Assessment for chronic constipation should begin with a discussion of the patient's complaint, to clarify what she or he means by "constipation." General information regarding the patient's bowel functions and habits should be obtained. The clinician should determine the patient's perception of a "normal" bowel movement by asking the patient about bowel movement frequency, level of straining, and stool consistency. The clinician should also assess the patient's medication profile to look for highly constipating medications and, if appropriate, recommend either a dose reduction or alternative therapies. Clear documentation of laxative use (ie, its frequency, efficacy, and duration of use) can also provide crucial historical data.
The focus of the physical examination should be the exclusion of systemic disease or a structural disorder of the intestines. A thorough exam can help to reveal the underlying pathophysiologic process when constipation does not respond to simple treatment. The physical exam should include a rectal examination to rule out an obstruction. The presence of any blood in the stool should be evaluated further. In addition, the abdomen should be examined for masses and stool-filled bowel loops.
Basic laboratory tests for an individual with chronic constipation include a complete blood count, serum blood urea nitrogen, serum creatinine, serum sodium, serum calcium, serum magnesium, a thyroid-stimulating hormone level, and stool for occult blood. Sigmoidoscopy or colonoscopy should be considered for any person with prolonged chronic constipation. An abdominal x-ray is also important to exclude fecal impaction. Additional tests that may be helpful include colon transit measurements, colonic manometry, anorectal manometry, balloon expulsion testing, and defecography.
When to Refer?
When evaluating a patient suffering from constipation it is important to look for "red flag" signs such as acute onset of constipation, weight loss, rectal pain, rectal bleeding, iron deficiency anemia, and family history of colon cancer. If any "red flags" are present, the patient will require urgent evaluation and referral to a gastroenterologist for colonoscopy.
The following red flags give an indication that specialty care may be warranted:
- Rectal bleeding (should always be referred)
- Rectal pain, especially with defecation (suggests an anal disorder)
- Unintentional weight loss: Has the patient experienced any dramatic weight loss that was not the result of a prescribed diet?
- Acute onset of chronic constipation, particularly after age 50 (be sure to refer any patient over age 50 who has not previously had a colonoscopy for that procedure)
- Family history of colon cancer, inflammatory bowel disease, or celiac disease
- Fecal urgency, fecal or urinary incontinence, and the need for manual disimpaction
- Abnormalities on the physical exam (eg, masses in the abdomen, abnormal rectal exam)
- Positive fecal occult blood test
- Anemia/decreased hemoglobin
- Increased white blood cell count
- Elevated C reactive protein or erythrocyte sedimentation rate (ESR)
- Abnormal serum chemistries or abnormal thyroid function studies
Last but not least, when a patient has had inadequate responses to all measures attempted to alleviate his or her chronic constipation, referral is an appropriate next step to explore other possible interventions.
Julia C. Pallentino, MSN, JD, ARNP, FAANP
Advanced Registered Nurse Practitioner
GI Associates of Tallahassee