A BONUS CHAPTER
The question, “how early can you diagnose celiac disease?” is a major concern for both parents and pediatricians. This is because like many diseases, celiac disease comes on slowly.
Celiac disease can develop slowly
Yes, celiac disease can develop slowly and subtly. It is a progressive disease. When you are first born, you cannot have celiac disease as you have never been exposed to gluten. However, if you have the right genetic make up (see: HLA celiac gene) with the right environmental circumstances, then celiac disease can develop. It can make its presence known at any age, during any decade.
Celiac disease is a condition defined as damage to the small bowel tissue. This damage is triggered by gluten. The technique to identify this gut damage is currently by people (histologists) looking down a microscope at tissue samples. The tissue that they are looking at has been obtained by the technique of upper endoscopy (a small bowel biopsy: see link to Is there a gold standard? ), where fragments of the small bowel skin (the mucosa) are taken whilst under anaesthetic.
Early antibody changes IgG-gliadin
Long before the tissue becomes obviously damaged by gluten, the body begins to react to the gluten that you eat in your diet.
The first sign of any gluten immune reaction is that your body produces antibodies to the gluten in your diet. The most common antibody is the IgG-gliadin antibody (also called anti-gliadin-antibody). Also, IgA-gliadin antibody can develop at this time (this antibody is made in the gut and takes a longer time to leak into the blood).
But, even in these early stages of gluten reactions (before the development of gut damage of celiac disease), the child can be unwell (see The Big List of symptoms). Many of the symptoms of celiac disease can be recognized at this time. I stress that this can be years before the tissue damage can be seen by the histologist.
Early bowel damage cannot be seen
The next thing to happen in this progression of illness is that the tissue in the small bowel gets functionally injured, but not enough disturbance to be identified by the histologist. However, such minor damage can be shown by an electron microscope. Also, the enzymes levels in the bowel tissue (the disaccharidase enzymes) become low. This very early damage can also be detected by the presence of the tTG antibody which is an antibody against tissue transglutaminase (see: the blood test section).
Usually, when the tTG/DGP blood tests goes up, then this is an indication to do the endoscopy and look for any tissue damage. However, early on the progression of celiac disease, this damage may not show up by conventional methods. Unfortunately, the small bowel biopsy and the histology are not perfect tests (see link to: Celiac disease biopsy – is there a Gold Standard ).
The new DGP tests (Deamidated Gliadin Peptide)
The Deamidated Gliadin Peptide (DGP) antibodies are a more recent test for celiac disease. This test detects antibodies to tiny fragments of gliadin (a gliadin peptide). These antibodies can only start to be produced by your immune system when there is established small bowel gut damage. Studies show that this test has a better correlation with gut damage than with the tTG test. Consequently, high DGP tests indicate that you are already in a late stage of gluten harm.
I reiterate, that these tissue damage tests of tTG and DGP are not testing for gluten-sensitivity. Thus, a negative tissue test does not rule out a gluten problem (See link to Gliadin antibody confusion: same name – different test!).
To act or to wait
My experience has been to see many children develop celiac disease whilst I have watched and waited. I have organized repeated blood tests and then several endoscopes. Sadly, all of this time these poor children have been unwell. However, I do not think that this is a good way to manage these children. This approach is to make the official diagnosis rather than care for the child. Some medical specialists remain adamant not make a diagnosis of celiac disease until the histologist can confirm the typical tissue damage.
However, I no longer take this approach. I carefully scrutinize the symptoms and the blood test results (both the gluten and tissue damage antibody levels). If these findings are leading towards the development of celiac disease, then I make a pre-emptive diagnosis of celiac disease, often before the gut gets badly damaged. I give these children (and adults) a trial of a gluten-free diet I see what the clinical response is. Most get completely better!
How long can you wait
The problem is that the diagnosis of celiac disease has been inextricably linked to the abnormal appearance of the small bowel. This has come about from the history of celiac disease. The demand for abnormal histology came from the days when there were no blood tests and no other ways to help make the diagnosis. Fortunately, times have changed and we now have wonderful blood tests to help make the diagnosis about gluten disease (see link to: History of celiac disease).
Helen s story
Helen is now 8 years old. Unfortunately she has a long story of illness.
At 10 months she became constipated and had anal fissures. She had a lot pain and distress. Oddly, later she began to get diarrhoea. She was moody and irritable and by the time she was two she began to say sore tummy and have tummy pains. At this stage it was clear that she was not growing very well and by four she was relatively short, had a pot tummy, and eczema.
So, at four years old it was suspected she could have celiac disease and she was given a blood test (see the table). This showed a high IgG gliadin of 64 units. However her tTG was normal at 7 units. Because of her symptoms an endoscopy was done and her small bowel biopsy was normal. She was therefore kept on gluten.
Helen’s test results ans symptoms over 8 years
At five years of age Helen was still not right and her blood tests were repeated. This again showed a high IgG gliadin of 81 units but still a relatively normal tTG of 12 units.
Yet a year later at 6 years old a third blood test now showed a high tTG reading of 43 and an even higher IgG gliadin of 90 units. This triggered another endoscopy. However the small bowel biopsy was surprisingly reported as normal.
A fourth blood test was done to check her HLA status which showed HLA DQ2 or DQ8 were detected. This meant that she did have the genetic predilection for celiac disease.
At this stage the family came to see me and ask for my interpretation of her results. She was reacting to gluten, and she now has tissue damage as shown by the high tTG. I know, from my experiences with looking after these children, that if she were to be left on gluten she would remain sick and eventually her endoscopy would become abnormal. So why wait any longer Helen went gluten-free and immediately was improved. Her parents said she is a different child . They said her bowels were good, her appetite humongous and Helen was at last happy!
Conclusion my approach
As you can see, it is difficult to say how early you can diagnose celiac disease. It is my practice to carefully assess children regarding their symptoms, their antibody levels and endoscopy results (if appropriate).
I do not think it is logical to leave children with significant symptoms waiting for the small bowel damage to eventually occur. Indeed, I think that these long delays in treatment are inhumane. Postponement of a gluten-free diet will result in these children suffering their ongoing symptoms. Worse, they can have growth failure, from which they may not recover.
My approach is to put these children on a gluten-free diet early. I watch and see if they have a clinical response: do they get better The evidence shows that you cannot rely entirely on the small bowel biopsy for your diagnosis of celiac disease.
The onset of celiac disease is progressive. Why wait till the bitter end
When to treat heart disease
If you had high blood pressure or high cholesterol, would you doctor wait until you had a heart attack before treating you? No!
Most illness is treated as early as practical. So why wait in the case of gluten?