Abstract
Introduction
four-year-old boy with morbid obesity was referred to pediatric sleep for nocturnal hypoxemia during inpatient admissions. He was found to have daytime hypoventilation, likely secondary to obesity hypoventilation syndrome (OHS).
Report of Case
During two inpatient admissions (wheezing, gastroenteritis), he desaturated to the 70s during sleep. At home, he received blow-by oxygen as he could not tolerate other interfaces. He underwent adenotonsillectomy. However, snoring, daytime sleepiness, hyperactivity and aggressive behavior persisted.
Birth history was unremarkable, though he became progressively more obese over time. His father had obesity and obstructive sleep apnea. Physical exam was notable for elevated blood pressure of 122/68 mmHg (above 99th percentile), weight and height above 99th percentile, and BMI of 32 kg/m2 (z-score ~4.3).
Despite extensive counseling, family declined polysomnography and labs. Awake end-tidal CO2s were elevated at 47 mmHg. Echocardiogram showed half-systemic PA pressures, right ventricular hypertrophy, and right atrial dilation.
Family began desensitization protocol in preparation for future PAP therapy and polysomnography. Pediatric endocrinology consultation revealed low suspicion for hormonal/metabolic concerns. He entered a pediatric weight loss program.
Conclusion
This 4-year-old boy demonstrated daytime hypoventilation, systemic and pulmonary hypertension, likely consequences of his severe obesity. OHS is defined as BMI >95th percentile in children and awake hypercapnia (PaCO2 > 45 mmHg) in absence of alternative hypoventilation causes (e.g. pulmonary, cardiac, neurologic, pharmacologic). Presenting symptoms may include hypersomnolence, morning headaches, cognitive deficits, and signs of cor pulmonale1. The literature consists primarily of case reports; prevalence of pediatric OHS is unknown. Obesity afflicts 18.5% of children in the United States2. Given the severity of OHS sequelae, maintaining a high index of suspicion is crucial. Consider further work-up in patients with unexplained low oxygen saturations, signs of pulmonary hypertension (unexplained dyspnea on exertion, pedal edema), polycythemia, and elevated bicarbonate1.
Obesity and Pulmonary Hypertension: A Review of Pathophysiologic Mechanisms
