Acute Abdominal Pain in the Elderly

Emerg Med 37(8):8-12, 2005

Why does the same abdominal pathology sometimes cause less pain and discomfort in an older patient than in a younger one? What age-related differences in presentation and course have been documented in such conditions as cholecystitis and appendicitis? Which clinical characteristics are of highest prognostic significance in the older patient with an acute abdomen? The authors address these and other questions.

By Michael D. Burg, MD, FACEP, and Lynda Francis, MSN, FNP

Roughly 5% to 10% of emergency department visits in the United States are for abdominal pain, and the elderly account for a disproportionate share of these presentations. In a large worldwide survey of more than 10,000 patients with acute abdominal pain, 23% were 50 years of age or older. Two large survey studies—one performed throughout continental Europe, the other limited to England—found a similar percentage of acute abdominal pain patients aged 50 or older.

Elderly patients are overrepresented because many medical conditions that cause or lead to painful abdominal disorders are more common in the elderly. These include intra-abdominal malignancies, vascular disease, cholelithiasis, and diverticulosis, among others. The elderly are more likely to have had prior abdominal surgery, making their evaluation potentially more challenging. In one study of acute appendicitis presentations in which an age of 50 years was used as a cut-off, 23% of those studied who were over age 50 had had previous surgery versus approximately 3% of those under age 50.

How is "elderly" defined in the literature on this subject?

Approximately 13% of the United States population is age 65 or older, which is how "elderly" is defined in this article. Within 20 years, almost 20% of the United States population will be age 65 or older. For research purposes, the elderly are divided into the young-old (age 65 to 74), the middle-old (age 75 to 84), and the old-old (age 85 or older).

Most of the studies that address abdominal pain in the elderly have focused on patients who are age 65 or older, although this age cutoff is arbitrary for clinical purposes. Many of these studies include some subgroup analysis based on the three categories of the elderly defined above.

Studies that used an age cutoff other than age 65 or older or found important differences in the three elderly subgroups will be cited in this review.

What factors account for the differences in presentation between elderly patients with abdominal pain and younger patients with the same complaint?

For a variety of reasons, the elderly—even those with serious intra-abdominal pathology—tend to delay seeking medical care. One study comparing patients under age 65 versus those over age 65 with culture-proven intra-abdominal infections found the older patients had symptoms for an average of nine days before seeking medical care versus four days with the younger patients. Additionally, elderly patients ultimately diagnosed with common intra-abdominal diseases and conditions (cholecystitis, for example) present atypically and are more likely than younger patients to have atypical physical examination and laboratory findings.

The reasons underlying delayed presentation for abdominal pain in the elderly are not well studied or elucidated in the literature. It has been suggested that the elderly do not sense pain as acutely as younger individuals or that perhaps they have less discomfort on average with a similar intra-abdominal ailment, but neither of these suppositions has been definitively demonstrated. Many physicians have observed that elderly patients with serious, even life-threatening intra-abdominal pathology (such as emphysematous cholecystitis, leaking abdominal aortic aneurysm, or perforated viscous) may present with minimal abdominal pain. Neuropathy—especially when linked to diabetes, a common age-associated disease„or the chronic use of certain medications (such as corticosteroids or pain relievers) may also blunt pain perception. The elderly may also lose abdominal wall muscle mass, making guarding either impossible or less apparent.

Does immunosenescence play any role in elderly patients' decreased pain perception?

Immunosenescence, a decline in immune system function with age, may also predispose the elderly to sense less intra-abdominal discomfort than younger patients. However, the very concept of immunosenescence, let alone how it impacts intra-abdominal disease presentations in the elderly, is not completely understood.

Certainly, physical changes associated with aging may result in the perception of less pain for a given condition, but social or cultural factors probably play a role as well. For example, many elderly people see the hospital as a place to go to die. Others may feel that the emergency department is appropriate only for patients with life-threatening conditions. Still others may simply be unwilling to visit an emergency department or other acute care setting for abdominal discomfort, which they may see as a minor annoyance. The desire "not to bother the doctor" or "to wait and see how things are in a couple of days" may lead to serious delays in presentation and ultimately in diagnosis and treatment.

Although it has not been the subject of rigorous scientific inquiry for abdominal pain patients, elderly patients' inability to provide an accurate history may interfere with the physician's assessment of their condition. "Feeling weak," "not feeling well," or "not eating" may be the only history elicited in an elderly patient. Obviously, the differential diagnosis for such vague complaints is extremely broad. Time spent investigating other potential causes of the patient's complaint may mean abdominal pathology goes undiagnosed for an extended period. Also, the high incidence of dementia and stroke limits the ability of the elderly to communicate with physicians and other health care providers.

Finally, the tendency of some elderly patients to minimize their abdominal symptoms may lead the unwary physician astray. Again, the yield or accuracy of particular styles of questioning has not been scientifically scrutinized, but using the patientÍs own words to help them describe their symptoms may be helpful. Rather than asking about abdominal pain in patients who say "I'm not feeling well," it would be better to ask them to describe what they mean. If they offer "stomach ache," use that term rather than "pain" to refer to their complaint. Words such as "soreness," "ache," "nausea," and "sick" can serve as surrogates for abdominal pain and help accelerate a focused work-up.

Are the physical examination findings in elderly patients with acute abdominal pain different from those in younger patients?

Not only do the elderly tend to complain less of abdominal pain, but their physical examination findings are less sensitive and specific than those of younger patients. This has been shown in multiple studies.

In one series of geriatric inpatients (mean age 82 years) with pathologically-proven peritonitis from a variety of causes, only 73% had abdominal tenderness, 34% guarding or abdominal muscle rigidity, 69% abdominal distension, and 52% diminished or absent bowel sounds. In this same group, tachycardia (heart rate over 100 beats/minute) was present in roughly 90% of patients, fever (defined in this study as a temperature over 98.6ÅF) in about 85%, and hypotension (not defined) in approximately 60%. However, these vital sign abnormalities are extremely nonspecific and may be present in a wide variety of conditions. In this highly selected population, the traditional physical examination findings of peritonitis were surprisingly infrequent.

In another study of geriatric emergency department patients, Marco cautioned that "most physical examination findings were not helpful in identifying patients with adverse outcomes." Of all the physical examination findings available for analysis in this study, only hypotension and abnormal bowel sounds were found to be helpful in identifying patients with a higher risk of adverse outcomes, again illustrating the nonspecific nature of physical findings in the elderly with abdominal pain.

At least one study has examined whether the presence of fever can be used to screen for surgery-related pathology in the elderly. This study concluded that temperature elevation alone was inadequate to differentiate nonsurgical from surgical abdominal pathology. In this same study, a wide variety of commonly performed screening laboratory tests were evaluated for their ability to identify patients with surgical versus nonsurgical conditions. All tests failed to reliably distinguish between the two patient groups.

Hypothermia in association with various intra-abdominal infections may be more common in the elderly. Using a cut-off of 96.8Å°F, one study by Cooper and colleagues found 14% of elderly patients (over age 65) to be hypothermic versus just 3% of those 65 years of age or younger. Interestingly, this study is one of the few to report that physical findings (abdominal tenderness, peritoneal signs, and lethargy) were similar between groups, although no statistics were provided in the paper to support this contention.

Have any studies been done that looked at specific conditions that can cause abdominal pain in the elderly?

Several condition-specific studies have been performed. In the case of cholecystitis, an investigation by Gruber et al found that the "absence of fever was as likely in patients younger than 60 years as it was in patients older than 60." However, the authors note that only 32% of their study subjects with pathologically-proven cholecystitis had a documented temperature elevation within eight hours of their arrival in the emergency department. This should serve as a caution for health care providers evaluating all patients with the possible diagnosis of cholecystitis. The classic presentation of abdominal pain, anorexia, nausea and vomiting with fever, and an increased white blood cell (WBC) count does not occur in a significant percentage of patients—young and old—with cholecystitis.

In another study of elderly patients (age 65 or older) with cholecystitis, 56% were afebrile, demonstrating that the classic physical exam findings reported in texts and taught in the classroom may not be so classic in practice.

Appendicitis in the elderly has been the subject of several studies. Horattas and colleagues estimate that "5% to 10% of all cases of appendicitis occur in the elderly." However, the morbidity and mortality of appendicitis are significantly increased in this population. In their study of 96 elderly patients (over 60 years of age) with appendicitis, Horattas and colleagues found that only 20% presented with the classic combination of anorexia, fever, right lower quadrant pain, and an elevated WBC count. Using a cutoff of 99.7°F, only 47% had fever and 23% had either diffuse abdominal tenderness or tenderness localized outside the right lower quadrant.

One survey of emergency physicians attempted to quantify what many of us may feel in daily practice—discomfort with our ability to manage and evaluate older patients with abdominal pain. A mailed survey found that emergency physicians reported more difficulty managing older patients with a variety of conditions, including abdominal pain, and felt they required more time and resources to evaluate. Given the information presented above, it seems as though this uncomfortable feeling is justified.

Are there diseases and conditions that cause abdominal pain in elderly patients that are different from those seen in younger adults?

The causes of abdominal pain in the elderly are not truly different, but their relative frequencies are.

Serious vascular disease causing abdominal pain (acute mesenteric ischemia and abdominal aortic aneurysm, in particular) is uncommon in all age groups but is rare in those under 50 years of age. Thereafter, its incidence climbs.

Roughly 75% of patients with acute mesenteric ischemia are age 70 or older. For those patients with transmural bowel necrosis and peritonitis, the mortality rate is 80% to 100% regardless of the diagnostic and therapeutic approach taken. The overall mortality rate for mesenteric ischemia is lower, especially in patients diagnosed before peritonitis occurs.

Dissection or rupture of an abdominal aortic aneurysm occurs primarily in the elderly. Elderly men with histories of smoking, hypertension, or other vascular disease are at particularly high risk. Up to one third of patients are initially misdiagnosed, often with catastrophic results. It is important to consider an intra-abdominal vascular event early in the evaluation of elderly patients with abdominal pain.

Intestinal obstruction is a common problem in the elderly. Large bowel obstructions are most commonly due to malignancies, although multiple other etiologies are possible. Small bowel obstructions generally result from adhesions, neoplasms, or hernias. Health care providers should always inquire about prior surgery when evaluating a patient with abdominal pain. In one large series, Dombal described roughly 3% of abdominal pain patients younger than age 50 having had prior abdominal surgery, versus 21% of patients over age 50.

Other common causes of abdominal pain in the elderly include cholecystitis, appendicitis, pancreatitis, diverticular disease, cancer, and hernias.

The diagnosis of nonspecific abdominal pain is made in approximately 40% of patients under age 50 but in only 15% of those over 50. It is well known that young people (especially those in their 20s and 30s) with nonspecific abdominal pain tend to have a benign course. This has not been convincingly demonstrated in those over age 50. Health care providers should be very wary of assigning the label "nonspecific abdominal pain" to patients over 50.

Are elderly patients with abdominal pain more likely than younger patients to have surgical conditions?

In general, diagnoses requiring surgery are far more common in the elderly. The risk of a surgical diagnosis doubles with each decade over 40.

Biliary disease, cancer, and vascular conditions occur with greater incidence in elderly patients. These conditions often require careful consideration for surgical correction. In patients older than 70, biliary tract disease and intestinal obstruction are the most common causes of abdominal pain requiring surgical intervention. In a large study involving 2406 elderly patients (defined as over age 50), cholecystitis was found to be the most common ailment. The frequency was greater than 50% in patients older than 70. Small bowel obstruction is five times more common in patients older than 50.

Additionally, intra-abdominal cancers and vascular conditions are more common in elderly patients. The incidence of an intra-abdominal malignancy is up to 24% in patients over age 70 with a complaint of abdominal pain.

Mesenteric ischemia and infarction are also more common in elderly patients. Conditions that increase the risk for this process include cirrhosis, abdominal infection, atrial fibrillation, prosthetic valves, and hypercoagulable states. The classic description of a patient with mesenteric infarction is that they have pain out of proportion to their physical findings. This textbook scenario, however, is not always present.

Mesenteric (or abdominal) angina patients often present with an adversity to eating and resultant weight loss due to their predictable postprandial pain.

Further complicating the diagnostic process is the fact that many conditions evolve differently in the elderly. Subtle differences in the presentation of common disease processes increase the time to diagnosis, resulting in disease progression. For example, the presenting symptoms of appendicitis are often subtle in the elderly, with predominant symptoms being vague periumbilical discomfort and anorexia. The incidence of perforated appendicitis is up to 37% in the elderly versus 4% in younger patients.

In general, when evaluating an elderly patient with abdominal pain, health care providers should have a low threshold for obtaining surgical consultation.

Are there high-risk factors in elderly patients with abdominal pain that predict a poorer outcome?

Certain factors are associated with a high risk of adverse outcomes in elderly patients with abdominal pain. A 1998 study by Marco et al reviewed the course of 380 elderly patients (age 65 or older) in an effort to identify variables strongly associated with a poor outcome, defined as death or need for surgery. Four factors were found to be associated with death: free air on abdominal radiographs, age over 84 years, other significant x-ray findings (such as kidney or gall stones or abdominal aortic aneurysm), and bandemia. Hypotension, abnormal bowel sounds, abnormal x-ray findings, and leukocytosis were all associated with a need for surgery.

The study authors cautioned that "the absence of these variables does not preclude significant disease." They also stated that physical examination is an unreliable method for predicting or excluding significant disease.

Another important variable to consider when evaluating elderly patients with abdominal pain is the high incidence of comorbid conditions. About 88% of older patients have comorbid conditions, compared to 48% of younger patients. More than half of the time, these comorbidities include cardiac diseases. Coexisting medical conditions may be more important than age as negative prognostic indicators. Coagulopathy, renal failure, coronary artery disease, and chronic pulmonary disease increase the likelihood of a negative outcome. Elderly patients with these conditions are less able to tolerate the physiologic stress imposed by an acute illness or surgery.

What is the mortality associated with acute abdominal pain in the elderly?

It is axiomatic that mortality rates rise steeply with age. For example, patients over 80 years of age presenting with abdominal pain have a mortality rate 70 times that of young adults.

Many factors contribute to mortality in this population, including physiologic frailty, low initial diagnostic accuracy (generally only 40% to 65%, dropping to less than 30% in patients over age 80), diagnostic delays, atypical and late presentations, and comorbid conditions.

One study of 334 patients older than 70 who underwent elective gastrointestinal surgery found a 6.7% mortality rate. However, the death rate tripled (to 20%) when elective surgical procedures were delayed and emergency gastrointestinal operations were required. In short, delayed elective surgery in the elderly patient leads to higher mortality rates.

The mortality rates for many intra-abdominal conditions in the elderly rivals that of serious cardiopulmonary diseases. Elderly patients with abdominal pain need to be evaluated just as carefully—and admitted just as liberally—as those with chest pain.

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