CHEST PAIN OF UNDETERMINED ORIGIN - OVERVIEW OF PATHOPHYSIOLOGY

Patients with unexplained chest pain represent a major clinical dilemma for primary-care physicians, gastroenterologists, and cardiologists. References to this prevalent clinical problem date to more than 150 years ago; confusion about its pathophysiology has resulted in the use of a variety of descriptive terms such as "noncardiac," "atypical," and "angiographically negative" chest pain. Since none of these terms applies to all cases, the description "chest pain of undetermined origin" may be preferable. Because the esophagus has a similar location and innervation as the heart, an esophageal source for unexplained chest pain syndromes has been frequently suggested. Recent studies have emphasized the importance of gastroesophageal reflux as a likely component of esophageal pain. Moreover, "irritable esophagus" is an emerging concept that implies a generalized alteration in esophageal pain threshold, that is, abnormal nociception. The potential effects of stress or altered psychological states in this phenomenon must be considered, and the role of "panic attacks" in the production of pain in these patients needs to be clarified. In addition, stress may produce altered esophageal motility and lead to manometric abnormalities such as the "nutcracker esophagus" or a hypertensive lower esophageal sphincter. Finally, the precise contribution of the heart in producing pain in patients with normal coronary angiograms remains unclear because the precise role of microvascular angina has yet to be clarified.