What is different about a child with a 22q11.2 deletion?

Children with a 22q11.2 deletion sometimes suffer from reflux to the extent that it can affect their ability to eat and grow normally. It is a complex subject with many causes and resulting difficulties.

Outlined below are some of the issues that contribute to reflux or cause the effects of reflux to be more severe:

Dysmotility

Poor muscle tone is often found with children with a 22q11.2 deletion which can result in poor movements (peristalsis) of the gullet which normally channel food into the stomach (by a wave action). Indeed it has sometimes been found that this action works in reverse, forcing food UP the oesophagus.

Aspiration

This is where food or liquids pass down the trachea or airway to the lungs.

It occasionally happens to most people and when "something goes down the wrong way" we cough, choke, feel very uncomfortable and often our eyes will water. This is called "over the top" aspiration and technically may not be related to reflux, but this illustrates the sensation felt when aspiration happens.

If it happens very frequently the normal choking response may become suppressed (silent aspirations) and so the aspiration goes unrecognised but the child will suffer repeated chest infections and pneumonias. They may be diagnosed with asthma, or have a persistent wheeze. It is also found that children can aspirate their saliva if they have really impaired swallowing even when they are asleep (micro-aspirations).

Persistent and severe aspirations can cause permanent lung damage and chronic lung disease. In a small number of very severe cases this can be a life-threatening condition.
All instances of aspiration are not equal. The effect of aspiration on the lungs and on health depends upon many features, including:

• Acid: When a child aspirates refluxed food that has been mixed with stomach acid (i.e., aspirated coming up) it is more likely to cause an aspiration pneumonia or damage the lungs than food or formula that is more alkaline (i.e., aspirated going down).

• Fat: Food or liquid containing fat molecules (i.e. milk, yoghurt, meat broth) is more dangerous to the lungs, and may trigger pneumonia faster, than food or liquid that has is composed primarily of water (i.e. fruits, vegetables, grains). This is because the lungs are used to handling water in the air we breathe and can release it more easily than a fat which is foreign to the lungs.

What are the investigations to see whether reflux is occurring?

Barium meal

This is an x-ray investigation which mainly examines the anatomy (structure) and physiology (function and process) of the oesophagus, stomach and duodenum (the first part of the small intestine). The child drinks barium liquid and its process is monitored throughout the entire gastro-intestinal tract. Sometimes reflux can be observed during this procedure but it can also be easily missed if reflux occurs more than 10 minutes after eating and drinking.

Put more simply a glass of liquid that contains a chemical that shows up on x-ray (this is called "radio-opaque") is given to the child to drink (often unwillingly!). X-rays are taken to see how the liquid is collected in the mouth and then moved down the throat, in to the stomach and beyond. It may show if the child is not managing to control the liquid and if the liquid is moving in the wrong direction, but it does not give a detailed picture.

Very rarely, an irradiated barium meal is used in a procedure called 'scintiscanning', which can look for occult aspiration.

24 hour pH study

This is the gold standard test to see if reflux is occurring and how severe it is.

A very small probe sits inside the child's oesophagus and they carry a recorder pack for a full day. The probe monitors the amount of acid in the oesophagus over the 24 hour period. Most people will have some acid for a small percentage of time (say 5-10%).

Camera investigations

A nasendoscopy involves a camera being passed down the nose to examine the palatal function during speech. Endoscopic investigations can show, in full colour and fine detail, the structure of the whole of the throat and oesophagus to look for damage to the lining of the oesophagus along with any malformations. This is a FEEST examination but is only rarely performed.

What can be done to help?

Posture

When feeding a small child or older baby, sit them squarely on their bum, this will encourage a straight back, and this in turn assists gravity to do its work!

A speech and language therapist may be able to supply a reflux chair. Improved posture can help to ease congestion of feeds at the back of the throat.

Very small babies could benefit from being placed on a foam wedge. They are put on their front at an angle of about 45 degrees, this encourages the refluxed feeds to pass out of the mouth rather than back down the airway (i.e. aspirate).

Change nappies before a feed rather than afterwards when the baby's tummy is full.

Speech and language therapy

A speech and language therapist can help with specific advice about encouraging good oral movements that will eventually enable some children to take food on the tongue, chew it properly, then collect the food into a bolus, control the movement of the bolus down the throat and in to the stomach without gagging. Some hospitals run feeding clinics.

It is vital that oral stimulation is continued all the time, even if the child is not physically able to feed orally, as very young babies can miss out on the phase of development that tells them to suck and eat. Also a very few children can develop a fear of eating. An "oral aversion" is difficult to overcome and may require the help of a specialist feeding psychologist.

Medicines

Very small babies that are totally failing to thrive can benefit from Total Parenteral Nutrition (TPN) for a few weeks so that they can get bigger and stronger to help them cope with food in their stomach. TPN is an intravenous feed that carries other risks. It is harsh on the liver and because an arterial line is needed there is a significant risk of serious infection

H2 blockers:

Such as cimetidine (Tagamet ®) and ranitidine (Zantac ®) reduce the acid secretion of the stomach and helps to prevent the discomfort of small amounts of reflux and lowers the frequency of refluxing. Omeprazole (Losec ®) is a relatively new drug and is fast becoming the most favoured reflux treatment. It is a more powerful acid lowering drug and remedies oesophagitis rapidly and in many cases eliminates reflux. There are some queries over it's long term use as this has not yet been proven. It can also cause acid rebound when it's use is stopped, so children need to be weaned off it. Gaviscon contains antacids and tends to float on top of the feed, thickening it.

Motility drugs:

Such as domperidone (Motilium ®), strengthen the anti-reflux mechanisms and speed up the emptying of the stomach (this can also help with the constipation so often reported).

Cisapride (Prepulsid ®) has been withdrawn from the market as it been suggested that it may cause heart arryhthmia in certain patients and sometimes abnormal movements or a rash, but it can still be prescribed on an individual basis.

Enteral feeding

Thickened feeds via a naso-gastric (NG) tube or gastronomy tube can help as it is more difficult to reflux thickened feeds. Carobel, Nestargel are add just before a feed and thicken it instantly. Thixo-D, Thick and Easy can be added just before a feed or mixed in advance when feeds are prepared and stored. Gaviscon is mentioned above.

Feeding your baby with slightly smaller volumes of milk given at more frequent intervals may also be helpful. It is also possible to put feed into the stomach continuously through the night (and day) which means that there are only small amounts of food in the stomach and this lower volume can reduce the reflux.

Fundoplication

In cases where other treatment methods have failed to prevent reflux, or where the condition is thought to be extremely severe then a fundoplication may be carried out. It is a very effective treatment as it normally prevents any vomiting. This is an operation where the top of the stomach is folded over and wrapped around the bottom of the oesophagus where it joins the stomach to tighten the sphincter.

There are drawbacks to the operation: The fold uses up to 30% of the stomach and so only smaller amounts can be held in the stomach. Sometimes it can be too tight and this interferes with swallowing, sometimes it can be too loose and come undone, and so the problem continues. It is very difficult for children to vomit but they may retch more following the operation.

What does the future hold?

All of the interventions mentioned above should be viewed as measures to be used until the child is hopefully able to cope with normal oral feeds.

Oral stimulation should continue at all times and once the reflux is under control then the child should be encouraged to taste, suck, and chew with a view to progressing slowly to an increased confidence with foods.

The good news is that with perseverance almost all children with a 22q11.2 deletion can look forward to eating normally.