Gastrointestinal motility disorders in the elderly

Gastrointestinal motility disorders in the elderly

The core teaching point of Pathy's chapter is that gastrointestinal motor function is relatively well preserved with healthy ageing, but there is a general decline in visceral sensation.

Systemic illness and medication — not age — impair gut function in the elderly. Consequences include swallowing disorders, impaired nutrition, altered drug absorption and altered bowel habit.

Sensory decline is demonstrable throughout the gut: reduced perception of balloon distension in the oesophagus, stomach and rectum, probably from loss of intrinsic sensory enteric neurons plus altered central processing. Perception of chemical stimuli such as acid also decreases.

In those over 60, upper oesophageal sphincter resting pressure is lower but shows less swallow-induced relaxation, indicating a degree of UOS resistance; reference ranges from young subjects must not be applied to older patients.

Reflex UOS contraction in response to laryngeal stimulation is impaired — a mechanism predisposing to aspiration; the frequency but not the magnitude of the response falls, implicating the sensory limb.

In the distal oesophagus there is reduced contraction amplitude and more frequent failed peristalsis; secondary peristalsis is less easily elicited. These changes begin as early as age 40.

Achalasia: peak incidence is in early-to-mid adulthood, but a second smaller peak occurs in the elderly. It presents with dysphagia for both liquids and solids; in older patients weight loss, regurgitation and aspiration are prominent while chest pain is less common.

Diagnosis of achalasia: barium swallow shows a dilated oesophagus with 'bird's beak' or 'rat's tail' tapering; manometry shows absent or incomplete LOS relaxation with type I (absent contractions), type II (pan-oesophageal pressurisation) or type III (premature spastic contractions).

Always exclude pseudo-achalasia — carcinoma of the distal oesophagus or cardia mimicking achalasia. A short history with disproportionate weight loss is the clue; endoscopy, and sometimes endoluminal ultrasound or CT, is mandatory in the elderly.

Treatment of achalasia: pneumatic dilatation and laparoscopic myotomy are the most efficacious for types I and II, each with about a 1% perforation rate. POEM allows calibrated myotomy and is particularly useful in type III. In a consecutive series of 51 patients aged ≥65 undergoing laparoscopic myotomy there were no deaths, few complications and a median stay of 3 days. For the frail elderly, endoscopic botulinum toxin injection into the LOS is a safe alternative.

Distal oesophageal spasm is more commonly diagnosed over age 50 and gives a corkscrew appearance on barium with premature contractions on manometry.

Minor disorders — ineffective oesophageal motility and fragmented peristalsis — account for more than one-third of presentations with dysphagia in patients over 65. Radiographic and manometric abnormalities correlate poorly with symptoms, no specific therapy exists, and management is acid suppression plus optimisation of nutrition.

Only a modest slowing of gastric emptying occurs with healthy ageing, confirmed longitudinally. However, altered perception of gastric distension and enhanced humoral responses to duodenal nutrients contribute to the anorexia of ageing.

Intraduodenal nutrients stimulate greater cholecystokinin release in healthy elderly, intraduodenal glucose is more satiating, and higher rates of H. pylori infection and atrophic gastritis are associated with lower ghrelin — a triad worth quoting for anorexia of ageing.

Drug absorption: slow emptying and altered gastric pH may affect absorption of oral medication; paracetamol absorption is slightly slower, but benzodiazepines, tetracycline and L-dopa absorption are not significantly altered by age.

Small intestine: MMC periodicity is preserved in the healthy elderly; phase III propagation velocity is modestly slower, and there are more propagated clustered contractions — a pattern also seen in IBS, of unclear significance. Transit is comparable to the young, in contrast to the delayed colonic transit characteristic of ageing.

Postprandial hypotension can legitimately be classified as a gastrointestinal motility disorder — the fall in blood pressure relates to splanchnic blood flow regulation and gut peptide release, is worst in type 2 diabetes with autonomic neuropathy, and is an under-recognised cause of syncope and falls. It is attenuated by octreotide, and by measures slowing gastric emptying and carbohydrate absorption (e.g. GLP-1 receptor agonists such as lixisenatide, guar, acarbose).

Diabetes: gastroparesis impairs nutrient and drug absorption and destabilises glycaemia; diagnose by endoscopy first to exclude obstruction, then scintigraphic gastric emptying. Treat with prokinetics — metoclopramide, domperidone or erythromycin (a motilin agonist). Cisapride was withdrawn for arrhythmia risk. Pyloric botulinum toxin is of unclear benefit and less likely to help patients over 50; gastric electrical stimulators lack adequate controlled evidence.

Up to 80% of patients with diabetic gastroparesis have abnormal small-intestinal motility. In diabetic diarrhoea, specifically exclude SIBO, coeliac disease and pancreatic exocrine insufficiency.

Progressive systemic sclerosis: peak incidence in the fifth and sixth decades; GI involvement in the majority. Oesophageal dysmotility in about 80% with very low LOS pressure and severe reflux; gastroparesis, pseudo-obstruction, bacterial overgrowth, malnutrition, constipation and faecal incontinence may all occur. Smooth muscle atrophy and fibrosis plus antibodies to M3 muscarinic receptors are implicated. High-dose PPI is often needed; prokinetics help when transit is delayed.

Parkinson's disease causes dysphagia, gastroparesis and constipation, and is a major contributor to bowel dysfunction; amyloidosis and other connective tissue diseases produce similar patterns.

Functional disorders are defined by Rome IV and are often overlooked in the elderly. 10–15% of people over 70 have IBS in community surveys; prevalence is greater in women at all ages.

Organic disease must be rigorously excluded — its prevalence is higher than in the young. Have a low threshold for colonoscopy with altered bowel habit, and remember that mesenteric ischaemia occurs more often in patients with IBS than without.

Treatment: low-FODMAP diet is first-line for IBS but almost unstudied in the elderly; antispasmodics (hyoscine, mebeverine, peppermint oil) and low-dose tricyclics have a good evidence base, with SSRIs better tolerated than tricyclics in older patients. Placebo response is 20–70%, so judge all therapies against it.

Opiates must be avoided for chronic abdominal pain — ineffective, and causing tolerance, opioid-induced hyperalgesia and narcotic bowel syndrome. Beware anticholinergic burden: sedation, urinary retention, postural hypotension, blurred vision and glaucoma.