Neonatology (1s)

Question 1

What is congenital dislocation of the hip?

Answer 1

• 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

Question 2

What is the aetiology of DDH?

Answer 2

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

Question 3

What are risk factors for DDH?

Answer 3

• 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

Question 4

What is the clinical presentation of DDH?

Answer 4

• 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

Question 5

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?

Answer 5

• 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

Question 6

What is the Ortolani test?

Answer 6

• 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

Question 7

Treatment for DDH depends upon the age at which the diagnosis is made.

What is the treatment for a newborn?

Answer 7

• 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

Question 8

DDH: What is the treatment for age group of 6 months old to 6 years old?

Answer 8

• 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

Question 9

DDH: What is the treatment for older than 6 years old?

Answer 9

• 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

Question 10

What is the prognosis like for DDH?

Answer 10

• 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

Question 11

Jaundice is the most common condition in newborns that requires medical attention. How common is neonatal jaundice?

Answer 11

• 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

Question 12

Describe bilirubin metabolism

Answer 12

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.

Question 13

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?

Answer 13

• 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

Question 14

Jaundice can be categorised in terms of time of presentation.

What are the causes if jaundice is presenting within 24 hours of birth?

Answer 14

• Haemolytic disease (Unconjugated)
  
  • rhesus incompatibility
  • ABO incompatibility
  • G6PD deficiency
  • hereditary spherocytosis
• Conjugated
  
  • ​congenital infection -> sepsis

Question 15

What are the causes of jaundice presenting between 24hrs and 2 weeks?

Answer 15

• breastfeeding jaundice -> unclear why, resolves without mx or complication, mothers should be encouraged to continue to breastfeed
• physiological jaundice
• polycythaemia
• infection eg UTI

Question 16

What are the causes of prolonged jaundice (not fading after 14 days in term babies, or 21 days in prems)?

Answer 16

• 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

Question 17

If there are still signs of jaundice after 14 days, a prolonged jaundice screen is performed, including what?

Answer 17

• 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

Question 18

What is the management for neonatal jaundice?

Answer 18

• 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

Question 19

What is phototherapy?

Answer 19

• 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

Question 20

What is exchange transfusion?

Answer 20

• uses warmed blood (37^oC)
• 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

Question 21

What is kernicterus?

Answer 21

• 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

Question 22

Respiratory distress syndrome refers to lung disease caused by surfactant deficiency. What is the pathophysiology of this?

Answer 22

• 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

Question 23

What are the risk factors for respiratory distress syndrome?

Answer 23

• 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

Question 24

What is the clinical presentation of respiratory distress syndrome?

Answer 24

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

Question 25

How is respiratory distress syndrome **prevented**?

Answer 25

* 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

Question 26

What is the **management** for RDS?

Answer 26

* **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

Question 27

What are the **complications** of respiratory distress syndrome?

Answer 27

* 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

Question 28

What is **prematurity** and how common is it?

Answer 28

* infant born **before 37 weeks** gestation * 7% of births

Question 29

What are the **risk factors** for prematurity?

Answer 29

* **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

Question 30

Outline **problems** associated in various **systems** in the very premature infant

Answer 30

* **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

Question 31

What is the **long-term outlook** for very premature babies?

Answer 31

* 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

Question 32

Discuss the **ethics** of interventions in the extremely premature

Answer 32

* ​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

Question 33

What is meant by '**small for gestational age**'?

Answer 33

* babies below the **10^th centile** on the growth chart for their gestational age * they may be genetically small or have experienced IUGR

Question 34

What is meant by **intrauterine growth restriction** (IUGR)?

Answer 34

* the baby is small for their gestational age AND appears thin + malnourished * something has prevented the foetus from reaching its genetic growth potential

Question 35

What are the **causes** of IUGR?

Answer 35

* **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_

Question 36

What is **asymmetrical** **IUGR**?

Answer 36

* _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

Question 37

What is **symmetrical IUGR**?

Answer 37

* 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**

Question 38

What are **complications** of IUGR?

Answer 38

* 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