What are the diagnostic criteria for central apneas in children?

Diagnostic Criteria for Central Apneas in Children

The diagnosis of central sleep apnea (CSA) in children requires a central apnea index (CAI) ≥ 5 events per hour on polysomnography, which remains the gold standard diagnostic test. 1, 2

Definition and Classification

• Central sleep apnea is defined by a central apnea index (CAI) ≥ 5 events per hour on polysomnography 1, 2
• Unlike obstructive sleep apnea, central apneas are characterized by absence of respiratory effort during cessation of airflow 1
• CSA can be classified based on the presence or absence of hypercapnia as well as the underlying condition it is associated with 3
• CSA is rare in children, occurring in approximately 3-5% of children referred for sleep studies 1, 2

Diagnostic Testing Requirements

• In-laboratory polysomnography is the diagnostic method of choice for diagnosing central sleep apnea in children 4, 5
• Home sleep apnea tests (HSATs) are not recommended for diagnosing sleep apnea in children, including central apnea 6, 5
• Key measurements required for accurate diagnosis include:
  • Central apnea index (CAI) 1, 2
  • Oxygen saturation monitoring 4, 1
  • Carbon dioxide monitoring (which most HSATs lack) 4, 5
  • Detection of arousals 4, 5
  • Video monitoring to assess clinical manifestations 6

Associated Features and Patterns

• Periodic breathing is frequently associated with central sleep apnea, present in up to 83% of children with CSA 1
• Periodic breathing episodes may appear after:
  • A sigh (40% of episodes) 1
  • An obstructive event (8% of episodes) 1
  • Breathing instability (6% of episodes) 1
  • Bradypnea (2% of episodes) 1
• Sleep-related hypoventilation may be present in approximately 24% of children with CSA 2

Clinical Considerations

• CSA is more common in children with underlying medical conditions than in healthy children 3, 7
• The most common underlying conditions associated with CSA include:
  • Neurological disorders, particularly Chiari malformation (13% of cases) 1, 7
  • Neurosurgical pathologies such as ganglioglioma 7
  • Genetic disorders including Prader-Willi syndrome, achondroplasia, and Down syndrome 7
• The highest clinical apnea index and percentage of time with periodic breathing are observed in children with encephalopathy and/or epilepsy 1
• Age distribution of children diagnosed with CSA:
  • 40% are under 1 year of age 1
  • 41% are between 1-6 years of age 1
  • 19% are 6 years or older 1

Diagnostic Pitfalls and Considerations

• Brain MRI is the most common investigation performed in children with CSA to identify underlying neurological causes 7
• CSA may be underdiagnosed if only HSATs are used due to their inability to monitor CO2 levels and detect arousals 5
• Children with neuromuscular disease, underlying lung disease, or obesity hypoventilation require CO2 monitoring, which most home testing devices lack 8
• The presence of CSA may influence the course of underlying diseases, making accurate diagnosis crucial 3

Management Implications

• Treatment approaches must be tailored to the underlying cause and may include:
  • Neurosurgery for structural abnormalities 1, 7
  • Oxygen therapy 1
  • Continuous positive airway pressure (CPAP) for associated obstructive events 1, 7
  • Non-invasive ventilation 1, 7
• Watchful waiting may be appropriate in some cases, with spontaneous improvement observed in approximately 90% of such patients 1
• Early diagnosis and timely therapeutic interventions are essential for children at high risk 3