You are in: eMedicine Specialties >
Pediatrics: General Medicine > Pulmonology
Obesity-Hypoventilation Syndrome and Pulmonary Consequences of Obesity
Article Last Updated: May 2, 2006
AUTHOR AND EDITOR INFORMATION
Section 1 of 11  
Author: Mary E Cataletto, MD, Associate Director, Division of Pediatric Pulmonology, Winthrop University Hospital; Associate Professor, Department of Clinical Pediatrics, State University of New York at Stony Brook
Mary E Cataletto is a member of the following medical societies: American Academy of Pediatrics, American Heart Association, and American Thoracic Society
Coauthor(s):
Gila Hertz, PhD, ABSM, Director, Center for Insomnia and Sleep Disorders, Clinical Associate Professor of Psychiatry and Behavioral Sciences, State University of New York at Stony Brook
Editors: Girish D Sharma, MD, Associate Professor, Department of Pediatrics, Rush University Medical Center, Rush Children's Hospital; Director of Pediatric Pulmonary Section and Rush Cystic Fibrosis Center; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Charles Callahan, DO, Professor, Deputy Chief of Clinical Services, Walter Reed Army Medical Center; Daniel Rauch, MD, FAAP, Director, Pediatric Hospitalist Program, Associate Professor, Department of Pediatrics, New York University School of Medicine; Michael R Bye, MD, Attending Physician, Pediatric Pulmonary Medicine, Columbia University Medical Center; Professor of Clinical Pediatrics, Division of Pulmonary Medicine, Columbia University College of Physicians and Surgeons
Author and Editor Disclosure
Synonyms and related keywords:
Pickwick syndrome, pickwickian syndrome, obstructive sleep apnea/hypoventilation, OSA/H, obstructive sleep apnea, hypoventilation
Background
Obesity in children is a complex disorder. Its prevalence has increased so significantly in recent years that many consider it a major health concern of the developed world. In the United States alone, 20-27% of all children and adolescents have obesity. Many factors, including genetics, environment, metabolism, lifestyle, and eating habits, are believed to play a role in the development of obesity. Obesity-hypoventilation syndrome is a relatively uncommon finding in children with obesity, with an estimated frequency of 1-3%. Stated from a different point of view, 10% of patients with obstructive sleep apnea are obese.
No firm diagnostic criteria to define obesity-hypoventilation syndrome exist; this fact, along with limited pediatric studies and discrepant definitions of obesity and abnormal pediatric polysomnographic findings, make the literature somewhat difficult. However, obesity, sleep disordered breathing, and hypercarbia during wakefulness are features generally described with obesity-hypoventilation syndrome. Other features include excessive daytime sleepiness, hyperactivity, poor school performance with difficulty attending to tasks and impaired memory, hypoxia, and signs of cor pulmonale.
In adult patients, male sex and obesity are common risk factors for obstructive sleep apnea. Witnessed apnea, loud disruptive snoring, and daytime sleepiness are frequent presenting complaints. However, in children, neither these risk factors nor the symptom profile is as predictive for obstructive sleep apnea, except in the child with obesity. In fact, 27% of children with obstructive sleep apnea have failure to thrive. In one study, daytime sleepiness occurred with the same overall frequency as in control subjects; in another study, daytime sleepiness was found to be more frequent in obese children with obstructive sleep apnea. Mental retardation also has been associated with obesity-hypoventilation syndrome.
Pathophysiology
The exact mechanism for development of obesity-hypoventilation syndrome is unknown; however, it is believed to be related primarily to abnormalities in ventilatory drive and response to hypoxia and hypercarbia rather than the mechanical factors related to excessive body weight. Other authors feel that body weight and, more importantly, the distribution of body fat, hormones, and upper airway size and dynamics play important roles.
Associated upper airway obstruction is important in the occurrence of obstructive sleep apnea/hypoventilation or hypopnea (OSA/H) because OSA/H is observed more frequently when the 2 conditions occur together, compared to the simultaneous presentation of OSA/H and simple obesity. Other factors that may play a role in the development of airway obstruction during sleep include rapid eye movement (REM) atonia, increased soft tissue and fatty infiltration around the neck, decreased chest wall compliance, and decreased lung volumes (especially in the supine position) secondary to the upward displacement of the diaphragm caused by increased abdominal fat. In children, tonsillar hypertrophy added to obesity appears to be more predictive of abnormal polysomnographic findings.
Frequency
United States
Of American children and adolescents, 20-27% are obese. Frequency of sleep-related breathing disorders in unselected children with obesity is unknown.
Mortality/Morbidity
Higher rates of morbidity and mortality are associated with childhood obesity. Childhood and, especially, adolescent obesity, is predictive of adult obesity with its increased incidence of diabetes, hypertension, gallstones, and hypercholesterolemia. Pulmonary consequences observed in children and adolescents include an increased frequency of reactive airways, poor exercise tolerance, increased work of breathing, and increased oxygen consumption. The few people who develop obesity-hypoventilation syndrome experience right-sided heart failure with right ventricular hypertrophy.
Race
Race and ethnicity are associated with increased rates of obesity in children and adolescents. Puerto Rican, Cuban American, and Native American preschoolers have an increased incidence of obesity. Black, Native American, Puerto Rican, Mexican, and native Hawaiian school-aged children have the highest rates of obesity in this age group. Approximately 25% of black adolescents have obesity. Rosen reported OSA/H to be more frequent in African American children than in Hispanic or white children.
Sex
During the second decade of life, females are more likely to be obese than males, except for African American teenagers in whom males are more likely to be obese than females. Although the male sex is associated with an increased incidence of OSA in adults, no differences have been identified in children before puberty.
Age
Adolescent obesity is predictive of adult obesity, with 80% of teenagers with obesity continuing to be obese as adults. Obesity is more likely to occur during specific periods of life, such as when children are aged 5-7 years and during adolescence. Tonsils and adenoids are at their peak size, relative to the size of the oropharynx, when children are aged 2-7 years.
History
Although pediatricians have long valued a good history and physical examination, studies have indicated that the predictive value of the recorded history and physical examination is only 30-50% compared to the overnight polysomnogram.
- Symptoms during sleep may include the following:
- Enuresis: This symptom alone has a predictive value for OSA of 46%.
- Snoring intensity higher than 30 dB: This symptom has a predictive value for OSA of 60%. Characteristically, snoring tends to be worse during flare-ups of nasal allergies and during upper respiratory infections. Approximately 10% of children who snore have significant sleeping and breathing problems.
- Restless sleep
- Parasomnias, especially nightmares and sleep walking
- Witnessed apneas
- Irregular breathing patterns in sleep
- Sweating at night
- Sleep with head extended
- During wakefulness, symptoms may include the following:
- Chronic mouth breathing
- Daytime sleepiness: This occurs much less frequently in children with OSA than in their adult counterparts, except in the case of children with obesity.
- Hyperactivity: Younger children are more likely to show symptoms of sleep deprivation than excessive daytime sleepiness (EDS).
- Morning headaches
- Cyanosis
- Cardiac rhythm disturbances
- Systemic and/or pulmonary hypertension
- Poor school performance, poor memory, and/or poor concentration
- Careful drug and alcohol history: Sleep apnea and daytime sleepiness can be aggravated by the use of alcohol, sedating antihistamines, CNS depressants, and some over-the-counter (OTC) cold preparations.
- Increased incidence of hyperreactive airways (ie, asthma) is observed in children with obesity (30%). Decreased exercise tolerance also is observed in children with obesity.
Physical
The physical examination begins in the waiting room. Evaluate sleepy children who cannot stay awake during the course of a physical examination or who consistently are found sleeping in the waiting room.
- Vital signs: With obesity, tidal volume can be decreased with a resultant increase in respiratory rate to maintain minute ventilation.
- Color: Cyanosis in this scenario is suggestive of cor pulmonale.
- Nutritional status and body habitus: The degree of obesity and fat distribution have an impact on the degree of respiratory symptoms during wakefulness and sleep. Although no strict definition of obesity is accepted universally, guidelines include body mass index (BMI) higher than 28 or weight higher than 120% of the predicted value for height.
- Head, ear, eye, nose, and throat (HEENT) examination: During a HEENT examination, pay specific attention to features of various cardiofacial dysmorphologies, especially those associated with macroglossia, retrognathia, micrognathia, or high-arched palate. Note large tonsils and adenoids, dental malocclusion, and oropharyngeal crowding secondary to a large uvula or low-hanging soft palate. Evidence of nasal obstruction can be sought by simple rhinoscopy. Large adenoids, nasal polyps, cysts, deviation of the nasal septum, and swollen nasal turbinates can limit nasal airflow.
- Neck: Search for evidence of compression secondary to chin folds, excessive fatty deposition, tumors, lymph nodes, or thyroid.
- Chest: Thoracic kyphosis has been associated with obesity. An acquired pectus excavatum, from increased muscle use in overcoming the extrathoracic obstruction with sleep, has been described in children with obstructive sleep apnea. Some of the syndromes (eg, Prader-Willi syndrome) associated with obesity-hypoventilation syndrome also have an increased incidence of scoliosis. Pay attention to the possibility of additional risk factors for restrictive ventilatory defects. Cor pulmonale may be suspected by a displaced cardiac impulse and a loud pulmonic second (heart) sound (P2). Measured tidal volume may be decreased.
- Abdomen: Abdominal obesity is associated with an upward displacement of the diaphragm, which is more pronounced in the supine position.
- Extremities: Ankle edema, in this context, is suggestive of congestive heart failure. Digital clubbing is associated with pulmonary osteoarthropathy.
Causes
- Drugs
- Environment
- Heredity
- Lifestyle
- Eating habits
- Genetic syndromes
Beckwith-Wiedemann Syndrome
Sleep Apnea
Other Problems to be Considered
Narcolepsy
Use/abuse of sedatives and antihistamines
Sleep deprivation
Obstructive sleep apnea
Sleep-related breathing disorders
Lab Studies
- Arterial blood gases: Obesity-hypoventilation syndrome may be associated with daytime hypoxemia and hypercarbia.
- Response to carbon dioxide is decreased in obstructive sleep apnea (OSA/S).
- Hematocrit may be elevated in children with chronic hypoxemia.
Imaging Studies
- Chest radiograph: Specifically note evidence of chest wall deformities, heart size, and evidence of congestive heart failure.
- Echocardiogram: Right ventricular hypertrophy can be observed with OSA/H in association with chronic hypoxemia.
Other Tests
- Pulmonary functions studies
- Flow volume loop: The sawtooth pattern associated with upper airway obstruction may be observed.
- Spirometry: Most children (58%) in Mallory's study had abnormal pulmonary function studies, primarily obstructive in nature. Fung's data showed significant changes in forced vital capacity (FVC) of overweight boys but not girls. This is consistent with the finding that fat distribution in overweight and obese adolescents differs from that of adults and is gender specific. Boys tend to accumulate fat in the abdominal area, while girls tend to accumulate fat in the subscapular area.
- Maximum voluntary ventilation may be decreased.
- Lung volumes: Patterns of fat distribution differ in overweight and obese adolescent males and females (as described above). Because of the impact of the abdominal fat on the diaphragm, the expiratory reserve volume (ERV) is decreased, and, as a result, the FVC also is decreased. Adult studies show the ERV to be decreased severely with both extreme and morbid obesity. Biring et al along found ERV to be the most sensitive indicator of obesity. Many reasons have been offered in addition to the mass effect on the position of the diaphragm. These include decreased diaphragmatic mobility, decreased respiratory compliance, decreased respiratory muscle strength, and fatty infiltration of the respiratory muscles.
- Diffusion: Results have been variable. Inselman reported children with decreased diffusing capacity of lung for carbon monoxide (DLCO). By contrast, Biring's group, aged 13-78 years, showed the DLCO and diffusing capacity of lung for carbon monoxide/alveolar volume (DLCO/VA) to be normal, except in those with extreme obesity.
- Airway resistance may be increased.
- Inspiratory and expiratory pressures were normal in Inselman's study.
- Overnight polysomnogram: In the case of children and adolescents, morbid obesity can be associated with hypoventilation, hypoxia, and hypercarbia during sleep. Others may present with evidence of obstructive sleep apnea.
- Multiple sleep latency test: The multiple sleep latency test (MSLT) can be useful in the evaluation of patients complaining of excessive daytime sleepiness. The MSLT is performed on the day following the overnight polysomnogram. Its findings can be used to assess pathological sleepiness and contribute to a diagnosis of narcolepsy.
- Electrocardiogram: Cardiac dysrhythmias and right bundle branch block (RBBB) have been reported.
Medical Care
- Dietary/nutritional intervention: Weight loss is recommended but often is difficult to achieve and sustain. In addition, while weight loss remains a cornerstone to the treatment of obesity, it may not always improve the symptoms of OSA/H.
- Pharmacologic care: Progesterone, theophylline, protriptyline, and buspirone have been used in limited studies.
- Perform nasal continuous positive airway pressure ventilation (NCPAP)
Surgical Care
- Tonsillectomy
- Adenoidectomy
- Adenotonsillectomy (may be successful even when weight loss alone does not produce satisfactory resolution of symptoms)
- Tracheostomy
- Uvulopalatopharyngoplasty (UPPP)
- Mandibular advancement surgery
Consultations
In pediatric patients, sleep medicine may be practiced within a variety of subspecialties, including pediatric pulmonology, pediatric otolaryngology, pediatric neurology, and child psychiatry. Also, a small number of board-certified sleep specialists are pediatricians.
- Pediatric pulmonology
- Pediatric cardiology
- Pediatric anesthesiology
- Pediatric otolaryngology
- Pediatric endocrinology
- Nutritionist
Diet
Tailor specific diets to meet the nutritional and growth requirements of the child and to facilitate weight loss.
Activity
A graded exercise plan is suggested.
- Consideration of the exercise tolerance of each individual child is important.
- Awareness of the increased incidence of asthma and lack of physical conditioning in these children is important when designing and implementing a graded exercise program.
The use of central respiratory stimulants appears in the literature intermittently. However, reports primarily are anecdotal or very limited. At the present time, noninvasive ventilatory support (eg, NCPAP) with supplemental oxygen, when necessary, is the treatment of choice along with weight loss.
Further Inpatient Care
- Obesity has been linked to metabolic syndrome, with a prevalence that increases with advancing degrees of obesity. This high prevalence warrants consideration in children who are obese, both inpatient and follow-up care.
- Cardiovascular risk factors, including evaluation of blood pressure, should be assessed.
In/Out Patient Meds
- Medications may be required for the treatment of comorbidities of obesity, which include hypertension, dyslipidemia, and metabolic syndrome. An increased incidence of asthma has been seen in obese children. Management guidelines for asthma are outlined in the United States Department of Health and Human Services National Asthma Education and Prevention Program Expert Panel Report and 2002 Update.
Deterrence/Prevention
- Childhood and adolescent obesity are both associated with an increased incidence of adult obesity.
- Good nutrition is a deterrent.
- Physical activity is a deterrent.
Complications
- In children with apnea, there is an increased risk of postoperative complications following relief of upper airway obstruction when the patient history includes young age (<2-3 y), morbid obesity, hypotonia, cor pulmonale, or severe OSA. In such patients, strongly consider cardiorespiratory monitoring in a pediatric recovery or special care unit. Postoperative pulmonary edema may be observed.
Prognosis
- Sustained weight loss is difficult. The cardiovascular consequences of obesity include dysrhythmias, right ventricular hypertrophy, and congestive heart failure. Children with obesity have an increased incidence of asthma, and exercise tolerance may be limited. Results of pulmonary function testing in children with obesity vary.
Patient Education
- Education about pediatric sleep disorders is limited in US medical schools. Attempts are underway to improve awareness of sleep disorders and their impact on the health of children with obesity.
- For excellent patient education resources, visit eMedicine's Sleep Disorders Center. Also, see eMedicine's patient education article Disorders That Disrupt Sleep (Parasomnias).
Medical/Legal Pitfalls
- Failure to diagnose
- Failure to diagnose comorbid conditions (eg, thyroid disease, diabetes)
- Failure to evaluate and diagnose potential complications (eg, cor pulmonale, systemic hypertension)
- Failure to treat appropriately
- Failure to anticipate risks (eg, increased risk of postoperative complications following an adenotonsillectomy for OSA in children with morbid obesity)
Special Concerns
- Rhodes data show decreased academic performance. Consider this diagnosis when evaluating a child who has obesity and a learning disability.
| Media file 1:
Histogram of an overnight polysomnogram of a patient with obesity and obstructive sleep apnea |
 |  View Full Size Image | |
Media type: Graph
|
- Biring MS, Lewis MI, Liu JT, Mohsenifar Z. Pulmonary physiologic changes of morbid obesity. Am J Med Sci. Nov 1999;318(5):293-7. [Medline].
- Coleman J. Disordered breathing during sleep in newborns, infants, and children. Symptoms, diagnosis, and treatment. Otolaryngol Clin North Am. Apr 1999;32(2):211-22. [Medline].
- Fung, KP, Harf, A, Perlemuter, L. Effects of weight on lung function. In: Archives of Diseases in Childhood. 1990:65, 512-515.
- Hudgel DW, Thanakitcharu S. Pharmacologic treatment of sleep-disordered breathing. Am J Respir Crit Care Med. Sep 1998;158(3):691-9. [Medline].
- Inselma LS, Milanese A, Deurloo A. Effect of obesity on pulmonary function in children. Pediatr Pulmonol. Aug 1993;16(2):130-7. [Medline].
- Mallory GB Jr, Fiser DH, Jackson R. Sleep-associated breathing disorders in morbidly obese children and adolescents. J Pediatr. Dec 1989;115(6):892-7. [Medline].
- Marcus CL, Curtis S, Koerner CB, et al. Evaluation of pulmonary function and polysomnography in obese children and adolescents. Pediatr Pulmonol. Mar 1996;21(3):176-83. [Medline].
- Marcus CL, Gozal D, Arens R, et al. Ventilatory responses during wakefulness in children with obstructive sleep apnea. Am J Respir Crit Care Med. Mar 1994;149(3 Pt 1):715-21. [Medline].
- Perkin RM, Downey R 3rd, Macquarrie J. Sleep-disordered breathing in infants and children. Respir Care Clin N Am. Sep 1999;5(3):395-426, viii. [Medline].
- Rhodes SK, Shimoda KC, Waid LR, et al. Neurocognitive deficits in morbidly obese children with obstructive sleep apnea. J Pediatr. Nov 1995;127(5):741-4. [Medline].
- Rosen CL. Clinical features of obstructive sleep apnea hypoventilation syndrome in otherwise healthy children. Pediatr Pulmonol. Jun 1999;27(6):403-9. [Medline].
- Schonfeld-Warden N, Warden CH. Pediatric obesity. An overview of etiology and treatment. Pediatr Clin North Am. Apr 1997;44(2):339-61. [Medline].
- Silvestri JM, Weese-Mayer DE, Bass MT, et al. Polysomnography in obese children with a history of sleep-associated breathing disorders. Pediatr Pulmonol. Aug 1993;16(2):124-9. [Medline].
- Strauss R. Childhood obesity. Curr Probl Pediatr. Jan 1999;29(1):1-29. [Medline].
- Tantisira KG, Litonjua AA, Weiss ST, et al. Association of body mass with pulmonary function in the Childhood Asthma Management Program (CAMP). Thorax. Dec 2003;58(12):1036-41. [Medline].
- Zwillich CW, Sutton FD, Pierson DJ, et al. Decreased hypoxic ventilatory drive in the obesity-hypoventilation syndrome. Am J Med. Sep 1975;59(3):343-8. [Medline].
Obesity-Hypoventilation Syndrome and Pulmonary Consequences of Obesity excerpt Article Last Updated: May 2, 2006
|
