Snoring & obstructive sleep apnoea in children
What are snoring and obstructive sleep apnoea?
Both snoring and obstructive sleep apnoea (OSA) (Americans spell apnoea as apnea) sit on either end of the same spectrum of a condition known as disordered sleep breathing. Both are caused by an obstruction of the upper airways during sleep. The level of obstruction determines whether a child will snore only (called a simple snorer) or have periods where he or she is struggling to breathe (known as apnoeas). Both snoring and apnoeas can occur at the same time.
Around 12-15% of young children snore regularly. Most of these children be simple snorers, that is they snore without experiencing periods of apnoea. Some snorers will also have periods of apnoea as well. A small proportion of children will experience apnoeic episodes only without any snoring at all. This is the most severe form of disordered sleep breathing.
Click here to look at a YouTube video showing a child experiencing apnoeic episodes during sleep.
What causes snoring and obstructive sleep apnoea in children?
Both are caused by an obstruction of the upper airways during sleep and the mechanism by which this obstruction happens is similar in children and adults.
The upper airways can be thought of as a muscular breathing tube. The muscles of this tube have good tone when the child is awake and hence keep the tube rigid and open and prevent structures like the tongue and soft palate from collapsing inwards and closing it off. When the child is asleep, the muscles of the tube, like all other muscles in the body, relax significantly, making the tube floppy and allowing the tongue and soft palate to collapse inwards, especially when the child breathes in. This is the case in all children.
Snoring occurs when the tube becomes so floppy and collapsible that the airway is partially obstructed. The collapsed tongue and soft palate then tend to vibrate when the child breathes in, causing a sound. This sound is called snoring. If the tube gets so floppy that is blocks the airway off completely, then no air can get in and the child has an apnoeic episode. The lack of oxygen during this episode is picked up by the breathing centre in the brain, which signals the child to wake up and start breathing again. The child then wakes up, but only enough to be able to take a gasp of breath, before falling fully to sleep again and experiencing another apnoeic episode. In this way the child has a fractured night’s sleep.
Some factors can increase the floppiness and collapsibility of the breathing tube during sleep, or act as additional obstructing structures to the tongue and soft palate. These include:
Large tonsils and/or adenoids – this is the most common cause of snoring and obstructive sleep apnoea in children and acts to further obstruct the airway during sleep in addition to the tongue and soft palate. Symptoms tend to be worse during a cold.
Childhood obesity – obese children have more fat deposited around the breathing tube, making it more likely to collapse during sleep.
Down syndrome – children with Down syndrome tend to have less overall muscle tone (called hypotonia), which makes their breathing tube more floppy and hence more likely to collapse during sleep. Their tongue is also larger in relation to the size of their mouth and hence tend to collapse inward more when breathing in during sleep.
Cerebral palsy – children with cerebral palsy also tend to have a reduced tone of their muscles due to a disorder of the neurological system. This makes the breathing tube floppy and more collapsible during sleep as well.
Nasal problems – some children snore because of nasal blockage, which can be as a result of rhinitis or hayfever. Such problems do not usually cause apnoeas on their own but can aggravate a co-existing problem such as enlarged adenoids.
Will all children with enlarged tonsils and adenoids snore or have apnoeas?
No. Many children with enlarged tonsils and adenoids sleep with no problems at all. Why some of these children will snore or have OSA and others not may be due to other factors such as variations in the overall dimensions of their upper airways or size of structures such as the tongue, soft palate or mouth.
What problems do snoring and sleep apnoea cause?
In simple snorers who snore only very mildly, there may be no problems. As children move up the disordered sleep breathing spectrum and become heavier snorers and/or develop apnoeas, problems can start to occur. Many of the problems have to do with the fact that they are not sleeping fully throughout the night (fractured sleep). These include a lack of energy during the day, difficulty concentrating at school or on tasks, irritability, hyperactivity or poor behaviour and a poor appetite. Some children also start bed wetting.
How is the diagnosis made?
In most cases, the diagnosis is made based on the description given by the parents who often express concerns about apnoeic episodes that they have witnessed. Many parents will bring videos taken on their phones of their child snoring or having apnoeas. These are extremely useful in making a diagnosis and are encouraged. Examination of the child’s ENT systems can also suggest the cause of the problem, such as enlarged tonsils that can be seen by examining the mouth, or enlarged adenoids that can cause nasal blockage, mouth breathing or a constantly runny nose.
Not all cases are immediately obvious, however. In those cases where there is more doubt about the diagnosis, a sleep study can be performed. The most common and easiest one performed is pulse oximetry, during which an oxygen probe is placed on the child’s finger during sleep and oxygen levels are recorded throughout the night. Significant and frequent dips in the oxygen levels can indicate apnoeas. This can be done as an overnight stay at the hospital or at home. Pulse oximetry is best interpreted together with the parents’ history and even if the pulse oximetry results are negative, a decision to treat may still be made based on the symptoms described or video evidence alone.
Children with severe apnoea may need a more complex sleep study called a polysomnograph, which measures other body functions such as heart rate and breathing rate as well. This is usually done during an overnight stay and carried out in a specialist paediatric centre.
How is it treated?
In the simplest cases of snoring, especially where there is a history of rhinitis or hayfever causing nasal blockage, the use of a steroid nasal spray (such as Fixonase or Nasonex) may be enough.
In most cases, an enlargement of the adenoids and/or tonsils are the problem and the child will then do very well with an adenoidectomy, tonsillectomy or both (adenotonsillectomy). Mr Trinidade can discuss with you further about which option is best for your child. Children with severe obstructive sleep apnoea, who have complex medical problems and who are very young (usually under 15 kg in weight) are at an increased risk of post-operative complications and therefore procedures are best performed in a centre with a Paediatric Intensive Care Unit (PICU), where there is further specialist support if this becomes necessary.
In cases where adenotonsillectomy does not help, or where the child has other issues contributing to obstructive sleep apnoea (such as Down syndrome, cerebral palsy or extreme obesity), a referral to a paediatric respiratory (lung) physician may be required to discuss the need for continuous positive airway pressure (CPAP), where a mask must be worn on the face at night. This mask channels air down the breathing tube which serves to tent the collapsed tube open and prevent obstruction of the airways.
Read more about tonsils and tonsillectomy here.
Read more about adenoids and adenoidectomy here.