Treating the Functional GI Aspects of IBD

Between 19% and 45% of patients with inflammatory bowel disease (IBD) who are in remission present with symptoms of irritable bowel syndrome (IBS), defined as abdominal pain 1 or more days per week within the prior 3 months, related to defecation, associated with changes in stool frequency and form, Kerri Glassner, DO, told the attendees at the September 26 virtual Advances in Inflammatory Bowel Disease 2020 regional meeting.

Dr Glassner is a gastroenterologist at Houston Methodist Hospital in Houston, Texas.

“IBS-type symptoms are more frequent in patients with Crohn disease (CD) than in those with ulcerative colitis (UC)—about 46% vs 36%, respectively,” she explained. And these symptoms have a negative effect “on psychological well-being and quality of life equal to patients with active IBD.”

There are several similarities between IBD and IBS, Dr Glassner said, including aspects of pathophysiology, such as alterations in immune response and gut microbiota; symptoms including abdominal pain, bloating, diarrhea, and urgency; low-grade inflammation and immune activation; and alterations in gut microbiota.

These factors make it challenging to determine whether the patient is presenting with subclinical IBD, complications of IBD, or even “true” IBS superimposed on IBD. Other possible etiologies include medications, small intestinal bacterial overgrowth (SIBO), carbohydrate malabsorption, pancreatic exocrine insufficiency, structural complications of IBD, and bile acid diarrhea.

A detailed workup is vital in such cases, Dr Glassner stated, beginning with a comprehensive history and physical examination, including checking laboratory markers such as erythrocyte sedimentation rate, C-reactive protein, and fecal calprotectin. The latter measure is especially important in assessing whether the patient is in remission or may have a relapse of the underlying IBD. Stool testing should be done to exclude infection along with colonoscopy and perhaps endoscopic evaluation if there appears to be upper GI tract involvement or suggestive symptoms.

She also recommended a biopsy “even if the mucosa appears normal.” If histology indicates inflammation, “consider optimization of medical therapy for IBD.” Various imaging studies, including balloon enteroscopy, video capsule endoscopy, and computed tomography (CT) scan may also be warranted. “Small bowel disease may be missed without magnetic resonance or CT enterography, capsule endoscopy, or enteroscopy,” Dr Glassner said.

Diarrhea and abdominal pain could be caused by certain medications and compounds, from metformin and magnesium to sugar alcohols. Constipation may be attributable to opiates, anticholinergics, antihistamines, and several other medications or supplements.

Up to 22% of patients with UC and 30% of patients with CD also have incidences of SIBO, which can be detected by lactulose hydrogen breath testing. Carbohydrate malabsorption, which causes bloating, excessive flatus, and diarrhea, is also not uncommon among patients with IBD.

Bile acid diarrhea (BAD) “is common in patients with CD who have had ileal disease or ileal resection and in patients with CD with persistent diarrhea that is unresponsive to conventional treatment,” Dr Glassner said. The 75 selenium homocholic acid taurine retention test is unavailable in the United States, but serum C4 and fecal bile acid excretion tests can be used.

Studies have shown that patients with CD and UC may also show pancreatic exocrine insufficiency (PEI), which can cause diarrhea. However, such symptoms may be transient, Dr Glassner explained, noting that in one study, elastase values normalized in patients with IBD at 24 months.

Prior surgery for anorectal conditions and vaginal deliveries complicated by anal sphincter surgery in women can contribute to fecal incontinence or overflow diarrhea/defecatory disorder. In addition, IBD itself can create structural complications that result in dyssynergic defecation and inadequate defecatory propulsion.

“Few trials specifically address impact of different treatments on IBS-like symptoms in patients with IBD,” Dr Glassner stated. A variety of therapies have shown some efficacy in treatment of IBS, including pharmacologic, dietary, microbiota-based, and psychological. “These are almost always used in conjunction with standard IBD-directed medical therapy to retain remission,” she stated.

Pharmacologic treatment options include fiber supplements, antispasmodics, antidiarrheals, antibiotics, probiotics, neuromodulators, 5-ASAs, constipation therapies, and some narcotics.

Dietary strategies include having patients keep a food diary to identify possible trigger foods and enable avoidance. Common trigger foods include milk, caffeine, alcohol, diet foods and beverages, fatty and fried foods, and processed foods.

Psychologic interventions such as mindfulness therapy and cognitive behavioral therapy have been shown to relieve IBS-like symptoms in IBD associated with anxiety, depression, and decreased quality of life.

“IBS-like symptoms in IBD remain challenging to diagnose and manage,” Dr Glassner said. “Biomarkers, genetic testing, or microbial signatures to assist in the diagnosis and the risk for IBS in IBD are needed, as are trials to assess the impact of therapies proven effective for IBS.”

Until such more-specific tools are available, Dr Glassner said, “Always evaluate for and exclude active disease. Fecal calprotectin is a helpful noninvasive tool to rule out active disease, especially if it is more than 40 μg/g. Rule out alternative diagnoses that occur frequently in IBD such as SIBO, carbohydrate malabsorption, BAD, PEI, defecatory disorders, and structural complications. And treat IBS-type symptoms in IBD as you would in patients without IBD.”

—Rebecca Mashaw

Reference:

Glassner K. Is it IBD or IBS: treating the functional GI aspects in the IBD patient. Talk presented at: Advances in Inflammatory Bowel Disease 2020 regional meeting; September 26, 2020; virtual.