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The Digestive Tract and Celiac Disease
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from a talk by Stephen M. Schutz, MD
[Dr. Stephen M. Schutz is a gastroenterologist at Wilford Hall Medical
Center, and is one of the medical advisors for the San Antonio Celiac
Sprue Support Group in Texas. He spoke to the San Antonio group at
one of their recent meetings and a transcript of his talk appeared in
their March 1998 newsletter. What follows is my summary of the
article that appeared in the San Antonio newsletter. Note that Dr.
Stephen uses the term "celiac sprue" throughout the article, whereas
we usually use the term "celiac disease". Both refer to the same
medical condition.--Jim Lyles]
Celiac sprue is a disease of the small bowel. It's easier to
understand how the small bowel impacts on digestion when you have some
understanding of how it all fits in to the bigger picture.
The process of digestion begins when you chew your food, changing it
from big pieces to smaller pieces. Chewed food then goes to the
stomach. Contrary to popular belief, the stomach does not absorb
nutrients. (The only thing the stomach absorbs is alcohol.) The
stomach's primary job is to continue the process of breaking food down
into smaller pieces. Your stomach sort of moves around and scrunches
the food, and in combination with the acid and other fluids, the big
chunks of food are broken down into little chunks. No matter how big
a bite you take, it won't leave your stomach until it has been broken
down into pieces 5 mm (1/5 inch) in diameter or smaller. At this
point, no actual digestion has taken place.
As the food trickles out of the stomach the action of digestion
begins. The cells in the beginning part of the small intestine, the
duodenum (where most of the damage from celiac sprue takes place),
produce hormones which tell the pancreas and gall bladder to spit out
enzymes and bile. These help break down food into its constitutive
nutrients, so that it can then be absorbed through the epithelial
lining in the small intestine.
All that--the work of your teeth, saliva, stomach, liver (where bile
is produced), gall bladder, and pancreas--has to take place before the
small intestine is asked to do its job. The food is broken down, not
just into smaller particles, but into its chemical components:
carbohydrates, triglycerides, other fat components, and amino acids.
These components are the material that the small intestine has to deal
with.
The small intestine damage in untreated celiacs, besides affecting the
ability to utilize broken down nutrients, also can affect the hormone
levels thereby decreasing the amount of bile and pancreatic enzymes
available to help with digestion.
The main problem untreated celiac sprue causes, aside from the reduced
hormone levels, is the flattening of the small intestinal lining. To
the naked eye the intestinal surface looks pretty flat, but under a
microscope you find that it has a bunch of hills and valleys all
scrunched together. As a result the surface area of the small
intestine is huge. This is important so that the broken-down
nutrients can be absorbed into the bloodstream. The small intestine's
large surface area makes this task much easier. But with untreated
celiac sprue the surface of the small intestinal lining has been
flattened to some degree, thus reducing its ability to absorb
nutrients.
In untreated celiacs, the small intestine does not absorb enough
nutrients, including some vitamins and minerals. That sounds simple
enough, but the effects of that single problem can be quite varied.
Classically, when some of the small intestine just isn't working at
all, you'll have diarrhea and sometimes weight loss. These problems
typically occur in people who are not diagnosed until they are in the
last stage of celiac sprue, where the small intestinal lining is
completely flat. In the past people were more often diagnosed during
this last stage, but now people are typically diagnosed sooner.
Many newly-diagnosed celiacs feel fine and don't have any symptoms at
all, though they often have iron deficiency. Iron deficiency is
common in celiacs because most iron is absorbed in the first part of
the small intestine, where you find most of the changes caused by
celiac sprue. So someone whose only symptom is iron deficiency may in
fact have celiac sprue. This is an example of why it can be difficult
to detect and diagnose celiac sprue.
One question that is often asked is, "Why do I need a biopsy? Aren't
the blood tests good enough?" Positive antigliadin and antiendomysial
antibody tests, when taken together, can be highly suggestive of
celiac sprue, but firm diagnosis is still reliant on a small bowel
biopsy. The antibody tests have gotten better and perhaps in another
five years we won't need to rely on the small bowel biopsy, but for
now a biopsy is still needed.
There is some new evidence suggesting that careful dental screening in
children can help detect celiac sprue. A group in Italy a few years
ago screened thousands of school-age children for certain dental
enamel defects. They found 50 children with these defects. Small
bowel biopsies revealed that 10 of these children did indeed have
celiac sprue and were put on a gluten-free (GF) diet.
Another common concern involves the risk of cancer. The risk is
increased in untreated celiacs, however, dietary compliance to a GF
diet decreases the risk. Two studies published in 1996 looked at
large groups of celiacs and found that adhering to a GF diet for five
or more years reduces the risk of cancer in celiacs to be equivalent
to that of the general population. That's the good news. But if you
don't adhere to the diet, insult and injury to the small bowel
continues through the years and the risk is going to be higher.
Dr. Shutz then answered some questions from the floor.
Q: Referring to the 10 children in the dental enamel study that were
found to have CD, should they go on a GF diet even though they
have no symptoms?
A: Absolutely.
Q: What causes celiac sprue? We know we have an intolerance to
gluten, but why?
A: All we know is that there is some reaction to gluten which damages
the lining of the small intestine. No one knows exactly why. The
immune system is almost certainly involved somehow. It is not an
allergy per se, but something immune-related that is like an
allergy.
Q: I was diagnosed after 62 years and I was a classic case of celiac
sprue. For 30 years I was told I had cancer, but they never could
find it. Why did it take so long to find a doctor who could tell
me what I had?
A: Doctors see people who are sick all day long. What happens is you
have people who come in and have exactly the same
complaints--weight loss, diarrhea, that sort of thing--and these
symptoms can be caused by many different medical conditions. It
is easy to overlook celiac sprue, because it is thought to be an
unusual disease. If you're a gastroenterologist and you have a
scope and biopsy, you won't miss it much.
Dr. Schutz knows how difficult it is to have celiac sprue and not
be diagnosed, so he does biopsies frequently. That includes
anyone with unexplained iron deficiency. Iron deficiency has
other causes, including colon polyps which could turn cancerous.
With older iron-deficient patients he checks for polyps and colon
cancer first; if they don't have either of those he then does a
small intestine biopsy. With most younger iron-deficient
patients, he does the biopsy first.
Knowledge about celiac sprue in the medical community, as in the
rest of the community, is low. What Dr. Schutz tries to do, and
encourages each of us to do, is to spread the word.
Q: How long does it take for the intestine to heal enough so that a
biopsy would find no damage?
A: It usually takes several months or a year, sometimes even longer.
Q: Is there a case of being a "mild" celiac where a little bit of
gluten wouldn't bother you? I have no symptoms. There's no
incentive for me to stay on this awful diet. I don't feel any
different.
A: It's quite variable. A lot of times you feel lousy only when you
have the disease pretty bad. In fact, you can feel pretty good,
yet still have problems that will cause you trouble down the road.
When you are much older, you might have more problems with bone
density than a celiac who adheres strictly to a GF diet.
Q: Can you be allergic to wheat and not to gluten?
A: Allergies are tricky. There can be just one small component of
food you are allergic to. Celiac sprue is a specific problem with
gluten. It's not just an allergy, it's much more. It's a
situation where your small bowel is severely damaged through
interaction with gluten. That doesn't happen with allergies. You
can be allergic to wheat and not have celiac sprue.
Q: Are there other diseases or problems in the intestine that cause
flattening?
A: Yes. There's something called tropical sprue. It is caused by
chronic intestinal infections you can get in tropical regions. It
flattens the villi completely, just like celiac sprue. It is
treated with an antibiotic. There are other, more unusual
diseases that can flatten the villi, and there are other problems
where the small intestine looks like active celiac disease. There
are a lot of digestive diseases that can be confused with celiac
sprue, which is another reason it can be so hard to diagnose.
Irritable bowel syndrome (IBS) is very common. What happens is
you have a spasm of the intestine which causes bloating, diarrhea
(sometimes alternating with constipation)--a lot of symptoms that,
for all the world, indicate celiac sprue. IBS is so common, and
celiac sprue is so uncommon, sometimes people get thrown into the
big IBS pile when they really belong in the small celiac sprue
cup.
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