What is the management plan for a 32-week preterm infant with bilateral pericentricular flaring and cavum septum pellucidum on neurosonogram?

Management of 32-Week Preterm Infant with Bilateral Periventricular Flaring and Cavum Septum Pellucidum

Continue serial cranial ultrasound monitoring every 1-2 weeks to assess for progression to posthemorrhagic ventricular dilation (PHVD), while simultaneously initiating standardized neurodevelopmental assessment and early intervention referral regardless of current clinical symptoms. 1

Immediate Clinical Assessment

Evaluate for signs of symptomatic hydrocephalus through:

• Progressive splaying of sagittal suture width (most reliable clinical indicator) 2
• Fontanel fullness and increasing head circumference plotted serially 2
• Apnea, bradycardia, lethargy, or decreased activity (nonspecific but concerning signs) 2
• Close coordination with neonatology team to distinguish these from other preterm complications 2

Serial Ultrasound Monitoring Protocol

Measure specific ventricular parameters on each ultrasound: 2

• Anterior horn width (AHW): Most sensitive early indicator of ventricular expansion
  • Normal: <3 mm
  • Concerning: 3-5 mm (unclear significance)
  • Abnormal: >6 mm 2
• Levene ventricular index: Measured from falx to lateral aspect of anterior horn
  • At 32 weeks corrected age, intervention threshold is approximately 15-16 mm (97th percentile + 4 mm) 2

Periventricular flaring specifically indicates: 1

• Potential white matter injury or edema
• Risk for evolving periventricular leukomalacia (PVL)
• Need for close monitoring as diffuse white matter injury is now the predominant form of brain injury in preterm infants (following 93% reduction in cystic PVL) 1

Cavum Septum Pellucidum Significance

The presence of cavum septum pellucidum at this age is developmentally normal and requires no intervention. 3

• Cavum septum pellucidum should be visualized in all normal fetuses between 18-37 weeks gestation 4
• Persistence through term (up to 42 weeks postconception) is not an independent risk factor for developmental delay 3
• Only becomes clinically significant if it enlarges into a symptomatic cyst causing obstructive hydrocephalus, which is extremely rare 5, 6

Intervention Thresholds

Surgical intervention is indicated only if the infant develops symptomatic hydrocephalus, defined by: 2

• Clinical signs of increased intracranial pressure (progressive suture splaying, bulging fontanel, apnea/bradycardia)
• AND ventricular measurements exceeding thresholds (AHW >6 mm or ventricular index >97th percentile + 4 mm)
• Combination of clinical examination and ultrasonographic findings drives decision-making, not imaging alone 2

If symptomatic PHVD develops, temporizing measures include: 2

• Serial lumbar punctures if lumbar subarachnoid space communicates with ventricular system
• Avoid acetazolamide and furosemide (randomized trial showed increased mortality and neurological morbidity at 1 year) 2
• Permanent VP shunt placement reserved for progressive symptomatic hydrocephalus unresponsive to temporizing measures 2

Advanced Imaging Considerations

MRI with diffusion-weighted imaging should be obtained at term-equivalent age (36-40 weeks corrected) for prognostic assessment, not for acute management decisions. 1

• Cranial ultrasound reliably detects severe cystic PVL, intraventricular hemorrhage, and hydrocephalus requiring intervention 1
• However, ultrasound significantly underdetects cerebellar hemorrhage (only 23% detection rate), which confers 5-fold increased risk of abnormal neurological outcomes 1
• Diffuse white matter injury—now the predominant pathology—is difficult to visualize with ultrasound 1
• Term-equivalent MRI provides superior neurological prognosis compared to acute ultrasound findings 1

Neurodevelopmental Surveillance

Initiate standardized assessment immediately, as this infant is approaching critical developmental thresholds: 7

• Hammersmith Infant Neurological Examination (HINE): Primary assessment tool
  • Scores <73 at 6-12 months indicate 90% risk of cerebral palsy 7
  • Scores <40 at 6-12 months almost always indicate cerebral palsy 7
• Alberta Infant Motor Scale (AIMS): Quantify motor development 7
• Critical milestone: Inability to sit independently by 9 months corrected age requires immediate comprehensive CP evaluation 7

Refer to early intervention services now—do not wait for complete diagnostic workup or symptom development. 7

• Preterm infants with any degree of periventricular white matter changes require close neurodevelopmental follow-up 1
• Early intervention improves outcomes even when diagnosis remains uncertain 7
• Refer to pediatric neurology or developmental pediatrics for comprehensive evaluation 7

Common Pitfalls to Avoid

• Do not adopt "wait and see" approach for neurodevelopmental surveillance—early detection enables access to interventions that improve outcomes 7
• Do not intervene surgically based on imaging alone—combination of clinical signs and ventricular measurements determines need for CSF diversion 2
• Do not order only neuroimaging—standardized neurological and motor assessments provide more actionable prognostic information 7
• Do not assume normal ultrasound excludes significant brain injury—diffuse white matter injury and cerebellar hemorrhage are frequently missed 1
• Do not use medications (acetazolamide/furosemide) for PHVD—evidence shows harm 2

Long-Term Monitoring

This infant requires: 1

• Serial ultrasounds until ventricular size stabilizes or term-equivalent age is reached
• MRI at term-equivalent age (36-40 weeks corrected) for comprehensive prognostic assessment 1
• Ongoing neurodevelopmental follow-up through early childhood given increased risk for cerebral palsy, epilepsy, and cognitive delays 1
• Physical therapy evaluation and treatment if motor delays emerge during surveillance 7