Diagnostic Tests for Constipation
Diagnostic Test list for Constipation:
The list of diagnostic tests
mentioned in various sources as
used in the diagnosis of Constipation
includes:
- Physical examination
- Inspection of external anus looking for disease that may cause constipation e.g. anal fissure; or pathology that may be a result of constipation e.g. hemorrhoids, anal fissure
- Digital rectal examination - if there are symptoms of intestinal obstruction and the rectum is empty it may suggest complete intestinal obstruction but if there are some feces in the rectum there may be an incomplete intestinal obstruction; if rectal mass is found it suggests colon cancer.
- Test perianal sensation and the anal reflex to support neurological cause of bowel infrequency
- Abdominal examination for tenderness, mass, fecal loading, abdominal distention or irregular liver edge (due to metastases from colon cancer)
- Blood tests
- Full blood count, electrolytes, thyroid function tests - to rule out systemic causes of constipation such as diabetes, hypothyroidism, hypercalcaemia, hyperparathyroidism.
- Carcinoembryonic antigen - a tumor marker for bowel cancer.
- Stool test for Occult blood
- Radiological investigations
- Abdominal X-Ray - if bowel infrequency is recent, to diagnose intestinal obstruction.
- Proctosigmoidoscopy
- Barium Enema
- Colonoscopy
- Anorectal manometry and Proctography - will help diagnose anorectal sphincter dysfunction.
- Rectal biopsy - if suspect Hirschsprung's disease.
- Physical exam
- Digital rectal exam
- Blood tests
- Thyroid tests
- Barium enema x-ray
- Sigmoidoscopy
- Colonoscopy
- Colorectal transit study
- Anorectal function tests
Home Diagnostic Testing
These home medical tests may be relevant to Constipation causes:
- Colon & Rectal Cancer: Home Testing
- Food Allergies & Intolerances: Home Testing:
- Digestive-Related Home Testing:
Tests and diagnosis discussion for Constipation:
Most people do not need extensive testing and
can be treated with changes in diet and exercise. For example, in young
people with mild symptoms, a medical history and physical examination may
be all the doctor needs to suggest successful treatment. The tests the
doctor performs depends on the duration and severity of the constipation,
the person's age, and whether there is blood in stools, recent changes in
bowel movements, or weight loss.
Medical History
The doctor may ask a patient to describe his or
her constipation, including duration of symptoms, frequency of bowel
movements, consistency of stools, presence of blood in the stool, and
toilet habits (how often and where one has bowel movements). Recording
eating habits, medication, and level of physical activity or exercise also
helps the doctor determine the cause of constipation.
Physical Examination
A physical exam may include a digital rectal
exam with a gloved, lubricated finger to evaluate the tone of the muscle
that closes off the anus (anal sphincter) and to detect tenderness,
obstruction, or blood. In some cases, blood and thyroid tests may be
necessary.
Extensive testing usually is reserved for people with severe symptoms,
for those with sudden changes in number and consistency of bowel movements
or blood in the stool, and for older adults. Because of an increased risk
of colorectal cancer in older adults, the doctor may use these tests to
rule out a diagnosis of cancer:
- Barium enema x-ray
- Sigmoidoscopy or colonoscopy
- Colorectal transit study
- Anorectal function tests.
Barium Enema X-Ray
A barium enema x-ray involves viewing the
rectum, colon, and lower part of the small intestine to locate any
problems. This part of the digestive tract is known as the bowel. This
test may show intestinal obstruction and Hirschsprung's disease, a lack of
nerves within the colon.
The night before the test, bowel cleansing, also called bowel prep, is
necessary to clear the lower digestive tract. The patient drinks 8 ounces
of a special liquid every 15 minutes for about 4 hours. This liquid
flushes out the bowel. A clean bowel is important, because even a small
amount of stool in the colon can hide details and result in an inaccurate
exam.
Because the colon does not show up well on an x-ray, the doctor fills
the organs with a barium enema, a chalky liquid to make the area visible.
Once the mixture coats the organs, x-rays are taken that reveal their
shape and condition. The patient may feel some abdominal cramping when the
barium fills the colon, but usually feels little discomfort after the
procedure. Stools may be a whitish color for a few days after the exam.
Sigmoidoscopy or Colonoscopy
An examination of the rectum and
lower colon (sigmoid) is called a sigmoidoscopy. An examination of the
rectum and entire colon is called a colonoscopy.
The night before a sigmoidoscopy, the patient usually has a liquid
dinner and takes an enema in the early morning. A light breakfast and a
cleansing enema an hour before the test may also be necessary.
To perform a sigmoidoscopy, the doctor uses a long, flexible tube with
a light on the end called a sigmoidoscope to view the rectum and lower
colon. First, the doctor examines the rectum with a gloved, lubricated
finger. Then, the sigmoidoscope is inserted through the anus into the
rectum and lower colon. The procedure may cause a mild sensation of
wanting to move the bowels and abdominal pressure. Sometimes the doctor
fills the organs with air to get a better view. The air may cause mild
cramping.
To perform a colonoscopy, the doctor uses a flexible tube with a light
on the end called a colonoscope to view the entire colon. This tube is
longer than a sigmoidoscope. The same bowel cleansing used for the barium
x-ray is needed to clear the bowel of waste. The patient is lightly
sedated before the exam. During the exam, the patient lies on his or her
side and the doctor inserts the tube through the anus and rectum into the
colon. If an abnormality is seen, the doctor can use the colonoscope to
remove a small piece of tissue for examination (biopsy). The patient may
feel gassy and bloated after the procedure.
Colorectal Transit Study
This test, reserved for those with
chronic constipation, shows how well food moves through the colon. The
patient swallows capsules containing small markers, which are visible on
x-ray. The movement of the markers through the colon is monitored with
abdominal x-rays taken several times 3 to 7 days after the capsule is
swallowed. The patient follows a high-fiber diet during the course of this
test.
Anorectal Function Tests
These tests diagnose constipation caused
by abnormal functioning of the anus or rectum (anorectal function).
Anorectal manometry evaluates anal sphincter muscle function. A catheter
or air-filled balloon inserted into the anus is slowly pulled back through
the sphincter muscle to measure muscle tone and contractions.
Defecography is an x-ray of the anorectal area that evaluates
completeness of stool elimination, identifies anorectal abnormalities, and
evaluates rectal muscle contractions and relaxation. During the exam, the
doctor fills the rectum with a soft paste that is the same consistency as
stool. The patient sits on a toilet positioned inside an x-ray machine and
then relaxes and squeezes the anus and expels the solution. The doctor
studies the x-rays for anorectal problems that occurred while the patient
emptied the paste.
(Source: excerpt from Constipation: NIDDK)
» Next page: Glossary
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