|
Home
>
Search
>
Acid Reflux
How is Acid Reflux diagnosed
and evaluated?
-
Esophageal acid testing
Esophageal acid testing is considered a
"gold standard" for diagnosing GERD. As
discussed above, the reflux of acid is
common in the general population. However,
patients with the symptoms or complications
of GERD have reflux of more acid than
individuals without the symptoms or
complications of GERD. Moreover, normal
individuals and patients with GERD can be
distinguished fairly well from each other by
the amount of time that the esophagus
contains acid.
The amount of time that the esophagus
contains acid is determined by a test called
a 24-hour esophageal ph test. (Ph is a
mathematical way of expressing the amount of
acidity.) For this test, a small tube
(catheter) is passed through the nose and
positioned in the esophagus. On the tip of
the catheter is a sensor that senses acid.
The other end of the catheter exits from the
nose, wraps back over the ear, and travels
down to the waist, where it is attached to a
recorder. Each time acid refluxes back into
the esophagus from the stomach, it
stimulates the sensor and the recorder
records the episode of reflux. After a 20 to
24 hour period of time, the catheter is
removed and the record of reflux from the
recorder is analyzed.
There are problems with using ph testing for
diagnosing GERD. Despite the fact that
normal
There are problems with using ph testing for
diagnosing GERD. Despite the fact that
normal individuals and patients with GERD
can be separated fairly well on the
basis of ph studies,
the separation is not perfect.
Therefore, some patients with GERD will have
normal amounts of acid reflux and some
patients without GERD will have abnormal
amounts of acid reflux. It requires
something other than the ph test to confirm
the presence of GERD, for example, typical
symptoms, response to treatment, or the
presence of complications of GERD.
Ph testing has uses in the management of
GERD other than just diagnosing GERD. For
example, the test can help determine why
GERD symptoms do not respond to treatment.
Perhaps 10 to 20 percent of patients will
not have their symptoms substantially
improved by treatment for GERD. This lack of
response to treatment could be caused by
ineffective treatment. This means that the
medication is not adequately suppressing the
production of acid by the stomach and
thereby is not reducing acid reflux.
Alternatively, the lack of response can be
explained by a wrong diagnosis of GERD. In
both of these situations, the ph test can be
very useful. If testing reveals substantial
reflux of acid while medication is
continued, then the treatment is ineffective
and will need to be changed. If testing
reveals good acid suppression with minimal
reflux of acid, the diagnosis of GERD is
likely to be wrong and other causes for the
symptoms need to be sought.
Ph testing also can be used to help evaluate
whether reflux is the cause of symptoms
(usually heartburn). To make this
evaluation, while the 24-hour ph testing is
being done, patients record each time they
have symptoms. Then, when the test is being
analyzed, it can be determined whether or
not acid reflux occurred at the time of the
symptoms. If reflux did occur at the same
time as the symptoms, then reflux is likely
to be the cause of the symptoms. If there
was no reflux at the time of symptoms, then
reflux is unlikely to be the cause of the
symptoms.
Lastly, ph testing can be used to evaluate
patients prior to endoscopic or surgical
treatment for GERD. As discussed above, some
20 % of patients will have a decrease in
their symptoms even though they don't have
GERD (the placebo effect). Prior to
endoscopic or surgical treatment, it is
important to identify these patients because
they are not likely to benefit from the
treatments. The ph study can be used to
identify these patients because they will
have normal amounts of acid reflux.
A newer method for prolonged measurement (48
hours) of acid exposure in the esophagus
utilizes a small, wireless capsule that is
attached to the esophagus just above the
LES. The capsule is passed to the lower
esophagus by a tube inserted through either
the mouth or the nose. After the capsule is
attached to the esophagus, the tube is
removed. The capsule measures the acid
refluxing into the esophagus and transmits
this information to a receiver that is worn
at the waist. After the study, usually after
48 hours, the information from the receiver
is downloaded into a computer and analyzed.
The capsule falls off of the esophagus after
3-5 days and is passed in the stool. (The
capsule is not reused.) The advantage of the
capsule over standard ph testing is that
there is no discomfort from a catheter that
passes through the throat and nose.
Moreover, with the capsule, patients look
normal (they don't have a catheter
protruding from their noses) and are more
likely to go about their daily activities,
for example, go to work, without feeling
self-conscious. Capsule ph testing is
expensive. Sometimes the capsule does not
attach to the esophagus or falls off
prematurely. For periods of time the
receiver may not receive signals from the
capsule, and some of the information about
reflux of acid may be lost. Occasionally
there is pain with swallowing after the
capsule has been placed. Use of the capsule
is an exciting use of new technology, but
with its inherent problems and lack of
widespread use and evaluation, it is not yet
clear what its role should be.
-
Esophageal motility testing
Esophageal motility testing determines how
well the muscles of the esophagus are
working. For motility testing, a thin tube
(catheter) is passed through a nostril, down
the back of the throat, and into the
esophagus. On the part of the catheter that
is inside the esophagus are sensors that
sense pressure. When the muscle of the
esophagus contracts, a pressure is generated
within the esophagus that is detected by the
sensors on the catheter. The end of the
catheter that protrudes from the nostril is
attached to a recorder that records the
pressure. During the test, the pressure at
rest and the relaxation of the lower
esophageal sphincter are evaluated. The
patient then swallows sips of water to
evaluate the contractions of the esophagus.
Esophageal motility testing has two
important uses in evaluating GERD. The first
is in evaluating symptoms that do not
respond to treatment for GERD. The abnormal
function of the esophageal muscle sometimes
causes symptoms that resemble the symptoms
of GERD. Motility testing can identify these
abnormalities and lead to a diagnosis of an
esophageal motility disorder. The second use
is evaluation prior to surgical or
endoscopic treatment for GERD. In this
situation, the purpose is to identify
patients who also have motility disorders of
the esophageal muscle. The reason for this
is that in patients with motility disorders,
some surgeons will modify the type of
surgery they perform for GERD.
-
Gastric emptying studies
Gastric emptying studies are studies that
determine how well food empties from the
stomach. As discussed above, about 20 % of
patients with GERD have a slow emptying of
the stomach that may be contributing to the
reflux of acid. For gastric emptying
studies, the patient eats a meal that is
labeled with a radioactive substance. A
sensor that is similar to a Geiger counter
is placed over the stomach to measure how
quickly the radioactive substance in the
meal empties from the stomach.
Information from the emptying study can be
useful for managing patients with GERD. For
example, if a patient with GERD continues to
have symptoms despite treatment with the
usual medications, doctors might prescribe
other medications that speed-up emptying of
the stomach. Alternatively, in conjunction
with GERD surgery, they might do a surgical
procedure that promotes a more rapid
emptying of the stomach. Nevertheless, it is
still debated whether a finding of reduced
gastric emptying should prompt changes in
the surgical treatment of GERD.
Symptoms of nausea, vomiting, and
regurgitation may be due either to abnormal
gastric emptying or GERD. An evaluation of
gastric emptying, therefore, may be useful
in identifying patients whose symptoms are
due to abnormal emptying rather than to GERD.
-
Acid perfusion test
The acid perfusion (Bernstein) test is used
to determine if chest pain is caused by acid
reflux. For the test, a thin tube is passed through one
nostril, down the back of the throat, and
into the middle of the esophagus. A dilute,
acid solution and a physiologic (normal)
salt solution are alternately poured (perfused)
through the catheter and into the esophagus.
The patient is unaware of which solution is
being infused. If the perfusion with acid
provokes the patient's usual pain and
perfusion of the salt solution produces no
pain, it is likely that the patient's pain
is caused by acid reflux.
The acid perfusion test, however, is used
only rarely. A better test for correlating
pain and acid reflux is a 24-hour esophageal
ph study during which patients note when
they are having pain. It then can be
determined from the ph recording if there
was an episode of acid reflux at the time of
the pain. This is the preferable way of
deciding if acid reflux is causing a
patient's pain.
 The
1 - 4 methods to diagnosed Acid Reflux
|
