Fecal impaction occurs because of hardened fecal matter retained in the large bowel which cannot be evacuated by regular peristaltic activity. If this is not recognized and treated early, it can give rise to the formation of fecoliths, or stone-like feces. Fecal impaction is a cause for increased morbidity and a significant cause of a decrease in quality of life among the elderly.
Fecal impaction commonly occurs among the elderly who are hospitalized patients or under institutional care. It is associated with generalized diseases, such as scleroderma and chronic renal failure, and conditions which cause an alteration in the normal anatomy such as congenital abnormalities in the anorectal region or previous surgical procedure of the intestine. In older adults who regularly consume nonsteroidal anti-inflammatory drugs, a higher occurrence of fecal impaction has been reported. Among hospitalized patients, administration in the elderly of medications with an opioid can result in fecal impaction, especially in those who have a history of chronic constipation and are bedridden.
Fecal impaction commonly occurs among elderly individuals, rarely presenting as an acute emergency to a hospital. Severe constipation is a significant problem that affects almost 70% of elderly people who are under care in nursing homes. Among those affected, about 7% will have the condition detected during a digital rectal examination. Fecal impaction is more common among older women who are in institutional care and have associated neuropsychiatric disorders. It is a cause for increased morbidity among the elderly, and if allowed to progress, this can lead to complications causing mortality in the older age group.
The continuous contact between the hard feces and the colonic mucosa can cause an increase in mucus secretion. Fecal impaction also causes an increase in intraluminal pressure in the colon which causes a decrease in perfusion of the colonic mucosa and wall. The resulting localized inflammation can give rise to colitis, ulcerations, and possible perforation. When stercoral perforation occurs, the most frequent site is the sigmoid colon. Stercoral perforation that occurs in the rectosigmoid region is attributed to feces being hardest in the rectosigmoid. Also, the diameter of sigmoid is the narrowest in the colon. These factors lead to an increased intraluminal pressure and result in hypoperfusion of the antimesenteric wall casing perforation. The impacted fecal mass may cause compression of adjacent structures such as urinary bladder, causing urinary retention. 
Patients with fecal impaction often give a history of inability to evacuate stools spontaneously and complain of total constipation. In most instances, an associated history of progressive abdominal distension with increasing abdominal discomfort or pain is present. Physical examination findings often reveal a distended abdomen. In thinly built or emaciated individuals, hard fecal mass masses may be palpable along the colon. Occasionally, patients may also present with a spurious or overflow diarrhea. The diagnosis of fecal impaction is primarily based on clinical signs. A detailed history of bowel habits and a full physical examination which includes a digital rectal exam is mandatory.
A digital rectal examination is mandatory as the first diagnostic evaluation to confirm the diagnosis of fecal impaction. When a rectal exam does not reveal fecal impaction or hard fecal masses in the rectum, the possibility of fecal impaction more proximal in the bowel or other causes, such as strictures or volvulus of the colon, should be considered. The most useful and commonly used radiological imaging for evaluation is a CT abdomen with oral or rectal contrast. A plain x-ray of the abdomen can, at times, reveal fecal overloading of the colon with colonic distention of the in the segment proximal to the region of fecal impaction. Rarely, a contrast enema or sigmoidoscopy are indicated in a patient who has no history suggestive of the colonic disease.
In many cases of fecal impaction, manual disimpaction is required. This is a helpful procedure if one can palpate hard stool in the rectal area. The procedure is best done using ample lubrication and gently removing the impacted stool with the index finger. Sometimes, the procedure can be aided with the use of an anoscope and suction. Most patients find immediate relief once fecal disimpaction is performed.
Proximal and Distal Fecal Impaction
If the abdominal x-ray reveals that the fecal impaction is located distally, then the use of enemas and suppositories can be helpful. The enema is best delivered with a Foley catheter past the hardened stool. The best method is to use ample water and combine it with docusate or sorbitol. It is important to administer small amounts of enema so as not to create discomfort in the patient. Once the enema is administered, one can help the process of evacuation by gently massaging the lower abdomen. This process may have to be repeated several times until only clear liquid passes.
For proximal fecal impaction, the ideal laxative is polyethylene glycol. One may have to administer from 1 to 3 liters of polyethylene glycol over a period of hours before a response is seen. If abdominal cramps and nausea occur, then no more polyethylene glycol should be ingested. Another laxative that can help with proximal impaction is magnesium citrate.
Polyethylene glycol can be given orally if conditions like volvulus or structural bowel obstruction due to any cause are ruled out. Administration of an appropriate laxative or fiber supplement with increased intake of water after the evacuation of the impacted fecal mass is administered to prevent recurrence. Early surgical evaluation and intervention are necessary if there are associated signs of peritonitis. Stercoral perforation is associated with a high mortality in the elderly if not recognized and treated early.
Sometimes impaction occurs after a barium study. Barium is not water soluble and can become a hard solid mass once the water is absorbed. Barium impaction is more likely to occur in patients who already have a functional or anatomical abnormality of the lower gastrointestinal tract. Barium impaction is also very common in people who have undergone some type of intestinal bypass procedure.
To prevent barium impaction, all patients should be encouraged to consume extra fluids. In some cases use of an osmotic laxative like sorbitol or milk of magnesia may be helpful. Barium impaction is usually seen on plain abdominal x-rays. Sometimes there may be perforation of the colon, which can also be visualized on the plain x-ray. If a perforation is noted, immediate surgery is required. If there is no perforation, barium removal is done similar to fecal impaction.
Lower Gastrointestinal and Rectal Surgery
In many people who have undergone repair of anal fistulas and removal of hemorrhoids, fecal impaction is quite rare but constipation is very common. The reason for fecal impaction is multifactorial and related to use of opiates, sphincter spasm, edema around the anal tissues, and a fear of going to the bathroom. In most mild cases, administration of an enema is sufficient; but in severe cases, one may need to perform manual disimpaction in the operating room. The patient will usually need some type of anesthesia to relax the anal sphincter complex before the fecal impaction can be removed.
These patients are encouraged to change their lifestyle, drink ample water, exercise, and eat a high fiber diet to prevent constipation.
Fecal impaction is a significant but preventable problem in the elderly population within hospitals and other institutions. The best way to treat it is to prevent it from developing in the first place. The cause of constipation should be identified early and managed appropriately. The patient should be educated about lifestyle measures and dietary habits to prevent fecal impaction. Unfortunately, recurrent fecal impaction is very common in elderly and institutionalized patients. Often these patients present to the emergency department because the presenting symptoms can mimic other sinister intestinal pathology.
The key to successful management of fecal impaction is a preventive and active management strategy with early recognition of severe constipation and prompt intervention to prevent the occurrence of fecal impaction. This proactive approach will prevent morbidity as well as increase the quality of life among the elderly and hospitalized patients.
Fecal impaction is a serious GI disorder that affects many seniors. The disorder is best managed with a multidisciplinary team that includes a gastroenterologist, nurse, pharmacist, neurologist, social worker and physical therapist.
The pharmacist should ensure that the patient is on no medications that slow down bowel movements and polypharmacy should be avoided. The dietitian should encourage an increase in fluid intake and high fiber diet. Both exercise and ambulation are vital. But it is usually the nurse who has to actually manage the patient with fecal impaction. Education of the family and patient about dietary habits and lifestyle are essential if one wants to prevent recurrences. If chronic constipation cannot be cured, then one must make attempts at improving the quality of life. (Level III)
Constipation and fecal impaction can affect the quality of life. Despite the availability of medications, recurrence of constipation and fecal impaction remains a chronic problem. (Level III) Many of these patients are old, non-ambulatory and reside in a nursing home. Thus, it is important to improve the quality of life rather than subject these patients to drastic surgery or regular invasive procedures which also have the potential to cause complications.