Constipation
Constipation
Author: David M. Cline, MD, Associate Professor of Emergency Medicine, Director of Research, Department of Emergency Medicine, Wake Forest University Health Sciences, Winston-Salem, NC.
Peer Reviewers: Charles E. Stewart, MD, FACEP, Emergency Physician, Colorado Springs, CO; and Catherine A. Marco, MD, FACEP, Clinical Professor, Department of Surgery, Division of Emergency Medicine, Medical University of Ohio, Attending Physician, St. Vincent Mercy Medical Center, Toledo, OH.
Constipation is a common medical problem that, in its simple, uncomplicated form is not an urgent medical problem. However, constipation is a frequent chief complaint of emergency department (ED) patients. Constipation may be a precursor or risk factor to much more serious conditions (i.e., volvulus), or patients may confuse a constellation of symptoms as constipation (i.e., ischemic colitis) and mislead the physician toward the incorrect impression with their self-diagnosis, sometimes with devastating consequences. The fear of worsening chronic constipation with laxatives may dissuade the emergency physician from using effective therapies, only to offer patients treatments that have proven to be no more effective than placebo (i.e., stool softeners).
Acute constipation is a term without a clear definition in the literature. Patients may complain of straining with stool, hard stools, incomplete evacuation, anorectal obstruction, or simply stool frequency they believe is inadequate. If the patient perceives that stooling frequency has changed for such that the patient is having physical discomfort or emotional distress, he or she may visit a physician for treatment. Chronic constipation has been defined using the Rome Criteria,1,2 and is presented in Table 1. The most objective measure using the Rome Criteria is stool frequency fewer than three times per week. Fecal impaction is the inability to pass a firm collection of stool (without treatment or assistance). Complications that can occur in the setting of constipation include fecal impaction, sigmoid volvulus, toxic megacolon, and colon obstruction and pseudo-obstruction.
| Table 1. Rome II Criteria for Functional Constipation |
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This review puts the complaint of constipation in the context of emergency medical disorders too important to miss. The review goes on to offer practical advice concerning the work-up and management of acute and chronic constipation, its complications, and serious disorders that masquerade as constipation.
Epidemiology
The prevalence of acute constipation is not known, as the definition varies; however, it is more common than chronic constipation meeting accepted criteria. Chronic constipation has a prevalence of 12-19% in North America.3 Estimates based on the Rome II criteria (see Table 1),1,2 are lower than estimates based on patient self-reporting. Rome II criteria provide a standardized guide to make a formal diagnosis of chronic constipation, which has implications for recommended testing such as outpatient colonoscopy. The female to male ratio is 2.2 to 1.1 Laxative use is more frequent in woman. Up to 26% of elderly men, and 34% of elderly woman complain of constipation. As much as 75% of elderly patients in nursing homes are given laxatives on a regular basis.
Pathophysiology
Constipation results when there is an imbalance between non-propulsive forces that determine fluid absorption in the large intestine, and the propulsive forces that move the fecal material toward the rectum. Colonic transit is affected by the smooth muscle function of the bowel wall regulating motility and the submucosal plexuses regulating absorption, with the overall control by the parasympathetic nervous system. Bowel contents affect transit time, especially fiber and water content. Typically only 100 mL/day of ingested fluid/and or secretions are lost in the stool, and when colonic transit times are prolonged, or inadequate fluid is ingested, stool becomes hard and difficult to expel. Elderly patients with idiopathic chronic constipation have prolonged transit times and therefore increased fluid re-absorption. Medications such as narcotics have similar actions. These changes typically are accompanied by decreased rectal sensitivity and decreased rectal reflexes. Ignoring the urge to defecate also may occur in the setting of painful anal lesions or changes in environment. Stool holding promotes fluid absorption and hardened stool. If chronic rectal distention results, motor tone also decreases, which exacerbates the problem.
Normal colonic transit ranges from 18-72 hours. Some patients have prolonged times; patients with slow transit constipation have times greater than 72 hours. Slow transit constipation is thought to be due to a disorder of the myenteric plexus. These patients are unlikely to respond to simple treatment measures like fiber.4 There are multiple disorders that are grouped as pelvic outlet dysfunction that involve high resting anal canal pressures or failure of anal sphincter relaxation during defecation that impede the outflow of stool. Rectoceles may result from years of straining, and worsen rectal evacuation.
Obstipation is the absolute inability to pass stool. Fecal impaction is the inability to pass a hard collection of stool, and can be regarded as extreme constipation. Risk factors for fecal impaction include physical and mental incapacitation, advanced age, institutionalization, and chronic laxative use. With age, the rectum and anus lose tactile sensitivity; therefore, the sensation of fullness in the rectum decreases. Anal lesions that cause pain can inhibit the passage of stool. While stool is retained, ongoing fluid absorption and colonic peristalsis combine to pack stool into a hard bolus that is difficult to pass through the fixed caliber of the anus.
Acute Presentations of Constipation
Etiology. The conditions associated with the complaint of acute constipation are numerous and are presented in Table 2. While the constipating effects of narcotics are well known, many drugs associated with constipation listed in Table 3 go under-appreciated, such as commonly used cardiovascular drugs, lipid-lowering agents, and nonsteroidal antiinflammatory agents. Emergency physicians should pay particular attention to the list of life-threatening conditions that may present with constipation (see Table 4), the most frequent of which is bowel obstruction. Despite the widespread use of CT scanning to better identify confusing presentations of bowel obstruction, autopsy studies continue to reveal missed bowel obstruction as an unexpected cause of death.5
| Table 3. Common Medications Associated with Constipation |
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| Table 4. Life-Threatening Conditions that May Present with Constipation |
• Abscess |
Clinical Features
The clinical presentation is highly variable, ranging from simple constipation amenable to small changes in diet to life-threatening disorders that have a constellation of symptoms that are compatible with constipation: reduced frequency of stooling, abdominal cramping, or pain with defecation. Patients with longstanding constipation may present with complications of the disorder such as volvulus or toxic megacolon. Clues to the diagnosis may be uncovered in the context of the complaint; constipation may be only one of the symptoms that contribute to the total clinical picture. As use of constipating medications is a common cause, both over-the-counter and prescribed medication use should be reviewed in detail (patients may recall additional medications after their list has been given to the triage nurse). History-taking should elicit recent and chronic bowel habits to determine the acute nature of the condition; the frequency of bowel movements should be elicited. Stool description including consistency, caliber, and presence of blood or purulent material should be elicited. Associated symptoms such as pain and vomiting should be determined; simple constipation may be associated with crampy pain, but severe pain and/or vomiting are more frequently associated with ominous conditions. The complaint of pain should be differentiated into abdominal and rectal pain as each has important implications regarding etiology and/or treatment. History of associated fever, weight loss, poor appetite, diarrhea (which may alternate with constipation), flatulence, and foul-smelling feces should be elicited. Systemic symptoms may indicate a systemic process such as hypothyroidism, (see Table 2 for symptom clues for common causes of acute constipation). Prevalence of constipation during pregnancy is reported as ranging from 11% to 38%,6 but a more frequent complaint appears to be the sensation of anal blockage, occurring in 34-42% of women.7 When pregnancy is identified, ectopic pregnancy should be considered and worked-up as the clinical presentation demands.
Abnormal vital signs suggest a serious condition causing constipation. Mild abdominal distention may be noted with simple constipation, but may also be a sign of bowel obstruction. Abnormal bowel sounds and signs of peritoneal irritation are more likely associated with serious conditions. Rebound tenderness is an unlikely finding in patients with simple constipation. In thin patients, stool may be palpable, but should be absent after treatment if this is indeed the cause of a palpable mass.
The rectal exam is an essential part of the evaluation to look for hemorrhoids, rectal fissure, abscess or fecal impaction. The stool should be checked for blood, as carcinoma must be considered in patients with positive occult blood testing. Decreased tone may be found and may be indicative of neurologic disease or long-standing constipation. While the neurologic exam at first may appear superfluous to the complaint, abnormal reflexes may be a clue to an acute electrolyte disorder that ultimately explains the presentation.
Diagnosis and Differential
Different causes of acute constipation are listed in Tables 2, 3, and 4. The presence of significant abdominal pain should alert the clinician to the possibility of serious conditions such as bowel obstruction, including volvulus, perforated diverticulum, and ischemic colitis. Rectal pain may be associated with fecal impaction, rectal abscess, rectal fissure, or hemorrhoids. Associated bright red blood may accompany these rectal conditions, but may also be associated with malignancy, inflammatory bowel disease, or diverticulitis.
Constipation with intermittent diarrhea may indicate an obstructing colonic lesion such as carcinoma, fecal impaction, or undisclosed rectal foreign body. Alternatively, mixed constipation with diarrhea may be associated with inflammatory bowel disease and irritable bowel syndrome. Flatulence, bloating, and foul-smelling feces may be associated with malabsorption syndrome. Vomiting (especially if recurrent) and inability to pass flatulence is associated with bowel obstruction. Volvulus is more frequent in patients older than 80 years and in the institutionalized patient. Decreasing caliber of stool could indicate an obstructing carcinoma, while small caliber stool since birth could herald Hirschsprung's disease in an infant.
Fecal Impaction. Patients with fecal impaction may have fever and/or leukocytosis,8 but the presence of these markers should prompt the physician to consider other more serious conditions such as diverticulitis, urinary tract infection, or pneumonia. Coexistent hemorrhoids are common with fecal impaction.8 When fecal impaction is suspected clinically, yet the patient has an empty rectal vault, a radiographic investigation for bowel obstruction is warranted, and may verify impaction beyond the reach of the examiner's finger (see below for a discussion for bowel obstruction associated with fecal impaction). Untreated fecal impaction will continue to yield abdominal distention, which can limit ventilation leading to tachypnea.9,10
Life-Threatening Conditions Presenting with Constipation. Emergency physicians should pay particular attention to Table 4, which lists the potentially life-threatening causes of constipation. While these patients typically would be expected to appear acutely ill, that is not always the case.
Abscess. Patients with rectal abscess typically complain first of rectal pain rather than constipation, but presentations vary. Classically, the patient will complain of throbbing or dull aching pain that is made worse immediately prior to bowel movements, and the dull pain persists between bowel movements. Patients fear the worsening of pain, therefore they hold stool, occasionally leading to the patient's conclusion that the problem is constipation. A rectal exam may confirm a superficial perianal abscess. Deeper abscesses may not be visible on external exam, but typically reveal significant rectal tenderness associated with a complaint of significant rectal pain. Confusing presentations may require CT scanning or evaluation with ultrasound for clarification.
Diverticulitis. The clinical diagnosis of diverticulitis is suggested in patients whose abdominal pain begins diffusely or in the hypogastrium and then localizes to the left lower quadrant. Co-existent diarrhea is more common than constipation, but constipation may occur, and is found more frequently in patients with obstruction. Colonic obstruction is more common in patients with recurrent episodes of acute diverticulitis. Patients with severe symptoms generally should receive investigation with CT scanning. Patients may go on to perforation, and these patients generally are sicker with fever, leukocytosis, and more severe tenderness. Surgical consultation should be considered for patients with marked tenderness, free air, any sign of air in the colon wall, or dilation greater than 10 cm.
Bowel Obstruction. The symptoms of severe constipation and bowel obstruction can be identical and, therefore, obstruction can be missed, sometimes with fatal results.5,11 In a study of pre-test diagnostic accuracy, the pre-CT suspicion of bowel obstruction was accurate in only 39% of cases; conversely, 50% of those found to have bowel obstruction by CT exam were suspected of other disorders prior to scan.12 Small bowel obstruction and large bowel obstruction may present with similar symptoms, but these conditions have very different risk factors. Chief causes of small bowel obstruction are adhesions, inflammatory bowel disease, incarcerated hernia, neoplasm, and congenital anomalies. Causes of large bowel obstruction include carcinoma, diverticulitis, and volvulus. Large bowel obstruction is common in the elderly and the institutionalized patient (fecal impaction as an entity is discussed above). In a small study of 19 patients who were found to have evidence of obstruction on plain film radiography (diffuse small or large bowel dilatations), constipation was the presenting complaint.13 Forty-two percent had impaction reachable by digital exam, 26% had leukocytosis, 53% had electrolyte abnormalities, and only 16% had air-fluid levels on plain abdominal radiographs. Patients were treated successfully with sigmoidoscopy providing relief of abdominal distension and pain. Based on 743 patients in a 2005 meta-analysis, the sensitivity of CT for the diagnosis of bowel obstruction with ischemia was 83%, the specificity of 92%, the positive predictive value was 79%, and the negative predictive value was 93%.14 Enteroclysis (oral contrast given with the assistance of a tube passed beyond the pylorus) with CT has been recommended in this setting, but may be beyond the capability of many EDs.15
Volvulus. Chronic constipation is a risk factor for sigmoid volvulus as a large redundant colon is produced and is more likely to twist.16,17 Other risk factors for sigmoid volvulus include advancing age, institutionalization, and prolonged bed rest. Volvulus occurs when a loop of large bowel twists on a fixed point at the base. Most commonly this occurs at the sigmoid, but also at the cecum and rarely in the transverse colon. Sigmoid volvulus presents identically to other forms of large bowel obstruction. Volvulus frequently is missed or misinterpreted on plain films. A 2006 retrospective study found that plain films of the abdomen missed 44% of 29 cases of sigmoid volvulus.17 In that review, it was found that only 58% of patients with sigmoid volvulus complained of pain, while 79% complained of abdominal distension and 55% complained of obstipation. In a Veterans Affairs study, 22% of patients with sigmoid volvulus presented with a clinical picture of constipation with nausea, vomiting, and abdominal pain; 67% had abdominal distension.16 Sigmoid volvulus is treated first with endoscopic detorsion, and is successful in approximately 81% of cases,16 unless the patient has signs of gangrene or peritonitis, in which case surgery is indicated. There is a high recurrence rate, as much as 43%.17 Constipation is not a clear risk factor for cecal volvulus; however, it is frequently misdiagnosed and should be considered in patients thought clinically to have bowel obstruction.17,18
Ischemic Large Bowel. There are two clinically distinct presentations of large bowel ischemia that may be associated with a complaint of constipation: bowel obstruction that has progressed to ischemia and ischemic colitis. Unlike small bowel ischemia, colonic ischemia is rarely due to major arterial occlusion. Ischemic colitis typically results from low flow states or small vessel occlusion. Risk factors include hypotension, vascular disease, diabetes mellitus, and vasculitis. Typical symptoms are cramp-like abdominal pain, distention, and bloody diarrhea, but may mimic constipation with overflow diarrhea and hemorrhoid bleeding, or may present without bleeding.11 Medical management is the mainstay of treatment except when signs of acute abdomen are present, such as guarding or rebound tenderness, or with evidence of perforation on CT scan (free air, air in the colon wall, or free fluid compatible with abscess). In these later cases, surgery is recommended. All patients suspected of having ischemia in association with obstruction require surgical consultation. CT has good but not excellent sensitivity for picking up ischemia in the setting of bowel obstruction, missing 17% of cases.14
Colon Cancer. A retrospective study of 358 patients referred for colonoscopy plus 205 patients referred for flexible sigmoidoscopy who complained of constipation revealed a prevalence of colon cancer of 1.6%, and a 14.4% prevalence of adenoma.19 The authors concluded: "the range of neoplasia in patients with constipation evaluated with lower endoscopy was comparable with what would be expected in asymptomatic subjects undergoing colorectal cancer screening." Indeed, constipation alone is not an indication for urgent colorectal screening for cancer, despite the fact that the incidence of cancer appears to be higher in this group.20
The association of constipation and occult blood in the stool is common with colon cancer. When these symptoms occur together, referral for colonoscopy with biopsy should be arranged. Colonoscopy also may reveal other sources of bleeding missed on CT scan. Colonoscopy typically is done as an outpatient. In the stable patient without signs of obstruction, even in the face of weight loss, there is no mandate for CT on an emergent basis; however, patients should have blood counts performed in the ED to help verify clinical stability. Assured follow-up is essential in patients sent home from the ED.
Toxic Megacolon. Megacolon can occur in association with chronic constipation, and may be difficult to distinguish clinically from volvulus even after obtaining plain film radiography.21 Toxic megacolon has defined criteria for the diagnosis using plain film radiography and clinical information. The diagnosis is made by any three of the following criteria: fever greater than 101.5° F (> 38.6° C); heart rate greater than 120 beats/min; white blood cell count greater than10.5 X 109/L; or anemia, plus any one of the following: dehydration, mental status changes, electrolyte disturbances, or hypotension.22 The majority of patients have a history of inflammatory bowel disease and present after an episode of exacerbation has started, initially with bloody diarrhea, fever, chills, and abdominal cramping. The onset of toxic megacolon is variable, but may present with abdominal distention, obstipation, and reduced bowel sounds accompanied by fever, tachycardia, and hypotension.23 On plain films, the colon is dilated greater than 6 cm, and dilations of up to 15 cm are not uncommon. CT scanning is recommended to better define sub-clinical perforations, and abscesses not apparent on physical exam or plain radiography.24 These patients typically appear ill and require admission for resuscitation including fluids, antibiotics, and surgical consultation.
Diagnostic Studies
Unlike chronic constipation, there is no authoritative document to guide the work-up and management of acute constipation. For simple constipation, plain film radiography has not been shown to be helpful, and may be misleading in both adults and children.25,26 The presence of stool in the large bowel on plain radiography is an expected finding and does not make the diagnosis of simple constipation at the exclusion of other more serious conditions. Indeed, all diagnostic testing performed in the ED for the evaluation of constipation should be aimed at the inclusion or exclusion of more serious conditions. Tests to consider include electrolytes, calcium level, renal function tests, complete blood count, and thyroid function tests. If suspecting obstruction, an upright chest and abdomen, and a supine abdomen radiograph may reveal dilated large or small bowel and/or air fluid levels. However, a CT scan of the abdomen and pelvis with oral and intravenous contrast may be needed to rule out more significant pathology, or confirm the presence of obstruction. Finally, in difficult cases, enteroclysis may be needed to identify small bowel obstruction (see discussion above concerning bowel obstruction) or contrast enema in case of suspected large bowel obstruction. An inpatient setting may be required to accomplish these later studies.
Alarm Symptoms. Certain symptoms found in association with constipation warrant a more extensive work-up, according to the American College of Gastroenterology Chronic Constipation Task Force.27 Those symptoms are: hematochezia, anemia, or occult blood in the stool; weight loss greater than 10 pounds; family history of colon cancer; family history of inflammatory bowel disease; and abdominal mass palpable on exam. Those recommendations were made for chronic constipation; however, they provide a guide for patients who require more urgent follow-up when such testing is not required for evaluation and treatment in the ED. Patients with alarm symptoms can be expected to have a higher rate of colon cancer, and therefore require more urgent follow-up. For patients who are stable and for whom discharge home is planned, the presence of alarm symptoms should prompt follow up within one to two weeks so further testing can be initiated.
Emergency Management
The most important management decision on behalf of patients presenting with a complaint of constipation is not what agent to use to relieve the symptoms, but the decision to further investigate with diagnostic testing as outlined above. The second decision is to determine whether or not manual dis-impaction is needed. After this has been accomplished or the rectum has been found to be empty of hard stool, a logical treatment plan can be initiated.
Treatment of Fecal Impaction. Patients with fecal impaction require manual removal.8,28 Topical anesthetic lubricant, such as viscous lidocaine, should be used to provide local anesthesia. Consideration should be given to sedation as well. The anus should be dilated using two fingers, and the stool broken up using a scissoring motion. As much stool as possible should be removed manually. These efforts can be followed by an enema; however, enemas are only helpful if the patient can retain it, making this treatment less useful in debilitated patients. Tap water or oil retention enemas are recommended,28 but the evidence for their preference over other enema formulations is weak. Soap suds can be a local irritant to the rectal mucosa and can cause colitis.29-31 It must be acknowledged that soap suds enemas have been used in EDs for decades, and the incidence of complications is unknown. An enema of water soluble contrast material (meglumine diatrizoate, or Gastrografin) can be used diagnostically as well as therapeutically, and this formulation has been successful in the setting of colonic pseudo-obstruction.32 A meglumine diatrizoate enema generally is given in the radiology suite. If stool is higher than what can be reached with simple enemas, polyethylene glycol (PEG) balanced solution is recommended as the best studied agent in the setting of fecal impaction.33,34 Administration of PEG typically requires an inpatient setting for patients with disability, and the dose is listed in Table 5. Oral treatment, with or without the balanced electrolytes, is recommended in children for the treatment of fecal impaction.35-37
| Table 5. Agents Used in the Treatment of Acute Constipation |
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General Treatment Measures. Multiple agents are used acutely, but few have been tested in well-designed clinical trials. Almost all trials have used definitions of chronic constipation for patient inclusion. Therefore, treatment recommendations for acute constipation as detailed in Table 5 are inferred from studies in the treatment of chronic of subacute constipation. Increasing dietary fiber would seem to be a sensible recommendation to patients with simple constipation,38 and it appears that all forms of dietary fiber are equally effective.39 Introduction of fiber to a patient's diet typically results in bloating that resolves over 3-4 weeks, and when introduced slowly is better tolerated. Dietary fiber, as well as psyllium, undergoes bacterial degradation in the intestine which contributes to bloating and flatus. Methylcellulose and polycarbophil are semisynthetic fiber that are relatively resistant to bacterial degradation (and less prone to bloating) but have not been shown to be as effective as the preferred bulk agent, psyllium.27 Psyllium has been shown to be more effective than docusate sodium.40 For simple transient constipation, dietary fiber will help the patient without significant pathology, and continues to be recommended in the literature, even if limitations of its effectiveness are acknowledged.41-43
Polyethylene glycol without electrolytes (such as Miralax) is an effective treatment, lacks the advantage of the balanced electrolytes, but is an acceptable alternative in patients unlikely to have preexisting electrolyte abnormalities or comorbidities, for both children and adults.37,44 Stool softeners such as docusate sodium have been shown to be no more effective than placebo.45 Mineral oil has been reported to be helpful by softening and lubricating stool, but is contraindicated in patients with swallowing disorders, and may prevent the absorption of fat soluble vitamins. Glycerin suppositories may be effective in mild cases, but also may cause local irritation and cramping. Magnesium citrate or milk of magnesia is used widely; magnesium toxicity is a potential adverse effect (a concern mainly in patients with renal insufficiency) along with the side effects of cramping and flatulence. Stimulant laxatives such as senna or cascara sagrada are converted to their active form by colonic bacteria and stimulate motility of the large bowel. These drugs have been thought to cause cathartic bowel, but pathologic confirmation of these changes is lacking.46 They cause a condition known as melanosis coli, which darkens the colonic mucosa and resolves after discontinuation of the laxatives.47 There is no known association of cancer with melanosis coli.48 In pregnant patients, fiber supplements are recommended, but stimulant laxatives such as senna can be used in patients who fail to respond to fiber.6
Enemas commonly are given in the ED as well as prescribed for home use. However, in general, enema therapy has been poorly studied, with no clinical trials to guide recommendations. Commonly used formulations are listed in Table 6. None can be recommended as evidence-based or without cautions; however, the incidence of any harmful side effects is equally unknown. Judging by case series and reports, complications are reported more frequently in children. Almost all enema formulations can cause cramping and bloating, which is less likely with tap water and mineral oil enemas. Individual concerns include cardiovascular compromise with milk and molasses use in children with chronic debilitating diseases,49 colitis with the use of soapsuds,29-31 water intoxication with the use of tap water,50,51 magnesium intoxication from use of Epsom salts (magnesium sulfate) enemas,52-54 and hyperphosphatemia and hypocalcemia with use of phosphate enemas.55 Rectal perforation is possible from any enema preparation due to instrumentation.56-58
| Table 6. Commonly Used Enema Formulations* and Associated Side Effects |
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Specific Treatments for Associated Disorders. Anal lesions may need local care. Hemorrhoids that are thrombosed will need excision and drainage. A meta-analysis has shown fiber to be an effective adjunct to the treatment of hemorrhoids, reducing bleeding and discomfort.59 Anal fissures will benefit from stool softeners (as contrasted to chronic constipation, where they have little benefit). If discovered, electrolyte disorders will need treatment, as well as other metabolic or hormonal disorders (i.e., hypothyroidism). The majority of life-threatening disorders discussed will require surgical or gastroenterology consultation.
Chronic Presentations of Constipation
Etiology of Chronic Constipation. Inadequate fiber in the diets of symptomatic patients is reported as the most common cause of chronic constipation.60 However, in the elderly, constipating medications (see Table 3) and inadequate caloric intake may be more important causes.61,62 It is commonly believed that inadequate fluid intake predisposes patients to constipation,28,41 and it has been shown that decreased fluid intake increases stool firmness.63 However, four studies failed to show an association between daily fluid intake and constipation.62,64-66 Using a definition of fewer than three bowel movements per week, patients with constipation have double the risk of developing colon cancer.20 Laxative use does not appear to be marker of similar significance.
Clinical Presentations of Chronic Constipation. Chronic conditions associated with constipation are listed in Table 7. The diagnosis and management of the patient's constipation typically would begin prior to evaluation in the ED, and care would need to be coordinated by a return visit to the patient's doctor. A review of the patients past medical history and recent history of illness should reveal the etiology of these disorders without diagnostic work-up. Two conditions deserve discussion here.
| Table 7. Chronic Causes of Constipation |
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Irritable Bowel Syndrome. Irritable bowel syndrome (IBS) is common; 15% of U.S. adults report symptoms compatible with IBS.67 IBS is more common in women, is the most frequent disorder seen by gastroenterologists, and accounts for 12% of the visits to primary care providers.68 Many theories have been described, but there remains no pathological basis for the disease.69 The diagnosis is made with clinical criteria based on consensus conferences, the Rome criteria. Three symptomatic forms exist, pain predominant, diarrhea predominant, and constipation predominant forms. Treatments for the constipation predominate form include dietary changes, osmotic laxatives, other laxatives, and 5-HT-receptor agonists; tegaserod currently is approved for short-term treatment in women.70,71 Tegaserod is not currently recommended in men, and is not recommended to be prescribed out of the ED.
Pseudo-obstruction (Ogilvie syndrome). Colonic pseudo-obstruction or Ogilvie syndrome may present with symptoms identical to colonic obstruction: vomiting, abdominal distention, and cramping pain. However, it typically has a more prolonged onset, occurring over several weeks or even months. On investigation with CT scanning or at surgery, no mechanical obstruction is found. It can lead to chronic dilation of the colon and can be fatal.72 Initial treatment consists of cessation of any drugs that may be causing the disorder (i.e., narcotics, anticholinergics,) bowel rest, and intravenous fluids and enemas as needed. Consultation for colonoscopic decompression may be needed. Exclusion of true obstruction may require Gastrografin or barium enema.
Diagnostic Studies for Chronic Constipation. In 2005, the American College of Gastroenterology Chronic Constipation Task Force published "An Evidenced-Based Approach to the Management of Chronic Constipation in North America" document.27 In the document they comment that no studies examine the utility of laboratory testing for patients who complain of chronic constipation (that is, complete blood count, serum calcium, electrolytes, renal function tests, thyroid function tests, cosyntropin test for adrenal insufficiency, and others). Patients who are suspected clinically to have a complication of constipation such as colonic obstruction should undergo acute testing including imaging, as guided by the section on acute presentations.
Patients without acute presentations should be referred for outpatient testing as guided by the alarm symptoms described in the Acute Constipation Diagnostic Studies section. The presence of alarm symptoms should be used to determine the urgency of follow-up, within two weeks if those symptoms are present.
Emergency Management of Chronic Constipation. The American College of Gastroenterology Chronic Constipation Task Force evaluated treatments for chronic constipation that provides a guide for outpatient treatment of constipation after the ED visit. Table 8 is based on that report; recommended treatments are "grade B" or better, which reflects efficacy as documented in randomized controlled studies.27 An acceptable alternative to the three treatments listed in Table 8 for use in the outpatient setting is polyethylene glycol 3350 without balanced electrolytes. This agent has been well studied in the chronic constipation population.37,44
| Table 8. ACGCCTF Recommended Evidence-Based Treatments for Chronic Constipation27 |
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Since the publication of the American College of Gastroenterology Chronic Constipation Task Force document, a double-blind, randomized, placebo-controlled trial assessing 10 mg of oral bisacodyl has been published.73 Patients in the treatment group had twice the number of stools as the placebo group. Incidence of adverse events was similar between groups.
Disposition
While no patient with simple constipation should be admitted to the hospital, no patient with unresolved or incompletely diagnosed abdominal pain and distension should be discharged home. The need to admit a patient complaining of constipation depends almost entirely on the underlying cause and the certainty of the diagnosis. A patient with a fecal impaction who is successfully treated with disimpaction and subsequently has a large stool output with or without enema, may be considered for discharge provided the patient is sufficiently mobile, and abdominal pain has resolved completely. However the patient may still require close follow-up. In general, the greater the patient's disability, the more likely that the patient will require admission for treatment of fecal impaction and/or continued diagnostic testing. Functional, independent patients with simple constipation will be well served with a treatment plan (see Table 5) and recommendations for follow-up, with the presence or absence of alarm symptoms to guide the urgency of follow-up. Patients over 50 years of age meeting Rome II criteria for constipation, even those without alarm symptoms, should have colonoscopy.74
Medicolegal Concerns and Pitfalls
The pitfalls associated with the management of patients presenting with constipation are similar to the medicolegal concerns: missing a surgical or life-threatening condition. Therefore the emergency physician should not assume the patient's chief complaint is the diagnosis: look for a potential serious cause of constipation. To a lesser extent, failing to recommend follow-up for all patients who present with constipation for colon cancer screening is a medicolegal concern, but this is not a commonly cited action against emergency physicians. All too commonly, emergency physicians recommend treatments for constipation with no efficacy (i.e., stool softeners) because of a belief that recommending a laxative will promote abuse. Tables 5 and 8 give the emergency physician a number of treatments that have been proven effective for both acute and chronic constipation.
Summary
The most important task for the emergency physician caring for patients who present with a complaint of constipation is identifying those patients at risk for serious disease using a careful history and physical exam, and selective use of diagnostic testing. Identification and treatment fecal impaction is an essential part of the management. Effective therapy and timely follow-up should be prescribed for those patients deemed to have non-serious presentations of constipation.
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Constipation is a common medical problem that, in its simple, uncomplicated form is not an urgent medical problem. However, constipation is a frequent chief complaint of emergency department (ED) patients.Subscribe Now for Access
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