Neonatology (1s) Flashcards
- DDH
What is congenital dislocation of the hip?
- 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
What is the aetiology of DDH?
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
What are risk factors for DDH?
- 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
What is the clinical presentation of DDH?
- 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
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?
- 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
What is the Ortolani test?
- 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
Treatment for DDH depends upon the age at which the diagnosis is made.
What is the treatment for a newborn?
- 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
DDH: What is the treatment for age group of 6 months old to 6 years old?
- 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
DDH: What is the treatment for older than 6 years old?
- 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
What is the prognosis like for DDH?
- 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
Jaundice is the most common condition in newborns that requires medical attention. How common is neonatal jaundice?
- 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
Describe bilirubin metabolism
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.
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?
- 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
Jaundice can be categorised in terms of time of presentation.
What are the causes if jaundice is presenting within 24 hours of birth?
-
Haemolytic disease (Unconjugated)
- rhesus incompatibility
- ABO incompatibility
- G6PD deficiency
- hereditary spherocytosis
-
Conjugated
- congenital infection -> sepsis
What are the causes of jaundice presenting between 24hrs and 2 weeks?
- breastfeeding jaundice -> unclear why, resolves without mx or complication, mothers should be encouraged to continue to breastfeed
- physiological jaundice
- polycythaemia
- infection eg UTI
What is the management for neonatal jaundice?
- 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
What is the clinical presentation of respiratory distress syndrome?
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
Discuss the ethics of interventions in the extremely premature
- 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
