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When Obesity Meets Obstructive Sleep Apnea

December 1, 2015

For this 5-year-old, it was just another well child visit—or was it? The first worry, of course, was the child’s weight of 110 lbs., a BMI of 38, and a history of eating sugary, high-fat foods. Adding the child’s history of loud snoring and episodes of apnea reported by the patient’s mother, the patient’s physician immediately ordered an outpatient sleep study—a decision, it turns out, that may have saved the child’s life. One hour into the study pulmonologists halted it and admitted the patient to the pediatric intensive care unit for emergency continuous positive airway pressure (CPAP) therapy.

“Immediately upon falling asleep she had obstruction after obstruction after obstruction without hardly any rescue breaths or recovery at all,” pediatric pulmonologist Laura Sterni reported at a recent case conference. “She had 320 events in one hour, which is absolutely the highest number I’ve ever seen,” she added, referring to the number of respiratory disturbances experienced by the patient. “She was essentially not breathing.”

The patient’s oxygen desaturation nadir of 54 percent was critically low, too, and she spent almost 50 percent of her time asleep with a saturation less than 70 percent. Sterni explained that dips below 80 percent are considered severe and may compromise brain and heart function. Also, during the brief period the study ran the patient did not enter REM sleep. Had this occurred, the study findings would have been even more severe.

“She would have been much worse in REM, a state of sleep in which your muscle activity is decreased and your airways collapse even more,” Sterni said. “Her sleep apnea was so severe we felt it wasn’t safe to continue the study. We wanted to initiate treatment right away.”

Although this was an extreme case of a morbidly obese child with obstructive sleep apnea (OSA), Sterni said it aptly illustrates the related health risks for overweight or obese patients and the challenges pediatricians face in treating them. Overweight or obese children and adults are at greater risk of OSA due to upper airway narrowing from fat infiltration. Also, the additional weight on obese patients’ chest wall compromises air reserves in the lungs, leading to more gasexchange abnormalities.

The effects of OSA, Sterni explained, lead to problems with behavior, learning, memory and executive function. And even mild to moderate OSA, studies show, may also contribute to hypertension and cardiovascular complications with potential long-term consequences, including structural changes in the heart, like left ventricular or right ventricular hypertrophy, and dysfunction. So, in a severe case like this can sleep apnea be lifethreatening?

“People don’t die suddenly from OSA, but over the long term severe sleep apnea can clearly become life-threatening,” Sterni said. “We know that it can lead to systemic hypertension, pulmonary hypertension, and pulmonary edema from heart failure.”

For pediatricians, Sterni said, the takehome message is vigilant screening for OSA. Treatment includes adenotonsillectomy as a first-line therapy, CPAP, exercise and diet— the latter the biggest challenge.

“In the end the treatment is weight loss,” said Sterni. “We know weight loss works— it will reverse the OSA—but it’s the hardest thing to accomplish.”

Presenting the case, pediatric resident Brandon Smith cited differential diagnoses like Prader-Willi and Cushing’s to consider as underlying secondary conditions, noting that a genetics workup is appropriate. He also noted the importance of aggressive follow-up by pediatricians in managing such cases.

“Seeing an obese child every two or three months and intervening more often with exercise and diet counseling may help to improve compliance,” Smith said.

That’s the approach being taken in a new obesity-hypertension clinic led by pediatric nephrologist Tammy Brady at Johns Hopkins Children’s Center.

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