and barlow's tests for DDH?
ortolani-opening out lower limbs, test to reduce a posteriorly dislocated femoral head
barlows-bumps back femoral head, detects whether femoral head can be dislocated.
why might the Moro reflex demonstrate asymmetry of limb movement?
or may be asymmetry of facial movement-facial nerve palsy e.g. following forceps delivery and because of small mastoid process.
or may be absent with significant IC pathology.
most common neonatal rash noted in 1st few days of life?
erythema toxicum neonatorum (or toxic erythema of the newborn)-erythematous macules anywhere on body except palms and soles, us. with central white or yellow papule/pustules.
typically presents in 1st few days of life, although onset can be as late as 2 wks, typically waxes and wanes over few days and each individual lesion usually present for no longer than a day.
begins on face, spreads to involve trunk and limbs.
infant otherwise well.
in what syndrome does a 'port wine stain' vascular malformation present at birth in trigeminal distribution accompany angiomatous malformation of the brain?
port wine stain (naevus flammeus)-vascular malformation of dermal capillaries, disfiguring lesions can be improved with laser therapy. This does not regress with age.
what are haemangiomata, when are they of a concern?
group of blood vessels appearing as red to purple papules or plaques with a normal epithelial surface
are (usually) NOT present at birth e.g. strawberry naevus (cavernous haemangioma), and grow out of proportion to rest of body for 24 wks, then involute slowly.
of concern if near eyes-can cause amblyopia as vision blocked, ears-auditory amblyopia, 'beard' region-may indicate underlying laryngeal involvement-in these cases may need corticosteroid or laser treatment.
when should baby be examined for a second time after initial newborn examination in 1st 72hrs?
importantly on second examination, must examine carefully for CVS problems that may not have been apparent on 1st examination e.g. VSD or ASD murmur, or coarctation,
hip examination-DDH can still present late
eyes-congenital cataract and causes of leukocoria
also look for new problems that may have arisen e.g. nappy rashes, haemangiomata, umbilical granulomata.
what hearing screening is carried out in newborns?
all newborns to have hearing test using automated otoacoustic emissions within 1st 4-5wks of birth.
*notes this test will not detect rare auditory neuropathy in child who is deaf as cochlea in these pts normal, this will be detected by automated auditory brainstem response.
if well baby has no clear response to test-lack normal echo from cochlea detected by microphone, then r/f for automated auditory brainstem response screening test.
if baby classified as high risk, having spent more than 48hrs in NICU or SCBU then screened using both tests.
what conditions are screened for using the newborn heel prick blood spot test at 5-8 days following birth?
PKU-test looks for combination of total biopterin and dihydropteridine reductase. essential for early diagnosis so can implement early phenylalanine restriction diet to prevent severe neurocognitive and neuromotor impairment.
congenital hypothyroidism-must rpt test if baby born at less than 32 wks gestation, at 28 days of postnatal age counting original expected birth date as day 0, or date of discharge home, whichever sooner.
sickle cell disease
CF-looking for immunoreactive trypsinogen raised levels-indicates pancreatic duct obstruction, but initial screening can MISS diagnosis
medium chain acyl-CoA dehydrogenase deficiency (MCADD)-early detection so pt can avoid fasting
maple syrup urine disease
glutaric aciduria type 1
which enzyme is deficient in PKU?
PAH: phenylalanine hydroxylase
usual cause of neonatal jaundice?
physiological immaturity of liver-unconjugated hyperbilirubinaemia, self-limiting over 1st week of life as liver function matures.
unconjugated=potentially toxic-kernicterus-brain injury, but can be physiological as well as pathological, conjugated=not toxic, but always pathological.
complication of unconjugated hyperbilirubinaemia on the neonatal brain?
kernicterus-irreversible brain damage from high levels of unconjugated bilirubin
results in nerve deafness, choreoathetoid cerebral palsy (dyskinetic type) and mental retardation.
symptoms in baby of neonatal jaundice?
may feed less well and be lethargic
in those who become dehydrated, there is haemoconcentration causing them to appear more jaundiced and so may feed less well, causing more dehydration.
how does location of neonatal jaundice on examination relate to disease severity?
limited to head and neck=mild
over lower trunk and thighs=moderate
extension to hands and feet=may require treatment.
4 situations in which baby should be investigated rapidly for serious causes of jaundice?
jaundice appearing in 1st 24 hrs of life, suggests underlying haemolysis
clinical evidence of deep jaundice
prolonged conjugated jaundice lasting more than 2 wks, suggests serious underlying cause
increasing levels of conjugated bilirubin, suggests severe hepatic cause of jaundice.
initial treatment of neonatal jaundice?
phototherapy-light degrades unconjugated bilirubin to non-toxic soluble compounds which are excreted in urine.
exchange transfusions necessary if levels continue to rise to potentially toxic level
if conjugated tment depends on cause.
investigations in jaundiced neonate?
FBC: neutrophilia or neutropenia suggests infection, thrombocytpenia suggests TORCH infection-toxoplasma, other-syphilis, rubella, CMV, HSV and VSV.
total serum bilirubin-only test for otherwise well moderately jaundiced baby presenting on 2nd or 3rd day, conjugated bilirubin, transcutaneous bilirubinometer
maternal and neonate blood groups and Coombs' test-ABO and rhesus incompatability
peripheral blood film for red cell morphology
red cell enzyme assays-G6PDD, pyruvate kinase deficiency
LFTs-hepatitis, cholestatic disease
infection screen-must exclude in any unwell baby or presents in 1st 24 hrs or after 3 days-congenital TORCH screen, surface swabs including umbilicus, throat swabs, urince culture, blood culture, CXR, LP
Hep B antigen-Hep B infection
reducing substance in urine-galctosaemia, as long as infant received sufficient milk quantities.
USS-internal haemorrhage, biliary atresia
when is jaundice clinically detectable in newborn?
when bilirubin levels are greater than 85 micromol/L
when does physiological jaundice in neonate present?
this is an unconjugated hyperbilirubinaemia due to liver immaturity and increased red cell b.down presenting in 1st 2-3 days after birth, starting to disappear by end of 1st wk and resolves by day 10.
baby usually remains well.
complications of phototherapy for neonatal unconjugated hyperbilirubinaemia treatment?
separation of baby from mother
dehydration-must increase fluid intake
what does use of phototherapy for neonatal jaundice depend on?
level of serum bilirubin
gestation of baby
rate of rise of bilirubin
likely underlying cause
indications for immediate phototherapy in neonatal jaundice?
jaundice at less than 24hrs
rapidly rising bilirubin expected e.g. haemolytic disease
features of extrahepatic biliary atresia in jaundiced neonate, and treatment required for good prognosis?
shortly after birth, well child with persistent jaundice, pale stools-but normal meconium passed initially, dark urine in term infant with normal birth weight
failure to thrive
hepatomegaly often present
splenomegaly if late presentation (after 3 mnths)-sign of PH
need surgery before 60 days of life for a better prognosis
how is congenital heart disease detected antenatally?
fetal anomaly US scan at 18-20wks gestation
if abnormality detected, detailed fetal ECHO performed by paediatric cardiologist
this is also performed on any fetus at increased risk e.g. suspected Down syndrome, where parents had previous child with HD or where mother has congenital HD.
why do many newborns with potential cardiac shunts e.g. ASD or VSD, NOT have symptoms or a murmur at birth?
pulmonary vascular resistance still high so lack of pressure difference between R and L sides of the heart
major complication of a L to R cardiac shunt if left untreated?
development of Eisenmenger syndrome: shunt reverses to R to L shunt producing cyanosis as there is increased pulmonary blood flow producing chronically raised pulmonary arterial pressure and flow leading to irreversibly raised pulmonary vascular resistance and subsequent high R sided heart pressures.
presentation of L to R shunts, and give examples?
asymptomatic or breathless
NOT cyanotic unless shunt reverses with irreversibly raised pulmonary vascular resistance-Eisenmenger syndrome
differentials for cyanosed newborn with respiratory distress (RR more than 60 breaths/min)?
cardiac-cyanotic congenital HD-R to L shunt-tetralogy of fallot, transposition of great arteries, common mixing-AVSD e.g. Downs syndrome.
resp-surfactant deficient lung disease, meconium aspiration, pulmonary hypoplasia
persistent pulmonary HTN of the newborn-failure of pulmonary vascular resistance to fall after birth
infection-septicaemia from group B streptococcus and other organisms
metabolic disease-metabolic acidosis and shock
RFs for neonatal group B streptococcal infection?
prolonged rupture of membranes (more than 18hrs)
maternal fever during labour
previously infected infant
indications for prophylactic intrapartum antibiotics for neonatal group B streptococcal infection?
high dose IV benzylpenicillin or ampicillin if:
GBS bacteriuria detected in current pregnancy
GBS detected on vaginal swab in current pregnancy
previous baby with neonatal GBS disease
Abx plus immediate inductiomn of labour if prelabour rupture of membranes at 37wks or more and mother known to be colonised with GBS
presentation of group B streptococcal infection in neonates?
early-onset sepsis-resp distress and pneumonia, can be septicaemia and meningitis
late-onset sepsis-usually meningitis, occasionally focal infection e.g. osteomyelitis or septic arthritis
why can a neonate be expected to deteriorate dramatically-collapse with shock, in 1st few days after being born if presence of coarctation of the aorta?
shock develops with left heart outflow tract obstruction following closure of the DA which occurs within the 1st few days.
DA in presence of aortic coarctation maintains the systemic circulation as blood travelling from PA to aorta via DA can pass into the systemic circulation, avoiding the narrowed aorta just proximal to entry of DA into aorta, so with DA closure, massive decrease in CO to systemic circulation, need to maintain ductal patency for early survival with PG E1 infusion before repair-surgery or balloon angioplasty with or without stenting.
why might congenital coarctation of the aorta NOT present in neonates and be diagnosed later in life?
less severe case may go unnoticed with development of collateral circulation of blood to lower body.
cardiac abnormalities assoc. with Turner syndrome?
coarctation of aorta
aortic valve stenosis
neonatal presentation of coarctation of the aorta?
congestive cardiac failure and SHOCK, assoc. with closing of DA
poor feeding, lethargy, tachypnoea within 1st 3 wks of life
reduced pulse amplitude, RF delay
upper limb BP higher than lower limb
lower limb cyanosis with sparing of upper body as blood flows through patent ductus from R to L
what birthmark has a similar appearance to a bruise and may be found on the lower back or buttocks of a newborn?
Mongolian spot (lumbosacral dermal melanocytosis)
blue-grey skin marking, usually spontaneously disappears by 4 yrs of age
usually in afrocaribbean or asian infants
infant failed to reach their full genetically determined growth potential and appear thin and malnourished.
this is a cause for baby to be small for gestational age, but SGA infants may also have grown normally but be small
SGA infants can be preterm, term or post-term.
define chronic lung disease of prematurity(CLD)/bronchopulmonary dysplasia
oxygen dependence at 36 wks of postmenstrual/conceptual age (gestational age plus chronological age)
oxygen dependence at 28 days with persistent resp signs and symptoms and abnormal CXR
most commonly occurs in premature infants who have needed mechanical ventilation and oxygen therapy for infant resp distress syndrome.
presentation of CLD/bronchopulmonary dysplasia in baby?
commonly a 23- to 26-weeks of gestation baby who over a period of 4-10 weeks progresses from needing ventilation to CPAP through to requiring supplemental oxygen.
Most babies have initial RDS and require resp support with ventilation or CPAP.
respond well to initial surfactant and ventilation with resp distress improvement but in some may be increase in O2 and ventilatory requirements in 1st 2 wks of life.
dependence on resp support tends to continue and, although many come off the ventilator or CPAP, O2 dependence continues.
Many continue to have tachypnoea, tachycardia and signs of resp distress e.g. grunting, intercostal recession, nasal flaring.
Infants with severe BPD have trouble feeding and gain weight poorly because of this and higher energy requirements.
Bronchial hyperreactivity and wheezing can also occur.
Some develop pulmonary HTN.
how does a PDA (patent ductus arteriosus) cause resp problems?
left to right shunt with increase L heart pressures and decreased R heart pressures after birth due to massive decrease in pulmonary vascular resistance and reduction in venous return to heart as loss of placenta, causing blood overflow to pulmonary circulation as blood passes from aorta to PA, causing raised pulmonary capillary hydrostatic pressure and subsequently pulmonary oedema and SOB.
CXR features of CLD/bronchopulmonary dysplasia?
diffuse haziness and coarse interstitial pattern reflecting atelectasis, inflammation and/or pulmonary oedema
management of CLD/bronchopulmonary dysplasia?
resp: use of nasal CPAP in premature infants rather than ventilation
with intubation and ventilation need strict monitoring and maintaining of tidal volumes and synchronised ventilation modes
early surfactant replacement therapy with extubation to nasal CPAP
SpO2 maintenance between 91-95%
prophylactic steroids to mothers at risk of premature labour to reduce infant RDS risk e.g. under 18 yrs of age or over 35, smokers, underweight or obese before pregnancy, previous premature labour or birth, multiple gestation, HTN, DM and gestational diabetes, UTIs.
?use of dexamethasone in ventilated babies for ST clinical improvement, but if used in 1st wk of life then increased risk of GI bleeding, intest. perforation, hyperglycaemia, HTN, hypertrophic cardiomyopathy and growth failure, and cerebral palsy.
diuretic use for fluid overload e.g. furosemide, and in preterm infants over 3 wks of age with BPD
inhaled bronchodilators in acute exacerbations of BPD
caffeine-increases resp drive, reduces apnoea and improves diaphragmatic contractility
complications of CLD/BPD?
poor neurodevelopmental outcome
frequent hosp. readmission in 1st 2 yrs after birth
chronic resp morbidity, may have evidence of airflow obstruction even as adults
serious pulm infection part. due to RSV-recommended use of palivizumab (RSV monoclonal Ab) in preterm infants with BPD during RSV season-monthly IM inections, consider also vaccination against influenza.
how is haemorrhagic disease of the newborn prevented?
by giving Vit K to all newborn infants-IM has better absoprtion
also, as anticonvulsants impair synthesis of Vit-K dependent clotting factors, mothers on anticonvulsants should recive oral Vit K prophylaxis from 36wks' gestation.
what might a tense fontanelle indicate?
raised ICP e.g. hydrocephalus-should do cranial USS.
late sign of meningitis
complications of macrosomia?
brachial plexus injury
neonatal problems associated with maternal diabetes?
hypoglycaemia-due to hyperinsulinism that occurred in response to high blood glucose during pregnancy as crosses placenta into fetal circulation.
RDS-delayed lung maturation
hypertrophic cardiomyopathy-may cause HF from reduced LV function, but regresses over several wks
polycythaemia-infant looks plethorix, may need partial exchange transfusion to reduce haematocrit and normalise viscosity.
fetal problems associated with maternal diabetes?
congenital malformations-includes increased risk of cardiac malformations, sacral agenesis and hypoplastic L colon compared with general population
IUGR-due to microvascular disease in mother
macrosomia-high insulin promotes growth by increasing cell number and size.
when might surfactant deficiency causing RDS occur in a term infant?
in those born to diabetic mothers
most common cause of congenital deafness in developed world?
developmental and permanent problems in baby due to rubella?
developmental: SN deafness, general learning disability, insulin dependent diabetes (often later onset), late onset disease at 3-12 months=rash, diarrhoea, pneumonitis and high mortality
congenital HD-PDA and peripheral pulmonary artery stenosis
eyes-cataract, congenital glaucoma, pigmentary retinopathy, severe myopia, microphthalmia
common features o/e of TORCH infection?
failure to thrive
low birth weight
hepatitis with jaundice and hepatosplenomegaly
microcephaly, mental handicap, seizures
how is surfactant therapy given to neonate?
via a tracheal tube to allow instillation directly into lung
signs a baby with RDS develops at delivery or within 4hr or birth?
tachypnoea greater than 60breaths/min
chest wall recession, part. sternal and SC indrawing, and nasal flaring
expiratory grunting-trying to create +ve airway pressure during expiration and maintain FRC
cyanosis if severe
CXR appearance of RDS?
diffuse granular or 'ground glass' appearance of lungs, air bronchogram
indistinct heart borders, obscured completely
try and prevent with antenatal corticosteroids to mum when risk of prematurity
neonate-surfactant therapy via tracheal tube, raised ambient O2, supplement with CPAP via nasal cannulae or artificial ventilation via ETT, mechanical ventilation may be needed.
high flow humidified O2 therapy via nasal cannulae may be used to wean babies from added O2 therapy.
complications of hypothermia in preterm infant?
increased energy consumption causing:
failure to gain weight and increased mortality
why are preterm infants susceptible to hypothermia?
large SA relative to their mass
little SC fat for insulation
thin skin which is heat permeable, so transepidermal water loss
often nursed naked and cannot conserve heat by curling up or generate heat by shivering.
aim of incubator for premature infant?
maintain temperature of small baby susceptible to hypothermia
also allow ambient humidity to reduce transepidermal heat loss.
why are preterm infants more susceptible to infection?
most IgG transference across placenta not till last trimester, and no IgA or IgM is transferred
also, infection in or around cervix often reason for preterm labour and may cause infection shortly after birth.
complications of infection in preterm infants?
contribution to bronchopulmonary dysplasia-due to infants requiring O2 therapy and positive pressure ventilation?
brain white matter injury
what serious illness involving bacterial invasion of ischaemic bowel wall may affect preterm infants in 1st few wks of life?
vomiting, may be bile-stained
blood in stool
preterm infants fed cow's milk formula more likely to develop condition
X-ray features of necrotising enterocolitis?
distended bowel loops and bowel wall thickening with intramural gas, may be gas in portal tract, disease may progress to bowel perforation-pneumoperitoneum and rigler's sign-both sides of bowel wall well defined.
management of necrotising enterocolitis?
stop oral feeding, need pareneteral nutrition
may need artificial ventilation and circulatory support
surgery for bowel perforation, may require ileostomy
LT problems: strictures, malabsorption.
why is unconjugated bilirubin capable of causing brain injury?
lipid soluble so able to cross blood brain barrier
what proportion of neonates becomes visible jaundices, and why is it so common?
more than 50% as:
marked physiological release of Hb from rbc breakdown due to high Hb concentration at birth-HbF
markedly shorter rbc lifespan of newborns (70 days) compared to adults (120 days)
hepatic bilirubin metabolism less efficient in 1st few days of life.
presentation of severe encephalopathy from bilirubin deposition in basal ganglia and brainstem nuceli?
those who survive may develop choreoathetoid cerebral palsy due to basal ganglia damage, learning difficulties and SN deafness.
causes of neonatal jaundice starting at less than 24hrs of age?
spherocytosis, pyruvate kinase deficiency-glycolysis enzyme in red cells
these are VERY important to identify as unconjugated hyperbilirubinaemia and bilirubin can rise very rapidly to reach extremely high levels.
congenital infection-CONJUGATED hyperbilirubinaemia, other abnormal clinical signs e.g. growth restriction, hepatosplenomegaly, thrombocytopenic purpura.
how is rhesus haemolytic disease of the newborn prevented?
anti-D immunoglobulin prophylaxis given to all rhesus -ve women who have not already been sensitised, which can be given at 28 and 34 wks antenatally, and soon after delivery.
also give after other sensitising events e.g. EP, abdo trauma, amniocentesis, miscarriage.
pathogenesis of rhesus haemolytic disease of the newborn?
starts with rbc from rhesus +ve fetus crossing placental barrier during pregnancy and delivery, enter maternal blood circulation and rhesus -ve mother develops primary immune response producing Abs against rhesus antigen (usually rhesus D). very small amount of fetal-maternal haemorrhage needs to occur, and primary exposure can also be result of amniocentesis and chorionic villus sampling.
subsequent pregnancies: large amounts of anti-D Abs produced, can cross placenta and bind to fetal rbc which are subsequently haemolysed.
how does examination findings of infant with ABO incompatibility differ from those in rhesus disease?
absence of hepatosplenomegaly
causes of jaundice at 24hr to 2 wks of age?
breast milk jaundice
infection e.g. UTI
haemolysis e.g. ABO incompatibility, G6PD deficiency
role of caffeine in premature neonates?
respiratory centre stimulant for immature resp centre to prevent apnoeas
stop at 34 wks
metabolic complications of prematurity?*
electrolyte imbalance-immature kidneys, inability to reabsorb effectively, high Na+ and HCO3- loss-metabolic acidosis
osteopenia of prematurity
why are premature neonates susceptible to intraventricular haemorrhages?
poorly developed capillary network around choroidal plexus cells, prone to rupture
most haemorrhages occur in 1st 72hr of life
more common following perinatal asphyxia and in infants with severe RDS
haemorrhage involving parenchyma can cause hemiplegia
large haemorrhage can impair CSF drainage and reabsoption, may produce hydrocephalus requiring ventriculo-peritoneal shunt*
causes of neonatal resp distress?
resp distress syndrome-surfactant deficiency in premature infants, and *those born to mothers with DM
transient tachypnoea of the newborn
persistent pulmonary HTN of the newborn
cardiac causes-congenital HD
meconium aspiration-deactivates surfactant*-so cause of RDS, skin yellow/green stained?*
tracheo-oesophageal fistula (TOF)
airway obstruction e.g. choanal atresia
IC birth trauma/encephalopathy
most common cause of resp distress in premature infant?
resp distress syndrome
but MUST consider infection in all infants
features of resp distress?
chest wall recession
tachypnoea-RR more than 60
how can differentials for resp distress be investigated?
CXR-RDS, diaphragmatic hernia, pneumonia, pneumothorax
transient tachypnoea of the newborn-fluid in horizontal fissure
when is heart failure likely to present in neonatal period?
premature infants with PDA
how can cyanosis in neonates due to resp disease be differentiated from that due to cardiac disease?
look for presence of resp distress-nasal flaring, expir grunting, tracheal tug, chest wall recession, tachypnoea.
triggers to meconium aspiration in premature infant?*
distress-infection, placental insufficiency
complications of aspirated meconium?
persisting pulmonary HTN
predisposition to infection
how is infection spread to cause congenital pneumonia?
post natal-ventilator colonised
what 6 inherited metabolic metabolic diseases are babies screened for in 1st 5-7days of life with heelprick testing?
maple syrup urine disease
glutaric aciduria type 1
what is MCADD? why is early education of parents necessary?
medium chain co-A dehydrogenase deficiency: an inherited metabolic disease, autosomal recessive, causing an inability to oxidise FA in the body
therefore, if child fasting, catabolism stimulates FA oxidation pathway which is blocked so there is accumulation of toxic metabolites, which can cause encephalopathy
parents must be aware that periods of illness e.g. vomiting, require presentation to hospital for sugar treatment to stop catabolism during periods of stress, and so the accumulation of toxic metabolites in the pathway. must have sugar treatment at home-SOS sachets.
avoidance of foods high in medium chain fatty acids e.g. cocounts
end stage=hypoglycaemia, not pt may be encephalopathic without hypoglycaemia.
causes of neonatal intestinal obstruction?
volvulus secondary to malrotation
a high GI obstruction in a neonate may not cause failure to pass meconium, but what stool abnormality would be noted?
stool does not change from meconium to products of milk digestion (the changing stool).
4 major clinical features of intestinal obstruction in neonates?
failure to pass meconium
features on AXR of complete bowel obstruction?
dilated bowel proximal to obstruction
AXR feature of duodenal atresia?
'double bubble'-air in stomach and 1st part of duodenum
commonest cause of congenital bowel obstruction?
commonest cause of resp distress in term infants?
transient tachypnoea of the newborn: due to delay in resorption and clearance of lung fluid
usually settles in 1st day of life but may take a several days to resolve completely
may increase risk of developing a wheezing syndrome early in life
what feature of the birth history makes neonatal resp distress more likely to be resulr of transient tachypnoea of the newborn?
if pt born by C section-lack the birthing pressures that squeeze the lungs to cause lung fluid resorption and clearance
what might cause meconium aspiration at birth?
fetla hypoxia-at birth infants may inhale thick meconium
asphyxiated infants may start gasping and aspirate meconium before delivery
CXR features of meconium aspiration?
lung over-inflation-more than 5-7 ribs seen anteriorly, upward slant to ribs
patches of collapse and consolidation
high incidence of air leak with pneumothorax and pneumomediastinum
management of infants with meconium aspiration?
artificial ventilation often required
why might adequate oxygenation in meconium aspiration be difficult to achieve despite high pressure ventilation?
due to development of persistent pulm HTN of the newborn
RFs for pneumonia in the neonate?*
prolonged rupture of the membranes
why are infants with BP dysplasia more susceptible to milk aspiration?
often have GOR
infants with a cleft palate are also prone to aspirating resp secretions or milk
associations of persistent pulm HTN of the newborn?
presentation of persistent pulm HTN of the newborn?
cyanosis soon after birth due to high pulmonary vasc resistance causing R to L shunting at atrial and ductal levels
heart murmurs and signs of HF often absent
must do urgent ECHO to rule out congenital HD
management of persistent pulmonary HTN of the newborn?
mechanical ventilation and circulatory support:
inhaled NO-potent vasodilator
ECMO-extracorporeal membrane oxygenation-for severe but reversible cases
usual location of diaphragmatic hernia in newborn?
L sided herniation of abdo contents through posterolateral foramen of the diaphragm
how can distension of intrathoracic bowel be prevented once diaphragmatic hernia detected?
NGT-pass and apply suction
after stabilisation can then repair hernia surgically
main problem in patients with congenital diaphragmatic hernia?
pulmonary hypoplasia-lung development in fetus has been prevented due to compression by herniate viscera throughout pregnancy
pulmonary hypoplasia has assoc. high mortality
importance of palpating femoral arteries in all neonates with resp distress?
as coarctation of aorta and interrupted aortic arch are important causes of HF in newborn infants
most common cause of prolonged (more than 2wks and more than 3 if preterm) unconjugated hyperbilirubinaemia?
breast milk jaundice
jaundice gradually fades and disappears by 4-5wks of age
differentials for prolonged/persistent neonatal jaundice?
conjugated-biliary atresia must be diagnosed promptly as delay in surgical treatment-kasai procedure, adversely effects outcome. liver disease indicated by conjugated, by dark urine and pale stools, may also be hepatomegaly and poor weight gain, and bleeding tendency.
neonatal hepatitis syndrome
unconjugated: breast milk jaundice-progesterone inhibition of liver conjugating enzymes
congenital hypothyroidism-jaundice apparent before features including coarse facies, hypotonia, constipation and dry skin.
what is biliary atresia?
progressive disease in which destruction or absence of extrahepatic biliary tree and intrahepatic biliary ducts.
surgical intervention needed or leads to chronic liver failure and death
how is biliary atresia diagnosis confirmed?
at laparotomy by operative cholangiography-fails to outline a normal biliary tree.
most common indication for liver transplantation in children?
biliary atresia, following unsuccessful kasai procedure-may be that bile drainage not achieved, or this may be achieved but still there is progression to cirrhosis and PH.
treatment for biliary atresia?
kasai procedure (hepatoportoenterostomy): surgical bypass of fibrotic ducts via loop of jejunum being anastamosed to cut surface of porta hepatis.
complications of kasai procedure?*
malabsorption of fats and fat soluble vits-A,D,E and K
cause of bile duct obstruction in neonates causing prolonged jaundice other than biliary atresia?
cystic dilatations of extrahepatic biliary system, presenting with cholestasis, although may present after infancy with abdo pain, palpable mass and jaundice or cholangitis.
diagnosed with USS or radionuclide scanning
choledochal cyst treatment?
excision surgically with formation of Roux-en-Y anastamosis to biliary duct
future complications=cholangitis, 2% risk of malignancy
how should neonates with conjugated hyperbilirubinaemia be screened?
genetic causes-alpha 1 antitrypsin deficiency, CF, galactosaemia
metabolic-plasma amino acids and urinary organic acids
risks of mother contracting rubella in 1st trimester of pregnancy?
very high risk of congenital rubella syndrome: this has transient, developmental and permanent effects
transient=jaundice, hepatosplenomegaly, haemolytic anaemia, IUGR, meningoencephalitis, developmental=SN deafness, general learning disability, permanent=congenital heart disease-PDA.
features of a cephalohaematoma?
appears a swelling on baby's head around 2-3 days after birth, due to bleeding between the periosteum and skull
most commonly in parietal region, and following instrumental deliveries, especially ventouse
swelling does not cross suture lines and eventually resolves over a number of wks (can take up to 3 months to resolve.)
features of a caput succedeneum?
head swelling in newborns immediately after birth due to prolonged pressure from dilated cervix or vaginal walls during delivery
generalised superficial scalp oedema which crosses suture lines
assoc. with prolonged labour
will rapidly resolve over a few days