# The History of Functional Bowel Disorders



## eric (Jul 8, 1999)

FYIwith permission from the UNC"History of Functional DisordersDouglas A. Drossman, MDCenter-Co-DirectorMelissa SwantkowskiNew York UniversityTHE PASTHISTORICAL PRECEDENTSHistorians and physicians have documented the presence of Functional GI disorders throughoutrecorded human history. However, until recently, limited attention has been granted to thesedisorders due to the lack of identifiable pathology and the absence of a conceptual framework tounderstand and categorize them. Systematic investigation of functional GI disorders did notbegin until the middle of the 20th century, and prior to this time, only occasional reports offunctional GI symptoms were published, the first appearing only 200 years agver the past 25 years, scientific attention to understanding and properly caring for patients withfunctional GI disorders has grown progressively. With the understanding comes the rationale foruse of medications directed at intestinal receptors as well as psychopharmacological, behavioral,and psychological forms of treatment. Additionally, there has been an increase in the rate ofscientific publications and greater media exposure to the public through television, radio, andInternet.To understand the historical classification of these disorders, two differing theories relating to theinteraction between the mind and body should be considered.o Holism: a theory built upon the foundation that the mind and body are integratedand utterly inseparable.o Dualism: a theory that proposes a separation between the mind and the body.Greek philosophers Plato, Aristotle, and Hippocrates first proposed the principleof holism about 3,000 years ago, and later in the 12th century; Jewish physicianand philosopher Maimonides reexamined this philosophy. Based on holism, thestudy of medical disease must take into account the whole person rather thanmerely the diseased part. However, societal concepts of illness and diseasedrastically shifted when European philosopher Rene Descartes offered the divergent theory ofdualism in the 17th century. Prior to the notion of dualism, the church discouraged humandissection on the premise that the spirit resided in the body. The acceptance of dualism paved the2way for the emergence of scientific investigation and new medical discoveries by lifting theprohibition of human dissection. This shift in medical thought was congruent with the societalchanges of the 17th century: the shift towards a separation in church and state.IMPLICATIONS FOR FUNCTIONAL GI DISORDERSBased on the concept of dualism, disease was now understood in terms of structuralabnormalities. Therefore, the validity of a disease rested with the observation of morphologicalabnormalities. Medical conditions occurring in the absence of such morphological abnormalitiesand symptoms were not considered legitimate, and were often viewed as psychiatric, consistentwith the concept of dualism. The concept of dualism had other effects with regard to treatment.For example, this would include all the functional GI disorders and other somatic syndromes,such as fibromyalgia. Until the latter part of the 20th century, a medical illness was consideredamenable to scientific inquiry and treatment. However, patients with psychiatric disorders wereinterred in insane asylums and considered to no longer be treatable by medical physicians.Unfortunately this concept leads to a clinical dilemma. Specific diseases explain only about 10%of medical illnesses seen by physicians. Furthermore, people with structural (i.e. organic)diagnosis such as inflammatory bowel disease or cancer show considerable variation in theirsymptom presentation and clinical behavior. Gastroenterologists (as well as other health carepractitioners) are all too familiar with the poor correlation between structural findings onendoscopy and their patient's symptoms.Although efforts to find morphological or even motility etiologies for functional GI disorders inthe latter part of the 20th century were unsuccessful, the assumption that functional GI disordersmust be psychiatric has developed and has permeated current thinking. However, in the face ofcurrent scientific research, this is being seriously challenged. Studies have shown that personswith irritable bowel syndrome who do not seek health care are psychologically much like healthysubjects.THE PRESENTCONCEPTUAL BASES FOR THE STUDY OF FUNCTIONAL GI DISORDERSo The recent acceptance of functional GI disorders as legitimate medical entities isbased on the following three developments The concept of the Biopsychosocial model of illness and diseaseo The development of new investigative methods for studying diseaseo The development of the Rome CriteriaBiopsychosocial ModelIn 1977, the publication of the concept of the Biopsychosocial model by George Engel, and itslater demonstration specifically for gastrointestinal disorders, marked an important change inthinking. A biopsychosocial model of illness and disease provides the needed framework to3understand, categorize, and treat common GI symptoms. These symptoms are the integratedproduct of altered motility, enhanced visceral sensitivity, and brain-gut dysregulation and oftenare influenced by psychosocial factors. Figure 1 illustrates the proposed relationship betweenpsychosocial and physiological factors with functional GI symptoms and the clinical outcome.Early in life, genetics and environmental influences (family attitudes toward bowel training orillness in general, major loss or abuse history or exposure to infection) may affect one'spsychosocial development (susceptibility to life stress, psychological state, coping skills, socialsupport) or the development of gut dysfunction (abnormal motility or visceral hypersensitivity).Additionally, the presence and nature of a functional GI disorder is determined by the interactionof psychosocial factors and altered physiology via the brain-gut axis. In other words, oneindividual afflicted with a bowel disorder but with no psychosocial disturbances, good copingskills and adequate social support may have less severe symptoms and not seek medical care.Another having similar symptoms but with coexistent psychosocial disturbance, high life stress,or poor coping skills may frequent his physician's office and have generally poor outcome.DEVELOPMENT OF NEW INVESTIGATIVE METHODSThe second concurrent process has been the expansion and refinement of investigative methodsthat allow the study of functional GI disorders in terms of biological, cultural, and psychosocial(i.e. brain) influences. These developments include:1. the improvement of motility assessment,2. the standardization of the barostat to measure visceral sensitivity,3. the enhancement of psychometric instruments to determine psychosocialinfluences,4. the introduction of brain imaging (PET, fMRI) to determine CNS contribution tosymptoms, and5. the molecular investigation of brain-gut peptides, which provide insight into howthese symptoms become manifest.In less than ten years, these methods have produced new knowledge of the underlyingpathophysiological features that characterize the age-old symptoms we now define as functionalGI disorders.ROME CRITERIAThe Rome Criteria is an international effort to characterize and classify the functional GIdisorders using a symptom-based classification system. This approach that has its precedentswith classification systems in psychiatry and rheumatology. The rationale for such a system isbased on the premise that patients with functional GI complaints consistently report symptomsthat breed true in their clinical features, yet cannot be classified by any existing structural,physiological or biochemical substrate. The Rome Criteria was built upon the Manning Criteria,which was developed from discriminate function analysis of GI patients.The decision to develop diagnostic criteria by international consensus was introduced as part of alarger effort to address issues within gastroenterology that are not easily resolved by usual4scientific inquiry or literary review. By 1992, several committees had met to discuss the criteria,which ultimately resulted in the publishing of many articles in Gastroenterology Internationaland a book detailing the criteria titled "The Functional Gastrointestinal Disorders (Rome I)".Elaboration of the Rome I criteria led to a second edition of the Rome criteria (titled Rome II) in2000 as well as the publication of a supplement to the journal Gut in 1999. Recently the RomeCoordinating Committee has met to begin Rome III, expected to be published in 2006. To learnmore about the Rome Committees and to see a summary of the Rome II book: go towww.romecriteria.com.PRESENT PATHOPHYSIOLOGICAL OBSERVATIONSDespite differences among the functional gastrointestinal disorders, in location and symptomfeatures, common characteristics are shared with regard to motor and sensory physiology,o central nervous system relationships,o approach to patient care.What follows are the general observations and guidelines.MOTILITYIn healthy subjects, stress can increase motility in the esophagus, stomach, small and largeintestine and colon. Abnormal motility can generate a variety of GI symptoms includingvomiting, diarrhea, constipation, acute abdominal pain, and fecal incontinence. Functional GIpatients have even greater increased motility in response to stressors in comparison to normalsubjects. While abnormal motility plays a vital role in understanding many of the functional GIdisorders and their symptoms, it is not sufficient to explain reports of chronic or recurrentabdominal pain.VISCERAL HYPERSENSITIVITYVisceral hypersensitivity helps to account for disorders associated with chronic or recurrent pain,which are not well correlated with changes in gastrointestinal motility, and in some cases, wheremotility disturbances do not exist. Patients suffering from visceral hypersensitivity have a lowerpain threshold with balloon distension of the bowel or have increased sensitivity to even normalintestinal function. Additionally, there may be an increased or unusual area of somatic referral ofvisceral pain. Recently it has been concluded that visceral hypersensitivity may be induced inresponse to rectal or colonic distension in normal subjects, and to a greater degree, in personswith IBS. Therefore, it is possible that the pain of functional GI disorders may relate tosensitization resulting from chronic abnormal motor hyperactivity, GI infection, or trauma/injuryto the viscera.5BRAIN-GUT AXISThe concept of brain-gut interactions brings together observations relating to motility andvisceral hypersensitivity and their modulation by psychosocial factors. By integrating intestinaland CNS central nervous system activity, the brain-gut axis explains the symptoms relating tofunctional GI disorders. In other words, senses such as vision and smell, as well as enteroceptiveinformation (i.e. emotion and thought) have the capability to affect gastrointestinal sensation,motility, secretion, and inflammation. Conversely, viscerotopic effects reciprocally affect centralpain perception, mood, and behavior. For example, spontaneously induced contractions of thecolon in rats leads to activation of the locus coeruleus in the pons, an area closely connected topain and emotional centers in the brain. Jointly, the increased arousal or anxiety is associatedwith a decrease in the frequency of MMC activity of the small bowel possibly mediated by stresshormones in the brain. Based on these observations, it is no longer rational to try to discriminatewhether physiological or psychological factors produce pain or other bowel symptoms. Instead,the Functional GI disorders are understood in terms of dysregulation of brain-gut function, andthe task is to determine to what degree each is remediable. Therefore, a treatment approachconsistent with the concept of brain-gut dysfunction may focus on the neuropeptides andreceptors that are present in both enteric and central nervous systems.THE ROLE FOR PSYCHOLOGICAL FACTORSAlthough psychological factors do not define these disorders and are not required for diagnosis,they are important modulators of the patient's experience and ultimately, the clinical outcome.Research on the psychosocial aspects of patients with functional GI disorders yields three generalobservations Psychological stress exacerbates gastrointestinal symptoms in patients withfunctional GI disorders and can even produce symptoms in healthy patients (but toa lesser degree).o Psychological disturbances modify the experience of illness and illness behaviorssuch as health care seeking. For example, a history of major psychological trauma(e.g. sexual or physical abuse) is more common among patients seen in referralcenters than in primary care and is associated with a more severe disorder and apoorer clinical outcome. Additionally, psychological trauma may increase painreportingtendency.o Having a functional GI disorder has psychological consequences in terms of one'sgeneral well-being, daily functional status, concerns relating to control oversymptoms, and future implications of the illness (e.g. functioning at work andhome).APPROACH TO TREATMENTThe approach to treatment for all functional GI disorders is founded on a therapeutic physicianpatientrelationship. The basis for implementing a strong physician-patient relationship issupported by evidence that patients with functional GI disorders have anywhere from a 30 to80% placebo response rate regardless of treatment.6Because functional GI disorders are chronic, it is important to determine the immediate reasonsbehind each visit, after which treatment can be based on severity and nature of symptoms,physiological and psychosocial determinants of the patientï¿½s illness behavior, and the degree offunctional impairment.These factors can separate patients into mild, moderate, and severe categories.Patients with mild symptoms usually seen in primary care,o do not have major impairment in function or psychological disturbance ando can maintain normal activity.These patients have concerns about their condition but do not need to make many visits to theirphysician. Regarding treatment, these patients require education about their disorder and itssymptoms as well as information regarding a proper diet and the kinds of medication that canhave adverse effects.Patients with moderate symptoms seen in both primary and secondary care facilities ando experience intermittent disruptions in activity on account of their symptoms.o may identify a close relationship between symptoms and inciting events such asstress, travel, or dietary indiscretion.For these patients, symptom monitoring to record time, severity, and presence of associatedfactors can help to identify inciting factors and give the patient a sense of control over thedisorder. Additionally, pharmacotherapy directed at specific symptoms, particularly those thatimpair daily function, can be helpful, as can psychological treatments (relaxation, hypnosis,cognitive-behavioral therapy, and combination treatments) in reducing anxiety and encouraginghealth promoting behaviors.Patients with severe symptoms have trouble functioning daily,o find their disorder to be disabling and debilitating in nearly every facet of life,o have a high frequency of associated psychological difficulties,o make frequent visits to their physicians , ando may hope for a magical cure.In these cases a long-term physician-patient relationship, which sets realistic treatment goals(such as improved quality of life rather than elimination of all pain) is necessary. The focus forthese patients needs to shift from treating a disease to coping with a chronic disorder, wheremuch of the responsibility is place on the patient, himself. Furthermore, antidepressants haveproven useful to control pain and alleviate associated depressive symptoms.7THE FUTUREFuture studies will identify pathophysiological subgroups, each having its own set ofdeterminants ad treatment. Examples are as follows Some patients will develop their disorders or exacerbate symptoms viasensitization of afferent transmission from infection, enhanced motility, or traumato the gut. They may respond to the newly developing neurotransmitter blockingagents.o Patients with more painful and severe symptoms may prove to have "abnormalperception of normal gut function" rather than abnormal function. Thisdysfunction in the central regulation of incoming visceral signs may be remediedwith a psychopharmacological treatment approach.o The symptoms of some patients could be attributed to genetic factors, which resultin abnormalities in central reactivity to stress, in which case genetic manipulationstrategies would prove beneficial.o Early learning within the familial structure and socio-cultural influences has beendemonstrated to affect symptom perception and illness behavior. Future studiesare also likely to identify psychological and behavioral interventions that aretargeted for this subgroup.While it is likely that there are potent new treatments that will follow our growingpathphysiologic knowledge of these disorders, it is unlikely that they will replace some of thefundamental clinical principles active listening,o careful decision making,o an effective patient-physician relationship, ando patient centered biopsychosocial plan of care. http://www.med.unc.edu/medicine/fgidc/hist...aldisorders.pdf


----------

