Table 1. Symptom Criteria for Constipation
Irritable Bowel Syndrome (IBS)
Criteria fulfilled for the last 3 months with symptom onset ≥6 months prior to diagnosis.
Recurrent abdominal pain, on average, ≥1 day per week in the last 3 months, associated with ≥2 of the following criteria:
- Improved with defecation
- Associated with a change in frequency of stool
- Associated with a change in form (appearance) of stool
IBS with predominant constipation (IBS-C):
More than one-fourth (25%) of bowel movements with Bristol stool form types 1 or 2 and less than one-fourth (25%) of bowel movements with Bristol stool form types 6 or 7.
Alternative for epidemiology or clinical practice: Patient reports that abnormal bowel movements are usually constipation (like type 1 or 2 in the picture of Bristol Stool Form Scale (BSFS), see Figure 1A).
Functional Constipation (FC)b
FC is a functional bowel disorder in which symptoms of difficult, infrequent, or incomplete defecation predominate. Patients with FC should not meet IBS criteria. Although abdominal pain and/or bloating may be present, they are not predominant symptoms. Symptom onset should occur ≥6 months before diagnosis, and symptoms should be present during the last 3 months.
General Definition of Constipation
- infrequent bowel movements, typically fewer than 3 per week and persistent
- hard stools
- a feeling of incomplete evacuation
- abdominal discomfort, bloating, and distention
- excessive straining
- a sense of anorectal blockage during defecation
- need for manual maneuvers during defecation
Prolonged and excessive straining before elimination
- When evacuatory defects are pronounced, soft stools and even enema fluid may be difficult to pass.
Need for perineal or vaginal pressure to allow stools to be passed or direct digital evacuation of stools
Diagnosis requires anorectal tests (manometry, rectal balloon expulsion, or defecography [barium or MRI]) suggestive of a defecatory disorder
Normal transit constipation (NTC)
Normal colonic transit and anorectal functions
Slow transit constipation (STC)
Slow colonic transit and normal anorectal functions
Some patients may have combination or overlap disorders (eg, STC with defecatory disorders), perhaps even associated with features of irritable bowel syndrome.
a Criteria fulfilled for the last 3 months with symptom onset ≥6 months before diagnosis.
b For research studies, patients meeting criteria for OIC should not be given a diagnosis of FC because it is difficult to distinguish between opioid side effects and other causes of constipation. However, clinicians recognize that these 2 conditions might overlap.
GRADE Strength of Recommendations and Implications
|Grade||Implications of strong and conditional (weak) |
|Strong||Patients: Most individuals in this situation would want the recommended course of action and only a small proportion would not. |
Clinicians: Most individuals should receive the recommended course of action. Formal decision aids are not likely to be needed to help individuals make decisions consistent with their values and preferences.
|Conditional (weak)||Patients: The majority of individuals in this situation would want the suggested course of action, but many would not. |
Clinicians: Different choices will be appropriate for different patients. Decision aids may well be useful in helping individuals making decisions consistent with their values and preferences.
Clinicians should expect to spend more time with patients when working toward a decision.
- If feasible, discontinue medications that can cause constipation before further testing (Strong; Low Quality of Evidence).
- A careful digital rectal examination that includes assessment of pelvic floor motion during simulated evacuation is preferable to a cursory examination without these maneuvers and should be performed before referral for anorectal manometry. However, a normal digital rectal examination does not exclude defecatory disorders (Strong; Moderate Quality of Evidence).
The key components of the rectal examination include:
- In the left lateral position, with the buttocks separated, observe the descent of the perineum during simulated evacuation and the elevation during a squeeze aimed at retention. The perianal skin can be observed for evidence of fecal soiling and the anal reflex tested by a light pinprick or scratch.
- During simulated defecation, the anal verge should be observed for any patulous opening (suspect neurogenic constipation with or without incontinence) or prolapse of anorectal mucosa.
- The digital examination should evaluate resting tone of the sphincter segment and its augmentation by a squeezing effort. Above the internal sphincter is the puborectalis muscle, which should also contract during squeeze. Acute localized tenderness to palpation along the puborectalis is a feature of the levator ani syndrome. Finally, the patient should be instructed to integrate the expulsionary forces by requesting that she or he “expel my finger.”
- An examination should then be conducted to evaluate for a rectocele or consideration be given to gynecologic consultation.
Testing for Medical Causes
- In the absence of other symptoms and signs, only a complete blood cell count is necessary (Strong; Low Quality of Evidence).
- Unless other clinical features warrant otherwise, metabolic tests (glucose, calcium, sensitive thyroid-stimulating hormone) are not recommended for chronic constipation (Strong; Moderate Quality of Evidence).
- A colonoscopy should not be performed in patients without alarm features (eg, blood in stools, anemia, weight loss) unless age-appropriate colon cancer screening has not been performed (Strong; Moderate Quality of Evidence).
- Anorectal manometry and a rectal balloon expulsion should be performed in patients who fail to respond to laxatives (Strong; Moderate Quality of Evidence).
- Defecography should not be performed before anorectal manometry and a rectal balloon expulsion test (Strong; Low Quality of Evidence).
- Defecography should be considered when results of anorectal manometry and rectal balloon expulsion are inconclusive for defecatory disorders (Strong; Low Quality of Evidence).
- Colonic transit should be evaluated if anorectal test results do not show a defecatory disorder or if symptoms persist despite treatment of a defecatory disorder (Strong; Low Quality of Evidence).
- After discontinuing medications that can cause constipation and performing blood and other tests as guided by clinical features, a therapeutic trial (ie, fiber supplementation and/or osmotic or stimulant laxatives) is recommended before anorectal testing
- (Strong; Moderate Quality of Evidence).
- Normal transit constipation (NTC) and slow transit constipation
- (STC) can be safely managed with long-term use of laxatives
- (Strong; Moderate Quality of Evidence).
- Anorectal tests should be performed in patients who do not respond to these measures (Strong; High Quality of Evidence).
- Pelvic floor retraining by biofeedback therapy rather than laxatives is recommended for defecatory disorders (Strong; High Quality of Evidence).
- When bowel symptoms are refractory to simple laxatives, newer agents should be considered in patients with NTC or STC (Conditional; Moderate Quality of Evidence).
- Anorectal tests and colonic transit should be reevaluated when symptoms persist despite an adequate trial of biofeedback therapy (Strong; Low Quality of Evidence).
- A subtotal colectomy rather than continuing therapy with chronic laxatives should be considered for patients with symptomatic STC without a defecatory disorder (Conditional; Moderate Quality of Evidence).
- Colonic intraluminal testing (manometry, barostat) should be considered to document colonic motor dysfunction before colectomy (Conditional; Moderate Quality of Evidence).
- Suppositories or enemas rather than oral laxatives alone should be considered in patients with refractory pelvic floor dysfunction (Conditional; Low Quality of Evidence).