Upper airway lymphoid tissue size in children with sickle cell disease

Background: The prevalence of obstructive sleep apnea syndrome (OSAS) is higher in children with sickle cell disease (SCD) as compared with the general pediatric population. It has been speculated that overgrowth of the adenoid and tonsils is an important contributor. Methods: The current study used MRI to evaluate such an association. We studied 36 subjects with SCD (aged 6.9 ± 4.3 years) and 36 control subjects (aged 6.6 ± 3.4 years). Results: Compared with control subjects, children with SCD had a significantly smaller upper airway (2.8 ± 1.2 cm³ vs 3.7 ± 1.6 cm ³, P<.01), and significantly larger adenoid (8.4 ± 4.1 cm³ vs 6.0 ± 2.2 cm³, P<.01), tonsils (7.0 ± 4.3 cm³ vs 5.1 ± 1.9 cm³, P<.01), retropharyngeal nodes (3.0 ± 1.9 cm³ vs 2.2 ± 0.9 cm³, P<.05), and deep cervical nodes (15.7 ± 5.7 cm ³ vs 12.7 ± 4.0 cm³, P<.05). Polysomnography showed that 19.4% (seven of 36) of children with SCD had OSAS compared with 0% (zero of 20) of control subjects (P<.05) and that in children with SCD the apnea-hypopnea index correlated positively with upper airway lymphoid tissues size (r = 0.57, P< 001). In addition, children with SCD had lower arterial oxygen saturation nadir (84.3% ± 12.3% vs 91.2% ± 4.2%, P<.05), increased peak end-tidal CO₂ (53.4 ± 8.5 mm Hg vs 42.3 ± 5.3 mm Hg, P<.001), and increased arousals (13.7 ± 4.7 events/h vs 10.8 ± 3.8 events/h, P<.05). Conclusions: Children with SCD have reduced upper airway size due to overgrowth of the surrounding lymphoid tissues, which may explain their predisposition to OSAS.