Acute Abdominal Pain in the Older Adult
Keywords
• Acute abdominal pain • Elderly • Emergency department
Older adults, defined as those who are 65 years and older, are the fastest growing segment of the population in the United States and the highest emergency department (ED) users of any age group.1 By some estimates, older patients will account for one-fourth of all ED visits in the United States by 2030.2 Abdominal pain is the most common presenting complaint to the ED,1 and in older adults, abdominal pain is the fourth most common chief complaint.3 Challenges to the diagnosis and management of abdominal pain in older adults are multifactorial but start with the lack of overt clinical findings and varying presentations of intra-abdominal disorders. In a survey comparing younger and older adult patients, emergency medicine physicians (EPs) consistently found older patients more complex, requiring more time and resources to diagnose and treat. Out of the surveyed diagnoses EPs found abdominal pain in older adults the most difficult to evaluate.4 This article starts with a review of the physical changes of aging and how these changes affect both the abdominal diseases to which the older adults are susceptible and the clinical features of abdominal pathology in this group. This discussion is followed by an analysis of the management of acute abdominal pain in older adults organized by the following pathologic processes: inflammatory, obstructive, vascular, and other causes.
Pathophysiologic changes in the older adult
Older adults are at a higher risk for more frequent and severe infections due to immunosenescence. Aging of B cells decreases the ability to develop humoral (antibody) immunity to new infections or antigens, thereby increasing the risk for recurrence.5 The T cell response also changes with aging, with decreased quantity and quality of the T cells and a decreased immune response to known antigens, possibly because of changes in the phenotype towards more immunosuppressive T cells.6,7 These derangements have consequences for interpretation of the white blood cell count; on the one hand, a low count does not exclude an acute inflammatory condition, on the other, an elevated count does not exclude functional immunodeficiency. Aging is associated with a decreased response to pyrogens, lower basal body temperature, changes in thermal homeostasis, and a decreased production and conservation of heat. In one study, 30% of older adults who had surgical abdominal pain did not present with either a fever or leukocytosis.8 Immunosenescence also results in decreasing immunosurveillance, the body’s main defense against developing cancerous cells.
Renal changes with aging include decreased numbers of glomeruli and decreased glomerular function. These changes are caused by both long-term damage from comorbidities, such as hypertension and diabetes, and dysautoregulation of the afferent and efferent arterioles resulting in glomerular damage. Glomerular filtration rate decreases with age starting in the fourth decade and then diminishes by about 8 mL/min/decade, resulting in a reduction in the clearance of drugs and metabolites. Changes to the basement membrane and the development of small diverticula in the distal renal tubules promote urinary stasis and bacterial growth.9 The aging kidneys also have diminished ability to concentrate urine, making older adults more prone to dehydration. Hormonally, the kidneys have reduced production of epoetin, inclining the older adult toward anemia from slow losses of blood.9
The effects of aging on the GI system also predispose patients to abdominal pathologic conditions. The stomach has a slightly decreased emptying time and fundal compliance. Acid secretion may increase secondary to decreased prostaglandin production. Liver mass and liver blood flow decrease with aging, resulting in decreased albumin synthesis and decreased phase 1 drug metabolism. The decrease in cytochrome P450 function and drug metabolism may be even greater in older men than in older women.10 In the colon, the number of diverticula in the bowel increases with age. Because of physiologic anorexia of aging, there is decreased fluid and nutrient intake, predisposing the older adult to constipation.11,12 Reduced physical activity for just 2 weeks almost doubles total colonic transit time in older adults,13 which may contribute to the higher rate of postoperative ileus in this population.
Both the central and peripheral nervous systems are affected by aging. The prevalence of dementia and cognitive impairment increases, obscuring symptoms and obfuscating the medical history. Peripherally, pain and temperature sensation decreases as the type of pain sensing nerves slowly switches from A delta fibers (fast, sharp, prickly pain) to a reliance on slower-conducting C fibers.14 This sensation decrease may contribute to the lack of peritoneal signs in many older adults. In a study of 212 patients with peritonitis, 55% had abdominal pain, but guarding or rigidity was observed in only 34%.15 A review of patients with perforated ulcers found that only 21% of older adults presented with peritoneal signs.16
Diagnostic obstacles
Among the difficulties complicating the diagnosis of intra-abdominal disorders in older adults are preexisting illnesses that alter classical manifestations; an inability to obtain an accurate history; medications that can cause, confound, or mask disease processes; and alterations in laboratory baseline and physical findings.15,17,18 In addition, older adults may be less likely to seek timely medical care and thus may have later-stage disease or more serious illness when they present for care.4,19,20 All these factors contribute to a higher morbidity and mortality for acute abdominal disorders in older adults.20
Chronic diseases accumulate with aging. Diabetes decreases peripheral nerve sensation in the abdomen as well as in the extremities. Previous abdominal surgery may diminish the perception of pain in the older adult.21 Atherosclerotic cardiovascular disease places the patient at risk for cardiac ischemia, mimicking as abdominal pain, as well as other vascular catastrophes, including mesenteric ischemia and aortic aneurysm.
The usual clinical approach of a diagnostic workup based on a history taking and physical examination is complicated in older adults by multiple factors. Some patients downplay their symptoms or are unable to understand questions pertaining to cognitive or hearing impairment. Caregivers may be a helpful source of history taking but are not always available. At times, the presenting symptom of an underlying intra-abdominal process may itself be altered mental status.22–24
With atypical and delayed presentations, pathophysiologic and pharmacologic effects, decreased ability to communicate, and higher morbidity and mortality rates, accurate diagnosis of older adults with acute abdominal pain can be extremely challenging. One approach, when presented with these patients, is to organize the differential diagnosis into categories based on underlying pathologic processes: inflammatory, obstructive, vascular, or other causes.25
Inflammatory Causes of Abdominal Pain
Peptic ulcer disease
Although the incidence of peptic ulcer disease (PUD) and the related complications and mortality of PUD have decreased over the past few decades in younger adults, hospital admission rates for PUD-related complications have increased in older adults. This increase may be secondary to increased use of aspirin and NSAIDs. Nearly 40% of older adults are prescribed NSAIDs, and age is an independent risk factor for developing gastroduodenal injury with NSAID use.26 The risk of bleeding from a peptic ulcer is higher in short-term versus long-term users of NSAIDs or aspirin.13,27–29 Another factor contributing to PUD is the increased prevalence of Helicobacter pylori colonization with age.30,31 Approximately 53% to 73% of older adults who have PUD are H pylori positive.32
In older adults, the typical presentation of epigastric pain is less common than in younger adults.33 About 35% of older adults with endoscopically proven PUD do not experience pain.34 In many cases, the initial presentation is with complications, the most common of which is GI bleeding. With long-term blood loss, patients may present with anemia or its consequent symptoms such as angina, decreased exercise tolerance, or congestive heart failure.
Perforation is a serious complication, more commonly seen with duodenal ulcers, and occurs in 5% to 10% of older adults with PUD. In one study, only 47% of patients with a perforated gastroduodenal ulcer had a sudden onset of pain and only 21% presented with rigidity.16 Disturbingly, plain radiographs failed to identify free air in 39% of cases of perforation.16 Once perforation occurs, the mortality is 30%, three times higher than in younger adults. Other less common complications of PUD include gastric outlet obstruction and penetration into adjacent organs. The overall mortality of PUD is 100 times higher in older than in younger patients.
Pancreatitis
Pancreatitis is the most common nonsurgical cause of abdominal pain in older adults.35 The top 2 causes of pancreatitis in older adults are gallstones and idiopathic causes compared with gallstones, hyperlipidemia, and alcohol use in younger patients.36,37 Classically, the disease presents with upper abdominal pain radiating to the back, but it can also present as diffuse abdominal, back, or chest pain, with associated nausea and vomiting. Imaging is particularly helpful in patients with atypical presentations. Recent guidelines suggest that 2 out of 3 of the following should be present for the diagnosis of pancreatitis: (1) upper abdominal pain; (2) elevated levels of pancreatic enzymes; and (3) findings suggestive of acute pancreatitis on ultrasonography (U/S), computed tomography (CT), or magnetic resonance imaging (MRI). In the acute setting, CT is the preferred confirmatory imaging modality.38
In one series, gallstone pancreatitis accounted for more than half the cases in older adults compared with only 36% of younger patients.39 Endoscopic retrograde cholangiopancreatography (ERCP) is the recommended therapeutic and diagnostic test for those patients who have common bile duct dilation on CT or U/S or a recent cholecystectomy.39 ERCP is safe in older adults with a complication rate insignificantly higher than in younger patients, even when considering the subset of older adults on anticoagulation. The complication rate for ERCP remains constant for the young-old (65–74 years), the old-old (75–84 years), and the very old (>85 years).40 Older adults may require subsequent ERCP sessions to completely clear the duct because of a higher stone burden.41
The Ranson criteria and the APACHE II (Acute Physiology and Chronic Health Evaluation II) criteria are used to predict patients at risk for severe disease and complications. In patients hospitalized for acute pancreatitis, older age is an independent risk factor for progression to organ dysfunction, systemic inflammatory response syndrome, or death.42 Although mild pancreatitis can be managed in a regular unit with fluid resuscitation, analgesia, and antiemetics, patients with severe pancreatitis should be managed in an intensive care unit (ICU) with early surgical consultation and increased attention to their comorbidities and decreased physiologic reserve. Thromboprophylaxis with low–molecular weight heparin is suggested, given the increased inflammatory state.43 Enteral nutrition via nasogastric or nasojejunal tube feed is the preferred mode of nutrition in severe acute pancreatitis because it seems to reduce oxidative stress, stabilize the catabolic state induced by pancreatitis, and improve outcomes.44,45
Biliary disease
Biliary tract disorders are the most common cause of abdominal pain in the older adult and the most common indication for intra-abdominal surgery.46 The incidence of gallstones increases with age, with the prevalence reaching 33% by the age of 70 years.47 Changes in bile acid production, bile cholesterol saturation, and decreased gallbladder sensitivity to cholecystokinin predispose older adults to the formation of gallstones.
Gallstones become symptomatic when they obstruct the neck of the gall bladder, resulting in intermittent symptoms of pain, often with associated anorexia, nausea, and vomiting. Symptomatic cholelithiasis can be managed by elective cholecystectomy if pain is controlled, if the patients are tolerating oral intake, and if patients do not appear sick. Early surgical intervention decreases repeat ED visits and complications, including acute cholecystitis (AC), pancreatitis, cholangitis, perforation and empyema.48 Choledocholithiasis occurs more frequently in older adults49 and can lead to obstructive jaundice, pancreatitis, and ascending cholangitis. U/S has low sensitivity but high specificity for detecting these stones. Magnetic resonance cholangiopancreatography and endoscopic U/S can detect bile duct stones with higher sensitivity and specificity than U/S and have comparable accuracy to ERCP but are much less invasive.49 ERCP is the first-line therapeutic intervention.
If gallbladder outlet obstruction lasts more than 12 to 24 hours, there is increasing likelihood of progression to inflammatory changes in the gallbladder walls and onset of AC. A third of older adults with AC will present with minimal abdominal pain and minimal to no peritoneal signs, and presentation may not correlate with the severity of disease.50 In one study of older adults with AC, 40% of severely ill patients had empyema of the gallbladder, gangrenous AC, or free perforation, and 15% had concomitant subphrenic or hepatic abscess; yet, of these patients, more than one-third were afebrile and a quarter did not have abdominal tenderness.51 Fever is also not a sensitive indicator in older adults, as in one series only 71% with nongangrenous AC and 59% with gangrenous AC were afebrile. Approximately, 32% lacked leukocytosis and 28% lacked both fever and leukocytosis. In patients with gangrenous AC, more than a quarter of the patients lacked leukocytosis, and 16% lacked both fever and leukocytosis.52 The ED treatment of AC begins with fluid resuscitation, administration of broad-spectrum antibiotics, and surgery consultation with cholecystectomy as definitive treatment.53
Emphysematous cholecystitis occurs predominately in older adults, particularly in men and diabetic patients, and is less likely to be associated with gallstones. This disease accounts for only 1% of all cases of AC but carries a mortality ranging from 15% to 25%, five times greater than the operative mortality for nonemphysematous AC.54 Gas-forming clostridial species are the most common causative agent. With the high risk of perforation, empiric broad-spectrum antibiotic administration, including anaerobic coverage and surgical intervention, are critical for survival. Diagnostic imaging considerations for biliary disease in the elderly are similar to those in other age groups.
Appendicitis
Acute appendicitis is a diagnostic challenge in patients of all ages, but more so in older adults. Appendicitis presents classically with periumbilical pain that later localizes to the right lower quadrant with associated anorexia, nausea, and vomiting. Approximately 3% to 4% of older adults presenting with acute abdominal pain will have appendicitis.46,55 The oldest old patients, octogenarians and older, have a significantly higher risk of delayed surgery and perforation compared with even younger-old (65–79 years old) patients.56 In a case series of 601 patients older than 65 years with acute appendicitis, patients with perforation tended to wait a day longer before presenting to the ED and to have greater delays from presentation to surgery. Age had a larger effect on perforation than comorbidities.57 As with other age groups, no laboratory test reliably diagnoses appendicitis in the elderly. Recent efforts to use C-reactive protein for this purpose and for risk stratification show some promise, but definitive imaging or laparotomy is still required.58,59 Diagnostic imaging considerations in the elderly are similar to those of other age groups.
Diverticulitis and colitis
Aging and lifestyle changes place the elderly at high risk for constipation and diverticulosis and thus for colitis and diverticulitis. In necropsy studies, the prevalence of diverticulosis increases from 13% in those younger than 55 years to 50% in those older than 75 years.60 In Western nations, left-sided diverticulosis and diverticulitis are more prevalent. Uncomplicated diverticular disease (diverticulosis) is not typically associated with acute abdominal pain.61 A prospective study following patients with bowel complaints (pain, constipation, bloating) and diverticulosis found a crossover of only 1.7% to acute diverticulitis over 5 years.62
Diverticulitis classically presents as left lower abdominal pain associated with cramping, change in bowel movements, nausea, or fever. Diagnosis is confirmed by contrast-enhanced CT. One study comparing CT with U/S showed similar accuracy for diagnosing diverticulitis.63 A recent meta-analysis shows summary sensitivities of 92% for U/S versus 94% for CT and summary specificities of 90% for U/S versus 99% for CT.64 CT, however, is the preferred test because it can rule out alternative diagnoses that may not be well visualized by other imaging modalities. Initial treatment consists of broad-spectrum antibiotics against gram-negative and anaerobic bacteria, with a typical course of 7 to 10 days.65 Admission decisions depend on the severity of the illness as well as the presence or absence of complications. Approximately, 25% of patients have a recurrence in which complications of abscess, phlegmon, or perforation are as likely as in the initial episode.66,67 In sick or unstable patients, ED surgical consultation should be obtained. With contraindications to surgery, CT-guided drainage of diverticular abscess is an alternative.
Colitis can have a similar presentation to diverticulitis. Causes include infectious agents, such as Clostridium difficile, and inflammatory bowel disorders, such as ulcerative colitis (UC) and Crohn disease. C difficile is the most common cause of infectious diarrhea in nursing homes in the United States with a mortality estimated at more than 17%.68 UC and Crohn disease have bimodal age distributions, and thus a significant portion of new diagnoses is made in older adults. Older patients make up more than 20% of admissions for Crohn disease and more than 30% of admissions for UC.69 Stool antigen analysis, CT scan, and colonoscopy may help delineate between these different causes of colonic inflammation.
Obstructive Causes of Abdominal Pain
In the elderly, bowel obstruction accounts for 10% to 12% of ED visits for abdominal pain.20,55,70 Obstruction is 3 times more common in older adults than in younger patients.50 After biliary disease, bowel obstruction is the second most common reason for emergency surgical intervention in this age group.71 Presentations vary and depend on the type and location of obstruction. Complications of obstructions include dehydration, ischemia, sepsis, and perforation. The types of obstruction can be broken down into small versus large bowel and mechanical versus functional obstruction.
Small bowel obstruction
The small bowel is the most common site of obstruction. The small bowel is more mobile, smoother, and smaller in diameter, making it more prone to both adhesions and herniation than large bowel.72 The 3 most common causes of small bowel obstruction (SBO) are adhesions (50%–74%), hernias (15%), and neoplasms (15%).71,73 As with younger patients, older adults with SBO present with colicky abdominal pain, nausea, vomiting, abdominal distension, and constipation. Gallstone ileus is a rare disease that accounts for 1% to 4% of mechanical obstructions.74
Plain radiography, often the initial study of choice, have a sensitivity of 66% and specificity of 57%.75 Flat and upright abdominal radiographs may show distended loops of bowel, collapsed loops of bowel distal to the obstruction, paucity of gas in the rectum, air fluid levels, or stack-of-coins appearance (Fig. 1). Plain radiography is limited in assessing the degree, location, and cause of obstruction. CT imaging should be obtained when radiographs are nondiagnostic or to discriminate between complicated (vascular involvement) and uncomplicated (bowel involvement only) obstruction and assess the location and cause of obstruction. Closed-loop obstructions have a higher risk of strangulation. When strangulation of the bowel occurs, mortality increases 10-fold.76 The clinician should bear in mind that even CT only has a sensitivity of 92% and specificity of 93% in the diagnosis of complete SBO.77
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
