Mr Daniel Tweedie - Consultant Paediatric ENT Surgeon, London

Snoring and obstructive sleep apnoea in children

Background

Around 12-15% of young children snore regularly. Most of these children have simple snoring: they may snore quite heavily, but their breathing is not obstructed enough to reduce oxygen levels in the body. A proportion of snorers, about 2% of all children, will have significant obstruction to their breathing when they sleep, causing brief periods where they are unable to breathe in, despite trying to. These are called apnoeas, literally “no breath”. Snoring and sleep apnoea are part of the same spectrum of breathing problems at night, also known as sleep disordered breathing.

What causes snoring and obstructive sleep apnoea in children?

All of us have a tendency towards snoring when we sleep. The throat can be thought of as a tube supported by muscles, and these hold the airway open like guy ropes when we are awake. But when we sleep, muscle tone drops significantly, and so the airway has a tendency to collapse when we breathe in air. If this collapse is partial, the soft tissues of the tongue and palate vibrate, causing air turbulence and a snoring sound. If the airway completely collapses during inspiration and is obstructed, then breathing stops briefly (an apnoea). This is called obstructive sleep apnoea (OSA).

Much less commonly, some children have periods where they stop breathing at night because the breathing centres in their brains do not work properly, and so the breathing muscles are not stimulated properly. This is called central sleep apnoea, and may be seen in children with certain neurological syndromes which affect the brain and nervous system.

Risk factors for childhood snoring and obstructive sleep apnoea (OSA) are:

• Large adenoids and/or tonsils.
• Obesity
• Cranio-facial differences (eg in Down’s Syndrome, achondroplasia)
• Ethnicity: Afro-Caribbean children are three times more commonly affected than their Caucasian counterparts
• Neuro-muscular problems, with low tone eg cerebral palsy
• Metabolic syndromes eg storage diseases

In the majority of otherwise healthy children, large adenoids and/or tonsils are the main culprits. Although the adenoids and tonsils tend to be prominent in many young children, only a limited proportion of children snore.  It is probably the case, therefore, that there are some other factors which make some otherwise healthy children snore while other similar children do not. Subtle differences in the geometry of the head, neck, tongue base and face may play a role, together with perhaps slightly reduced muscle tone at night in snorers compared to non-snorers. 

Either way, the evidence shows that removing the adenoids and/or tonsils will tend to benefit the great majority of children who snore and/or have obstructive sleep apnoea.

What problems does snoring and obstructive sleep apnoea cause?

When apnoeas occur, breathing has stopped, causing a rapid drop in oxygen levels (desaturation) and a rise in carbon dioxide in the blood. For much of the night, the brain is in a deep sleep. The brain responds to apnoeas by trying to wake up from a deep sleep to a lighter level of sleep, which is called a microarousal. Obstructive sleep apnoea leads to repeated microarousals during the night, affecting the quality of sleep significantly- bearing in mind that children tend to grow and develop their brains and nervous systems when they are asleep. In parallel with this, persistently reduced oxygen levels may put strain on the heart and lungs (in severe cases).

In adults, sleep apnoea tends to produce tiredness during the day, and a tendency to fall asleep. But in children, the consequences may be more variable, including:

• Tiredness during the day, with difficulty waking up in the morning
• Hyperactivity and/or poor behaviour
• Poor concentration
• Lack of energy
• Poor weight gain and growth
• Poor appetite
• Irritability
• Bed wetting

However, obstructive sleep apnoea may produce little in the way of daytime effects, and can therefore be easily overlooked by parents, teachers and doctors.

It was previously thought that simple snoring, without apnoeas or drops in oxygen levels, was not a serious problem for children. However, there is good evidence that even simple snorers may suffer consequences of disrupted sleep, including poor concentration and mild educational difficulties. Importantly, many of these problems are fully reversible with prompt treatment.

Diagnosis

Parents’ history

Parents are usually the first to notice a problem with their child’s sleep. Children are likely to snore, often heavily, and may be very restless, moving around the bed, stirring or even waking up, and may have other features, as above. Some children will get into unusual positions in bed, eg with their head stretched up, to allow them to breathe more easily. The situation will often be worse during coughs and colds. Those children with more severe snoring may show sucking in of the chest or the area under the ribs as a result of obstructed breathing. If the airway is fully obstructed, causing an apnoea, then the child will struggle to breathe in against the obstruction, with a pause of a few seconds before they are able to take air in. An excellent video from the British Lung Foundation is available by clicking here. 

But, it should also be noted that studies have shown that parents do not always spot obstructive sleep apnoea. In some cases, particularly milder ones, it can be very difficult to diagnose.

Doctor’s examination

Your GP or ENT specialist will assess your child’s general condition, including a full ear, nose and throat examination. The tonsils may or may not be enlarged, and there may be signs of a blocked nose which is full of mucus, but with no apparent inflammation of the nose lining. This suggests large adenoids at the back of the nose. Older children may allow examination of their noses with a small telescope (endoscope) which will confirm whether or not the adenoids are enlarged. The ears and hearing should be assessed, and other more subtle features should also be checked, including your child’s weight (which is compared against their predicted weight for age in the Red Book).

In reality, examination findings- in particular the size of the tonsils and adenoids- are not reliable ways of knowing whether children have obstructive sleep apnoea or not. For instance, some children with huge tonsils are not affected, and some with small tonsils are.

Oxygen level monitoring (simple sleep study)

Oxygen levels in the blood can be measured with a small probe with a red light, attached to the child’s finger or toe. This is called pulse oximetry. The probe stays on all night, and the child’s pulse and oxygen levels are recorded through the night by a small machine. Most hospitals and some community services will offer this, and it can usually be done at home.

The results are analysed with a computer, to show the maximum, minimum and average oxygen levels during the night, and how often the oxygen level dipped from the normal level (a desaturation). The average number of these desaturation events per hour gives us an estimate of the numbers of apnoeas occurring: the more often the desaturations occur, the more severe the disturbance of sleep.

Pulse oximetry is easy and quick, and is a useful screening tool. A “positive” test, with multiple desaturations usually confirms a problem. But on the other hand, it may miss some children with milder sleep apnoea, where smaller desaturations are not picked up. A “negative” result should therefore be looked at in the context of the parents’ history and the clinical findings.

For these reasons, some ENT specialists tend to refer only a limited number of heavy snorers for sleep studies. If the parents’ history is very convincing, then the diagnosis is pretty certain. But if there is a doubt about the diagnosis, or if the child has very severe symptoms and major complications, then a sleep study might be useful.

Polysomnography (complex sleep study)

This is a far more complex test, done over one or more nights in a specialist children’s sleep unit. As the name suggests, it involves monitoring a large number of different variables during sleep, including pulse, oxygen levels, air flow at the nose and mouth, the heart beat (ECG), blood pressure, position of the child and respiratory effort, sometimes with brain activity tracing (EEG) and video monitoring.

This is the gold standard test for sleep apnoea, and provides a great deal of information- particularly whether the apnoeas are obstructive, central or a mixture of the two. Such tests are very expensive and time consuming, as well as requiring a stay in hospital, and so are reserved for severely affected children, often with major medical problems.

Other investigations

Children with OSA and heart or lung problems should be reviewed by specialists in those areas as part of their initial review.

Treatment of snoring and sleep apnoea

Treatments for snoring and sleep apnoea are tailored to the individual child.

Children with mild, simple snoring often require no treatment, and doctors may simply keep an eye on them. A pulse oximetry home sleep study may be helpful in these circumstances to completely rule out drops in oxygen levels (desaturations). However, some children will still have quite disrupted sleep without obvious oxygen drops. In these cases, and particularly where parents are concerned, it may still be worth offering treatment.

Children with more severe symptoms and/or sleep study findings showing oxygen desaturations are likely to have obstructive sleep apnoea. In such cases, some form of treatment is usually necessary. Without treatment, these problems may persist for many years, often into adolescence, with the effects described above.

Medical treatment

In some cases, medication may occasionally be useful in the treatment of snoring and sleep apnoea. This is the case, for example, in children with nasal inflammation and allergies (rhinitis), who may benefit from anti-inflammatory nasal sprays. Similarly, infants with blocked noses may be helped by using saline drops in the nose to loosen secretions. However, in most cases medical treatment is unlikely to resolve significant snoring and sleep apnoea.

Surgery for adenoids and tonsils

In most cases of childhood snoring and sleep apnoea, large adenoids and/or tonsils are responsible for much of the problem. Removing one or both will usually make a dramatic difference to the breathing at night, while also reversing the other associated problems.

In infants and young children, particularly those with obviously blocked noses who breathe through their mouths, removing just the adenoids (adenoidectomy) may be enough to cure the problem. If the tonsils are large, and particularly in slightly older children, then removal of the adenoids and tonsils (adenotonsillectomy) may be necessary.

Deciding which of these procedures to perform is not always straightforward, and should be tailored to the needs of the individual child. Adenoid removal is generally a quicker operation, with quicker recovery, less pain and smaller risks of bleeding than tonsil removal (tonsillectomy). But removing just the adenoids may not always improve the breathing at night, and tonsil removal may be required, too. Adenoid and tonsil removal (adenotonsillectomy) may be done at the same time. Alternatively, in some cases it may be worth removing the adenoids first, then seeing if the child’s breathing improves or not before considering removing the tonsils at a later date. More information about these procedures is available in the tonsils and adenoids sections.     

Where should the surgery be carried out?

Children who have significant breathing problems, and particularly very young children and those with other medical problems, may be at risk of breathing difficulties for the first night or two after surgery. This results from some swelling at the back of the nose and/or throat after removing the adenoids and/or tonsils, and the fact that heavy snorers have often adapted over time to have a reduced stimulation for breathing when asleep: in simple terms, they are used to lower oxygen levels, and so do not always breathe well once their airways are opened up and they have more oxygen available. Their breathing systems may need a few days to adapt to these changes.

For these reasons, it is generally recommended that children who have significant sleep apnoea symptoms, those under 15kg or with other medical problems should be looked after in a specialist children’s hospital with a Paediatric Intensive Care Unit (PICU) on site in the unlikely event of difficulties after surgery.  

Other treatments

Although removing the adenoids and/or tonsils will help in the majority of cases, some children will continue to snore heavily despite these measures. Further treatments are considered according to individual circumstances, and may require the involvement of different teams of specialists.

Cases where severe symptoms persist after adenotonsillectomy are often referred to a paediatric lung specialist, preferably one with an interest in sleep problems. They will usually organise a complex sleep study (polysomnography, above). Some support for the breathing at night may be needed, usually delivered by a face mask secured over the nose and/or mouth and connected to a pump, allowing air to be delivered under pressure to keep the airways open. This is known as Continuous Positive Airway Pressure ventilation, or CPAP. Please click here to watch this. 

Further information

An excellent review of Paediatric Obstructive Sleep Apnoea by Mr Steven Powell (a paediatric ENT consultant in Newcastle) is available. Please click here to download the article.  

Another excellent ENT journal article all about snoring and sleep apnoea in children can be downloaded by clicking here.