OSA in infants is usually caused by craniofacial abnormalities, low muscle tone, and/or altered soft tissue size.5 The 2 most common causes of OSA in older children are adenotonsillar hypertrophy6 and obesity.7 MRI studies of children with OSA have shown that most obstructions are in the area of the adenoids (which reach their maximum size at age 6 years) and the soft palate; these studies show that the size of the soft palate in children between the ages of 3 and 7 years who have OSA is increased by 30% compared with soft palates in children who do not have OSA.8 The increase in the size of the soft palate represents edema, which is probably secondary to vibratory trauma.
Obesity increases the likelihood of childhood OSA by a factor of 1.3- to 9-fold7,9; it does this by increasing the size of the fat pads in the neck, causing fatty muscle infiltration and producing changes in chest wall mechanics. This can lead to a decrease in the functional residual capacity of the lungs, which, in turn, increases sensitivity to relatively small changes in respiratory patterns.
MORBIDITY ASSOCIATED WITH OSA IN CHILDREN
The following effects of OSA are seen in patients of all ages:
|•||Excessive daytime sleepiness (which has been found to be greater in obese children than in nonobese children with a similar degree of obstruction10).|
|•||Impaired glycemic control.12|
|•||Increased cardiovascular13 and cerebrovascular disease.14|
Researchers are discovering that in children, OSA has additional deleterious neurocognitive, developmental, and behavioral consequences. Connections between OSA and reduced verbal IQ,15 decreased executive function,16 lower Bailey developmental scores,17 poor school performance,18 attention-deficit/hyperactivity disorder,19 and failure to thrive20 have become widely recognized. Many of the studies cited have described improvement in the parameters examined following successful treatment of OSA—an improvement not seen in untreated children. It is still unclear what the precise mechanisms are that cause the neurocognitive and behavioral deficits; however, there is evidence that changes in cerebral blood flow21 and the presence of inflammation22 play significant roles.
DIAGNOSIS OF CHILDHOOD OSA
It is always a good idea to ask parents whether their child snores. If parents report that their child snores—or volunteer information about other signs and symptoms listed in Table 2—a workup for OSA is indicated. The first step in the workup is to take a detailed history. Questions to ask the child and parent are listed in Table 2.
|Table 2 — Questions to include in the history taking for a child with suspected obstructive sleep apnea (OSA)|
|•||Does the child snore; if so, is this a consistent or variable finding and is it accompanied or interrupted by gasps, snorts, or choking?|
|•||Does the child breathe through an open mouth (suggestive of nasopharyngeal obstruction)?|
|•||Does the child sleep on multiple pillows or in strange positions (eg, seated upright, folded over, or with the neck hyperextended)?|
|•||Does the child sweat profusely at night?|
|•||Is there a history of bed-wetting that has reappeared after several months of the child's being dry at night (secondary nocturnal enuresis), and has that developed in conjunction with the emergence of other signs of OSA?|
|•||Has the child had parasomnias, such as sleep walking, night terrors, or confusional arousals (all of which can be precipitated by OSA)?|
|•||Does the child complain of a dry mouth in the morning, or of morning headaches?|
|•||Does the child not seem refreshed despite getting an adequate amount of sleep?|
|•||Does the child fall asleep in the car on short drives, fall asleep at school, or nap in a manner inappropriate for his or her age?|
|•||Has the child gained a lot of weight recently?|
|•||Have there been recent changes in school performance or behavior concurrent with weight gain or onset of sleep disturbances?|
|•||If the child is at high risk for hypothyroidism, have thyroid functions been tested recently?55|
|•||Is there a family history of OSA?|