Impaction
Etiology of impaction
Signs and symptoms of impaction
Assessment of impaction
Treatment of impaction
Etiology of impaction
Five major factors precipitate impaction:
Signs and symptoms of impaction
The patient may exhibit symptoms similar to constipation or present with
symptoms unrelated to the gastrointestinal system. If the impaction presses on
the sacral nerves, the patient may experience back pain. If the impaction
presses on the ureters, bladder, or urethra, urinary symptoms can develop.
These symptoms include increased or decreased frequency or urgency of
urination, or urinary retention.
When abdominal distention occurs, movement of the diaphragm is compromised,
leading to insufficient aeration with subsequent hypoxia and left ventricular
dysfunction. Hypoxia can, in turn, precipitate angina or tachycardia. If the
vasovagal response is stimulated by the pressure of impaction, the patient may
become dizzy and hypotensive.
Movement of stool around the impaction may result in diarrhea, which can be
explosive. Coughing or activities that increase intra-abdominal pressure may
cause leakage of stool. The leakage may be accompanied by nausea, vomiting,
abdominal pain, and dehydration and is virtually diagnostic of the condition.
Thus, the patient with an impaction may present in an acutely confused and
disoriented state, with signs of tachycardia, diaphoresis, fever, elevated or
low blood pressure, and/or abdominal fullness or rigidity.
Assessment of impaction
Assessment includes the questions discussed previously for the patient with
constipation (refer to the Assessment of Constipation section of this summary for the list of questions). Additional
assessment includes auscultation of bowel sounds to determine if they are
present, absent, hyperactive, or hypoactive. The abdomen should be inspected
for distention and gently palpated for any masses, rigidity, or tenderness. A
rectal examination will determine the presence of stool in the rectum or
sigmoid colon. An abdominal x-ray (flat and upright) would show loss of haustral
markings, gas patterns reflecting gross amounts of stool, and dilatation
proximal to the impaction.[2]
If a diagnosis of fecal impaction is uncertain, a laboratory workup can rule
out other problems. A complete blood cell count, appropriate blood
chemistries, chest x-ray, and an electrocardiogram can be performed. If the
patient has become dehydrated, the blood urea nitrogen, creatinine, and serum
osmolality will be elevated. There may be an elevation of the hemoglobin and
hematocrit indicating hemoconcentration. The white blood cell (WBC) count may
be slightly elevated in the presence of a fever. If the WBC count is extremely
elevated and the patient is exhibiting a high fever and abdominal pain, an
obstruction, perforation, infection, or inflammatory process must be ruled out.
With marked distention of the cecum (diameter ≥12 cm), there is a risk
of bowel perforation.
Treatment of impaction
The primary treatment of impaction is to hydrate and soften the stool so that
it can be removed or passed. Enemas (oil retention, tap water, or
hypertonic phosphate) lubricate the bowel and soften the stool. Caution must
be exercised; fecal impaction can irritate the bowel wall, and enemas in excess
may perforate the bowel. The patient may need to be digitally disimpacted if
the stool is within reach. This is best done after administering an enema to
lubricate the bowel.
Nonstimulating bowel softeners such as docusate can be used to help soften
stool higher in the colon. Mineral or olive oil can be given to loosen the
stool. Caution should be used when giving docusate sodium with mineral oil
because there could be an increased systemic absorption of the mineral oil
leading to systemic lipid granulomas.[3] Glycerin suppositories can also be
used. Any laxatives that might stimulate the bowel or cause cramping should be
avoided so that the bowel is not damaged further.
References
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Cefalu CA, McKnight GT, Pike JI: Treating impaction: a practical approach to an unpleasant problem. Geriatrics 36 (5): 143-6, 1981.
[PUBMED Abstract]
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Bruera E, Suarez-Almazor M, Velasco A, et al.: The assessment of constipation in terminal cancer patients admitted to a palliative care unit: a retrospective review. J Pain Symptom Manage 9 (8): 515-9, 1994.
[PUBMED Abstract]
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Brandt LJ: Gastrointestinal Disorders of the Elderly. New York, NY: Raven Press, 1984.
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