<<Disclaimer: Verify this information before applying it to your situation.>>
 
Q.  One case I know of had elevated gliadins (both types) but normal EMA
and ARA, plus an inconclusive biopsy.  Do you see this often?
 
K.  If the tests are performed using well standardized tests with known
positive and negative predictive values then you can make the statement
that if the serological tests are negative CD can virtually be ruled
out.  The problem is that some of these assays, especially the gliadin,
can give you false positive results.  In our laboratory we rarely see
positive AGA results in the absence of EMA and ARA antibodies.
 
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Q.  Are there any unique factors to be considered for children?  I've
heard that the serology has a lower predictive value for children under
age two, since IgA may be depressed, or with anyone who has a condition
which depresses IgA.
 
K.  Not really.  It is not true that the serological methods have lower
predictive value in children less than two years of age.  In all the
studies that we did, there was 100% correlation of the EMA to the
disease activity irrespective of the age.
 
H.  There are age dependent changes in several blood parameters during
childhood.  It is well known that immunoglobulin levels depend on the
age of children.  E.g. the IgA class immunoglobulins reach the adult
level only by 16 years of age, and the blood level of IgA
immunoglobulins is only 1/5th of adult value below two years of age.  A
large study from Europe (Brgin-Wollf et al. Arch Dis Child
1991;66:941-947) showed that the endomysium antibody test is less
specific and sensitive in children below two years of age.  They found
that the sensitivity of the EmA test decreased from 98% to 88% in
children younger than 2 years of age.  It means that 12% of their
patients with celiac disease, who were younger than two years of age,
did not have an increase in their endomysium antibody levels.
 
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Q.  How important is it for a confirmed celiac to have repeat biopsies
or serology when on a gluten free diet?
 
K.  It is important for the serum tests to be negative in patients with
CD.  These tests provide strong indicators that the gluten free diet
followed is effective and is free of gluten.  Sometimes drugs or other
intakes may be contaminated with gluten that may continue sensitization
and the disease process which may be subclinically.  We and others
believe once the diagnosis of CD is confirmed and the patient is on a
gluten free diet, repeat tests once in 3-6 months may be sufficient.
 
H.  If a patient has histologically (endoscopy) and serologically
(antibody tests) proved celiac disease, and his/her symptoms disappeared
on a gluten-free diet, a repeat biopsy is not necessary.  The
serological tests are useful tools for estimating the effectiveness of
the diet after 3-6 months on a gluten-free diet.  The disappearance of
antibodies from the blood takes months, if there was not any accidental
gluten challenge (dietary mistake).
 
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Q.  There are different practices amongst g/i's on repeat biopsies vs.
serology, and on gluten challenges.  My son's g/i, for example, took the
position that since my son's symptoms stopped on a GF diet, and his
previously sky-high EMA and ARA went back to normal, that it was
unnecessary to do either a repeat biopsy or a gluten challenge.  From
the celiac list correspondence, I now see that my g/i is rather liberal.
 
K.  I think your son's GI is doing the right thing.  That is, if the
EMA, ARA are normal (<1:2.5) and he is on a gluten free diet then there
is no need to perform biopsy studies.  The previous studies relating the
EMA to biopsy studies tend to confirm this impression.
 
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Q.  Should my child have general anesthesia or conscious sedation prior
to the biopsy?
 
H.  The biopsy is a small piece of tissue, such as from the inside
lining of the intestine, that has been removed to look for diseases.
The biopsy itself is not painful, because there are no pain-sensitive
nerves inside the small intestine.  An intestinal biopsy can be done in
either of two ways depending on the age of the children and the
tradition of the institution.  Sometimes a blind biopsy procedure is
performed by a biopsy capsule.  This is thin flexible tube with a
capsule at the tip, which has a hole and a tiny knife inside the
capsule.  This capsule is introduced into the intestine under
fluoroscopy (X-ray) control.  Alternatively, with an endoscopy the
doctor can see inside the digestive tract without using an x-ray to
obtain biopsies.  The biopsy specimens are processed and viewed under
the microscope to identify or exclude celiac disease.  An important
basic rule is that the biopsy should be performed safely.  For a safe
procedure children (and adults) should be sedated.  There are two
methods of sedation:  unconscious (general anesthesia) and conscious
sedation.  During both kinds of sedation the vital parameters (heart
rate, blood pressure, oxygen saturation) of patients are continuously
monitored.  The method of choice depends on the child.
 
Conscious sedation is performed with two different intravenous
medications.  One of them is a sedative medication (e.g. Versed), which
causes amnesia in 80-90% of children, and even older children do not
recall the procedure.  The second medication is a pain-killer type
medication (e.g. Fentanyl), which further reduces the discomfort
associated with the procedure.  In addition, the throat is sprayed with
a local anesthetic in older children, which makes the throat numb and
prevents retching at the introduction of the endoscope.
 
During general anesthesia the anesthesiologist uses sleep-gases (e.g.
halothan) and intravenous medications and then places a tube into the
trachea.  Children are completely unconscious.  This is a safer way
to perform endoscopy, because the patients are fully relaxed and their
airway is protected.  However, the anesthesia itself has certain
complications.
 
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