BMH Medical Journal - Narendranathan

BMH Med. J. 2020; 7(Suppl): Early Online. Geriatrics & Gerontology Initiative: International Workshop on Care of the Elderly

Abstract

This brief review addresses the changes that occur in the gut in the elderly and discusses the clinical implications of these changes. This review addresses the changes that occur in the stomach, small bowel, gut microbes and the colon in old age and examines its effect on clinical presentation. The gastric dysmotility and hypochlorhydria contribute to anorexia and anaemia. Small bowel disease in the elderly almost always denotes organic disease. The effect of old age on the colon is due dysmotility and presents as constipation and its sequelae like faecal impaction and faecal incontinence. The changes in the microbiota can interact with the immune system and leads to a condition termed “inflamm-ageing.” Comorbidities influence the clinical presentation in old age. Diabetes, hypothyroidism and Parkinsonism are some examples. The increased usage of drugs also influences the gut – some examples being calcium channel blockers, antispasmodics, anti-hypertensives and drugs used in Parkinsonism. The paper highlights the coexistence of many diseases in the elderly. In a person presenting with bleeding PR, the search should not end once a source of bleeding like haemorrhoids is identified. This paper stresses the fact that organic diseases, like colon cancer, are more common in the elderly and that caution should be exercised in attributing a symptom just to old age.

Key words: Adipokine, Air-lock syndrome, Bystander apathy, Colonic transit, Constipation, Faecal impaction, Faecal incontinence, Fundal compliance, Gut Microbiota, Hypochlorhydria, Myo-contractile protein, Sarcopenia.

Majority of our interventions in health care have been in reducing mortality and prolonging survival. This is the reason why the American writer Frank Howard Clark remarked: “We have put more efforts into helping folks reach old age than helping them enjoy it.” As the population ages many health-related issues crop up and this write up is a short narrative on how a clinician looks at the ageing gut. There is extensive literature on ageing and the gut. This write up gives only a bird’s eye view of the existing literature. Space constraints do not allow a detailed discussion on the treatment of GI disorders in the elderly in this write up.

Old age has been defined differently in different contexts. The chronological age and the biologic age are not necessarily synonymous. The age of 60 or 65, which is the age of retirement in most countries is said to herald old age.

Clinical Presentation

Visits for GI complaints such as constipation, diarrhoea, weight loss, dysphagia, faecal incontinence and gastro-oesophageal reflux, comprise about thirty percentage of the total medical visits to primary care physician. About 30% of ER visits in our hospital are by persons above sixty. It must be emphasized that multiple disease states can coexist in the elderly. There can be multiple comorbidities like impaired hearing, dementia, Parkinsonism, hypertension, diabetes mellitus, coronary artery disease, COPD, chronic renal failure etc. The elderly can also present with multiple lesions that can produce the same clinical picture. Age related functional or motility disorders should be entertained as a diagnosis only after organic diseases have been convincingly ruled out as the risk of organic disease in a person reporting to the hospital increases with age. A peculiar situation seen in Kerala is the extensive use of alternate systems of medicine and the elderly prefer ayurvedic drugs mainly for the treatment of constipation and bone and joint diseases. Any clinical evaluation should take this also into consideration. Never assume that a person is beyond cure just because he is old. Some of the common symptoms in the elderly, related to the gut are discussed below. Some of the age-related changes in the stomach, small bowel and colon will be discussed in the following sections followed by some of the common symptoms encountered in old age.

Stomach

Gastric distension plays a key role in appetite and satiety response. The aging process is thought to reduce gastric compliance particularly of the fundus leading to earlier arrival of food at the antrum with earlier antral stretch and early satiety. Furthermore, there may be an element of hypersensitivity of the antrum in the elderly as demonstrated by prolonged satiety post-prandially related to a relatively small antral volume. Alterations in fundal compliance may predispose to reflux via delayed emptying, particularly if cholecystokinin secretion is enhanced. Other changes in gastric motility are usually secondary to disease process such as diabetes mellitus, neurological or connective tissue disease rather than a consequence of ageing per se. Changes in acid secretion are particularly common in the elderly. Hypochlorhydria is the commonest abnormality and is seen in those with a recent or past Helicobacter pylori infection. The process of hypochlorhydria can predispose to iron malabsorption, small bowel bacterial overgrowth and vitamin B12 deficiency. B12 deficiency may also be due to associated autoimmune atrophic gastritis and reduced parietal cell mass which in turn result in reduced secretion of intrinsic factor. Reduced fundal compliance contributes to early satiety. Hypochlorhydria can contribute to malabsorption and subsequent malnutrition.

Small Bowel

There is little evidence to show any structural or functional change in the small bowel attributable to the normal healthy ageing process. Biopsies from healthy elderly volunteers and from mice models have demonstrated no correlation between age and areas of duodenal surface epithelium, crypts and lamina propria, height of villi and surface epithelium, depths of crypts, crypt to villus ratio, the number of intraepithelial lymphocytes, duodenal architecture, enterocytes or brush borders.

The small intestine has both a secretory and absorptive functions. Disorders of the small intestine can result in excess secretion and malabsorption. Diarrhoea of small bowel origin is more often high output. Improvement of diarrhoea after fasting postprandial diarrhoea, bloating, malodorous flatus, and large volume sticky, pale stools suggest malabsorption. Similarly, weight loss despite a normal appetite also indicates small bowel disease. In the absence of comorbid disease, there is currently no evidence within the literature to support any significant alteration in small bowel function associated with ageing. Therefore, in patients presenting with clinical features suggestive of small bowel malabsorption, active investigation for underlying pathology is indicated.

An interesting syndrome described in the elderly is the “air-lock syndrome.” This syndrome occurs when elderly patients with poor bowel tonus lie in one position for prolonged periods. Fluid accumulates in dependent loops of the atonic bowel and cannot be expelled, thus producing bowel obstruction. Treatment consists of turning the patient repeatedly from recumbent to prone, which allows the gas to pass distal to the obstruction caused by the locked in fluid.

Colon

Colonic transit time increases with age due to a reduction in the propulsive activity in the colon. This is attributed to a reduction in the number of neurons and to the reduction in neurotransmitters like NO and acetyl choline. A reduction in the myo-contractile protein, Klotho, in the colon has also been demonstrated. All these lead to increased transit time and can lead to constipation. The role of colon in nutrition is the salvage of fibre derived energies. This may in fact increase in old age due to increased transit time. This is also the reason for increased occurrence of wind and flatulence in the elderly. In conclusion, the effect of aging on the transit time in the gut has not been sufficiently investigated. Transit time could be prolonged in the stomach and the colon. This effect seems weak for the general population but could be significantly more pronounced in elderly with masticatory deficiency, reduced physical activity, and frailty syndrome. The diversity of experimental approaches measuring regional transit time also explains result inconsistency. These methods include mainly scintigraphy, radio-opaque markers, ultrasonography, breath tests, and paracetamol test, the last three methods being specific for the stomach. In addition, the use of wireless motility capsule is developing. This technology can provide information on intraluminal pH and pressure. This method is relatively inexpensive and can be done in the ambulatory patient, and the data correlate well with scintigraphy. Wireless motility capsule is thus a very interesting tool to increase knowledge on the evolution of the regional gut transit during aging.

Microbiota

The gut microbiome is key to maintaining the natural barrier against pathogens and facilitating absorption. The data surrounding alterations to the microbiome with ageing are conflicting. One recent study, investigating the microbiome across the ages, found no significant changes between the young and a population of 70-year olds. However, when investigating centenarians, they found a change in the microbiome with a rearrangement in the Firmicutes population and enrichment in facultative anaerobes, notably pathobionts. These changes appeared to lead to a host inflammatory response and a process coined ‘inflamm-ageing.’ Changes in the gut microbiome with ageing still require further investigation. The role alterations in the microbiome may play in contributing to onset of disease, or in disease activity, is yet to be defined. There is no evidence that the use of probiotics in ageing alter disease activity or onset. The composition of the microbiota of elderly significantly correlates with measures of frailty, co-morbidity, nutritional status, and markers of inflammation. Functional metagenomics showed that the age-related trajectory of the gut-microbiome is characterized by loss of genes for short-chain fatty acid production and an overall decrease in the saccharolytic potential, while the proteolytic potential seems to increase. In line with these observations, a lower colonic fermentation has been observed in elderly women, compared to young women, after ingestion of a test meal.

Anorexia

Food intake gradually diminishes with age being an appropriate response to decreased energy needs due to reduced physical activity, decreased resting energy expenditure, and loss of lean body mass. The process of anorexia of ageing involves changes in taste and smell, gastric fundal compliance, GI and adipose-derived (adipokine) hormone secretion and altered autonomic nervous system feedback. All these factors contribute to a reduction in intake. During ageing, olfactory function declines, including the ability to discriminate between smells. Much of the overall flavour sensation of food is produced by food stimulating the retro-nasal olfactory receptors. Therefore, what is often labelled as a loss of taste is, in fact, due to decline in olfactory receptors. Gastric distension is known to play a key role in appetite and satiety response. This is discussed in the section on stomach.

Cachexia and Sarcopenia

Cachexia can be associated with anorexia, inflammation and insulin resistance, increase acute phase response, CRP production and down-regulation of albumin due to pro-inflammatory cytokines: IL-1, IL-6, TNF-a that enhance lipolysis, muscle protein breakdown, and nitrogen loss. The sarcopenia syndrome is characterized by the loss of muscle mass, strength, and performance. It does not necessarily require an underlying medical problem. Sarcopenia is associated with increased rates of functional impairment, disability, falls and mortality.

Constipation

Constipation affects about 50% of elderly nursing home residents. Constipation is ranked among the top 5 most common physician diagnosis for gastrointestinal outpatient visits. Women are more often affected than men. One of the causes is decreased mobility, cognitive impairment, co-morbidities and polypharmacy. Even though decreased colonic motility can contribute, this is not always the case. In the elderly it is the transit in the left colon that is usually delayed. Pelvic floor hypertonicity, or dyssynergia, is characterized by failure of anorectal coordination and paradoxical hypertonicity of the anal sphincter and muscles used for evacuation. It results in prolonged storage time of stool in the rectum, with symptoms of anal blockage, severe straining, slow evacuation, and a sense of incomplete rectal emptying. Affected patients may need to self dis-impact. A common cause of constipation in the elderly is postponement of defaecation which leads to reduced water content of the stools.

Stool impaction is a significant complication. Constipation is the major factor leading to faecal impaction. Many other factors contribute to this. These are inadequate fluid intake, metabolic illnesses like diabetes, hypothyroidism, medications like calcium channel blockers, antipsychotics and drugs used in the treatment of Parkinsonism and anatomical and functional abnormalities of anorectum. Many resort to manual methods for evacuation of stool.

Faecal incontinence is another disturbing consequence and can be mistaken for diarrhoea. Rome IV criteria for constipation may not apply to the elderly [4]. It stipulates that loose stools are rarely present without the use of laxatives. Many elderly patients with constipation present with the complaints of loose stools. This is in fact due to pseudo-diarrhoea seen in constipated individuals. This is due to softening of stools in the large bowel, proximal to hard stools in the colon. This is more often seen in the elderly and a common mistake is to prescribe loperamide or other anti-diarrhoeal drugs for these individuals. Some individuals complain of diarrhoea just because of embarrassment of admitting that they have faecal incontinence.

In severe cases, constipation can be associated with stercoral ulcerations, intestinal obstruction and even perforation. Constipation in the elderly can be distinguished from IBS-C by the lack of abdominal pain and discomfort.

Malnutrition

Malnutrition in the ageing population is one of the contributory factors in decline in independence, well-being and health. Malnutrition affects 10% of the population over the age of 65 years. Furthermore, the elderly population is less likely and less able to recover from malnutrition. After a few weeks of a malnutrition, both elderly and young subjects lost weight; however, the elderly were unable to regain that weight and lack the compensatory hyperphagia observed in young adults. Malnutrition in the elderly is related to social circumstances, the morbidity associated with chronic disease and to polypharmacy. Most factors contributing to malnutrition in this age group, therefore, occur before nutrition reaches the gut for the complex process of digestion and absorption.

Bystander apathy and the elderly patient

Bystander apathy is a term used to denote the unwillingness of bystander to offer help to a person in need as they may feel that someone else will intervene. But a different type of bystander apathy occurs in the care of the elderly. The bystanders who cannot understand the disease process in the elderly often misinterpret the symptoms of disease as a stubbornness or as non-cooperation or as laziness. I have seen a ninety-three-year-old lady who had faecal incontinence being scolded by her bystander saying that old lady enjoys defaecating in the bed. Another instance was in Parkinsonism. An eighty-five-year-old lady with Parkinsonism who was slowly moving forward was made fun of by her bystander asking her whether she is practicing imaginary skating. This bystander had seen her suddenly jump into her bed fearing that there was a reptile underneath the bed. The bystander cannot understand that the reaction to the imaginary reptile was due to kinesia paradoxa. In this condition individuals who typically experience severe difficulties with the simple movements may perform complex movements easily.

Bystander apathy must be understood and appreciated by the treating doctor. If he accepts the words of the bystanders, many organic diseases in the elderly will be missed. A treating physician should spend time with the relatives so that the bystander apathy is taken care of.

Endoscopic practice for the elderly

Endoscopy in the elderly poses a challenge to the endoscopist. Because of hearing impairment and other disabilities, the endoscopist may communicate more with the relatives than with the patient himself. The endoscopic procedure should be explained to the elderly patient and the consent should be obtained from the patient himself/herself (if he/she can give consent) and not from their relative. There are instances where a court has found the endoscopist to be negligent as the consent for colonoscopy was obtained from the relative and not from the elderly patient. Clinicians have a low threshold to perform procedures in symptomatic patients as organic disease is more prevalent in the elderly. Most diagnostic and therapeutic endoscopic interventions can be safely performed in elderly patients. For upper GI endoscopy in the elderly with comorbidities and compromised cardiac or pulmonary function, we prefer un-sedated endoscopy with the paediatric upper GI scope. If there is difficulty in intubating the oesophagus think of Zenker’s diverticulum or osteophytes in the cervical vertebra.

For colonoscopy avoid sodium phosphate in the elderly, especially if renal or cardiac dysfunction is present. Important to maintain adequate hydration throughout the bowel prep. Do not use Mg-based bowel prep as only preparation. ASGE (American Society for Gastrointestinal Endoscopy) recommends that electrolyte-balanced polyethylene glycol–based colonoscopy preparations be used in elderly individuals to avoid potentially harmful fluid and electrolyte shifts [5]. They also recommend that lower initial doses of sedatives than standard adult dosing and more gradual titration in the elderly. Poor prep in the elderly is much higher (16-21%) because the elderly are less likely to tolerate high volume of oral prep. One should be gentle when manoeuvring (consider study with paediatric colonoscope if severe diverticular disease in sigmoid) the scope. A meta-analysis of 20 studies also concluded that octogenarians had a higher rate of cumulative adverse events (incidence rate ratio 1.7; 95% CI, 1.5-1.9) and a greater risk of perforation during colonoscopy (incidence rate ratio 1.6; 95% CI, 1.2-2.1) compared with younger patients.

Virtual colonoscopy

On many occasions when the elderly patient is not suitable for sedation because of multiple comorbidities, we resort to virtual colonoscopy with good results. Many elderly individuals opt for this when the pros and cons of both classical colonoscopy and virtual colonoscopy are explained.

CT Colonography is easier for patients since it does not require any sedation and there is a much lower risk of complications, such as perforating the colon. Studies have shown that virtual colonoscopy is as effective in spotting precancerous polyps when comparing older participants to younger participants. Additionally, CT Colonography was found to be comparable to standard colonoscopy for identifying significant polyps in seniors. The obvious disadvantage is that one cannot get tissues for biopsy with virtual colonoscopy.

Case Study

An eighty-four-year-old gentleman was admitted with history of bleeding PR. The bleeding was bright red and was mixed with stools. One of the first differential diagnosis in this individual would be carcinoma colon. As per the literature the possible causes would be - diverticular bleeding 17-56%, angiodysplasia 3-30%; haemorrhoids, 3-28%; polyps 2-30% and colon cancer 3 to 11%. This gentleman underwent sigmoidoscopy. He had diverticula, telangiectasia, sigmoid polyp and haemorrhoids. Each of this lesion could produce bleeding PR. This is an example of how multiple diseases can coexist in the elderly and that the evaluation of elderly must be thorough.

Presence of organic disease

It must be emphasized that organic disease is more common in old age. In a study of patients with bleeding PR it was observed that in patients in the age group 50 to 69 there was a 5 times greater chance of colorectal cancer compared to those below fifty years and the chances of malignancy rose to eight times in persons above 69 years [7]. In a person with anorexia the symptoms should be attributed to GI dysmotility only after organic disease has been ruled out. The absence of alarm symptoms/signs in the elderly does not justify an incomplete work up of the case.

Conclusion

The management of elderly individuals who suffer from GI disease possesses a unique challenge. Clinicians involved in management of this patient population should be familiar with unique characteristics of this population. It is frequently confusing which changes in GI function represent a part of normal aging processes and which of them are pathological results of a disease process. There is a relative lack of research on this topic and available literature is commonly conflicting. The management of GI diseases in elderly, including diagnostic algorithm as well as therapeutic intervention, is further complicated by frequent presence of comorbidities, polypharmacy, and a limited life expectancy. The elderly patients commonly have atypical presentation of a disease; hence physicians who are not familiar with these might miss the opportunity to make a diagnosis in a timely manner. Polypharmacy and medication side effects further contribute to the complexity of the clinical picture and can derail treating physicians in the wrong direction. Additionally, polypharmacy and comorbidities predispose elderly patients to a more complicated clinical course and increase the probability for development of complications. It is equally important to discuss the goals of care with elderly, so our diagnostic and therapeutic interventions align with their expectations. In summary, our elderly patients represent a specific population with unique needs regarding diagnostic and therapeutic approaches.

References

1. Britton E, McLaughlin JT. Ageing and the gut. Proc Nutr Soc. 2013 Feb;72(1):173-7.

2. D'Souza AL. Ageing and the gut. Postgrad Med J. 2007 Jan;83(975):44-53.

3. Ginsberg DA, Phillips SE, Wallace J, Josephson KL. Evaluating and managing constipation in the elderly. Urol Nurs. 2007 Jun;27(3):191-200.

4. Lacy BE, Patel NK. Rome Criteria and a Diagnostic Approach to Irritable Bowel Syndrome. J Clin Med. 2017 Oct 26;6(11).

5. Qureshi WA, Zuckerman MJ, Adler DG, Davila RE, Egan JV, Gan SI, Lichtenstein DR, Rajan E, Shen B, Fanelli RD, Van Guilder T, Baron TH; Standards of Practice Committee, American Society for Gastrointestinal Endoscopy. ASGE guideline: modifications in endoscopic practice for the elderly. Gastrointest Endosc. 2006 Apr;63(4):566-9.

6. Remond D, Shahar DR, Gille D, Pinto P, Kachal J, Peyron MA, Dos Santos CN, Walther B, Bordoni A, Dupont D, Tomas-Cobos L, Vergeres G. Understanding the gastrointestinal tract of the elderly to develop dietary solutions that prevent malnutrition. Oncotarget. 2015 Jun 10;6(16):13858-98.

7. Robertson R, Campbell C, Weller DP, Elton R, Mant D, Primrose J, Nugent K, Macleod U, Sharma R. Predicting colorectal cancer risk in patients with rectal bleeding. Br J Gen Pract. 2006 Oct;56(531):763-7.

8. Salles N. Basic mechanisms of the aging gastrointestinal tract. Dig Dis. 2007;25(2):112-7.

9. WHO. 2012. Health statistics and information systems. Metrics: Proposed working definition of an older person in Africa for the MDS Project. https://www.who.int/healthinfo/survey/ageingdefnolder/en/

The Aging Gut