Paediatric obstructive sleep apnoea - KKH shares on risk factors, symptoms, diagnosis and treatment for this condition.
Children with Obstructive Sleep Apnoea (OSA) experience partial or complete obstruction of the upper airway during sleep, resulting in oxygen desaturation, hypercapnia and arousals from sleep. It is estimated that up to 20% of normal children snore occasionally, with OSA occurring in 1% - 6% of the paediatric population.
Both boys and girls are equally affected, with the peak incidence of OSA occurring between the ages of 2 to 8 years old (coinciding with the age where lymphoid hyperplasia and adenotonsillar hypertrophy are common).
A second peak occurs in the older children and adolescents who are usually obese.
The risk factors for OSA in children differ greatly from that of adults. In children,
adenotonsillar hypertrophy is the most recognised risk factor of OSA.
Other common risk factors are obesity and allergic rhinitis.
Other risk factors include children with :
- Neuromuscular disorders (such as muscular dystrophies, cerebral palsy and so forth)
- Craniofacial abnormalities (such as micrognathia and midface hypoplasia)
- Trisomy 21 (Down Syndrome)
- Prader-Willi Syndrome
- A family history of sleep and breathing disorders
WHAT TO LOOK OUT FOR?
The symptoms of OSA may be difficult to elicit, and the guidelines from the American Academy of Paediatrics recommend that children and adolescents be screened for snoring during their routine medical visits.
Night-time symptoms include snoring, witnessed apnoeas, snorting or gasping during sleep, restless sleep, increased effort in breathing, excessive sweating and enuresis.
Daytime symptoms include daytime sleepiness, unrefreshed sleep, hyperactivity, attention-deficits, behavioural problems and academic deterioration.
Untreated OSA is associated with significant complications, including neurocognitive morbidities (such as behavioural issues, mood disturbances and attention-deficits) and cardiovascular morbidities (such as hypertension, endothelial dysfunction, cardiac failure), as well as diabetes, obesity, poor growth, and in very severe and rare cases, even death.
A DIAGNOSTIC APPROACH
A detailed history of snoring, especially habitual snoring (i.e. for 3 or more nights in a week), and other symptoms of OSA (as previously mentioned) should be sought. The physical examination should include an assessment of the child’s growth, the tonsillar size, features of atopy, and craniofacial structure.
However, clinical history and physical examination are not sufficiently reliable to differentiate between OSA and primary snoring (snoring without evidence of sleep disruption or gas exchange abnormalities). Whenever available, a Polysomnography (PSG) is the gold standard for the diagnosis of OSA.
In children, an attended PSG in the Sleep Laboratory is preferred. This would involve an overnight stay in a single-bedded room, with the continuous monitoring of the child’s oronasal airflow, the nasal pressure, the Electrocardiogram (ECG), the Electroencephalogram (EEG), the oxyhaemoglobin saturation, chest and abdominal respiratory efforts, as well as muscle tone.
The ‘hook-up’ of the monitoring leads is done by a certified sleep technician before the child goes to sleep, and most children are able to fall asleep after they get used to the setup. During the study, a caregiver is usually encouraged to stay overnight with the child.
When a PSG is not available, an alternative would be an overnight pulse oximetry. This can be done in the comfort of the child’s own home. However, this monitoring may miss episodes of obstruction of the airway that are associated only with EEG arousals, and is useful only when the OSA is associated with significant oxyhaemoglobin desaturation. In paediatric studies, the positive and negative predictive values of oximetry testing were estimated to be at 96.8% and 58.1% respectively. A positive study is useful in deciding on the subsequent management. However, a negative study does not rule out the diagnosis of OSA, especially in the presence of suggestive symptoms.
The treatment of paediatric OSA depends on the underlying cause, and involve surgical and medical measures.
In children with OSA due to adenotonsillar hypertrophy, the first-line treatment would be adenotonsillectomy. In a large randomised, controlled trial (The Childhood Adenotonsillectomy Trial, CHAT), where early adenotonsillectomy was compared to the watchful waiting of children with mild to moderate OSA, there was normalisation of the PSG findings in 79% (versus 46%) after 7 months. A reduction in symptoms, and an improvement in behaviour and the quality of life was also reported in the group that underwent surgery.
The risk factors for residual OSA (post-surgery), include the following:
- Severe OSA (pre-surgery)
- Significant weight gain after the surgery
- Trisomy 21
- Neuromuscular weakness
- Craniofacial abnormalities
In children who are obese, weight reduction measures such as healthy eating and regular exercise, are encouraged. They may be referred to paediatric specialists, for enrolment into weight management programmes, and to screen for co-morbidities, such as for diabetes, hypertension and hyperlipidaemia.
In contrast to the management of adult OSA, the use of nocturnal Continuous Positive Airway Pressure (CPAP) is less common. It is reserved for children who do not have the option of surgery, or if they continue to have significant residual OSA, following adenotonsillectomy.
Adherence to CPAP is a major limitation in the treatment of paediatric OSA. Often, a multidisciplinary team comprising of a paediatric sleep specialist, a sleep nurse, homecare or community nurses, and a child psychologist, is beneficial in ensuring regular usage of CPAP, as well as adequate education and training of the caregivers. Follow-up sleep studies (titration studies to check for an optimal CPAP pressure) are also recommended.
The concurrent control of allergic rhinitis, with the use of intranasal corticosteroids, antihistamines and/or leukotriene receptor antagonists, is important in children with atopy.
In a selected few, orthodontic treatment involving rapid maxillary expansion or a mandibular advancement device may be beneficial for their OSA.
In the past few decades, there has been increasing awareness of the importance of paediatric OSA. The significant morbidity, with its neurobehavioural, cardiovascular and endocrinological implications, emphasise the importance of early recognition and timely evaluation.
Adenotonsillectomy should be considered as first-line therapy for most children, and close post-operative follow-up is important to monitor for any residual disease, especially in those patients with accompanying risk factors.
Current research point towards greater understanding of the underlying complexities of the pathogenesis of OSA. Future advances include the use of biomarkers to aid in the diagnosis, as well as to individualise the therapies for improved care.
Primary care doctors play an important role in the screening of snoring and other symptoms during a child’s regular clinic visits, and in making the onward referral of a child suspected of having OSA to the sleep specialist for further investigation.
GPs can call for appointments through the GP Appointment Hotline at 6294 4050 for more information.
By: Adjunct Assistant Professor Petrina Wong, Consultant, Respiratory Medicine Service, Department of Paediatrics, KK Women’s and Children’s Hospital; Duke-NUS Medical School; SingHealth Duke-NUS Sleep Centre
Dr. Petrina Wong is a Consultant at the Respiratory Medicine Service, Department of Paediatrics at the KK Women’s and Children’s Hospital (KKH).
She did her paediatric sleep training in the Children’s Hospital of Philadelphia in 2013, and her main clinical interests are in behavioural sleep disorders and sleep-disordered breathing in neuromuscular disorders. She is an appointed Adjunct Assistant Professor at the Duke-NUS Medical School, and a Clinical Lecturer at the Yong Loo Lin School of Medicine and the Lee Kong Chian School of Medicine.
She is a diplomate of the European Respiratory Society and the Asian Paediatric Pulmonary Society in Paediatric Respiratory. Dr. Wong is also the current KKH Site Chief at the SingHealth Duke-NUS Sleep Centre.
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