Obstructive sleep apnoea syndrome in children

Synonym: obstructive sleep apnoea, OSA

What is obstructive sleep apnoea?¹

Obstructive sleep apnoea/hypopnoea syndrome' (OSAHS) is a sleep-related breathing disorder characterised by recurrent episodes of complete or partial obstruction of the upper airway during sleep, causing apnoea (complete airflow obstruction with temporary absence or cessation of breathing) or hypopnoea (decreased airflow).

OSAS in children is a similar condition to obstructive sleep apnoea syndrome in adults.

How common is obstructive sleep apnoea? (Epidemiology)¹

• There is a peak incidence of about 2% in children between 2–8 years of age due to adenotonsillar hypertrophy.²

• Tonsillar and adenoid hypertrophy, male gender, obesity and habitual snoring are considered important factors in the development of OSAS.³

• Congenital abnormalities associated with narrow pharyngeal airways (eg, Down's syndrome or achondroplasia) have an increased risk of OSAS.

Causes of obstructive sleep apnoea (aetiology)¹

• Adenotonsillar hypertrophy. However, many children with adenotonsillar hypertrophy do not have OSAS.

• Obesity - the likelihood of an obese child developing OSAS is four to five times greater than in a non-obese child.⁴

• Neck-to-waist ratio, an index of body fat distribution, predicts OSAS in older children and youth, especially in those who are overweight or obese.⁵

• Neuromuscular diseases - eg, presence of craniofacial abnormalities.

• A small maxilla and/or mandible may predispose children to OSAS.⁶

Presentation of obstructive sleep apnoea¹

Suspect a diagnosis of OSAS in a child with:

• Witnessed snoring and breathing pauses while sleeping (apnoeas), which may be followed by a gasp or snort.

• Restlessness and sudden arousals from sleep, laboured breathing, unusual sleep posture (eg, neck hyperextended).

• Nocturnal enuresis (decreased appropriate arousals during sleep).

• Daytime symptoms, eg, tiredness, sleepiness, behavioural problems, irritability, hyperactivity, reduced concentration, reduced school performance, mouth breathing.

Assessment of obstructive sleep apnoea

History

• Include symptoms as above so that you have a full sleep history. Parent/carer observation of the child's sleep pattern is useful for the initial history but may be too unreliable to make the diagnosis.

• The question of whether a child stops breathing is a poor discriminator of apnoea and is better phrased by asking whether a child sounds 'strangled' during sleep, or whether a period is noted where the child's breathing goes quiet and is then overcome by a gasp.⁷

• Enuresis may occur in these patients.⁸

• In primary care the following should alert you to taking an OSAS history:
  

  • Symptoms of recurrent blocked nose.

  • Recurrent nasal or throat infections.

  • Recurrent ear infections.

  • Any risk factors as above.

  • Any children whose parents are concerned about snoring.

Whom to refer¹

• Arrange referral to a paediatric ears, nose, and throat (ENT) specialist if a child has clinical features of nasopharyngeal obstruction such as adenotonsillar hypertrophy and regular snoring at night.

• Arrange referral to a paediatrician if a child has a congenital or developmental disorder that may be contributing to symptoms, or an associated condition (eg, behavioural problems, irritability, reduced concentration, reduced school performance, or faltering growth) and/or obesity.

Investigations

• The majority of cases are diagnosed on clinical grounds.

• In children, apnoeic episodes may only need to be a few seconds long before desaturation occurs.

• The overnight in-laboratory polysomnography (PSG) continues to be the gold standard instrument for the investigation of sleep-disordered breathing in children.⁹

Polysomnography (PSG)

• • During sleep studies the following are usually monitored:
    

    • Oxygen saturations and heart rate.

    • Airflow at nose or mouth.

    • Chest and abdominal movements.

    • ECG, electroencephalogram, electromyogram and sometimes electro-oculogram (eye movements).

  • On average, more than one apnoeic or hypopnoeic episode with oxygen saturations <92% is abnormal.

  • However, PSG may be normal despite sleep disturbance. This is particularly so when there is upper airways obstruction rather than the full-blown OSAS. If this is causing reduced academic performance or behavioural problems, it is just as important as a diagnosis of OSAS.

Other investigations that may be needed

• Airway assessment - to determine the cause of OSAS - eg, video photography (invasive).

• Several radiological techniques (eg, lateral neck radiography, CT and MRI) may be used to investigate the role of any possible structural alterations.¹⁰

• NB: pulse oximetry alone is inadequate for the diagnosis of OSAS.⁷

Management of obstructive sleep apnoea¹¹

Children who have intermittent snoring only, with no history of apnoeas, no underlying medical conditions and no daytime features, can be managed conservatively. The goal of treatment is to restore optimal breathing during the night and to relieve associated symptoms.

Medical

• Continuous positive airway pressure (CPAP) can effectively treat OSAS in selected groups of children, improving both nocturnal and daytime symptoms. However, poor adherence is often a limiting factor.

• Weight loss is very important in obese children.

• There is no role for antibiotics (unless tonsillitis is present) or for steroids.

Surgical

• For uncomplicated cases in children, surgical intervention with removal of the tonsils and adenoids can lead to significant improvements.

• Uvulopalatopharyngoplasty - thick soft palate and long uvula. (May also be combined with adenotonsillectomy if there is severe OSAS.)

• Tracheostomy - very rarely indicated and only as an exceptional last resort.

Other treatments

• Orthodontic treatments, such as orthopaedic mandibular advancement or rapid maxillary expansion, have been shown to be effective treatments.⁶

• Starting an orthodontic treatment as early as symptoms appear is important in order to increase the efficacy of treatment.¹²

• Some children actually improve with time, so watchful waiting rather than adenotonsillectomy may be appropriate for some children.¹³

Complications of obstructive sleep apnoea

• If left untreated, OSAS is associated with adverse effects on growth and development, including deleterious cognitive and behavioural outcomes.⁷

• Evidence exists also that untreated OSAS impacts on cardiovascular risk.

• Daytime hyperactivity.

• Cognitive deficits.

• Failure to thrive.

• Some studies have shown that children with OSAS have greater impulsivity when crossing streets which increases their risk of injury.¹⁴

• School-aged children are at risk of developing future obesity if they have OSAS.⁴

Prognosis

• Treatment is associated with improved learning and behaviour and quality of life.

• Adenotonsillectomy improves short-term and long-term quality of life in children with OSAS.¹⁵