consensus on the diagnosis and treatment of irritable bowel syndrome

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147 Chinese Journal of Digestive Diseases 2003; 4; 147–149 Consensus on the diagnosis and treatment of irritable bowel syndrome Chinese Medical Association & Chinese Society of Gastroenterology INTRODUCTION Irritable bowel syndrome (IBS) is a functional bowel disease with the characteristics of abdominal pain or discomfort accompanied by altered bowel habits, in particular disordered defecation. It lacks morpho- logical changes and biochemical abnormalities that could explain the symptoms. Studies elsewhere show that IBS is a common disease worldwide; the inci- dence in the Western population is 5–24%, and because approximately 25% of patients seek medical advice for IBS, it has a high expenditure annually and influences to a certain extent the patient's quality of life. In 1996, a Beijing survey showed that according to the Manning and Rome Criteria the incidence of IBS was 7.26% and 0.82%, respectively, and that 20% of these patients attended the clinics frequently. In 2001, another survey in Guangzhou revealed that the incidence was 5.6% according to Rome II Criteria and the rate of seeking medical advice was 22.4%. Hence, IBS is a medical problem worth noting in China. The etio-pathogenesis of IBS remains unclear. It is generally believed to be a multifactorial psycho- physiological disorder. The patho-physiological basis is mainly abnormal gastrointestinal motility and visceral perception, but the mechanism of these changes remains incompletely elucidated. It has been known that psychic and social factors are closely related with its occurrence. Recent attention has been focused on the induction of IBS after acute enteric infection in susceptible individuals. Regulatory dysfunction of the neuro-endocrine secretion of the brain–gut axis and the abnormality of the enteric immune system affecting this particular regulatory function have recently aroused particular interest. DIAGNOSTIC CRITERIA, SUBGROUPS AND DIAGNOSTIC APPROACH Diagnostic criteria The internationally recognized Rome II criteria of IBS issued in 1999 are recommended. Abdominal pain or discomfort occurs in the previous 12 months, for at least 12 weeks or more, which need not be consecu- tive, accompanied by two of the following three features: (i) abdominal pain or discomfort relieved with defecation; (ii) changes in frequency of defeca- tion; and (iii) change in the form (appearance) of stools. The following symptoms are not absolutely required for the diagnosis of IBS, but are frequently seen: abnormal frequency of defecation (>3 times per day or <3 times per week); abnormal stool consist- ency (lumpy/hard or loose/watery stool); abnormal stool passage (defecation with straining, urgency or sensation of incomplete fecal evacuation); passage of mucous; bloating or feeling of abdominal distension. The more frequent the symptoms, the more likely is the diagnosis of IBS. There are no morphological changes and biochemical abnormalities that can explain the symptoms. Subgroups The subgroups of IBS are (1) diarrhea predominant (2) constipation predominant and (3) alteration of constipation and diarrhea, based on the following clinical symptoms: (i) less than three bowel move- ments per week; (ii) more than three bowel movements per day; (iii) lumpy or hard stools; (iv) loose or watery stools; (v) stool passage with straining; (vi) urgent stool passage. 1 Diarrhea predominant (concordant with at least one of (ii), (iv) and (vi), but not (i), (iii) or (v); or at least two of (ii), (iv) and (vi), which can be accompanied by one of (i) or (v), but not (iii). Correspondence to: Ping Jin HU, Division of Gastroenterology, Dr Sun Yat-Sen University Medical Sciences, Guangzhou 510080, China. Email: [email protected]

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Page 1: Consensus on the diagnosis and treatment of irritable bowel syndrome

147

Chinese Journal of Digestive Diseases

2003;

4

; 147–149

Consensus on the diagnosis and treatment of irritable bowel syndrome

Chinese Medical Association & Chinese Society of Gastroenterology

INTRODUCTION

Irritable bowel syndrome (IBS) is a functional boweldisease with the characteristics of abdominal pain ordiscomfort accompanied by altered bowel habits, inparticular disordered defecation. It lacks morpho-logical changes and biochemical abnormalities thatcould explain the symptoms. Studies elsewhere showthat IBS is a common disease worldwide; the inci-dence in the Western population is 5–24%, andbecause approximately 25% of patients seek medicaladvice for IBS, it has a high expenditure annually andinfluences to a certain extent the patient's quality oflife. In 1996, a Beijing survey showed that accordingto the Manning and Rome Criteria the incidence ofIBS was 7.26% and 0.82%, respectively, and that 20%of these patients attended the clinics frequently. In2001, another survey in Guangzhou revealed that theincidence was 5.6% according to Rome II Criteria andthe rate of seeking medical advice was 22.4%. Hence,IBS is a medical problem worth noting in China.

The etio-pathogenesis of IBS remains unclear. It isgenerally believed to be a multifactorial psycho-physiological disorder. The patho-physiological basisis mainly abnormal gastrointestinal motility andvisceral perception, but the mechanism of thesechanges remains incompletely elucidated. It has beenknown that psychic and social factors are closelyrelated with its occurrence. Recent attention has beenfocused on the induction of IBS after acute entericinfection in susceptible individuals. Regulatorydysfunction of the neuro-endocrine secretion of thebrain–gut axis and the abnormality of the entericimmune system affecting this particular regulatoryfunction have recently aroused particular interest.

DIAGNOSTIC CRITERIA, SUBGROUPS AND DIAGNOSTIC APPROACH

Diagnostic criteria

The internationally recognized Rome II criteria of IBSissued in 1999 are recommended. Abdominal pain ordiscomfort occurs in the previous 12 months, for atleast 12 weeks or more, which need not be consecu-tive, accompanied by two of the following threefeatures: (i) abdominal pain or discomfort relievedwith defecation; (ii) changes in frequency of defeca-tion; and (iii) change in the form (appearance) ofstools. The following symptoms are not absolutelyrequired for the diagnosis of IBS, but are frequentlyseen: abnormal frequency of defecation (>3 times perday or <3 times per week); abnormal stool consist-ency (lumpy/hard or loose/watery stool); abnormalstool passage (defecation with straining, urgency orsensation of incomplete fecal evacuation); passage ofmucous; bloating or feeling of abdominal distension.The more frequent the symptoms, the more likely isthe diagnosis of IBS. There are no morphologicalchanges and biochemical abnormalities that canexplain the symptoms.

Subgroups

The subgroups of IBS are (1) diarrhea predominant(2) constipation predominant and (3) alteration ofconstipation and diarrhea, based on the followingclinical symptoms: (i) less than three bowel move-ments per week; (ii) more than three bowelmovements per day; (iii) lumpy or hard stools; (iv)loose or watery stools; (v) stool passage withstraining; (vi) urgent stool passage.

1 Diarrhea predominant (concordant with at leastone of (ii), (iv) and (vi), but not (i), (iii) or (v); orat least two of (ii), (iv) and (vi), which can beaccompanied by one of (i) or (v), but not (iii).

Correspondence to: Ping Jin HU, Division of Gastroenterology, Dr Sun Yat-Sen University Medical Sciences, Guangzhou 510080, China. Email: [email protected]

Page 2: Consensus on the diagnosis and treatment of irritable bowel syndrome

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Chinese Medical Assoc. and Chinese Soc. Gastroenterology

Chinese Journal of Digestive Diseases

4

, 147–149

2 Constipation predominant (concordant with atleast one of (i), (iii) and (v), but with the absenceof (ii), (iv) and (vi) or at least two of (i), (iii) and(v), accompanied by one of (ii), (iv) and (vi).

3 Alteration of constipation and diarrhea (alterationof the foregoing symptoms).

The diagnostic criteria of IBS rest mainly on symp-tomatology. The Rome criteria II are established onevidence from recent epidemiological and clinicalstudies with some modification of previous research;they highlight the following important principles: thediagnosis of IBS must be established on the basis ofexclusion of organic bowel diseases; IBS belongs tothe category of functional bowel disorders; emphasisshould be laid on the relevance of abdominal pain ordiscomfort associated with defecation, which as aspecific syndrome differs from other functional boweldisorders such as functional diarrhea, functionalconstipation and functional abdominal pain. Thediagnostic criteria allow the duration of the illness tobe prolonged to 12 months, not necessarily consecu-tive, hence, they reflect the chronic, relapsingcharacteristic of IBS. Moreover, use of the criteriashould reduce the misdiagnosis rate of organic boweldisease, in particular, that of intestinal tumors. Thereare no strict restrictions of the prerequisite of thenumber of bowel movements and stool form in theabsolutely required diagnostic criteria, but theyemphasize the presence of abdominal discomfort orabdominal pain accompanied by alterations in thenumber of bowel movements and stool form, whichenable more cases to be diagnosed with increaseddiagnostic sensitivity.

Diagnostic approach

Using the diagnostic criteria and excluding organicbowel diseases, IBS can be correctly diagnosed andunnecessary methods of examination can be avoided.It is very important not to misdiagnose organic boweldiseases, to ensure that the patient’s economicexpenditure and psychological stress is not increased.

1 A detailed history and systemic physical examina-tion are most essential. If there are ‘premonitorysymptoms and signs’ such as fever, loss of weight,bloody stool or melena, anemia, abdominal massor other symptoms or signs inexplicable as func-tional bowel disorders, the appropriate examina-tions and investigations should be performed toclarify the cause of the illness. If persistent altera-tions of stool passage (i.e. frequency, consistency)

and episodic attacks are relatively recent and differfrom that in the past, or if there is progressiveenhancement of symptoms in those with a familyhistory of colon cancer or who are older than 40years, colonoscopy or barium enema should beroutinely performed. In the absence of these pre-monitory symptoms and signs, if the patient’s age isless than 40 years with good general health, butwith typical IBS symptoms, routine stool examina-tion is still necessary (i.e. red blood cells, leuko-cytes, occult blood test and parasites) and otherrelated examinations can be selected. Treatmentcan be given at first and the response monitored,and further examinations can be selected on thatbasis.

2 Select relevant laboratory and investigative exami-nations on the basis of clinical manifestation andthose required to rule out organic bowel diseases.The following items are absolutely required:routine blood, urine and stool examinations; stoolculture; blood biochemistry (i.e. blood sugar, liverand kidney function tests); erythrocyte sedimenta-tion rate; colonoscopy or barium enema; B-modeabdominal ultrasonography.

3 Follow-up study is helpful for discovery of latentorganic bowel disease.

PRINCIPLES OF TREATMENT

The purpose of the treatment of IBS is to relieve theanxiety, improve the symptoms and enhance thequality of life. On the basis of an established gooddoctor–patient relationship, and on the basis of thedegree of severity of symptoms, give symptomatictreatment for the predominant pattern of IBS; thetreatment measures should be comprehensive andindividualized.

General measures

Tell the patient that the illness is IBS and explain thenature of the disease in detail to relieve any anxietyand enhance the patient's confidence in the treatmentof the disorder. Conduct a thorough, detailed inquiryof the history of illness and establish the reason forseeking medical advice, such as cancer phobia. Try tofind out and eliminate causative factors, such asdietary factors, stressful events, and to provide adviceon dietary and lifestyle adjustments that will relievesymptoms. Tranquillizers can be given for insomniaand anxiety. A good doctor–patient relationship is ofimportance throughout the course of treatment and is

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Consensus on IBS

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Chinese Journal of Digestive Diseases

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, 147–149

the cardinal basis of treatment of IBS. Patients withmild illness do not require further treatment.

Drug therapy

For those with more severe symptoms, drug therapycan be given for control of symptoms, usually in theform of antispasmodics (anticholinergics such asatropine, probanthin, scopolamine) for the abdom-inal pain, but adverse events can occur. Calciumchannel blockers, an enteric smooth muscle relaxant,such as pinaverium bromide, and antidiarrheal agents,such as loperamide or a diphenoxylate compound,may be prescribed, but adverse events are constipationand abdominal fullness; an absorbent, such as diocta-hedral smecta can be selected for mild cases. Laxativescan be used for mild constipation. Generallyspeaking, mild cathartics can be used to reduceadverse events and drug-dependence; the mostfrequently used are voluminous cathartic psylliumpreparations or methyl cellulose, or osmotic catharticssuch as polyethylene glycol, lactulose and sorbitol.The gut motility and visceral perception modulator,and 5-HT

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receptor partial agonist, tegaserod, hasbeen reported recently as effective in improvingconstipation, abdominal pain and abdominal full-ness, and is therefore suitable for patients who areconstipation predominant. Antidepressants can betried for severe abdominal symptoms not responsive

to the other therapies, especially in those with signifi-cant psychiatric symptoms.

Psychiatric therapy

Treatment for psychological behavior should be givento those who are not responsive to the general treat-ment, selecting from psychotherapy, cognitive therapy,hypnotic therapy and bio-feedback therapy.

Miscellaneous

It has been recently reported that probiotics can beused for the treatment of IBS, but their efficacy andmechanism of action need further study.

Traditional Chinese medicine and herbal medicine

Some studies have indicated that traditional Chinesemedicine and herbal medicine are effective in treatingsome patients with IBS and further investigation isneeded.

1,2

REFERENCES

1 Gu YM. Clinical observation of irritable bowel syndrome treated with Gu-chang-zhi-xie pills.

Chin J Gastroenterol

2003;

8

(Suppl.): A22 (in Chinese).2 Zhang T. The treatment of irritable bowel syndrome

constipation predominant subgroup with Shu-gan-run-chang method.

Chin Trad Med J

2003;

21

: 565 (in Chinese).