Making the Diagnosis: Sleep expert warns about OSA risk in obese children

Minneapolis, Minn.—The most significant danger to children now is obesity, and of the many related comorbidities that affect obese children, obstructive sleep apnea (OSA) will impact a child’s life more than anything else, according to Carole Marcus, MD, an invited lecturer here last month at SLEEP 2011, the 25th Annual Meeting of the Associated Professional Sleep Societies.Dr. Marcus is a professor of pediatrics at the University of Pennsylvania and director of the sleep center at Children’s Hospital of Philadelphia.

Data from population studies bear out her experience, she said, showing a two- to four-fold increase in snoring in obese children (Chest. 2004;126:790; Pediatrics. 2001;108:1149) and a four-fold increase in OSA (AJRCCM. 1999;159:1527). Data from the Centers for Disease Control and Prevention also highlight the growing prevalence of obesity Current statistics show obesity in about 12.5 million or 17 percent of children and adolescents between two and 19 years of age. This is triple the number of children deemed obese in the 1980s.

Evaluation

Dr. Marcus encourages all physicians to consider OSA in obese children who come in for clinical evaluation. “Diagnosing early is just the tip of the iceberg,” she said, emphasizing the impact OSA and other comorbidities, such as diabetes and hypertension, will have on these patients.

In her talk, Dr. Marcus explained that OSA in children involves both a structural problem and a problem in neuromuscular tone. “Every patient has both abnormal neuromuscular activation and structural narrowing,” she said.

Pediatric patients, she said, have a less collapsible upper airway than adults because of increased reflex neuromotor activation. It is speculated, she added, that normal children may compensate for a narrower upper airway by an increased ventilatory drive during sleep. In children with OSA, these reflexes may be deficient, she said.

Dr. Marcus and colleagues are currently researching the effects of obesity on this pathophysiology of OSA. Using magnetic resonance imaging to look at the structural component has shown them that obese adolescents have larger parapharyngeal lateral wall tissue in the upper airway, similar to obese adults, and increased lymphoid tissue similar to that seen in children. Their research, which has not yet been published, is also finding that obese adolescents with OSA have blunted upper airway reflexes during sleep, in contrast to obese adolescents without OSA, in whom the upper airway neuromuscular reflexes are active during sleep. Dr. Marcus speculated that obese adolescents without OSA have increased neuromotor tone that compensates for the enlarged soft tissue structures but believes that they may be at risk of developing OSA later in life.

“Sleep apnea is very common in obese children, and data show that many kids will respond well to surgery. Even if they are not cured, they will have significant improvement.”

—Carole Marcus, MD
 

Treatment

Tonsillectomy and adenoidectomy remain the primary treatments for children with OSA, even for those who are obese, Dr. Marcus said. “Sleep apnea is very common in obese children, and data show that many kids will respond well to surgery,” she said. “Even if they are not cured, they will have significant improvement.”

For children who have persistent OSA after surgery, Dr. Marcus is increasingly using continuous positive airway pressure (CPAP). However, as with adults, adherence remains the primary challenge of successful treatment with CPAP.

To better understand the challenges to adherence in these children, Dr. Marcus and colleagues looked at a number of factors, including the severity of OSA, the level of hyperactivity of the child and family issues. They found that the most important indicator of adherence was maternal level of education, with mothers with higher education linked to a child’s increased adherence to CPAP use. Dr. Marcus said this suggests the need to target CPAP compliance educational efforts. Improving adherence is important, she said, because children with better CPAP usage not only have improved sleep but also experience improvement in behaviors and quality of life. These outcomes were found even with suboptimal CPAP adherence.

Another challenge with using CPAP in children, she said, is the difficulty of finding appropriately sized masks. Not only does this interfere with CPAP adherence and optimal outcomes, she said, but ill-fitting masks have also led to the development of craniofacial abnormalities in some infants. More research and machines appropriate for children are needed, she said.

Fielding a question from a physician in the audience who wanted her opinion on treating a child for OSA without a sleep study, Dr. Marcus acknowledged the lack of resources and accessibility that often make it difficult to obtain a sleep study before surgery, but urged physicians to get a sleep study or any objective data prior to surgery.

“A vast majority of kids in this country get surgery without any objective study of any kind, but there is a lot of data showing that in probably 50 percent of those cases, a sleep study would have been normal,” she said.