The doctor has requested that the nurse administer a enema to
Mrs. Wilson to help her alleviate a constipation problem.
The main medical usages of enemas are:
As a bowel stimulant, not unlike a laxative, the main difference being that
laxatives are commonly thought of as orally administered while enemas are
administered directly into the rectum, and thereafter, into the colon. Their use
has been replaced in most professional healthcare settings by oral laxatives and
laxative suppositories. In-home use of enemas for constipation and alternative
health purposes is somewhat harder to measure.
Bowel stimulating enemas usually consist of water, which works primarily as a
mechanical stimulant, or they may be made up of water with baking soda (sodium
bicarbonate) or water with a mild hand soap dissolved in it; buffered sodium
phosphate solution, which draws additional water from the bloodstream into the
colon and increases the effectiveness of the enema which often can be rather
irritating to the colon, causing intense cramping or "griping," or mineral oil,
which functions as a lubricant and stool softener, but which often has the side
effect of sporadic seepage from the patient's anus which can soil the patient's
undergarments for up to 24 hours. Other types of enema solutions are also used,
including equal parts of milk and molasses heated together to slightly above
normal body temperature. In the past, castile soap was a common additive in an
enema, but it has largely fallen out of use because of its irritating action in
the rectum and because of the risk of chemical colitis as well as the ready
availability of other enema preparations that are perhaps more effective than
soap in stimulating a bowel movement. At the opposite end of the spectrum, an
isotonic saline solution is least irritating to the rectum and colon, having a
neutral concentration gradient. This neither draws electrolytes from the body
as can happen with plain water nor draws water into the colon, as will occur
with phosphates. Thus, a salt water solution can be used when a longer period of
retention is desired, such as to soften an impaction.
Cleansing the lower bowel prior to a surgical procedure such as sigmoidoscopy or
colonoscopy. Because of speed and supposed convenience, enemas used for this
purpose are commonly the more costly, sodium phosphate variety often called a
disposable enema. A more pleasant experience preparing for testing procedures
can usually be obtained with gently administered baking soda enemas; cleansing
the lower bowel for colonoscopy and other bowel studies can be effectively
achieved with water based, or water with baking soda, enema administration.
The administration of substances into the bloodstream. This may be done in
situations where it is undesirable or impossible to deliver a medication by
mouth, such as antiemetics given to reduce nausea (though not many antiemetics
are delivered by enema). Additionally, several anti-angiogenic agents, which
work better without digestion, can be safely administered via a gentle enema.
Medicines for cancer, for arthritis, and for age-related macular degeneration
are often given via enema in order to avoid the normally functioning digestive
tract. Interestingly, some water based enemas are also used as a relieving agent
for Irritable Bowel Syndrome, using cayenne pepper to squelch irritation in the
colon and rectal area. Finally, an enema may also be used for hydration
purposes. See also route of administration.
The topical administration of medications into the rectum, such as
corticosteroids and mesalazine used in the treatment of inflammatory bowel
disease. Administration by enema avoids having the medication pass through the
entire gastrointestinal tract, therefore simplifying the delivery of the
medication to the affected area and limiting the amount that is absorbed into
General anesthetic agents for surgical purposes are sometimes administered by
way of an enema. Occasionally, anesthetic agents are used rectally to reduce
medically-induced vomiting during and after surgical procedures, in an attempt
to avoid aspiration of stomach contents.
A barium enema is used as a contrast substance in the radiological imaging of
the bowel. The enema may contain barium sulfate powder, or a water-soluble
contrast agent. Barium enemas are sometimes the only practical way to "view" the
colon in a relatively safe manner. Following barium enema administration,
patients often find that flushing the remaining barium with additional water,
baking soda, or saline enemas helps restore normal colon activity without
complications of constipation from the administration of the barium sulfate.
In certain countries such as the United States, customary enema usage went well
into the 20th century; it was thought a good idea to cleanse the bowel in case
of fever; also, pregnant women were given enemas prior to labor, supposedly to
reduce the risk of feces being passed during contractions. Under some
controversial discussion, predelivery enemas were also given to women to speed
delivery by inducing contractions. This latter usage has since been largely
abandoned, because obstetricians now commonly give pitocin to induce labor and
because women generally found the procedure unpleasant.