Managing Chronic Constipation in Women

Case Summary

A healthy 42-year-old woman presents with a long-standing history of constipation presents for evaluation. She reports that she has been taking psyllium daily, eats a high-fiber diet with prunes, vegetables, and drinks plenty of fluids. She reports worsening constipation with bowel movements once every 3–4 days. The stool is usually hard and like small pellets. She also reports bloating and increased flatulence. She denies unintentional weight loss or blood in her stool. The examination is normal. Blood tests show normal complete blood count, thyroid stimulating hormone, and metabolic panel.

What is the next best step in her management?

Answer: B.

This patient presents with symptoms of chronic constipation without associated alarm features such as anemia, unintentional weight loss, or blood in the stool, suggesting she suffers from chronic idiopathic constipation (CIC). Chronic constipation, characterized by infrequent and difficult bowel movements without an identifiable underlying cause, affects ∼14% of adults worldwide and is seen more commonly in women, older individuals, and those of a lower socioeconomic status. ^1,2 This review will discuss CIC's diagnosis and treatment options based on current clinical practice guidelines and published literature.

The diagnosis of CIC is primarily based on the patient's clinical history and physical examination. Laboratory testing, colonoscopy, and other specific testing may also be indicated in some patients. ³ The Rome IV criteria guide the diagnosis of CIC, defining it as chronic constipation symptoms (less than three bowel movements per week) associated with two or more of the following: straining, incomplete evacuation, hard or lumpy stools, the sensation of obstruction or blockage, fewer than three spontaneous bowel movements per week, need for manual maneuvers, and insufficient criteria for irritable bowel syndrome.

The criteria require that symptom onset be at least 6 months before the diagnosis and present for at least 3 months before the diagnosis can be made. ³ When evaluating a patient for CIC, a thorough medical history should be obtained, including frequency of bowel movements, stool consistency, presence of straining, and use of laxatives.

A medication review is important to identify possible medications with constipating side effects. A physical examination, including a rectal examination, should also be performed to evaluate for structural abnormalities such as rectal prolapse or evidence of pelvic floor dyssynergia. Several references are available regarding digital rectal examination techniques in patients with constipation. ^{4 –6}

In addition to the patient's clinical history, various tests may be considered as part of the evaluation for CIC. A complete blood count to screen for anemia is recommended by the American Gastroenterology Association. ⁶ Metabolic testing, such as thyroid, calcium, or glucose testing, is not strictly required for constipation symptoms, although it can be considered if other clinical features warrant further investigation. In the absence of alarm features, colonoscopy is not typically recommended.

However, colonoscopy can be considered for patients who need age-appropriate colorectal cancer screening. It should be noted that in 2021 the United States Preventive Services Task Force updated its colon cancer screening recommendations to include a Grade B recommendation for initiating screening in adults at age 45. ⁷ Additional testing such as anorectal manometry and colon transit studies may be useful for patients whose symptoms are refractory to laxative therapy.

Initial management strategies for CIC include lifestyle and dietary modifications. ⁸ Increased physical activity, adequate hydration, fiber consumption, and establishing a regular bowel routine and allowing time for bowel movements are important first steps. As noted earlier, conducting a medication review to identify potential transit-slowing agents can also be helpful, especially when these medications can be discontinued.

Using a squatting stool at the toilet's base to promote proper defecation positioning can be beneficial. Finally, consuming adequate dietary fiber is also an important strategy for managing CIC. Dietary fiber has diverse effects on the gastrointestinal tract, and studies have shown that dietary fiber and fiber supplementation can improve constipation symptoms. ^9,10

In addition to lifestyle and dietary modification, multiple pharmacological therapies are also available to treat CIC. PEG-based products are recommended early in the treatment course and can be used in conjunction with fiber supplementation. ⁸ PEG is an osmotic laxative that draws water into the intestinal lumen, allowing softer stools to pass more easily.

Although generally well tolerated, some patients may experience bloating, nausea, and loose stools. Other osmotic laxatives that could be considered include magnesium oxide and lactulose syrup. Notably, magnesium oxide should be avoided in patients with renal insufficiency due to a risk of hypermagnesemia. Compared with lactulose, PEG has been shown in at least one meta-analysis to be superior for treating constipation. ¹¹

Stimulant laxatives, such as senna and bisacodyl, are also available over the counter for the treatment of CIC. The long-term safety of these medications has not been well studied; thus, use is typically recommended for short-term rescue therapy. A direct comparison between osmotic laxative therapy with magnesium oxide, stimulant laxative therapy with senna, and placebo showed that both senna and magnesium oxide improved the frequency of bowel movements and quality of life compared with placebo. ¹² The use of sennasoides is not recommended for pregnant patients. ⁸

Prescription laxative therapies, which include secretagogues and 5-HT₄ agonists, are also available for patients who fail or have suboptimal responses to the aforementioned interventions. ¹³ These agents may be particularly useful in patients with long-standing chronic constipation refractory to other therapies. Prescription laxatives can be used as replacements or adjuncts to over-the-counter laxatives. ⁸ Side effects may include diarrhea, headache, abdominal pain, and nausea. Suicidal ideation/behavior has also been reported with the use of prucalopride, a 5-HT₄ receptor agonist, although this is rare. Availability of these agents may be limited by insurance coverage and cost, which can be prohibitive.

Further testing, such as anorectal manometry and defecography, may be warranted for patients who continue to endorse constipation symptoms despite treatment. Biofeedback and pelvic floor muscle therapy can be considered for patients with anorectal dysfunction or pelvic floor disorders.

Answer: The correct answer is (B).

Option A: Fiber supplementation is recommended as initial therapy for patients with CIC. If symptoms do not improve, therapy can be escalated to laxative use. Discontinuation of fiber is not necessary and may exacerbate constipation.

Option C: Reassurance is inappropriate as the patient still has symptomatic constipation.

Option D: Colonoscopy is usually unnecessary unless a patient has alarm symptoms or needs age-appropriate colorectal cancer screening.

Option E: Linaclotide and other prescription medications may be needed but should be considered after patients fail lifestyle modification, dietary change, and over-the-counter laxative therapy.