Investigation of severe constipation

A small minority (probably5%) of all patients with constipation have cases that are considered
severe or “intractable”; these are the patients most likely to be seen
by gastroenterologists or in referral centers. Further observation of the
patient may occasionally reveal a previously unrecognized cause, such
as an evacuation disorder, laxative abuse, malingering, or psychiatric
disorder. In these patients, recent studies suggest that evaluations of
the physiologic function of the colon and pelvic floor and of psychological
status aid in the rational choice of treatment. Even among these
highly selected patients with severe constipation, a cause can be identified
in only about 30%.

1. Measurement of Colonic Transit

A)Radiopaque marker transit tests

are easy,
repeatable, generally safe, inexpensive, reliable, and highly applicable
in evaluating constipated patients in clinical practice. There are several
validated methods that are very simple. For example, radiopaque
markers are ingested, and an abdominal flat film taken 5 d later should
indicate passage of 80% of the markers out of the colon. This test does
not provide useful information about the transit profile of the stomach
and small bowel, and avoidance of laxatives or enemas during the
testing period is essential.

B)Radioscintigraphy

with a delayed-release capsule containing radiolabeled
particles has been used to noninvasively characterize normal,
accelerated, or delayed colonic function over 24 to 48 h with low
radiation exposure. This approach simultaneously assesses gastric,
small-bowel, and colonic transit. The disadvantages are the greater cost
and the need for specific materials prepared in a nuclear medicine
laboratory.

2.Anorectal and Pelvic Floor Tests

Pelvic floor dysfunction is suggested by
the inability to evacuate the rectum, a feeling of persistent rectal fullness,
rectal pain, the need to extract stool from the rectum digitally,
application of pressure on the posterior wall of the vagina, support of
the perineum during straining, and excessive straining. These signifi-
cant symptoms should be contrasted with the sense of incomplete rectal
evacuation, which is common in irritable bowel syndrome.
Patients with clinically suspected obstruction of defecation should
also be evaluated by a psychologist to identify eating disorders or a
“need to control,” to provide stress management or relaxation training,
and to identify depression.

3.Neurologic testing (electromyography)

is more helpful in the evaluation
of patients with incontinence than of those with symptoms suggesting
obstructed defecation. The absence of neurologic signs in the
lower extremities suggests that any documented denervation of the
puborectalis results from pelvic (e.g., obstetric) injury or from stretching
of the pudendal nerve by chronic, long-standing straining.
Ultrasonography identifies sphincter or rectal wall defects and may
help select patients for surgical correction. Spinal-evoked responses
during electrical rectal stimulation or stimulation of external anal
sphincter contraction by applying magnetic stimulation over the lumbosacral
cord identify patients with limited sacral neuropathies with
sufficient residual nerve conduction to attempt biofeedback training.
In summary, a balloon expulsion test is an important screening test
for anorectal dysfunction. If positive, an anatomic evaluation of the
rectum or anal sphincters and an assessment of pelvic floor relaxation
are the tools for evaluating patients in whom obstructed defecation is
suspected

What is constipation?
Common causes of constipation
Treatment for constipation
Dietary fibers and constipation
Herbal medicine (complementary/alternative medicine) for constipation