Hyperventilation and seizures in an adolescent female

Area of Science:

• Pediatric Neurology
• Sleep Medicine
• Cardiology

Background:

• A 16-year-old female presented with recurrent episodes of dyspnea, stridor, cyanosis, and altered consciousness since age 11.
• Electrocardiogram (ECG) revealed prolonged rate-corrected QT intervals, suggesting potential cardiac involvement.

Observation:

• Daytime polysomnography showed a high apnea-hypopnea index (AHI) of 13.2 events/hour, characterized by central apneas and hypopneas with severe oxyhemoglobin desaturation.
• Nighttime polysomnography revealed normal respiratory parameters (AHI=1.1 events/hour).
• Diurnal monitoring indicated marked hyperventilation with low transcutaneous pCO2 (PtcCO2) levels (8-15 mmHg) during daytime episodes.

Findings:

• Twenty-nine episodes of severe arterial desaturation (SpO2<50%) were recorded, coinciding with apnea events and followed by hyperventilation.
• Neurological symptoms including cyanosis, loss of contact, jaw clenching, and partial seizures occurred during apneic events.
• Treatment involved daytime application of a mask to manage hyperventilation and prevent rapid PaCO2 drops.

Implications:

• This case underscores the importance of differentiating between daytime and nighttime respiratory events in diagnosing sleep-related breathing disorders.
• The findings suggest a link between hyperventilation-induced hypocapnia and central apneas in this patient.
• Intermittent positive airway pressure ventilation during the day may be a viable strategy for managing such complex respiratory and neurological symptoms.