Pediatric Obstructive Apnea Sleep Syndrome:
Not a Chip Off the Ol' Block!

James A. Daly III, M.D., FCCP Diplomate, American Board of Sleep Medicine, Medical Director, Southeast Sleep Disorder Centers, Candler Sleep Disorder Center, Savannah, GA
 

"At night the child's sleep is greatly disturbed; the respirations are loud and snorting, and there are sometimes prolonged pauses, followed by deep, noisy inspirations," astutely wrote Sir William Osler in 1892 and succinctly described obstructive sleep apnea in a pediatric patient. Charles Dickens also characterized the features of severe Pediatric Obstructive Sleep Apnea Syndrome (POSAS) in Joe: "…and on the box sat a fat and red-faced boy, in the state of somnolency." The year was 1836! Presently, it is ironic that the last great frontier of clinical Sleep Disorders medicine lies in the same area in which the field began - Pediatrics. Housewives, hairdressers, pedestrians, and some astute physicians easily recognize the symptoms of AOSAS. One "cannot swing a dead cat" without bumping into an article, advertisement, radio talk show, or public service announcement addressing the problem of loud snoring and OSAS in adults. POSAS, on the contrary, has received relatively little attention and is woefully under appreciated in medical practice. Why have we as a profession lost sight of our "roots"?

The science of Sleep Disorders Medicine has intensively studied the AOSAS while POSAS remains poorly characterized and lacks consensus. Important issues differentiating POSAS from AOSAS are all but unknown. In the case of POSAS, father is not like son! Dramatic differences in presentation and polysomnographic features differentiate pediatric OSAS as a separate disorder from adult OSAS _ it's not a "chip off the ol' block!" When the unknowing practitioner extrapolates adult OSAS features and polysomnographic criteria to children, the consequence is often confusion, misdiagnosis, and poor medical care.

The objective of this article is to familiarize the reader with Pediatric OSAS and encourage greater appreciation of this common sleep disorder. An overview of the various presentations of OSAS, risk factors, polysomnographic features, and approaches to treatment will be presented. Sleep apnea in the infant and SIDS will not be covered.

Prevalence

The prevalence of POSAS is estimated to be about 1-3%. However, small numbers and methodological flaws confound the few studies of POSAS prevalence. Also the disorder occurs equally in girls as in boys, which is in contrast to AOSAS where there is a strong male predilection. It is also important to appreciate that the vast majority of children with OSAS snore. However, not all children who snore have POSAS. Again from population studies, approximately 7% of children snore regularly. Since only about 2% of children suffer from POSAS, these statistics suggest that about 25-30% of children who regularly snore have OSAS. The challenge is how to identify these 25-30% of regular snorers who have POSAS. Regretfully, our capacity to clinically predict which child suffers from OSAS is poor.

Clinical Presentation

The presentation of POSAS differs with age. Younger children generally in the age range of 2 to 9 often demonstrate hyperactivity, impaired attention, and behavior problems as signs of POSAS. The child often becomes very combative before sleep. Loud snoring is common, but other abnormal respiratory noises are frequently present such as grunting and stridor. Pauses in snoring are common. Parents commonly report the use of accessory respiratory muscles and suprasternal/intercostal retractions. Patients may frequently sweat heavily and sleep in unusual positions such as prone with the neck extended. Frequent body movements are also typical, leading the parent to report the child as a restless sleeper. Enuresis is frequently present. Mouth breathing is so common in children that it is often not helpful in differentiating the child with nasal congestion from that with OSAS. In fact, recent studies have found the typical sleep histories accurately predict POSAS only about 50% of the time in children with polysomnographically proven OSAS.

Whereas older children (about 8-9 into teenage years) generally experience hypersomnolence symptoms including difficulty arising from bed, daytime naps, irritability, and impaired concentration and attention (often manifested as deteriorating academic performance). Hypersomnolence as typically expected in AOSAS may or may not be elicited during a history, which is related in part to the child's lack of insight into and appreciation of the effects of sleep deprivation and impaired sleep quality. Additionally, typical subjective assessments of excessive sleepiness used in adult sleep disorders medicine (e.g., an Epworth Sleepiness Scale) are obviously not applicable in POSAS. Loud snoring and respiratory sounds are present, generally with a typical staccato pattern. Nocturnal gasping, stridor, sweating, and mouth breathing are common. Occasionally, patients complain of morning headaches.

 

Predisposing Factors

Factors that predispose children to the development of POSAS are primarily associated with compromised patency of the upper airway. Obesity, which serves as a major risk factor for AOSAS, plays a lesser role in POSAS. Impaired neurological control of breathing or upper airway muscle tone is also important. Table 1 provides a quick overview of the more common or important predisposing factors.

Complications

A myriad of problems and clinical disorders can be related to POSAS. Table 2 summarizes the more common and important problems.


 

 Polysomnographic Features

Polysomnography (sleep study) is essential for the confirmation of the diagnosis of POSAS. As discussed above, our capacity to clinically predict which child has POSAS is no better than a coin toss. Therefore, sleep studies are essential tools for the assessment of the pediatric patient suspected as having POSAS. The sleep study serves to: (1) confirm the diagnosis, (2) aid in establishing the severity of the disorder, and (3) help in excluding other possible causes of poor sleep or sleepiness in children (i.e., narcolepsy).

The physician managing POSAS must appreciate that Adult sleep study scoring and diagnostic criteria for OSA do NOT apply to the pediatric sleep study. There are important polysomnographic features of POSAS that are considerably different than those of AOSAS, and, consequently, the scoring and diagnostic criteria must differ from AOSAS. In contrast to normal adults where up to 5 hypopneas and apneas per hour may be seen, normal children normally have rare if any obstructive hypopneas or apneas during sleep. Consequently, an Apnea-Hypopnea Index (or Respiratory Disturbance Index) of > 1 is considered abnormal in children. Also, children _ typically the younger ages _ may demonstrate sustained obstruction of breathing during sleep that does not conform to typical apnea or hypopnea criteria and is termed Obstructive Hypoventilation. Obstructive hypoventilation is characterized by:

  1. The finding of an elevated PetCO2 of > 55 mm Hg in conjunction with partial airway obstruction, or
  2. A PetCO2 of > 50 mm Hg for more than 10% of the total polysomnographic study time, or
  3. A PetCO2 of > 45 mm Hg for more than 60% of the total polysomnographic study time.

(Obviously, end-tidal CO2 monitoring is essential in performing pediatric polysomnography.) POSAS is confirmed by the finding of either an RDI > 1 or obstructive hypoventilation in conjunction with the appropriate history and associated clinical features.

In addition, the scoring of obstructive hypopneas and apneas also varies with many events being shorter than the typical 10 second minimum for respiratory event scoring in adults. This is particularly applicable to the scoring of sleep studies in younger children.

There are no satisfactory alternative procedures to polysomnography. Home video tapes, overnight pulse oximetry, and other techniques lack the sensitivity and/or specificity as diagnostic tools to supplant polysomnography as the diagnostic procedure of choice.

Treatment

The majority of children with POSAS suffer from adenotonsillar hypertrophy and surgical excision is generally the treatment of choice. However, several important caveats must be appreciated. Children with milder forms of OSAS may respond to topical and systemic anti-inflammatory and decongestant therapy that can alleviate the obstruction and obviate (or delay) the need for surgery. Children with severe OSAS secondary to adenotonsillar hypertrophy require surgery, however, it is becoming more evident that not all patients are effectively cured by surgery. A sizable number of children with severe POSAS (up to 15 to 20%) may still manifest significant POSAS post-operatively on repeat sleep studies performed weeks after surgery. Therefore, all children require at least clinical follow-up post operatively. Those with severe POSAS should likely have a follow-up sleep study post-operatively (at about 6 weeks) to demonstrate that surgery has been effective.

Tracheostomy is also a very effective treatment for patients with severe POSAS who have co-morbidities or anatomic abnormalities where routine therapy would be ineffective or not feasible. The uvulopalatopharyngoplasty (UPPP) procedure, commonly used in the surgical management of selected cases of AOSAS, has not been considered as appropriate for use in children. Maxillomandibular and facial reconstructive surgeries are appropriate for special craniofacial and upper airway abnormalities. These procedures require a multidisciplinary (ENT, oral surgery, orthodontics, etc) approach with several intermediary steps in order to achieve the desired results.

Nasal CPAP (continuous positive airway pressure) therapy has become the treatment of choice for most AOSAS but has been historically thought not to be very applicable to POSAS patients. Currently, there is growing experience with the successful use of CPAP in POSAS. Selected children have accommodated to the use of this device better than expected and tolerate it well as long term therapy. CPAP seems to be best suited for children with inoperable craniofacial and upper airway abnormalities such as Down's syndrome. BiPAP (dual level CPAP) has also been effective in children with severe OSAS pre-adenotonsillectomy as well as those with persistent OSAS post adenotonsillectomy. Children who have morbid obesity (growing problem in pediatrics as well as internal medicine, unfortunately) as the major factor leading to the development of POSAS may be treated effectively with CPAP while they are on a weight management program. When initiated with a close support program, BiPAP has been well accepted and tolerated.

Supplemental oxygen alone is not advisable for the treatment of POSAS. Oxygen may actually lead to more prolonged airflow obstruction via reduction in ventilatory drive and less of an arousal response to impaired breathing due to the absence of hypoxemia.

Oral appliances have been used in AOSAS, however, these have no defined role for application in POSAS. Likewise, there are no pharmacologic agents that are generally considered helpful in the treatment of POSAS. Weight loss is strongly advised for children who are overweight.

Conclusion

OSAS is common in children, but is under-recognized by practitioners. Although the field of Sleep Disorders Medicine had its infancy in pediatrics, there is a paucity of information and studies on the pathophysiology, adverse health consequences, diagnosis, and treatment of POSAS. There are also significant differences between POSAS and AOSAS so that POSAS needs to be viewed as its own syndrome and distinct from AOSAS. Thus, POSAS is not a "chip off the ol' block!"

Selected Readings

  1. Ferber, R. and Kryger, M. (eds): Principles and Practice of Sleep Medicine in the Child. Philadelphia, W.B. Saunders, 1995.
  2. Sheldon, S., Spire, J., and Levy, H. Pediatric Sleep Medicine. Philadelphia, W.B. Saunders, 1992.
  3. American Thoracic Society: Cardiorespiratory sleep studies in children: establishment of normative data and polysomnographic predictors of morbidity. Am J Respir Crit Care Med 1999, 160:1381 - 1387.
www.dcmsonline.org March, 2001/ Jacksonville Medicine

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