- [Voiceover] The name celiac
disease doesn't actually tell us much about what the disease does, but there's another name
that I think is a little bit more informative. And that's gluten-sensitive enteropathy. Entero refers to small intestine and pathy refers to disease, so there's a disease
of the small intestine that's caused by gluten. It's also important to
note that celiac disease is an autoimmune disease, that is, the immune system is
attacking the small intestine. We don't actually know
why that's happening, but we do know that some
people have a genetic predisposition towards
developing the disease. We also know that people
who have celiac disease are more likely to develop
other autoimmune diseases as well, such as type 1
diabetes or thyroid disease, and we know that it's more
common in people who have down syndrome. Now even though we don't exactly
know why the immune system is attacking the small intestine, we can still kind of look
at the pathophysiology and what's exactly going on in there. Now remember that gluten is
composed of two different proteins. There's gliadin and there's glutenin. We'll mostly focus on gliadin. Now let's say you eat
something that contains gluten. That gluten will eventually
make its way into the small intestine, and here I
kind of have a diagram of the different layers
of the small intestine. Once it reaches this
point, for some reason, your body will start to
produce antibodies against the gliadin. This will then recruit
all sorts of lymphocytes, or white blood cells,
into your small intestine. Because you have a lot of
lymphocytes and antibodies in your small intestine, we
say that there is inflammation in there. So it's almost as if
there's a war zone going on in your small intestine, and that war zone kind of
causes damage to the wall of the small intestine. Now remember that the wall
is responsible for absorbing food and water, so, the
process of absorption will be disrupted. For example, you can't really
absorb much water anymore. That water will just
end up in your stools, in a condition simply known as diarrhea. Similarly, you can't absorb
fats very well either, and that will manifest in
your stools in a condition known as steatorrhea. And finally, you may be
unable to absorb iron or vitamin B12. As a result, you may start
to experience anemia. So these are some of the
major symptoms associated with problems in absorption, but there's actually one more
symptom that's not really associated with absorption. Let's say that here we
have the body of someone who has celiac disease,
and they've eaten something that contains gluten in it. All of a sudden, they may
start to see these rashes and blisters forming on
their abdomen and their arms. These rashes and these blisters
are going to be extremely itchy. This is a condition known
as dermatitis herpetiformis. It's not too common. It affects about 10% of people
who have celiac disease, but, it's one of the many
symptoms that doctors may look for when diagnosing the disease. Now, speaking of diagnosis, I
want to talk a little bit more about how some doctors can
determine if someone has celiac disease. First, what they'll do is
they'll determine if you have a high probability or low
probability of developing the disease. They'll determine this by
looking at your family history, because remember that
people have a genetic predisposition towards developing it. If they see a lot of family
members having the disease, then they may order
what's called a biopsy. A biopsy's when we collect
a small sample of the tissue that we're interested in. After you collect that
sample, you then look at it under a microscope to see
if it looks healthy or not. The way we collect this
tissue is through a procedure called an upper endoscopy. They basically take this
camera that looks like a tube called an endoscope, and they put it through your mouth, down your esophagus, through your stomach, and then eventually, into your small intestine. Because it's a camera, the
doctors can then actually see what's going on in
the small intestine, and, they can collect that sample. Now, let's say that you may
have a low probability instead. If, for example, you don't
have a lot of family members who have celiac disease, or even any other autoimmune disease, you may not want to subject
the patient to this really invasive procedure, so
first, what we'll do is a few blood tests. We're mostly going to be
looking for different antibodies that are characteristic of celiac disease, because remember, that this
is an autoimmune disease. So there are five classes of antibodies, called IgA, IgD, IgE, IgG, and IgM. We're mostly going to look for
antibodies that fall in the IgA category, and there
are two different types. There's anti-tissue transglutaminase, and there's anti-endomysial. If these blood tests turn out positive, that is, you have these
antibodies in your system, then there's a chance that
you may have celiac disease, so then the doctor may go on
to continue with a biopsy, just to confirm things. Now, let's take a look at that
biopsy in a little bit more detail, so here we have
two different pictures of the small intestine
under the microscope. On the right, we have a
healthy small intestine, and on the left, we have the
small intestine of someone who has celiac disease. First, I want to highlight
what's good about the healthy one. You'll notice that it has
these finger-like protrusions called the villi. These guys are responsible for absorption in the small intestine. There are also these
grooves between the villi known as crypts. In the disease sample, you'll
notice that these villi are actually blunted. This is known as villous atrophy. In addition, those crypts
are actually elongated so they're becoming a little bit bigger. And that's because all sorts
of cells are dividing there, so we call this crypt hyperplasia, so it's kind of like the
mountains of the villi are getting smaller, and
the valleys of the crypts are getting deeper. Now, there's one more
comparison picture that I want to show you as well. In this case, on the left, we have someone who is healthy, and on the right, we have
someone who has celiac disease. Now, remember, that in celiac
disease, you have a lot of inflammation in the small intestine. That means that you have a
lot of lymphocytes in there. So it would be a good idea
to actually look for these lymphocytes, so, you'll
see these kind of blobs that are in the villi of
the small intestine, right? And, the celiac disease
tissue actually has a lot more of them. Now, these blobs are
corresponding to the lymphocytes, and it's pretty clear in
this picture that there are way more lymphocytes in
the disease tissue than in the healthy. Now, these are really the
main signs that we look for with regards to celiac disease, and if the tissue sample shows this, then that's how we can diagnose it, but diagnosing it is one thing. I mean, how can we really treat it? Well, unfortunately, there
aren't really many medicines or procedures available
to treat celiac disease. Once the gliadin from
the gluten makes its way into the body, it's pretty
difficult to stop the antibodies from marking them, so, ultimately, the best
thing that anyone can do is to simply go on a gluten-free diet. Now, usually, these gluten-free
diets are pretty strict. But I think that now, given
that there's this rise of gluten-free diets, it's
becoming a little bit more easy for people to maintain these diets. As long as you don't consume gluten, then you should be okay, even
if you have celiac disease.