Irritable Bowel Syndrome in the Elderly

Gastroenterologic Problems

Irritable Bowel Syndrome in the Elderly Elizabeth O'Keefe, BM, BCh, MRCP,* and Nicholas J. Talley, MB, BS, PhD, FACP, FRACPf He whose intestines are constipated . . . all his days will be painful ones and his strength will wane.

The functional gastrointestinal disorders represent a group of conditions characterized by chronic or recurrent gastrointestinal symptoms that are not explained by structural or biochemical abnormaliSymptoms may in turn be attributed to disorders of the oropharynx, esophagus, stomach, biliary tree, small or large bowel, or anorectum. Functional bowel disorders themselves can be further subdivided into the irritable bowel syndrome (IBS), which is characterized by either abdominal pain and an irregular pattern of disturbed defecation, or functional constipation or functional diarrhea in which the disturbed bowel pattern is more constant and abdominal pain is not a prominent feature.32A number of studies suggest that there are physiologic differences between patients with IBS and those with functional constipation or functional diarrhea, although this theory remains to be firmly e ~ t a b l i s h e d . ' ~ , ' ~ . ~ ~ , " ~ Functional bowel disorders have been reported to be the most common cause of gastrointestinal dysfunction in patients over the age of 65 who present for gastrointestinal evaluation (Table Of those aged from 65 to 74 years in the general population, 2% to 4% were aware of ever having had a diagnosis of spastic colon or mucous colitis; this represents over one million people in the United States alone. Considerable morbidity is associated with IBS; conservative estimates indicate that, annually, in people over the age of 65 years, half a million visits are made to physicians by patients with IBS and 334,000 prescriptions are written for it.g0 Moreover, in 1979, overall hospitalization rates for IBS were similar to those encountered in inflammatory *Senior Associate Consultant, Section of Internal Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota !Senior Associate Consultant, Division of Gastroenterology and Internal Medicine, Mayo Medical School and Mayo Foundation, Rochester, Minnesota Clinics in Geriatric Medicine-Vol.

7, No. 2, May 1991

265

Table 1. Most Common Diagnoses in 900 Patients over the Age of 65 Seen in Gastroenterologic Practice DIAGNOSIS

PERCENTAGE OF PATIENTS

Functional bowel disorders Peptic ulcer disease Neoplasm Diverticular disease Hiatal hernia Cholelithiasis Liver disease Miscellaneous

31 16 15

7 6

5 4 9

Adapted from Sklar M: Gastrointestinal diseases in the aged. In Reichel W (ed): Clinical Aspects of Aging, ed 2. Baltimore, Williams & Wilkins, 1983, p 556.

bowel disease.lo6 Yet although symptoms compatible with IBS are common in the general p o p u l a t i ~ n , ~only ~,~ a minority ~ , ~ ~ ~ of the population visit their physician because of them.g1 The pathophysiologic mechanisms responsible for IBS remain poorly understood. Indeed, it is unclear whether IBS is primarily a psychosomatic disorder with gastrointestinal manifestations, a gastrointestinal motility disorder that results in psychosocial disturbances, or a manifestation of learned illness behavior.lZ1The lack of advances in the understanding of the pathophysiology of IBS has meant that treatment remains idiosyncratic, empiric, and often unsatisfactory. Very little has been written about IBS in the elderly, although epidemiologic studies suggest that it is a common problem in this age group. Our thesis is that IBS is underrecognized in elderly patients yet represents a significant cause of morbidity in this age group. Herein, we synthesize what is known and what is not known about IBS in the elderly and map out where future studies are clearly required.

DEFINITION Since Powell first described IBS in 1820, the syndrome has had 30 different names, including membranous enteritis, membranous colitis, neurogenic mucous colitis, mucous colitis, and spastic colon. Moreover, the definition of IBS has changed over the years, reflecting the different concepts regarding the underlying etiopathogenesis. Recently, an international working team met to formulate an acceptable research definition for the syndrome. They determined that IBS should be defined as a functional gastrointestinal disorder with continuous or recurrent symptoms of:

1. abdominal pain or discomfort relieved with defecation or associated with a change in frequency or consistency of stool, and 2. an irregular (varying) pattern of defecation at least 25% of the time, with three or more of the following: altered stool frequency, altered stool form (hard or loose and watery), altered stool passage (straining or urgency, feeling of incomplete evacuation), passage of mucus, and bloating or feeling of abdominal distention32

Chronic functional constipation is common in the elderly; it is characterized by a more constant disturbance of defecation than is found in IBS, with straining, hard or infrequent stools, and less-prominent pain. It appears to result from one of at least two mechanisms, namely colonic inertia or rectal outlet obstruction.lll It has been questioned whether IBS is a true disease, particularly because the symptoms are so prevalent in the general population. It is generally agreed, however, that the associated morbidity and economic cost justify consideration of IBS as a very important disorder, if not a disease. lo6 CLINICAL FEATURES The irritable bowel syndrome is, by definition, a chronic condition marked by waxing and waning symptoms, with exacerbations that may occur in response to stress. Most literature describing the features of IBS has not included subjects over the age of 65; however, Thompson and Heaton,lo7 in a study of 100 people aged from 60 to 9 1 years, did not find any evidence that IBS was different in character in the young and old. Abdominal Pain The abdominal pain in IBS is often poorly localized but is frequently reported in the mid- or lower abdomen. The character of the pain also is variable, but it is most commonly cramplike or aching, occurring in bouts and classically relieved by defecation or the passage of flatus. It may also be associated with an increased frequency of defecation or with looser stools at the onset of pain. Disturbed Defecation Patients with IBS typically experience intermittent disturbances in defecation, with normal bowel habit intervening. This may take the form of constipation, diarrhea, or alternating constipation and diarrhea. The constipation may be reported as decreased bowel frequency, passage of inspissated feces, straining during defecation, or inability to achieve complete evacuation. Elderly women might be expected to experience a feeling of incomplete evacuation more often because of the frequency of perineal descent, and preliminary findings of a large community survey of the elderly population in Olmsted County, Minnesota, have confirmed this e ~ p e c t a t i o n Constipation .~~ is the most commonly encountered disturbance of defecation in the elderly,76J07 and therefore it seems likely that constipation-predominant IBS would represent a particular problem in this age group, although this has not been formally studied. Mucus in the stool, abdominal distention, borborygmi, and excessive flatus also are often reported by patients diagnosed as having IBS. Rectal Urgency and Fecal Incontinence Rectal urgency is another common finding in IBS patients; up to 14% of subjects in one population survey had a sensation of urgency,30

and this may be even more important in elderly patients. Urgency has not been associated with an increased incidence of fecal soiling, at least in younger subjects, but no data on the elderly are available.30 A significant proportion (up to 20%) of all patients with IBS may . ~ ~ explanation for report symptoms of fecal soiling or i n c o n t i n e n ~ eThe this is not clear. The prevalence of incontinence in IBS in the elderly is unknown but is likely to be even greater because fecal incontinence appears to be an age-related complaint in both men and women. Incontinence occurs more frequently in hospitalized populations (10%25%) and affects up to 50% of elderly persons in nursing homes.'ll The elderly person with IBS and diarrhea or with IBS associated with constipation and overflow incontinence is at a greater risk for incontinence. Other Symptoms Nausea and vomiting, dysphagia, and early satiety have all been reported more often by patients with IBS than by controls matched for age, sex, and social class.123The significance of these symptoms in elderly patients with IBS is unknown. Early surveys found a high incidence of previous abdominal surgery in patients with IBS, with most of the operations performed after the onset of IBS symptoms and failing to alleviate those sympt o m ~ . ~This ~ , finding ~ ~ , ~remains ~ controversial because others have found no significant difference in the cholecystectomy or appendectomy rates between patients and controls.123 Nocturia, frequency and urgency of micturition, incomplete bladder emptying, back pain, an unpleasant taste in the mouth, fatigue, headache, and, in women, dyspareunia and dysmenorrhea also are reported to be more common complaints in outpatients with IBS,27,123 but the presence of such symptoms has not been studied in those over the age of 65 years. Functional Status In one survey, a quarter of patients with IBS had taken a week off work because of their illness in the year preceding the study.lZ3NO information exists on how these symptoms affect the functional status of elderly people, but pain and incontinence associated with IBS are likely to have a significant impact in this age group. EPIDEMIOLOGY Outpatient Data The irritable bowel syndrome is an extremely common disorder, accounting for 13% to 52% of new referrals to gastroenterolog i s t ~ . ~ , In ~ 1985, ~ , ~ people ~ . ~ ~over . ~the ~ ~ age of 65 in the United States made more than half a million visits to their physicians for IBS.90The majority of patients with IBS present in the third or fourth decade of life, and presentation after the age of 60 has been said to be uncom-

m ~ n . ~ It~ may , ~be,~ however, * ~ ~ that , ~physicians ~ ~ underrecognize IBS complaints in the elderly or apply other labels (e.g., "painful" diverticular disease) to their illness. A female predominance of between 2: 1 and 3 : 1 has been noted in both the young and the old who present for medical care. 17727.90

Community Data Few data on IBS symptoms in healthy elderly persons have been reported. Thompson and Heatonlo7interviewed 100 people aged from 60 to 91 living in elderly-persons' apartments. A questionnaire that sought symptoms believed to be characteristic of functional gastrointestinal disorders was completed at interview. The same questionnaire was also administered to selected groups of young and middle-aged people. There did not appear to be an age-related difference in the prevalence of abdominal pain relieved by defecation. Constipation, however, was more common in the elderly (Table 2). Some recently published data on IBS in the community, which included the elderly, was derived from six large, systematic national health surveys in the United States. These data provided information on prevalence, physician visits, hospitalizations, and medication use. The prevalence rates for IBS in different age groups are presented in Table 3. Overall, the rates reported were found to be lower than those that had previously been reported in selected nonpatient populations, which estimated that one quarter of the population have symptoms compatible with IBS.31,91,107Although the national surveys were more representative, they probably seriously underestimated the prevalence, because they relied on self-reported diagnoses of "spastic colon" or "mucous colitis." The irritable bowel syndrome may be somewhat less common in the elderly than in younger age groups. Based on national survey data, the prevalence rates of IBS in the elderly appear to drop to between 78% and 92% of those in the middle aged. Similarly, in a study of a random sample of elderly subjects, we found that IBS symptoms were still highly prevalent in the elderly but were less common than in younger persons (Table 4).76 Because the data are cumulative, one would expect the opposite, i.e., that rates in the elderly should be equal to or exceed the rates in younger people. Why the rates are lower in the elderly remains unexplained; it could be because of underreporting, but i t is conceivablethat the symptoms burn out with age. Table 2. Percentage of Subjects with Bowel Dysfunction in Each Age Category AGE RANGE TYPE OF DYSFUNCTION

17-27

45-65

60-91

Abdominal pain relieved by defecation >6 timesly Frequent straining at stool Frequent runny stools

19 3 4

7 8 6

14 20 4

Adapted from Thompson WG, Heaton KW: Functional bowel disorders in apparently healthy people. Gastroenterology 79:283-288, 1980.

Table 3. Average Rate of Reported Spastic Colon or Mucous Colitis by Age, Sex, and Race in the United States (Rate per 1000 people) AGE RANGE - --

Total Male Female White Black

25 - 44

45- 64

65- 74

17.5 6.5 27.8 19.1 8.9

25.7 12.3 38.0 27.9 5.3

20.0 9.1 28.4 21.7 8.0

Adaptedfi-om Sandler RS: Epidemiology of irritable bowel syndrome in the United States. Gastroenterology 99:409 -415, 1990.

Most patients with IBS do not require hospitalization, but the elderly are more likely to be admitted to the hospital and to spend more time there.g0Hospital discharges with a primary diagnosis of IBS have shown a striking decline since 1982, possibly related to the institution of diagnosis-related groups because IBS alone would usually not be considered sufficient justification for admission. Presenters Versus Nonpresenters. Although IBS is very common in the community, only one in three people with symptoms sees a physician for them. It is not known why some people with functional bowel symptoms seek medical advice whereas others do not. It seems likely that there are many elderly people with IBS who have never visited a physician for this p r ~ b l e m . ~ ~ , ' ~ ~ At least in younger populations, those with IBS who consult physicians are more likely to report abdominal pain and bowel dysfunction in response to stress than those who do not, but pain alone does not seem sufficient to explain doctor visit^.^^,^',^' Fecal soiling is more likely among those who go to the doctor, particularly in men, but explains only a small proportion of the visits made. The presenters are also more likely to see physicians for nongastrointestinal symptoms, suggesting that these patients could have a behavioral dist~rbance.~' Studies of Table 4. Percentage of Middle-aged and Elderly Subjects from a Community Random Sample Reporting the Manning Symptom Criteria for IBS AGE RANGE

SYMPTOM

Abdominal pain relieved by defecation Looser stools at pain onset More frequent stools at pain onset Abdominal distention Mucus per rectum Feeling of incomplete evacuation

30- 64 (n = 835)

65-93 (n = 337)

27 22 17 21 15 21

22 14 12 18 6 24

Adapted from O'Keefe EA, Talley NJ, Zinsmeister AR, et al: Does the irritable bowel syndrome burn out in the elderly? [abstract] Gut 31:A1168, 1990; with permission.

symptomatic subjects with IBS who had not presented for medical care have shown that they have significantly less psychopathology than do IBS presenters and do not differ significantly from normal suband it has been speculated that psychoneurotic individuals are simply the minority most likely to bring their complaints to a doctor.lo7 Perhaps, elderly patients give up going to their physicians because they have learned that the doctor has nothing more to offer in the way of treatment. Alternatively, they may become more comfortable with their symptoms and no longer need the support that they sought when they were younger. CAUSES AND PATHOGENESIS The irritable bowel syndrome is probably a heterogeneous syndrome with probably several different underlying causes. Most investigators believe that abnormal smooth muscle function is, at least in part, responsible for the symptoms. In addition, psychologic abnormalities, altered pain perception, and dietary factors are of potential importance. Physiologic Factors The Elderly Gut. Physiologic changes in the elderly gut could theoretically b e important in the way that IBS manifests in the aged, but most evidence suggests that age-related changes are not striking. Only a few studies of colonic transit and motility in healthy elderly people have been performed, but the findings do not differ from those however, transit may be considerably proin younger longed in immobile elderly persons.lO.ll This would be consistent with population-based surveys that have found little evidence to suggest there is a change in bowel habit with age a l ~ n e . ~ ~ Age .~O also does not appear to affect the small-bowel motility index in the fasting state, but after a meal the motility index and frequency of contractions are significantly lower in healthy elderly subjects than in younger contro1s.l Studies of anorectal physiology conflict with regard to the importance of age-related changes, but it appears that the anal squeeze pressure decreases with age, whereas the resting pressure is maintained in the fecally continent patient.5,6,59,65,67 Moreover, elderly subjects require smaller rectal volumes to inhibit anal sphincter tone and appear to have less compliant r e c t ~ m s . ~ The J l ~ decreased pressures may be due in part to age-related changes in muscle mass and contractility and in part to pudendal nerve damage associated with perineal descent in elderly women. Anal sensation is impaired in patients with fecal incontinence and i m p a ~ t i o n . ~ ~These . " ~ changes may explain why fecal incontinence increases with age. Colonic Motility. There are at least two distinct types of motility observed in the distal colon: segmenting contractions, which occur asynchronously in adjacent segments of the bowel, and peristaltic contractions, which occur only once or twice a day. Segmental contractions

might impede the passage of feces towards the anus; thus, constipation has been associated with increased resting sigmoid tone, whereas, conversely, some forms of diarrhea may show decreased t ~ n e . ~Such ',~~ findings remain controversial, however; others, for example, have reported more frequent fast contractions in patients with diarrhea-predominant IBS than in those with constipation-predominant IBS.llg Both constipation-predominant and diarrhea-predominant IBS patients have been shown to have increased segmental motility in response to various stimuli, including food,98 bile acids,'05 cholecystokinin,43.95and balloon di~tention."~ Thus, the postprandial diarrhea experienced by many patients with IBS may result from an exaggerated gastroileocolic response induced by eating.92On the other hand, there are no reliable differences between IBS and non-IBS subjects in the motility pattern of the unstimulated b o ~ e 1 . ~ ~ , ~ ~ , ~ ~ , ~ ~ ~ The increased motor response to various stimuli in IBS patients may reflect differences in the rhythmic fluctuation of transmembrane smooth muscle potential. Two major types of myoelectric activity are recorded, the basal electrical rhythm (BER) and spike action potentials. Normal subjects have a BER depolarization frequency in the colonic smooth muscle of 6 cycleslminute 90% of the time, with 3 cycles/minute the rest of the time. It has been reported that IBS patients have a higher proportion of the "slow" 3-cycles/minute pattern, occurring 40% of the time.96.104,"9 The increased slow wave activity appears unrelated to muscle contractions at rest but correlates with increased motor activity when the gut is stimulated with a 1000-calorie meal, cholecystokinin, or pentagastring5vg8;however, normal subjects and psychoneurotic patients without IBS may also have this abnormality, and therefore its significance has been q ~ e s t i o n e d Whether .~~ this pattern occurs in the elderly is unknown. Myoelectric recordings demonstrate an increase of short spike bursts in constipation-predominant IBS patients. On the other hand, patients with painless diarrhea have been found to have a different pattern, with absence of short spike bursts and a significant decrease in long spike burst activity. Isolated postprandial pain has been associated with an absence of long spike bursts, leading to the hypothesis that these are responsible for colonic propulsive activity, which would clean out the colon and prevent distention.12J3 Anorectal Abnormalities. Anorectal abnormalities may be present in some IBS patients, particularly those with diarrhea predominance. Moreover, differences have been shown between diarrhea- and constipation-predominant IBS with the use of anorectal manometry; the group with diarrhea have displayed significantly greater sensitivity to rectal balloon inflation and had a lower rectal compliance in some studies, whereas subjects with constipated IBS were no different from controls except in the volume at which discomfort was perceivedaa3 Thus, both aging and IBS may produce anorectal abnormalities. Their effects would be difficult to separate and might be synergistic in some cases.

Other Motility Patterns. The irritable bowel syndrome is associated with abnormal motility in other parts of the gut as well. Two specific patterns of small-bowel motor activity -ileal propulsive waves and clusters of jejunal pressure activity-have been found to be more common in IBS.52Furthermore, the ileum has been shown to be more sensitive to cholecystokinin, fat, and balloon distention in IBS patients than in healthy controls.53 These motor abnormalities have also been observed to be accompanied by abdominal symptoms in some cases. Moreover, small-intestinal transit is more rapid in diarrhea-predominant IBS patients and slower in constipation-predominant or pain-predominant IBS.15 Gastric emptying is usually normal in IBS.15 Esophageal motility may also be abnormal in IBS patients.122Conversely, patients with esophageal contraction abnormalities have been found to complain more to physicians about bowel symptoms and more often have been diagnosed as having IBS than are patients with achalasia.lg These findings suggest that IBS may be a generalized motor disorder that can affect the smooth muscle of the entire gastrointestinal tract. Diet Food intolerance has been cited as a major pathogenetic factor in diarrhea-predominant IBS,51 but other studies have failed to confirm this finding.8,68A wide range of food intolerances have been implicated, particularly those to dairy products and grains. True hypersensitivity has only been documented in patients with childhood allergic diatheses. Notwithstanding, exclusion diets might be beneficial in selected although these are less likely to be helpful in the elderly, in whom constipation appears to be the dominant bowel disturbance. A low-fiber diet has been incriminated in the pathogenesis of IBS, although this finding is still not well e ~ t a b l i s h e dWhereas .~~ 30 to 40 g of fiber is the recommended daily intake, the average American diet contains less than half this amount, and this is probably particularly true of the diet of many older persons. Despite the varied results of treatment trials with dietary fiber, in our experience increasing fiber intake is very often helpful, especially in constipation-predominant IBS. Psychosocial Factors The association of personality, stress and emotion with bowel dysfunction in IBS is based on clinical observations and numerous studies. Personality Characteristics and Psychiatric Disease. Earlier studies that evaluated the psychiatric status of IBS patients suggested that 54% to 100% of outpatients with IBS might have an associated psychiatric illness, including chronic anxiety, depression, hysteria, somatizaDoubt has been cast on this, however, tion, and panic with more recent reports that IBS patients and patients with organic gastrointestinal disease did not differ on personality scores including

anxiety, phobia, and s o m a t i z a t i ~ n . ~Indeed, ~ . ~ ~ ~no J ~unique ~ personality profile has been identified in IBS. The lack of an adequate definition for IBS until recently might partly explain the discrepancy between these reports; earlier studies may have included patients that would now be categorized as having a somatization disorder rather than IBS.lo2 Clinical depression in community-dwelling elderly has been estimated to be as high as 11%,42whereas as many as 24% of those with concurrent medical illness are reportedly d e p r e s ~ e d , suggesting ~~.~~ that an association of IBS and depression is likely to be particularly important in the elderly. In those with psychiatric symptoms, it remains uncertain whether these symptoms cause the gastrointestinal complaints or develop secondarily to the stress of chronic bowel dysfunction, or the combination of bowel symptoms with the presence of psychiatric illness leads to consultation behavior.l12 Retrospective studies have suggested that psychiatric distress usually precedes abdominal symptom^,^^,^^,'^^ but no prospective studies are available. Others have found that those with IBS show more preoccupation with illness than do those with peptic ulcer disease and were significantly more likely to report special treatment of illness during childhood, supporting the hypothesis that learned illness behavior contributes to the cause of IBS.121 Stressful Life Events. Studies using life-event inventories have failed to find that more anxiety-provoking life events occur in IBS patients than in patients with organic gastrointestinal disease; however, many IBS patients recall an acute episode of stress preceding the onset of bowel symptoms, and perhaps at least half report that their symptoms can be made worse by s t r e s ~ .NO ~ ~studies , ~ ~ of the effect of the death of a spouse in the elderly have been undertaken to determine whether this could be related to IBS symptoms in this age group. Although stress is not proven to be a causative factor, it may prompt patients to seek care. Indeed, lack of social support in the elderly might produce sufficientstress to precipitate symptoms of IBS or the inability to cope with them. Pain Perception. It is possible that patients with IBS experience pain differently. It has long been known that IBS patients report gastrointestinal pain sooner and more intensely than do control subjects when ~~."~.~~~; subjected to stepwise colonic balloon d i l a t a t i ~ n ~ ~ . ~however, young patients with IBS do not have a reduced threshold for pain produced by electrocutaneous ti mu la ti on^^ or a lower tolerance for holding one hand in ice water.120Furthermore, balloon tolerance is not correlated with neuroticism or other psychologic traits in IBS.120 A peripheral mechanism such as altered receptor sensitivity may be the cause of pain with bowel distention in IBS. Alternatively, a pathologic dysregulation of a more central structure, such as has been proposed for the locus coeruleus in anxiety disorders, might account for an increased awareness of pain.99Another explanation is that patients with IBS may have a greater tendency to report bowel pain than do healthy

individuals, possibly as a result of learned illness behavior in childhood.121 RELATION T O DIVERTICULAR DISEASE Fifty per cent of people over the age of 70, and 66% over the age of 80, have diverticular disease of the colon.18 It is controversial whether diverticular disease causes bowel symptoms in the elderly in the absence of diverticulitis. The Scandinavian literature generally does not differentiate between patients with symptoms typical of IBS who have diverticula and those who do not, but these conditions have often been considered separately in the United Kingdom and the United States.77 The evidence suggests that diverticulosis alone is not a symptomatic entity. The presence of diverticula does not appear to affect the natural history of IBS.77Others have found no significant differences in intraluminal pressure and motility index measurements in patients with symptoms typical of IBS, with or without di~erticula."~ Treatment results have also been reported to be similar in patients with IBS and "painful" diverticular disease. Therefore it is probable that "painful" diverticular disease is really a manifestation of IBS in a patient who coincidentally has diverticulosis. In such cases, it is reasonable to treat the patient as if he or she simply had IBS, in the absence of clinical features suggesting a complication of diverticulosis such as diverticulitis or perforation. DIAGNOSIS AND DIFFERENTIAL DIAGNOSIS No standard for diagnosing IBS exists; the diagnosis therefore involves careful delineation of a characteristic s,v m ~ t o mc o m ~ l e xand the exclusion of structural and biochemical abnormalities. The history is far more helpful than is the physical examination in making the diagnosis of IBS. In 1978, Manning and colleagues formulated symptom criteria that, when present, strongly suggested a diagnosis of IBS (Table 4).64 The more of these criteria that are present, the more likely is IBS. Although the Manning criteria have not been formally validated in an elderly population and many IBS patients do not have these symptoms, they are probably still useful symptom criteria in geriatric practice. The length of time that bowel symptoms have been present is an i m ~ o r t a n factor t in the aeed: if the ~ a t i e n has t had bowel dvsfunction for 2 or more years, cancer of the colon becomes much less likely and the diagnosis of IBS is favored. A history of gastrointestinal infection preceding bowel dysfunction is commoner in younger patients and may be obtained rarely in the elderly. Recent stressful life events might suggest a precipitating cause for the onset of bowel symptoms, but many patients do not relate stress to their bowels. Lactose intolerance may occasionally produce IBS symptoms but is even less commonly L

L

u

,

L

-

-

encountered in elderly patients. The presence of significant weight loss, vomiting, dysphagia or bleeding strongly suggests that IBS is not the correct diagnosis. Physical examination in the elderly is nonspecific and helps mainly to exclude other disorders. Most authors advocate a positive approach to diagnosis based on the history, physical examination, and sigmoidoscopy; however, certain disorders are particularly important to consider in elderly patients with the onset of new symptoms: carcinoma of the colon, diverticulitis, ischemic colitis, drug-related bowel dysfunction, and complications secondary to simple constipation, such as fecal impaction, megacolon, and sigmoid volvulus. All elderly patients presenting with bowel dysfunction should have their colon evaluated by barium enema or colonoscopy. A suggested program of investigation in the elderly is outlined in Table 5, and the differential diagnosis of chronic or recurrent bowel dysfunction is presented in Table 6. If fecal incontinence is also present, it should be independently evaluated as though IBS were not present.28

TREATMENT Because IBS is a common chronic disorder that is associated with significant disability, there is a great need to identify truly efficacious therapies. Unfortunately, the design and conduct of treatment trials for this condition are difficult. Klein undertook a comprehensive review of published controlled-treatment trials for IBS and highlighted serious problems common to many of them.54In particular, the definitions of IBS have varied greatly, the determination of efficacy of the treatment has often been inadequate, and trial design has been suboptimal. One of the major problems in interpreting treatment trials in IBS has been the very variable, but usually high, placebo response rate, ranging from 20% to 70%.l12 With such high placebo response rates, very large

Table 5. Diagnostic Evaluation of Chronic or Recurrent Bowel Dysfunction in the Elderly Initial evaluation History and physical examination Pelvic examination Stool analysis for blood Flexible sigmoidoscopy (rectal biopsy if diarrhea) Barium enema or colonoscopy Full blood count Biochemical profile Urinalysis Thyroid-function testing Predominant diarrhea Fecal leukocytes Stool ova, cysts, and parasites Stool fat

Table 6 . Differential Diagnosis of Chronic or Recurrent Bowel Dysfunction Associated with Abdominal Pain in the Elderly Irritable bowel syndrome Neoplasia Adenocarcinoma of the colon Villous adenoma Diverticulitis Complications of constipation Fecal impaction Megacolon and sigmoid volvulus Urinary tract infections Inflammatory bowel disease Ulcerative colitis Crohn's disease Drug effects Diarrhea (e.g.,laxatives, antibiotics, digoxin) Constipation (e.g., verapamil, amitriptyline) Psychiatric disorders Depression Somatization disorders Spinal compression fractures Ischemic colitis Intestinal parasites Abdominal angina

numbers are needed to reach statistical significance, and many trials involving only small numbers of patients have failed to reach significance although important benefits may have been present. None of the trials have studied therapy in the elderly IBS patient. With this in mind, we review the treatment options available. Agents for Treatment Dietary Fiber and Bulking Agents. Dietary fiber affects a number of functions of the large intestine. It increases the amount of fecal output and usually makes the feces softer. Fiber speeds up colonic transit in most people, although it may paradoxically slow down transit when it is faster than average. Evidence suggests that fiber tends to lower sigmoid pressures, although it is unknown whether it affects pressures elsewhere in the colon or small intestine.47 Several doubleblind placebo-controlled trials of bulking agents for the treatment of IBS have been undertaken. Most have reported negative results, but given the enormous placebo response in these studies (63%-71%) and the modest number of patients enrolled in each, the failure to reach significance may have been due to a type 2 error.2,3,23,61,62,97 One study involving primarily constipated patients showed significantly improved well-being with therapy with isphagula, but the only specific measure that improved was constipation; there was no improvement in abdominal pain or b l ~ a t i n g . ~ ' Older people usually tolerate the controlled addition of dietary fiber without too much dificulty, although some may have increased

abdominal discomfort, with excessive flatulence and distention, especially if they are immobile. Of the various types of fiber, wheat bran may be the most efficacious in shortening transit times. Furthermore, cooked bran tends to be better tolerated than raw bran or raw fruits and vegetables, in our experience. If diet fails, treatment with psyllium should be started, at a dose of one teaspoon twice a day, and gradually increased until a soft, bulky stool is produced or side effects prevent further increase; the maximal dose is three tablespoons a day. Gas syndromes may be improved by reduced intake of beans, cabbage, legumes, apples, grapes, and raisins. Because IBS in the elderly is associated far more commonly with constipation than with diarrhea, manipulation of the diet to increase the fiber content with the judicious addition of bulking agents such as psyllium is often successful, in our experience. Even patients with diarrhea-predominant IBS can benefit, and we usually advise that slightly less fluid be consumed with the bulking agent in this situation. Despite the lack of firm evidence, dietary fiber and bulking agents still compose the mainstay of treatment for IBS in the elderly. Antispasmodics. A large number of treatment trials for IBS have involved antispasmodics, the majority of which are anticholinergics. There are several studies that have shown positive results, but all appeared to be flawed by methodologic problems.4~9,20~39~63,72,79~81 Thus, despite their widespread use in IBS, there is no convincing evidence that antispasmodics are e f f i c a c i o u ~ . ~ ~ The use of anticholinergic drugs in the elderly is problematic because of their side effects. Anticholinergic side effects may be prominent both centrally (delirium, confusion, cognitive impairment) and peripherally (tachycardia, urinary retention, constipation, blurred vision, dry mouth). These agents are therefore contraindicated in a number of conditions, including glaucoma, unstable cardiovascular status, gastrointestinal or urinary tract obstruction, paralytic ileus, toxic megacolon, and reflux esophagitis. Still, anticholinergics remain useful in the management of elderly patients with IBS who can tolerate them and who have severe or resistant postprandial pain. Sublingual administration may give the best results, at least according to anecdotal data. A preparation of peppermint oil in an enteric-coated capsule has attracted a lot of attention. This and other essential oils have been shown to relax smooth muscle. Despite initial reports of beneficial r e s ~ l t s ,recent ~ ~ , ~studies ~ involving more patients and using appropriate statistical methods have shown negative results.75 Peppermint oil has therefore not been shown to be effective in IBS. Several anticholinergic-barbiturate preparations are on the market for treatment of IBS. Two double-blind, placebo-controlled, crossover trials have shown some e E i ~ a c y , but ~ ~ ,the ~ ~ assessment was based solely on patient preference; it might not be surprising that patients preferred a barbiturate to placebo even if IBS symptoms were not improved. Barbiturates, with their tendency to cause sedation and dependence, should definitely be avoided in the elderly. Similarly, narcotic-based analgesics should be totally avoided.

Antidepressants and Psychotherapy. Antidepressants may be useful in severe, resistant IBS, even in the absence of depression, in our experience; however, the anticholinergic side effects of antidepressants are particularly troublesome in the elderly. Although trials of antidepressant therapy have been reported, the majority of studies have not made satisfactory measurement of mood state, most studies have used antidepressants in subtherapeutic doses, and the numbers enrolled have not been great enough to overcome the high placebo response rate.25 Nevertheless, several studies have shown some benefit both in relieving symptoms of IBS and in decreasing the degree to which these symptoms interfere with daily living.41,48,73,109 Troublesome side effects of antidepressants in the elderly include sedation, insomnia, orthostatic hypotension, nausea, and anticholinergic effects. Some newer antidepressants, such as fluoxetine and trazodone, have less anticholinergic action and may be better tolerated in the elderly. When precautions are taken, antidepressants can generally be used safely, even in patients with severe cardiac disease.50 It is reasonable to initiate treatment with small doses and increase the dose slowly until a therapeutic level is reached or side effects become troublesome. Measurement of serum levels is useful in monitoring therapy. Psychotherapy has been used to try to alleviate the financial, marital, and occupational stresses often associated with the onset of bowel symptoms in younger persons, but it is less likely to be effective in the elderly, who are more set in their ways and would find it difficult to make changes. Hypnotherapy, for example, has been used successfully in some refractory patients, but patients over the age of 50 did less well with this treatment.124 Behavioral therapy has been useful in some cases, especially when patients were able to identify stressors that correlated with their IBS symptoms and could modify their response to such stressors with the use of relaxation techniques. Again, there is little experience in treating the elderly, and controlled studies remain to establish this approach as being useful. When fecal incontinence is a problem, biofeedback treatment appears to be of value in geriatric patients.lls Miscellaneous Agents. Loperamide has been studied in three parallel design t r i a l ~ . l ~ ,Evidence * ~ , ~ ~ of global improvement has not been clearly demonstrated, but subgroups with diarrhea have benefited over placebo. Cholestyramine may be useful in diarrhea-predominant IBS, because these patients may be more sensitive than normal to bile acids, but controlled trials are lacking. Initially, there was great hope that the calcium channel blockers would be of use in IBS because of their demonstrated efficacy in the treatment of esophageal spasm, but a double-blind crossover trial of diltiazem versus placebo showed no convincing benefit.80 Timolol, phenytoin, and domperidone also have been tried, but the findings have been d i ~ a p p o i n t i n g . ~ ~ Approaches to Treatment The treatment of IBS remains largely empiric, symptomatic, and individualized. Reassurance, explanation, and sensible dietary alter-

ations remain the mainstay of treatment. In the elderly, one should start by increasing the fiber content of the diet in a palatable fashion and then add a bulking agent in patients who remain constipated. Diarrhea may respond to bulking agents; if they fail, loperamide or cholestyramine may sometimes be of significant benefit. Although anticholinergic drugs may sometimes be useful in the treatment of abdominal pain, they must be used with caution. Depression should be treated appropriately if present; moreover, antidepressants may help alleviate some IBS symptoms, particularly in resistant cases. Management of Resistant Idiopathic Constipation. Increasing fluid intake and exercise and adding adequate amounts of fiber are often beneficial in improving severe constipation. If this approach is ineffective or poorly tolerated, however, then lactulose is the only laxative we recommend for daily use on a chronic basis; doses of 7.5 to 30 mL/day have been shown to be effective."' Mineral oil should be avoided because of its potential to cause lipid pneumonia if aspirated. Stimulant laxatives should not be prescribed de nouo, but if an elderly patient has been taking them for many years and is reluctant to stop, they should be persuaded to limit their use to once or twice a week. There is usually no place for surgical management of constipation in the elderly, even in the presence of a rectocele or rectal prolapse, unless prolapse is frequent, severe, or irreducible. Fecal impaction can be effectively treated with saline, water, or sodium phosphate and biphosphate (C.B. Fleet Co., Lynchburg, VA) enemas."' Soap enemas are contraindicated because they may cause mucosal damage. The addition of large amounts of polyethylene glycol-electrolyte solutions (e.g., Golytely, Braintree Laboratories, Braintree, MA) given orally or by nasogastric tube may help in difficult cases. Manual disimpaction is rarely necessary. On the other hand, idiopathic megacolon associated with chronic fecal impaction requires a different approach."' In such individuals, fiber supplements are not helpful, and a fiber-restricted diet with cleansing enemas once or twice weekly is the recommended management. Management o f Fecal Incontinence. In elderlv ~ a t i e n t who s do not have underlying fical impaction with overflow ihcbntinence and who are not demented or neurologically impaired, a variety of therapeutic approaches may be employed."' These include bowel-retraining programs, biofeedback techniques, pharmacologic agents, and surgical procedures. Although biofeedback is effective in some patients, experience with the elderly suggests that many have learning difficulties due to short-term memory loss or anxiety about the procedure. Similarly, bowel retraining programs have not yet been documented to be efficacious in the elderly. When fecal incontinence is associated with chronic diarrhea, loperamide often causes symptomatic improvement; it has also been shown that this drug increases sphincter tone.28 In the absence of severe, symptomatic rectal prolapse, surgery may rarely be considered when all the other forms of therapy have failed, because the surgical approaches for obstructive defecation have reu

ported variable success rates and a high incidence of postsurgical complications.

PROGNOSIS Early studies of the prognosis of IBS, which included only a small number of patients over the age of 65, painted a rather dismal picture, with only a third of patients becoming symptom-free or showing some clinical improvement at the end of 12 months' f o l l o w - ~ p . For ~~,~~~ example, Waller and Misiewicz113 found that the nature of the symptoms tended to remain constant, although the severity usually varied, during a 12-month follow-up. Although there was little change in the severity of the symptoms at the end of a year, most patients seemed better able to cope with them and life in general. A more recent study in a similar population was much more optimistic, however; 85% had become virtually symptom-free in the short term, and 67% remained symptom-free 5 to 8 years later.44The response to treatment was best in men, those with predominant constipation, those with a short history, and those whose symptoms were triggered by an acute gastrointestinal upset. It was felt that the better long-term results obtained were due to differences in treatment, with greater emphasis on highfiber diets and bulking agents in the latter study. These findings are corroborated by another study that found that half the patients improved over a 5- to 7-year period whereas the other half remained unchanged or d e t e r i ~ r a t e d The . ~ ~ effect of age on prognosis has not been delineated.

FUTURE PROSPECTS The irritable bowel syndrome remains an important, although probably underrecognized, disorder in the elderly, and it is surprising that so little is known about it. We need to document the prevalence and incidence of IBS in those over 65. We also need to investigate the pathophysiology of IBS in the aged to establish whether it is similar to that in younger people; it is conceivable that the aging gut, perhaps in conjunction with other factors such as chronic dietary alterations, results in different pathophysiologic alterations. Invasive studies in this age group pose a particular problem, but new, noninvasive studies of colonic and whole-gut transit in older people with IBS are becoming available.84 Furthermore, investigation of personality, psychiatric symptomatology, mental state, and functional status in the elderly with IBS is indicated. The impact of IBS in this age group is completely unknown but is likely to be of major economic and social importance in the face of the exponentially expanding elderly population of the United States. To counter this, we need to establish effective treatment for IBS in the older person.

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Elizabeth O'Keefe, BM, BCh, MRCP Department of Internal Medicine Mayo Clinic Rochester, MN 55905