Functional Gastrointestinal Pain Syndromes
Michael D. Crowell
The Johns Hopkins University School of Medicine,
The Johns Hopkins Bayview Medical Center,
Marvin M. Schuster Center for Digestive and Motility Disorders
Functional gastrointestinal pain syndromes may be referred to the esophagus, stomach, small bowel, colon, and/or rectum. Presentation is often complex and symptoms may overlap, but generally include complaints of nausea, vomiting, bloating, altered bowel patterns, and most commonly chronic intermittent pain. Broadly defined, these disorders include non- cardiac chest pain (NCCP), nonulcer dyspepsia (NUD), and the irritable bowel syndrome (IBS). Together, these functional pain syndromes constitute the most frequent reasons for consultation with gastroenterologists. Abdominal pain is the defining characteristic and the least understood manifestation of these syndromes. The goal of this chapter is to evaluate the mechanisms responsible for pain complaints in gastrointestinal pain syndromes and to determine if each represents different manifestations of a common altered physiology, or whether each reflects different symptom and pathophysiologic profiles. The biopsychosocial aspects of chronic pain in functional bowel patients are also reviewed to emphasize the complexity of providing care for the patient with chronic visceral pain.
Merskey and Bogduk ( 1994) defined pain as the sensory and emotional sequelia resulting from insult to tissue. However, most patients with functional bowel disorders experience pain chronically or intermittently without evidence of organic lesions. Chronic pain may, therefore, be defined