Neonate Screening and Hearing Tests

Neonate Screening

• Newborn screening aims to identify life-threatening or long-term health disorders before symptoms appear.
• Conditions screened include inborn errors of metabolism, endocrine disorders, hemoglobinopathies, immunodeficiency, cystic fibrosis, hearing loss, and critical congenital heart disease.
• Early intervention can reduce morbidity and mortality in affected newborns.
• Congenital hearing loss is a condition screened for in newborns. Criticals congenital heart disease is also screened, typically using pulse oximetry.
• Newborn blood spot panels are used to screen for inborn errors of metabolism and immunity. Other conditions also screened for include congenital hypothyroidism, congenital adrenal hyperplasia, hemoglobinopathies, cystic fibrosis, and spinal muscular atrophy.

Two-Stage Newborn Hearing Screening

• Screening for newborns who are admitted to a well-baby nursery.
• Two stages:
• Stage 1: Otoacoustic Emissions (OAE) testing measures the inner ear's response to sound and is typically done on infants unable to respond to behavioral tests.
• Stage 2: If Stage 1 is passed, screening is complete. If not, further testing and referral to an audiologist is needed.

Newborn Screening for Critical Congenital Heart Defects

• Pulse oximetry is a simple bedside test that estimates oxygen levels in a baby's blood.
• Low oxygen levels detected by pulse oximetry may indicate a critical congenital heart defect (CHD), prompting further evaluation and management.
• The test is painless and takes only a few minutes.
• Early detection allows for timely intervention and improves outcomes for infants with CHDs.
• A modified screening algorithm using pulse oximetry measurements at different times can be used to diagnose CHD.

Developmental Dysplasia of the Hip (DDH)

• Describes a spectrum of conditions related to hip development in infants and young children.
• Includes abnormal development of the acetabulum and proximal femur and mechanical instability of the hip joint.
• Higher incidence in breech babies, those with oligohydramnios or large birth weights.
• Often asymptomatic in newborns. Requires specific maneuvers for screening.

DDH Classification

• Typically, DDH occurs in otherwise healthy individuals without any underlying condition.
• Teratologic hip dislocations have visible causes (e.g., arthrogyposis, or genetic syndromes) and occur before birth.

DDH in Neonates

• Screening and physical exam need to be performed in a warm, comfortable setting, where infants are unclothed.
• Crucial maneuvers include the Barlow and Ortolani tests for identifying DDH. These tests evaluate hip joint stability, and identifying potential problems.

Age-Specific Findings of DDH

• Infants under three months: Assess hip stability. Use the Barlow and Ortolani maneuvers.
• After three months, assessment includes evaluating limited abduction, thigh-length discrepancies, Galeazzi, Klisic tests. These indicators are more reliable.
• Walking-aged children with DDH show hip abductor weakness detected using the Trendelenburg test (pelvic tilt, inability to maintain pelvis horizontally while standing on one leg) and potentially a Trendelenburg lurch when walking.

Clinical Features of Bilateral DDH

• Wide perineum: A likely result of the lateral positioning of the femoral heads and their necks.
• Hyperlordosis: caused by superior and posterior displacement of the femoral heads and necks.

Diagnostic Testing - Ultrasonography

• Ultrasound is the preferred diagnostic method for DDH in infants before femoral head ossification. Physical exam is preferred over ultrasound in neonates due to the high incidence of false positives.
• Ultrasound measures specific points of interest to assess the acetabulum, labrum, and femoral head.

Diagnostic Testing - Radiography

• Radiographs are essential once the femoral epiphysis ossifies (around 4-6 months old).
• Radiographs are more efficient, cost-effective, and less dependent on operators than ultrasounds, hence used to assess hip development.
• Interpretations involve using classic lines (e.g., Shenton and Hilgenreiner lines) to visualize and understand hip shape.

DDH in Infants Aged 3-6 Months

• The Galeazzi sign (one leg appears shorter) could be used to assess unilateral hip dislocations. One leg may appear shorter as a result.

Asymmetrical Thigh Folds

• Asymmetric thigh folds might be caused by the presence of DDH. Bunching of skin and muscle is a likely indicator of the hip dislocation.

Klisic Test

• Used to assess the presence of a dislocated hip. A line drawn between the Anterior Superior Iliac Spine and the greater trochanter normally passes through the umbilicus or above it. Placement below the umbilicus can signal a possible dislocation.

The Walking Child

• Common presenting symptoms includes limp, waddling gait, or leg-length discrepancy. Infants may toe-walk on the affected side.
• The Trendelenburg sign and the abductor lurch are common indicators in walking children.
• The Galeazzi sign may be present. It involves examining the degree of different levels of knees when hips are flexed.

Trendelenburg Test

• The Trendelenburg test assesses gluteal muscle weakness, which is a consequence of DDH. The test looks at the tilt of the pelvis when standing on one leg. The pelvis is supposed to be relatively level when standing, but with gluteal weakness, one side of the pelvis will drop relative to the other side. The position of the hip on the affected side is different from the unaffected side.

Diagnostic Testing - Radiography

• Radiographs are a crucial diagnostic tool once the proximal femur ossifies (or around 4–6 months of age). They are generally more effective, cost-effective, and require less operative dependency.

DDH Treatment

• Infants under 4 weeks: Mild cases often resolve spontaneously. Avoid overdiagnosis and treatment.
• 4 weeks to 6 months: Re-evaluation, ultrasound. If issues persist, consider treatment via Pavlik harness.
• Older than six months: Reduction under anesthesia.

DDH Outcome

• Long-term outcome depends on age at diagnosis, severity and treatment success.
• Treatment with a Pavlik harness is often successful in most cases.
• Patients should be monitored regularly using radiographs throughout their musculoskeletal development to monitor any potential long-term complications.

This quiz covers newborn screening practices aimed at identifying critical health disorders in neonates. It focuses on various conditions screened, such as metabolic and endocrine disorders, including a detailed look at the two-stage newborn hearing screening process. Participants will gain insights into early interventions that can significantly impact the health of newborns.