Common Functional Gastroenterological Disorders Associated With Abdominal Pain

Abstract

Although abdominal pain is a symptom of several structural gastrointestinal disorders (eg, peptic ulcer disease), this comprehensive review will focus on the 4 most common nonstructural, or functional, disorders associated with abdominal pain: functional dyspepsia, constipation-predominant and diarrhea-predominant irritable bowel syndrome, and functional abdominal pain syndrome. Together, these conditions affect approximately 1 in 4 people in the United States. They are associated with comorbid conditions (eg, fibromyalgia and depression), impaired quality of life, and increased health care utilization. Symptoms are explained by disordered gastrointestinal motility and sensation, which are implicated in various peripheral (eg, postinfectious inflammation and luminal irritants) and/or central (eg, stress and anxiety) factors. These disorders are defined and can generally be diagnosed by symptoms alone. Often prompted by alarm features, selected testing is useful to exclude structural disease. Identifying the specific diagnosis (eg, differentiating between functional abdominal pain and irritable bowel syndrome) and establishing an effective patient-physician relationship are the cornerstones of therapy. Many patients with mild symptoms can be effectively managed with limited tests, sensible dietary modifications, and over-the-counter medications tailored to symptoms. If these measures are not sufficient, pharmacotherapy should be considered for bowel symptoms (constipation or diarrhea) and/or abdominal pain; opioids should not be used. Behavioral and psychological approaches (eg, cognitive behavioral therapy) can be helpful, particularly in patients with chronic abdominal pain who require a multidisciplinary pain management program without opioids.

Figure 1

Common Functional Gastrointestinal Disorders. These disorders are defined by specific criteria but often coexist. Conditions associated with pain are marked with an asterisk (*).

Figure 2

Diagnostic Criteria and Algorithm for Common Functional Gastrointestinal Disorders Associated With Abdominal Pain. This algorithm applies the Rome criteria, which are widely used in research studies. Irritable bowel syndrome is defined by abdominal pain accompanied by 2 of these 3 criteria: relief with defecation, altered stool consistency (loose or hard stools), or altered frequency (less or more frequent). The other syndromes are defined by the listed criteria. The criteria also specify the duration and frequency of symptoms, in general, a duration of 6 months and frequency of 2 days every week or more often.

Figure 3

Pathogenesis of Common Functional Gastrointestinal Disorders. Genetic predisposition and psychological factors contribute to a variety of gastrointestinal sensory and motor dysfunctions that contribute to symptoms (left panel). Center panel shows some factors (eg, bile acids, postinfectious inflammation) that alter mucosal permeability, stimulate enterochromaffin cells, and activate immune mechanisms to stimulate afferent nerves. Central sensitization may result from this peripheral sensitization and/or reduced descending inhibition, which normally gates visceral sensation in the spinal cord.

Figure 4

Multidisciplinary Management of Functional Gastrointestinal Disorders. After a meticulous clinical assessment, many patients with mild symptoms can be effectively managed with limited tests, sensible dietary modifications, and over-the-counter medications tailored to symptoms. Gastrointestinal endoscopy and imaging should be performed only when indicated. Behavioral and psychological approaches can be very helpful, particularly in patients with chronic abdominal pain who require a multidisciplinary pain management program without opioids.