Refractory Constipation: A Case Study in Evaluation and Management

A presentation on October 13, 2013, at the American College of Gastroenterology Annual Scientific Meeting by Satish Rao, MD (Georgia Regents University, Augusta, GA):

Rao SS. Management of Refractory Constipation

In this ACG 2013 session, Satish Rao, MD, gives us an approach to prevent the increasing numbers of hospital admissions for constipation that speaker Saurabh Sethi, MD, documented in his study, presented the following day.

Constipation is often treated as a simple functional disorder that responds well to improvements in diet, hydration, and exercise. And usually, that’s appropriate. For most elderly people, some degree of functional constipation is fairly routine, and they and their doctors tend to work through it. But Dr Rao is a consultant-so he sees the difficult cases. The one he comes back to over and over again in this discussion is a younger patient who ended up with an extensive workup. Most routine cases won’t need this. But all will need a bit of careful attention-or they can end up as one of Dr Sethi’s admission statistics.

Dr Rao’s case presentation concerned a 40-year-old woman, employed as a nurse, with chronic constipation that worsened over the past 2 years. She has only weekly, hard bowel movements, with straining but no hematochezia. Multiple laxative trials have produced diarrhea followed by absent bowel movements for up to 2 weeks. She has recurrent right lower quadrant pain that radiates superiorly, worsening postprandially and after evacuation. She has chronic bloating and gas, worsening postprandially. Her quality of life has declined, and she has missed weeks at work.

Results of basic laboratory screen, anoscopy/colonoscopy, CT scan, EGD, and MRI of spine have all been normal. Physical exam is unremarkable, including intact anocutaneous reflex, with adequate resting and squeezing anal tone. There was good perineal descent, but incomplete relaxation.

At this point, the differential diagnosis included:
• Colonic inertia
• Severe slow-transit constipation (STC)
• Dyssynergic defecation
• Carbohydrate malabsorption
• Opioid abuse (remember, this is a health care worker)

Which do you suspect? Click here to read on.

Dr Rao reminded us that constipation is common in the general population, becoming more common with aging, and more common in women. Prevalence from various cited studies ranges from 7% to 19% for men, and 18% to 34% for women; its likelihood doubles or triples between middle-age and age 80. Significant costs are associated with its treatment. There are 3 functional subtypes in primary constipation (those where no secondary cause is identified):
1. Slow-transit constipation (STC): 47% of cases
2. Irritable bowel syndrome with constipation (IBS-C): 58%
3. Evacuation disorders, such as dyssynergic defecation, or outlet obstruction (rectocele, descending perineum syndrome, or rectal prolapse): 59%

There is significant overlap among the 3 groups. Before going any further in a primary care workup, there would be secondary causes of constipation to rule out:
• Medications, most notably opioids
• Malignancy: we think of colorectal cancer, but ovarian cancer is a culprit as well
• Mechanical obstruction from any anatomic cause
• Endocrine disorders: hypothyroidism comes to mind
• Neurologic disorders
• Metabolic disorders
• Collagen vascular and muscle disorders
• Pregnancy

Dr Rao quickly ruled out all the obvious causes, and embarked on a specialty-oriented workup. Breath tests included glucose, fructose, and lactose, looking for carbohydrate malabsorption syndromes. The patient had anorectal and colonic manometry, and defecography, looking for evidence of evacuation disorders or neurologic conditions, and a wireless motility capsule evaluation (SmartPill^®).

It was the SmartPill^® that made the diagnosis: slow transit constipation.

Gastric emptying time was only slightly high, and small-bowel transit time was normal, but colonic transit time was 111 hours (normal is 17 to 59 hours). Breath testing was consistent with lactose intolerance but glucose and fructose were normal, excluding small-intestinal bacterial overgrowth (SIBO) and dietary fructose intolerance (DFI).

Testing ruled out neuropathy, so this problem should be manageable with lifestyle/behavior modification, diet, and possibly medications.

Treatment

Current treatment options in STC include tegaserod, lubiprostone, polyethylene glycol (PEG), and laxatives.

In IBS-C, the options are the same, with one exception-no laxatives, but SSRIs can be helpful. And dyssynergic defecation can be treated with the newer biofeedback therapies.

So who needs a workup?

Consider it for anyone with chronic constipation (more than 12 weeks) without an obvious secondary or dietary cause. Careful workup and management can prevent hospitalization (see Hospitalization for Constipation: A Most Preventable Admission.)