Neonatology (1s) Flashcards
- DDH
1
Q
What is congenital dislocation of the hip?
A
- now known as developmental dysplasia of the hip (DDH)
- describes spectrum of hip abnormalities
- ranging from dysplasia (underdevelopment of joint) to subluxation through to frank dislocation
- early recognition is vital as DDH usually responds well to conservative mx at an early stage, whereas late diagnosis is complex + often surgical mx needed
- incidence is 1.5 per 1000 live births, girls affected 7x more commonly than boys
- left hip is more often affected than the right + 20% of cases are bilateral
2
Q
What is the aetiology of DDH?
A
Unclear but thought to be multifactorial:
- genetic factors -> DDH tends to run in families, inheritable features contributing to hip instability are generalised joint laxity + a shallow acetabulum
- hormonal changes -> changes occurring in late pregnancy may aggravate ligamentous laxity in infants
- post-natal factors -> neonatal positioning of child may contribute to DDH
3
Q
What are risk factors for DDH?
A
- female
- first born
- positive family history
- breech presentation at delivery
- maternal oligohydramnios (due to restriction of intrauterine foetal movement)
- associated neuromuscular disorders eg. cerebral palsy
4
Q
What is the clinical presentation of DDH?
A
- asymmetry of skin folds around hip (unless bilateral DDH)
- painless limp (unless in adolescence or adulthood)
- limited abduction of the hip
- swayback walk
- leg length discrepancy
5
Q
It is ideal to diagnose every case of DDH at birth. Screening forms part of the examination of the newborn ad 6-8 wk old babies. Screening takes the form of Barlow and Ortolani tests.
What is the Barlow test?
A
- stabilise the non-test hip
- for the side being tested -> adduct hip + push femur into acetabulum
- this will dislocate a dislocatable hip, giving a “click” + moving the hip posteriorly
6
Q
What is the Ortolani test?
A
- starts in the position where a hip has been dislocated
- stabilise pelvis by firmly holding symphysis pubis + coccyx between thumb + mid finger
- then, w/ baby’s hips + knees flexed, and the index finger of examiner’s other hand on the greater trochanter -> abduct baby’s hip
- a palpable ‘clunk’ signifies relocation of a posteriorly dislocated hip
- infants w/ positive test should have hip USS + urgent review in a neonatal or specialist hip clinic for follow-up
7
Q
Treatment for DDH depends upon the age at which the diagnosis is made.
What is the treatment for a newborn?
A
- can be corrected conservatively by putting baby in double nappies or by using a harness that holds hips abducted + flexed
- a padded Von Rosen splint can be used for babies up to 3 months old
- but Pavlik Harness should be used for older infants who would otherwise be able to crawl out of a Von Rosen splint
- if worn correctly for roughly 12 wks, a stable hip will be achieved
- following removal of splint, hip is examined radiologically or with USS to ensure that hip is reduced
8
Q
DDH: What is the treatment for age group of 6 months old to 6 years old?
A
- the hip must be reduced + held in this position until acetabular development is adequate
- closed reduction is performed gradually over 3 wks as manipulation under anaesthesia carries a high risk of avascular necrosis
- traction applied to both legs + abduction increased until legs widely separated
- if reduction achieved -> legs are splinted in plaster cast in the flexed, abducted + slightly internally rotated position
- if closed reduction unsuccessful -> formal open reduction in theatre may be required
9
Q
DDH: What is the treatment for older than 6 years old?
A
- unilateral DDH is usually managed w/ open reduction, sometimes combined w/ a corrective osteotomy of femur
- bilateral disease results in symmetrical deformity + therefore less noticeable
- surgical management carries greater risk as failure on one side results in asymmetrical deformity
10
Q
What is the prognosis like for DDH?
A
- without treatment, DDH results in progressive deformity + disability
- increased risk of secondary osteoarthritis
- earlier the treatment, more likely the child will develop a normal (or near normal) hip
11
Q
Jaundice is the most common condition in newborns that requires medical attention. How common is neonatal jaundice?
A
- about 50-70% of term babies + 80% of preterm babies develop jaundice in the first week of life
- jaundice usually appears 2-4 days after birth + resolves 1-2 wks later without need for treatment
- most cases physiological
- jaundice in the first 24 hrs of life is considered pathological
12
Q
Describe bilirubin metabolism
A
Newborns have higher bilirubin level than expected in adult population, due to foetal Hb gives RBCs shorter lifespan of 90 days vs 120 days for adults. They have immature livers + reduced elimination of bilirubin due to low volume of colostrum babies receive in first 24-48hrs of life.
13
Q
Physiological jaundice is usually noted at postnatal day 2, peaks on days 3 to 5, and then decreases. Serum bilirubin levels up to 205.2 micromol/L (12 mg/dL) are considered physiological in term neonates.
What are the causes of physiological jaundice?
A
- increased bilirubin load secondary to increased RBC volume, decreased RBC lifespan or increased enterohepatic circulation
- decreased uptake by liver bc of decreased ligandins or binding of ligandins to other anions
- reduced conjugation in liver bc of reduced UDPGT activity
- reduced excretion into bile
14
Q
Jaundice can be categorised in terms of time of presentation.
What are the causes if jaundice is presenting within 24 hours of birth?
A
-
Haemolytic disease (Unconjugated)
- rhesus incompatibility
- ABO incompatibility
- G6PD deficiency
- hereditary spherocytosis
-
Conjugated
- congenital infection -> sepsis
15
Q
What are the causes of jaundice presenting between 24hrs and 2 weeks?
A
- breastfeeding jaundice -> unclear why, resolves without mx or complication, mothers should be encouraged to continue to breastfeed
- physiological jaundice
- polycythaemia
- infection eg UTI
16
Q
What are the causes of prolonged jaundice (not fading after 14 days in term babies, or 21 days in prems)?
A
-
Unconjugated:
- physiological or breast feeding
- UTI
- haemolytic disease
- congenital hypothyroidism
- cystic fibrosis
-
Conjugated:
-
bile duct obstruction (eg. biliary atresia)
- most important condition to exclude + requires surg mx
- presence of pale stools + dark urine implies limited passage of bile into gut
- neonatal hepatitis
-
bile duct obstruction (eg. biliary atresia)
17
Q
If there are still signs of jaundice after 14 days, a prolonged jaundice screen is performed, including what?
A
- total serum bilirubin levels -> conjugated or unconjugated
- coombs test -> ABO or Rh
- TFTs
- FBC, haematocrit, reticulocytes, blood groups
- urine MC+S + reducing sugars
- U+Es + LFTs
18
Q
What is the management for neonatal jaundice?
A
- plot bilirubin measurements on graph of bilirubin against age in hours to determine when + whether phototherapy or exchange transfusion is required
- the treatment threshold is lower for preterms
- phototherapy most common treatment
- can use exchange transfusion
- supportive: hydration, albumin tranfusion, IV IG
19
Q
What is phototherapy?
A
- uses light energy to convert bilirubin to soluble products (lumirubin + other isomers)
- can be excreted without conjugation
- efficacy depends on irradiance - so exposing baby will lead to more rapid reduction in serum bilirubin, as will using light from above and below
- breast feeds should be brief to maximise time under lights
- SE: eye damage, diarrhoea, separation from mother, fluid loss
- intense phototherapy is an adjunct to exchange transfusion
- refer to NICE / local trust guidelines for thresholds
20
Q
What is exchange transfusion?
A
- uses warmed blood (37oC)
- 160 mL/kg (double volume)
- given ideally via umbilical vein IVI with removal via umbilical artery
- the aim is to remove bilirubin in those with severe or rapidly rising hyperbilirubinaemia
21
Q
What is kernicterus?
A
- encephalopathy caused by deposition of unconjugated bilirubin
- neurotoxic effects of bilirubin may be transient or permanent
- clinical features:
- lethargy, poor feeding, hypertonicity, opisthotonus (back arching due to muscle spasm), shrill cry, seizures
- risk increased w/ extremely high bilirubin levels (360umol/L; lower in prems)
- long-term sequelae incl athetoid movements, deafness, cerebral palsy + reduced IQ
- prevented by photoherapy +/- exchange transfusion
22
Q
Respiratory distress syndrome refers to lung disease caused by surfactant deficiency. What is the pathophysiology of this?
A
- surfactant is a mixture of proteins (10%) + phospholipids (90%) excreted by type II pneumocytes in the alveolar epithelium
- it keeps the alveoli open by increasing alveolar surface tension
- it is first produced by the foetus at 34wks
- in RDS, there is deficiency of surfactfant, hence -> alveolar collapse + inadequate gas exchange
23
Q
What are the risk factors for respiratory distress syndrome?
A
- born before 34wks
- 91% if born at 23-25wks
- 52% if 30-31 wks
- caeserian delivery
- hypothermia
- perinatal hypoxia
- meconium aspiration
- maternal diabetes
- past family history
- males
- 2nd twin
24
Q
What is the clinical presentation of respiratory distress syndrome?
A
Signs of respiratory distress develop within 4 hours after delivery:
- tachypnoea (>60/min)
- grunting
- nasal flaring
- intercostal recession
- cyanosis
- CXR -> diffuse granular patterns (ground glass appearance) +/- air bronchograms
25
Q
How is respiratory distress syndrome prevented?
A
- mothers expecting to deliver prematurely given corticosteroids antenatally
- help promote maturity of type 2 alveolar cells
- betamethasone/dexamethasone, 2 doses, 12hrly given to mother 1-7 days before birth
- last dose given at least 24hrs before birth
26
Q
What is the management for RDS?
A
- delay clamping of cord to promote placento-fetal transfusion
- give oxygen via an oxygen-air blender, start w/ 21% + increase if no improvement in HR, despite good chest movement
- attach oxymeter + follow local guidelines for sats
- sats of 85% are normal in first 5-10mins of life if baby active
- if not, inc O2 by 10% every minute until improving
- if spontaneously breathing, stabilise w/ CPAP
- if gestation <27wks -> intubate + give prophylactic surfactant via ET tube +/- 2 further doses if ongoing O2 demand/ventilation requirement
- aim for sats 85-93%
- wrap up warmly + take to NICU/SCBU incubator
- if any deterioration check DOPE: displaced ET tube, Obstructed (secretions, blood), Pneumothorax, Equipment failure (ventilator, tubing)
- Abx -> give penicillin + gentamicin until congenital pneumonia excluded
- fluids + nutrition -> 10% glucose IVI, inositol essential nutrient promoting surfactant maturation + helps reduce complications
- full parenteral nutrition can be started day 1
- minimal enteral feeding w/ expressed breast milk can also be started on day 1
27
Q
What are the complications of respiratory distress syndrome?
A
- pulmonary haemorrhage or infection
- persistent pulm hypertension of newborn
- pneumothorax caused by artifical ventilation
- bronchopulmonary dysplasia caused by pressure + volume trauma caused by artifical ventilation, oxygen toxicity + infection
- death
- intraventricular haemorrhage + patent ductus arteriosus
28
Q
What is prematurity and how common is it?
A
- infant born before 37 weeks gestation
- 7% of births
29
Q
What are the risk factors for prematurity?
A
- placental - placenta praevia, abruption, insufficiency
- uterine - malformation, cervical incompetence
- maternal - pre-eclampsia, chronic illness, infection, smoking, drug abuse, BV, GD, underweight or obese
- foetal - distress, multiple preg, chromosomal abnormality, infection
- other - premature rupture of membranes, trauma, iatrogenic, prev pre-term birth
30
Q
Outline problems associated in various systems in the very premature infant
A
- Resp - RDS, bronchopulmonary dysplasia, pneumothorax, apnoea
- CVS - patent ductus arteriosus, hypotension
- GI - jaundice, necrotising enterocolitis, inguinal hernia, feed intolerance
- Neuro - intraventricular haemorrhage, ischaemic brain injury, hydrocephalus, retinopathy, sensori-neural deafness
- Haem - anaemia of prematurity, imapired leucocyte function
- Metabolic/Endo - hypothermia, hypocalcaemia, hyponatraemia, hypoglycaemia, osteopenia
- Infection - septicaemia, meningitis, UTI, fungal/viral infections
- Social - parental anxiety + distress, family relationship disruption
31
Q
What is the long-term outlook for very premature babies?
A
- survival under 23 wks gestation is v rare
- neurodevelopment problems include cognitive delay, seizures, educational difficulties, behavioural problems, cerebral palsy
- those requiring artifical ventilation @ 36wks -> bronchopulm dysplasia (chronic lung disease of prematurity) -> at risk of developing chest infections, given monoclonal antibody to resp syncitial virus
- retinopathy + blindness occurs in 20% of v low weight preterms
- sensorineural hearing loss common
- iron supplementation required up to 6 months corrected age to prevent anaemia
- those born after 32wks -> excellent prognosis
32
Q
Discuss the ethics of interventions in the extremely premature
A
- neonate born <24wks or less than 500g has a negligible chance of surivival
- parents do not always receive sufficient counselling during an emergency admission
- so aren’t well-informed to accept withdrawal of treatment or quality of life decisions
- prospective parents not educated earlier in pregnancy about extreme prem delivery
- crucial info explaining neonatal issues only offered to labouring women during emergency admission
- most have difficulty understanding risks and benefits of baby’s treatment
- parents confronted by ethical decision on whether to continue treatment or not
33
Q
What is meant by ‘small for gestational age’?
A
- babies below the 10th centile on the growth chart for their gestational age
- they may be genetically small or have experienced IUGR
34
Q
What is meant by intrauterine growth restriction (IUGR)?
A
- the baby is small for their gestational age AND appears thin + malnourished
- something has prevented the foetus from reaching its genetic growth potential
35
Q
What are the causes of IUGR?
A
-
Maternal:
- undernutrition
- maternal hypoxia: cyanotic heart disease; chronic resp disease
- drugs: alcohol, cigarettes, illicit drugs
-
Placental:
- reduced vascular supply: pre-eclampsia, HT, diabtes, renal disease
- thrombosis or infarction: sickle cell, anti-phospholipid syndrome
- sharing: multiple foetuses
-
Foetal:
- chromosomal disorders or syndromes
- structural
- congenital infection
36
Q
What is asymmetrical IUGR?
A
- commonest form of IUGR
- caused by uteroplacental insufficiency late in pregnancy
- baby’s weight or height is in a lower centile than the head circumference bc the vital organ growth eg. the brain, is spared at the expense of the liver glycogen stores + subcutaneous fat
- example is maternal pre-eclampsia
- infants rapidly put on weight after birth
37
Q
What is symmetrical IUGR?
A
- caused by prolonged period of poor intrauterine growth
- normally due to foetal factors
- head circumference + body weight lie in similar centiles
- these infants are likely to remain small
38
Q
What are complications of IUGR?
A
- intrauterine hypoxia + death + perinatal asphyxia
- monitoring of foetus is required to assess if + when an elective caeserean needs to be done
- neonatal problems:
- hypothermia due to relatively large SA compared to mass
- hypoglycaemia due to lack of fat + glycogen stores
- hypocalcaemia
- polycythaemia
- later life: evidence IUGR associated w/ HT, DMT2, CHD + stroke
