Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 458

Functional gastrointestinal diseases are often overlooked in the elderly.⁷⁴ They are characterised by recurrent or persistent symptoms referable to the gut, occurring in the absence of demonstrable organic disease. This group of disorders includes functional dyspepsia (upper abdominal pain, bloating, or nausea) and irritable bowel syndrome (IBS) (abdominal discomfort, which may be relieved by defecation, associated with abnormal bowel habit), as well as other syndromes related to the oesophagus, anorectum, and biliary tract, defined most recently by the Rome IV criteria.⁷⁵

The prevalence of IBS appears to be less in the elderly than the middle‐aged in the United States; nevertheless, 10–15% of people over 70 had IBS based on a large community survey,⁷⁶ so the condition is still common in the older age group. At all ages, the prevalence is greater in women than men. Somewhat surprisingly, the incidence, as opposed to prevalence, of IBS has been reported to increase with age, in at least one US population.⁷⁷ This may potentially reflect an increase in healthcare‐seeking behaviour in the elderly, although no information regarding consulting behaviour in IBS is available specifically for this age group. As in younger patients with functional gastrointestinal disorders, it is common for different symptoms to be gained or lost over time so that the overall prevalence remains relatively constant.⁷⁸ In the general population, around 10% of functional gut disorders follow a bout of infectious gastroenteritis, but there is evidence to suggest that the elderly are less prone to developing chronic post‐infective symptoms than the young. In contrast to IBS, there is little information regarding the prevalence of functional dyspepsia in older populations.

While, as discussed, visceral sensitivity seems to decline in healthy ageing, patients with functional dyspepsia or IBS have, as a group, increased sensitivity to gastric and rectal distension. Nevertheless, chronic gastrointestinal symptoms consistent with IBS are common in the elderly, although not markedly greater than in the young, with the possible exception of constipation. Visceral sensitivity has not been studied in the elderly with gut symptoms; nor has tolerance to visceral pain (the lowest level of stimulation at which a subject withdraws or asks for the stimulus to cease). The latter may be relevant since pain tolerance for somatic stimuli appears to decrease with ageing. The prevalence of Helicobacter pylori is greater in the older individuals than the young but is decreasing over successive generations; and in the absence of peptic ulceration, its contribution to dyspepsia is uncertain.²⁵

It is important to exclude organic diseases such as cancer and mesenteric ischemia when gut symptoms arise in older patients, particularly as the prevalence of organic disease is greater than in the young.⁷⁹ For example, when patients present with altered bowel habits, the threshold for colonoscopic investigation should be low. However, it is interesting to note that mesenteric ischaemia seems to occur more often in patients with IBS than those without.⁸⁰ The relevance of comorbidities such as Parkinson’s disease, medications, thyroid disease, diabetes, depression, and small‐bowel bacterial overgrowth must also be considered.

Chronic gastrointestinal symptoms impair quality of life, but many elderly do not present to their doctors, and symptoms may not be volunteered, so their impact may go unrecognised in older populations. Depression associated with chronic pain does not appear to be greater in the elderly than the young, but it should be borne in mind that gut symptoms like anorexia and bowel habit disturbance can also be features of depression. The potential effects of anxiety on the perception of persistent, as opposed to acute, pain have received little attention to date.⁷⁹

All potential therapies for functional gut disorders must be evaluated against the high placebo response rate (between 20 and 70%) associated with these syndromes, but no clinical trials have focussed specifically on the elderly,⁸¹ and the potential for adverse effects (e.g. sedation, urinary retention, postural hypotension, blurred vision, or glaucoma with tricyclics or hyoscine) needs to be borne in mind in this group. A diet that is low in fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) is effective in reducing IBS symptoms and is considered a first‐line therapy for IBS,⁸² but almost no information is available about its application in the elderly.⁸³ For the management of abdominal pain, the antispasmodics hyoscine, mebeverine, and peppermint oil and antidepressants have a good evidence base.⁸⁴ The dose of tricyclic antidepressant used in functional gut disorders is typically lower than standard doses used to treat depression. Selective serotonin reuptake inhibitors (SSRIs) may be better tolerated than tricyclics, but there are less data regarding their efficacy in IBS, and venlafaxine appears less helpful than tricyclics in functional dyspepsia.⁸⁵ The use of opiates should be avoided in the management of chronic abdominal pain; they are typically ineffective, and their use is associated with tolerance and substantial adverse effects, including opioid‐induced hyperalgesia and narcotic bowel syndrome.⁸⁶ Probiotics may be of benefit for bloating, but individual preparations are poorly validated. Psychological therapies, including cognitive behavioural therapy and hypnotherapy, have shown considerable promise in managing functional bowel disorders, and their efficacy may be comparable to pharmacological therapies like antidepressants,⁸⁴ but no information is available about their applicability to the elderly.

When constipation is a feature of IBS, adequate hydration and fibre supplements should be tried, with the caveat that bloating and abdominal pain may be exacerbated by high fibre intake. Soluble fibre supplements, in particular, have had positive outcomes in randomised controlled trials.

When diarrhoea and faecal urgency predominate, loperamide can be beneficial; a liquid formulation, if available, makes dose titration easier. Alosetron (a 5‐HT3 antagonist) may have a place in diarrhoea‐predominant IBS in women, but the association of this drug with ischemic colitis suggests the need to exercise caution, especially in older patients. Randomised controlled trials have included only a few patients over 65.