In young children, the signs and symptoms of obstructive sleep apnea hypopnea may be more subtle than in adults, making diagnosis more difficult to establish. Polysomnography is useful in confirming diagnosis. Evidence of fragmentation of sleep on the polysomnogram may not be as apparent as in studies of older individuals, possibly because of the high homeo- static drive in young individuals. Symptoms such as snoring are usually parent—reported and thus have reduced sensitivity. Agitated arousals and unusual sleep postures, such as sleeping on the hands and knees, may occur. Nocturnal enuresis also may occur and should raise the suspicion of obstructive sleep apnea hypopnea if it recurs in a child who was previously dry at night. Children may also manifest excessive daytime sleepiness, although this is not as com- mon or pronounced as in adults. Daytime mouth breathing, difficulty in swallowing, and poor speech articulation are also common features in children. Children younger than 5 years more often present with nighttime symptoms, such as observed apneas or labored breathing, than with behavioral symptoms (i.e., the nighttime symptoms are more noticeable and more often bring the child to clinical attention). In children older than 5 years, daytime symptoms such as sleepiness and behavioral problems (e.g., impulsivity and hyperactivity), attention-deficit/ hyperactivity disorder, learning difficulties, and morning headaches are more often the focus of concern. Children with obstructive sleep apnea hypopnea also may present with failure to thrive and developmental delays. In young children, obesity is a less common risk factor, while delayed growth and "failure to thrive" may be present.
Genetic and physiological. The major risk factors for obstructive sleep apnea hypopnea are obesity and male gender. Others include maxillary-mandibular retrognathia or micro— gnathia, positive family history of sleep apnea, genetic syndromes that reduce upper airway patency (e.g., Down’s syndrome, Treacher Collin’s syndrome), adenotonsillar hy- pertrophy (especially in young children), menopause (in females), and various endocrine syndromes (e.g., acromegaly). Compared with premenopausal females, males are at in- creased risk for obstructive sleep apnea hypopnea, possibly reﬂecting the inﬂuences of sex hormones on ventilatory control and body fat distribution, as well as because of gender differences in airway structure. Medications for mental disorders and medical conditions that tend to induce somnolence may worsen the course of apnea symptoms if these med- ications are not managed carefully.
Obstructive sleep apnea hypopnea has a strong genetic basis, as evidenced by the sig- nificant familial aggregation of the apnea hypopnea index. The prevalence of obstructive sleep apnea hypbpnea is approximately twice as high among the first—degree relatives of probands with obstructive sleep apnea hypopnea as compared with members of control families. One-third of the variance in the apnea hypopnea index is explained by shared fa- milial factors. Although genetic markers with diagnostic or prognostic value are not yet available for use, eliciting a family history of obstructive sleep apnea hypopnea should in- crease the clinical suspicion for the disorder.
There is a potential for sleepiness and fatigue to be reported differently across cultures. In some groups, snoring may be considered a sign of health and thus may not trigger con- cerns. Individuals of Asian ancestry may be at increased risk for obstructive sleep apnea hypopnea despite relatively low BMI, possibly reﬂecting the influence of craniofacial risk factors that narrow the nasopharynx.
snoring.
Polysomnography provides quantitative data on frequency of sleep-related respiratory disturbances and associated changes in oxygen saturation and sleep continuity. Polysom— labored breathing, partial obstructive hypoventilation with cyclical desaturations, hyper- capnia and paradoxical movements. Apnea hypopnea index levels as low as 2 are used to define thresholds of abnormality in children.