Recently my son has fallen quite ill, so I thought Id write up this advice since its not really something that is commonly known.
Obstructive Sleep Apnea can be potentially fatal if left untreated, so please take this seriously if your child has something similar.

So what is

Obstructive Sleep Apnea?
OSA is basically a term used when children or adults have trouble breathing whilst they're asleep.
There are many contributing factors to this illness, but the main causes are enlarged tonsils & adenoids, and a thick tongue.
When the airways are obstructed, the body can only hold oxygen for a few seconds, anything longer than that and severe impairment can follow.
Interestingly enough, it is one of the main causes towards attention and behavioural problems.

Symptoms:

• The first symptom often recognised is when a child  snores. You may argue that most children snore at some point. But this is a different type of snore. It is often more struggled, and alot louder.
• The tonsils and/or adenoids are more than often enlarged
• A child breathes through the mouth, and is often caught gasping for air, especially after a physical activity, such as playing ball or running.
• Problems sleeping at night, therefore making child sleepy during the day, and waking up very groggy in the morning due to lack of sleep at night.
• Due to lack of sleep, other problems can arise, eg poor attention span, bad behaviour, a symptom commonly mis-diagnosed as Attention Defecit Disorder.
• Being overweight is also another main cause of this illness.
  
• Children with Downs Syndrome are also at major risk of OSA.

So how is OSA diagnosed?
In the first instance you should take your child to your family GP. In some cases he may note the enlarged tonsils, but send your child home untreated to see whether the tonsils go down on their own accord.
If they continue to grow, a follow up visit is reccommended, in which case your GP will refer you to an Ear Nose and Throat specialist, where further investigations will follow, including a sleep study.
A sleep study is just an overnight stay in hospital, where your child will be hooked up to a bunch of non-invasive machines, which monitor brain, eye, and oxygen activity, amongst other things.
Following the sleep study, the specialist may or may not decide that a tonsilectomy and or adenoidectomy is then required.

What happens if I leave my child un-treated?
OSA is a very serious illness and if left for too long it can be fatal. Other side effects of the illness are such things as your child not developing properly, having learning difficulties, and ultimately brain damaged due to lack of oxygen reaching the brain.

If you, your child, or anyone else you know, has been having any of the above symptoms, I strongly urge you to seek medical advice. Their life could be at risk.

I have put alot of research into this topic, and the sources of information come from many different sources, too many to list. For copyright reasons I have translated this information into all of my own words and have not directly cut and pasted anything from another source.