Discussion
As with adults, there are all sorts of reasons why children do not sleep
well. Some of those reasons are more serious than others. In our study,
the sleep problem of the majority of the children (51.3%) was OSAS;
however, only 7.4% of the total pediatric patients in the study
underwent surgery for OSAS, even though some of the children with OSAS
underwent surgery without undergoing preoperative PSG.
The etiologies of pediatric OSAS are multiple, and can be classified
into intrinsic upper airway narrowing or increased upper airway
collapsibility 4. Adenotonsillar hypertrophy is
currently the most common cause of intrinsic upper airway narrowing,
with other anatomical features resulting in upper airway narrowing
including craniofacial syndrome, achondroplasia, Down syndrome, Beckwith
Wiedemann syndrome, and MPS. In our study, three patients had underlying
diseases with intrinsic upper airway narrowing: one had Prader-Willi
syndrome, one had Down syndrome, and one had MPS. Adenotonsillectomy was
suggested for these three patients, but their families refused this
surgical intervention.
A decrease in muscle tone in the upper airway can cause increased upper
airway collapsibility, with potential cause of such decreases including
cerebral palsy, neuromuscular disorders, or inflammatory conditions such
as allergic rhinitis and asthma. In our study, 2 OSAS patients had the
underlying disease of Duchenne muscular dystrophy, and 24.5% (37/159)
of the OSAS patients had allergic rhinitis or asthma.
Obesity appears to facilitate the emergency of OSAS; therefore, there is
a high prevalence of OSAS among obese children. However, there is a
higher proportion of children with OSAS who are obese. Thusm it appears
that both OSAS and obesity can coexist and potentiate the adverse
impacts of one another 5. The prevalence of OSAS is
increasing globally due to the growing occurrence of obesity in society.
In obese children, the fat deposits in the upper respiratory tract cause
breathing difficulties during sleep, thus causing OSAS6,7, with reports of the prevalence of OSAS in obese
children ranging from 13 to 59% 8. In our study,
3.1% (5/159) of the children with OSAS were also obese, and all of them
were male patients. One of these 3 patients had severe OSAS and
underwent an adenotonsillectomy, while it was recommended that the other
2 patients achieve body weight reductions through an increase in their
dialy intense physical activities. A recent cross-sectional, prospective
multicenter study, the NANOS study, assessed the contribution of obesity
and adenotonsillar hypertrophy to pediatric OSAS and found that 46.6%
of obese children in the community had OSAS 9.
Adenotonsillectomy is generally considered the first-line therapy in
children with moderate or severe OSAS. In our study, there were 65
children with moderate OSAS and 9 with severe OSAS, and it was suggested
that 26 of the moderate cases and all 9 of the severe cases undergo an
operation. Of those 37 patients, 62% (23/37) underwent the operation.
Some of the patients did not receive the operation because they their
family members wanted to further observe their symptoms for a period of
time. For these fourteen patients who did not undergo the operation,
repeated PSG studies were performed for 3 of them who come back for
follow-up visits, and their AHI results were found to be decreased in
those follow-ups.
PSG prior to adenotonsillectomy is indicated for children with some
conditions that increase the risk of perioperative respiratory
complications. These conditions include obesity (especially if severe),
Down syndrome, craniofacial abnormalities, neuromuscular disorders,
sickle cell disease, or MPS 10. The purpose of the PSG
in these high-risk children is to improve diagnostic accuracy and define
the severity of OSAS to optimize perioperative planning. In our study,
the OSAS children for whom the operation was suggested did have at least
one of the aforementioned conditions, but some, including 3 with
obesity, 2 with Duchenne muscular dystrophy, 1 with Down syndrome, 1
with MPS, and 1 with Prader-Willi syndrome did not undergo the
operation.
Several authors have recommended that a clinical reevaluation be given
to all children several months after adenotonsillectomy to determine
whether snoring and the symptoms of OSAS have been resolved, especially
in those children with higher risk of persistent disease, such as those
with severe obesity or craniofacial syndromes. Furthermore, a
postoperative PSG should be considered even in the absence of snoring or
other symptoms in order to determine whether additional treatment is
necessary for residual OSAS4.
However, no studies to date have evaluated the timing of postoperative
PSG evaluations, and this issue is not specifically addressed in the
practice guidelines regarding the management of pediatric OSA. In our
study, we did not collect postoperative PSG data, so further studies
should be designed for evaluating this issue.
Medical therapies such as anti-inflammatory agents or CPAP are used as
alternatives to adenotonsillectomy for children with OSAS, depending on
the severity and specific locations of airway obstruction in the
individual patient, and on associated comorbidities.
The second most common sleep problem among the children in our study was
primary snoring, and the management of pediatric primary snoring
consists of treating any upper airway obstructions or observation in
cases in which there is no upper airway obstruction.
The third most common sleep problem in our study was PLMD. Thirty-one
children (10%) had PLMD proven by PSG, and 7 of those 31 also had OSAS.
In the large clinical case series reported by Gingras JL et al., PLMD
was found to be common, affecting 14% of the 468 referred children11. It is relevant to note that there are no Food and
Drug Administration-approved treatments for PLMD in children. However,
most children with PLMD have low iron storage; therefore, iron therapy
should be considered as the first line of treatment in children with
PLMD whose iron levels are low. In our study, the iron level was checked
in 9 children, and only one child with PLMD had a low iron level and was
thus treated with iron therapy. Therefore, our management for PLMD
consisted non-pharmacologic treatments, such as education, massage,
exercise, or observation only.
The fourth most common sleep problem in our study was idiopathic
hypersomnia, which is extremely rare in children. Hypersomnia is present
in 4% to 6% of the general population, with only 1% of the population
having idiopathic hypersomnia and most of the people with that being
adolescents or adults 12. According to a report by
Han
F et al., 86% (361/417) of the children presenting with a complaint of
primary hypersomnia to a sleep clinic in China met the criteria for
narcolepsy with cataplexy 13, while only 20% (3/15)
of the children with excessive daytime sleepiness in our study had
narcolepsy.
The clinical characteristics and experiences of CSA are very limited in
children compared to the adult population, and it is thought to occur in
about 1-5% of healthy children 14. CSA has been noted
to occur more commonly in children with underlying diseases, and the
presence of CSA may influence the course of those diseases14. In our study, there were 8 children who had CSA; 6
of them had secondary CSA and 2 had idiopathic CSA. Idiopathic CSA is
really rare in children, and it cannot be reliably identified or
diagnosed on the basis of history or a specific set of signs and
symptoms 14. For the 2 children with a PSG-based
diagnosis of CSA in this study, we suggested a magnetic resonance
imaging (MRI) evaluation to assess for neuroanatomical abnormalities,
but neither of the children came back for a follow-up visit.
A study by Felix O et al. reported that 18 of the 441 (4.1%) patients
recorded during the study period had CSA, while 8 of the 310 (1.9%)
patients in our study had central apnea 15. In the
study by Felix O et al, the underlying disorders were dominated by
neurosurgical disorders; however, congenital heart diseases dominated in
our study.
Many parasomnias in children can be recognized by history alone, but
some require nocturnal PSG for appropriate diagnosis and management. In
our study, there were 7 patients who had enuresis, 5 who had bruxism,
and 1 who had sleep walking according to the PSG results, with these 13
patients accounting for 4.2% of all the patients who underwent PSG. We
believe however that there are still so many children with parasomnias
who do not go to pediatric OPDs for help.
There were several limitations in our study. The first was that our
study was only a 2-year retrospective study, and some children with
sleep problems, especially those suspected of having insomnias and
parasomnias, may go to psychiatric OPDs for help, not pediatric OPDs,
and thus may not undergo a PSG study. Second, long-term follow-up is
necessary for children with sleep problems in order to observe whether
their symptoms are relieved or their AHI results are decreased after
treatment, especially for those with OSAS after adenotonsillectomy.
Third, blood sample tests, such as tests of serum Fe or ferritin levels,
are not typically conducted for children with PLMD. Further studies
prospectively collecting PSG data from children with pediatric sleep
disorders will thus be required.