|Vol.9 No. 1|
|Editors: Dr. Kwong Ling Karen|
|Dr. Kwan Yin Wah Elaine|
Dr. Daniel KK Ng, Dr. MY Cheung, Dr. KL Kwok and Dr. KW Chau
Department of Paediatrics, Kwong Wah Hospital
In this article, Dr. Ng and coauthors outline for us the clinical approach in the management of a common childhood problem - snoring. General advice on snoring and obstructive sleep apnoea syndrome is given. Polysomnography is useful in the investigation of sleep-disordered breathing. It would be helpful if paediatricians include questions about sleep in their history taking.
Snoring is the commonest symptom of obstructive sleep apnoea syndrome (OSAS), which is the extreme end of a spectrum of sleep-disordered breathing (SDB). The clinical spectrum of SDB includes: 1) primary snoring 2) upper airway resistance syndrome 3) obstructive hypoventilation 4) obstructive sleep apnoea.
The Local Scene
According to a recent community survey involving over 2000 parents on the presence of habitual snoring (i.e. snoring more than every other night), conducted by the department of Paediatrics, Kwong Wah Hospital, the frequency of habitual snoring was 10%. In another study involving the out-patient population of Kwong Wah Hospital, 10% of the habitual snorers were found to have OSAS. In contrast to overseas study, we observed that boys were more likely than girls to snore and to have OSAS. Children with allergic rhinitis were found to have a higher likelihood of snoring than children with other diseases.
In the systemic review, three important questions need to be asked: 1) Does the child snore regularly? 2) Have you ever seen the child struggle to breathe with no breath sound heard? 3) Is the child sleepy or hyperactive or inattentive in the daytime? From our own case series, habitual snoring and observed apnoea were found to be the most important predictive factors of OSAS. Presence of either or both symptoms has a positive predictive value of 63%. Absence of both symptoms has a negative predictive value of 100%. Physical signs of increased tonsil size and retrognathia are helpful but not diagnostic of OSAS. Sleep video recording during the period of difficult breathing is helpful if definite obstructive apnoea is witnessed.
Diagnosis of SDB rests on sleep polysomnography (PSG). PSG is a simultaneous recording of EEG, chin EMG, breathing efforts, ventilation, SpO2, ECG, snoring sound and limbs movement. PSG allows detection of apnoea, desaturation during sleep as well as associated responses like arousals in the EEG, tachycardia and limb movement. It is important to have a technologist that is comfortable with handling infants and children. Otherwise, the failure rate would be high with poor signals or no signals at all. PSG must be scored manually, and never automatically by computer programs because of its high inaccuracy. A satisfactory PSG should capture enough sleep duration of at least 5 hours and sleep efficiency of at least 85% (i.e. total sleep time / total time in bed).
The normal upper limit is one episode of obstructive sleep apnoea per hour. Mild OSAS denotes apnoea of less than or equal to 5 episodes per hour. In moderate OSAS, there is greater than 5 and less than or equal to 15 episodes per hour. In severe OSAS, there is greater than 15 episodes per hour.
Medical Treatment of SDB
General measures include avoidance of sleep deprivation (Table 1) and avoidance of sedatives, e.g chlorpheniramine. Allergic rhinitis is an important aggravating factor for SDB. Treatment of allergic rhinitis includes self-administered 2% NaCl nasal lavage and topical nasal steroids. The newer topical nasal steroids, e.g. mometasol, fluticasone, are preferred for their less systemic and growth suppression effects.
|Table 1. Average sleep requirement in children.|
|Sleep duration||11 hours||10 hours||9 hours||8 hours|
Surgical Treatment of OSAS
Tonsillectomy and adenoidectomy (T&A) is the surgical treatment of choice in childhood OSAS. In young children with syndromal disorders, the site of obstruction may not be the tonsil and adenoid. Sleep endoscopy is helpful in delineating the sites of obstruction in these children, which may be at the base of the tongue and at the uvula. A range of surgical options is available for these sites of obstruction, including radio-frequency ablation and laser ablation.
Obstruction in OSAS is dynamic and could be overcome by air pressure. Both continuous positive airway pressure (CPAP) and bi-level positive airway pressure (BiPAP) are effective. Determination of optimal pressure setting requires concomitant PSG monitoring by a trained PSG technologist. Automatic CPAP machine is not of proven value in children. The main problems of CPAP and BiPAP include inappropriate size of available mask, contact dermatitis, irritant conjunctivitis, deformity of nasal bridge and maxilla.
Follow-up of Children with SDB
Regular follow-up for children with primary snoring and OSAS is recommended, as the natural history of primary snoring is not well established. Some children may progress to OSAS with increase in size of tonsils and adenoids that peak at around 4 to 6 year of age. Some children develop recurrent OSAS after T&A as a result of re-growth of adenoids.
OSAS is a readily treatable disease that if unrecognized, could result in impaired learning, hypertension and growth failure. It is important that paediatricians should include standard questions about sleep in their history taking.
1. Ng DKK, Cheung JMY. Childhood snoring- what's the problem? HK Pract 2000;22:495-503.
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