Acute Abdominal Pain in Older Adults

By Benjamin Cornwell, MD, and R. Gentry Wilkerson, MD

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Introduction

Abdominal pain is a common chief complaint for patients presenting to an emergency department (ED). Approximately 8% of the estimated 100 million ED visits each year are due to abdominal pain.¹ As the population in the United States ages, an increasing number of these patients will be older adults. According to the U.S. Census Bureau, between the 2010 census and the 2020 census, adults 65 years of age and older had the fastest growth since the period between 1880 and 1890. As of the 2020 census, this group now accounts for 16.8% of the U.S. population.

This patient population can be challenging for the emergency physician because the typical findings of acute abdominal pathologies, such as peritoneal signs or significant tenderness, often are blunted or absent. In addition, history-taking may be limited because of cognitive impairment, or prolonged due to communication barriers such as difficulty hearing or speaking. Regardless, efficient diagnosis and treatment are paramount. Older adult patients with abdominal pain have an increased morbidity and mortality — up to six- to eight-fold higher when compared to younger individuals.² This article will discuss history and physical exam findings, diagnostic tools, and analgesia, as well as several, but not all, pathologies that can cause acute abdominal pain in an older adult.

History and Physical

Despite advances in modern diagnostics, the patient history and the physical exam remain foundational in the initial evaluation of any patient, especially an older adult patient with abdominal pain. This initial evaluation guides the course of patient care, whether that means emergent surgical consult for the patient with a distended, rigid abdomen and hypotension; further investigation with laboratory measurements and imaging; or a urinary catheter placement for acute urinary retention causing significant discomfort. Obtaining the primary reason the patient is presenting to the ED may be especially difficult in an older adult population. Factors such as impaired vigilance, cognitive deficiencies, and psychologic stress all can contribute to delayed, incomplete, or unobtainable history taking.³ Coupled with increased comorbidities and sometimes poor insight into medical conditions, extra time often is required to overcome these barriers.

Despite the time required, it is vitally important to obtain a thorough history of any older adult patient presenting to the ED. Questions about recent changes to medications should be included in the history, since up to 10% of hospital admissions for older adults were found to be related to adverse medication side effects.⁴ Performing a focused chart review is similarly important. This should involve searching for medications like anticoagulants or antiplatelet agents, past surgeries, as well as any new or chronic medications that would change the differential diagnosis for an older adult patient with abdominal pain. Lastly, seek out collateral information. This can include family members, referring facilities such as a nursing home, or any other caregivers who may have a better understanding of why the patient is coming to the ED.

Just as with obtaining a history, the physical exam in an older adult patient can prove challenging. The physiologic changes that come with aging lead to higher rates of uncommon presentations for common diseases. Expected findings of appendicitis, such as fever, leukocytosis, and right lower quadrant abdominal pain, may be either absent or significantly diminished. With age, there is atrophy of the musculature in the abdominal wall, leading to decreased rebound or guarding.⁵ Medications frequently taken by older adults also may change the physical exam. Baseline analgesics, such as opioids or nonsteroidal anti-inflammatory drugs (NSAIDs), being used for other comorbid conditions can reduce pain or can blunt a fever, potentially obscuring the presence of a serious condition.

Laboratory Testing

Laboratory testing can be helpful in differentiating the various potential pathologies that may exist in the older patient with abdominal pain. However, normal results are not always indicative of the absence of pathology. Testing usually should include a complete blood count, comprehensive metabolic panel to include liver enzymes, a serum lipase level, and a urinalysis. Consideration can be given to obtaining coagulation studies, including international normalized ratio (INR)/prothrombin time and partial thromboplastin time. Patients who should have coagulation studies ordered include those taking anticoagulants and those with known or suspected pathologies that would affect the synthetic function of the liver, such as in hepatitis or cirrhosis. If there is concern that the abdominal pain may be referred from a cardiac origin, such as a patient with epigastric abdominal pain, cardiac biomarkers and an electrocardiogram (ECG) should be ordered in addition to evaluating for abdominal causes.

A lactate level often is ordered to identify older adults with critical acute abdominal emergencies. Lactate is a nonspecific marker that also may be elevated in other conditions. Type A lactic acidosis is due to tissue hypoperfusion resulting from hypovolemia or shock states. In contrast, type B lactic acidosis is associated with impaired cellular metabolism, often due to toxins or regional ischemia as seen in occlusive mesenteric ischemia.⁶ In one retrospective study of older adults presenting to the ED with abdominal pain, of the 153 patients in whom lactate was measured, it was higher in the group diagnosed with serious causes of abdominal pain compared to non-serious causes. A lactate measurement of ≥ 2 mmol/L had a sensitivity of 42% and specificity of 80% for serious causes of abdominal pain.⁶ A single lactate measurement should be interpreted with caution. For example, in acute mesenteric ischemia, the initial lactate may be normal, with elevation occurring as a late finding.⁷

As with lactate levels, normal values for the white blood cell count may not indicate a lack of abdominal pathology in older adult patients. This patient population does not produce as much of a robust immune response to infection, and leukocytosis may not be present despite a diagnosed infection or surgical pathology. Potts and Vukov published findings of their retrospective analysis of patients 80 years of age and older with an acute abdomen where 35 of 115 patients (30.4%) did not have an elevated white blood cell count.⁸ In the Dadeh and Uppakarnnuntaku study, the mean white blood cell count was only slightly elevated at 11,150 cells/μL for patients with serious abdominal conditions.⁶

The urinalysis likewise should be carefully interpreted. Bacterial colonization of the urinary tract is more common in older adults, as are urinary tract infections (UTI). While pyuria and bacteriuria can indicate a UTI when localizing urinary symptoms are present, be careful when ascribing the cause of acute abdominal pain to a UTI.⁹

Laboratory testing in older adult patients with abdominal pain has a role in the diagnostic process; however, normal results should be interpreted with caution because they may provide false reassurance of a lack of pathology.

Imaging Studies

Imaging studies used in evaluating an older adult patient with abdominal pain frequently involve the use of ultrasound, computed tomography (CT), and, to a lesser extent, radiographs and magnetic resonance imaging (MRI).

While abdominal radiography (AXR) does not provide the detailed images as with CT or ultrasound, there still is a limited role for its use. If there is clinical concern for perforated viscous, AXR is fast, portable, and provides enough information to act quickly, if needed. AXR frequently is used to screen for bowel obstruction where gas and fluid collect in the intestines, creating a pattern called “air-fluid levels.”

In a study by Alshamari et al, the sensitivity of AXR for determining the diagnosis of acute nontraumatic abdominal pain was only 46%.¹⁰ In a study by Driver et al that included patients with suspected constipation who underwent AXR, 55% of the patients with low stool burden were given the final diagnosis of constipation and 45% were treated for constipation in the ED. For patients with moderate or greater stool burden, 42% received no treatment in the ED, 38% were given no medications at discharge for the treatment of constipation, and 28% were given an alternative diagnosis.¹¹ Thus, plain films have no role in confirming the diagnosis of constipation. The history and physical exam should be able to lead to this diagnosis, and if there is concern for additional pathology, more advanced imaging will need to be obtained to determine the cause.¹²

Bedside ultrasonography in the ED continues to have an expanded role as a diagnostic tool. While the radiation-sparing aspect compared to CT may not be as relevant in an older patient population, it still plays an important part in evaluating an older adult with abdominal pain. Critical diagnoses, such as an abdominal aortic aneurysm, can be expeditiously diagnosed at the bedside, leading to faster surgical consultation and surgical management if indicated. If appropriate views can be obtained, this diagnosis can be made on average in less than five minutes, according to one study.¹² Ultrasound, either performed at the bedside or in the ultrasound suite, is useful in diagnosing pathologies such as cholecystitis or hydronephrosis or in detecting free fluid in the abdomen, as is seen with blood in a trauma patient or ascites from cirrhosis.

Despite the ease of use and portability of bedside ultrasound, obtaining appropriate diagnostic views can be difficult. Prior surgeries can lead to adhesions or changes in anatomic locations of organs, which may mislead a clinician when obtaining images.¹³ The presence of intestinal gas acts as a reflector to ultrasound waves, limiting their transmission and obscuring visualization of structures deep to the gas. Skill is required to correctly interpret the presence of normal intraluminal air vs. pathologic free air in the abdomen.¹⁴

The use of CT imaging has had a large impact in the evaluation of older adult patients with abdominal pain. As discussed previously, the challenges in history-taking and relative unreliability of a physical exam lead to a lower threshold to obtain CT imaging.¹⁵ The results of these imaging studies are important to patient care. Esses et al studied the impact of CT imaging on the diagnosis and disposition of adults older than 65 years who presented with abdominal or flank pain. Diagnosis was altered in 45% of patients, and disposition changed in 26%.¹⁶

Another study by Gardner et al evaluated the care of patients ≥ 80 years of age who presented to the ED with abdominal pain. CT imaging was positive in 55% of the study population, and the positive CT results changed treatment plans for 65% of patients. Statistically significant changes also were found in admissions or discharges, with positive or negative CT results influencing each disposition respectively.¹⁷ Both of these studies demonstrate the importance of abdominal CT imaging in older adult patients with acute abdominal pain. Not only were diagnoses and disposition significantly affected by these imaging results, but so were treatment plans, including the use of antibiotics, the need for additional consultations, or providing a diagnosis of a malignancy.

Analgesics

An important aspect of managing older adults with acute abdominal pain is to treat their pain while the workup is ongoing. Despite this seemingly obvious statement, older adults frequently receive significantly lower doses of analgesia, with an inverse relationship between age and adequate pain treatment.^18-20 Consideration should be given to comorbidities when selecting an agent to treat pain. Avoiding the use of NSAIDs in patients with renal dysfunction or acetaminophen in those with hepatic abnormalities are commonly understood.

Likewise, there is concern about prescribing opioids in older adults. A retrospective observational cohort study by Hwang et al in 2010 found that older adult patients were less likely to receive opioids for moderate to severe pain and more likely than younger adults to receive NSAIDs for mild pain.²¹ A later study by Hwang et al in 2014 confirmed the finding that older (≥ 65 years) and oldest (≥ 85 years) adults were less likely to receive analgesics compared to younger (< 65 years) adults.²¹ In the first study, Hwang et al found that older adults had a lower reduction in initial to final recorded pain score.^21,22 However, in the second study they found that older adults had a greater reduction in pain scores.²²

The propensity to inadequately treat older adult patients’ pain can have negative outcomes clinically. Two studies assessing older adults who required surgical repair for hip fractures found that postoperative pain increased hospital length of stay, delayed ambulation, and resulted in long-term functional impairment.^23,24 Emergency physicians need to be intentional about the selection of analgesic agent, balancing adequate pain control with the potential for adverse side effects.

The use of NSAIDs is remarkably common in adults older than age 65 years outside of the ED. Young et al performed a cross-sectional study of the National Ambulatory Medical Care Survey from 2009 and 2016 limited to adults older than age 65 years. NSAIDs were prescribed at 23.2% of outpatient visits, making that class the most frequently prescribed medication.²⁵ Common uses both in outpatient or emergent settings include musculoskeletal injuries and inflammatory conditions, such as arthritis.

While NSAIDs are effective at treating pain and decreasing inflammation through the inhibition of cyclooxygenase (COX) enzymes, these benefits do come with risks. The COX-2 isoenzyme is expressed by the kidneys and its inhibition by NSAID use can lead to reversible kidney ischemia. The use of NSAIDs is associated with an increase in the risk of an acute kidney injury or progression to chronic kidney disease.²⁶ The use of NSAIDs is associated with an increased risk of upper gastrointestinal bleeding. For COX-2 selective NSAIDs, the risk is increased approximately 2.9-fold, whereas for nonselective NSAIDs the risk is 4.3-fold higher.²⁷

These medications also may have adverse effects on the cardiovascular system. Use of NSAIDs has been associated with the development of congestive heart failure (CHF) and with increased rates of hospitalization for CHF.²⁸ Chronic use of NSAIDs should be avoided in older adults, according to recommendations by the British Geriatrics Society and The British Pain Society.²⁹ The 2023 update to the American Geriatrics Society Beers Criteria makes a strong recommendation, based on moderate quality of evidence, to avoid chronic use of NSAIDs and to avoid short-term scheduled use when used in combination with corticosteroids, anticoagulants, or antiplatelet agents unless other alternatives are not effective and the patient can take a gastroprotective agent, such as a proton pump inhibitor.³⁰

Acetaminophen is another commonly used agent for pain management in older adults with acute abdominal pain. Consideration should be given to known or suspected abnormal hepatic function, such as alcohol-related liver disease, cirrhosis, ascites, or acute hepatitis. Patients already may be taking acetaminophen routinely, as the American Geriatrics Society recommends its first-line use for mild to moderate chronic pain.³¹ Using data from the French Impact of Educational and Professional Supportive Interventions on Nursing Home Quality Indicators project (IQUARE) study, Girard et al found that acetaminophen was not associated with an increased risk of myocardial infarction or death; however, there was an increased risk of stroke in patients with diabetes.³² Acetaminophen may be a good first-line choice for mild to moderate pain, and taking acetaminophen in conjunction with other analgesics (such as NSAIDs) can increase the effect with one singular agent.³³

In the ED, opioids are the mainstay of treatment for moderate to severe pain. Because of the potential opioid side effect profile, which includes sedation, nausea, constipation, and respiratory depression, there is hesitation to use opioids in older adults with moderate to severe acute pain, including abdominal pain. There is limited evidence to guide which opioid is preferable to use in the older adult population and at what dose. A systematic review of the literature through 2017 found only one randomized controlled trial comparing the efficacy of different opioid analgesics for the treatment of acute pain in older adults.³⁴ In that study, Chang et al compared a single dose of 0.0075 mg/kg intravenous hydromorphone to a single dose of 0.05 mg/kg intravenous morphine and found no statistical difference between the two groups for the treatment of acute pain in older adults.³⁵ Clearly more studies need to be performed to provide better guidance for safe and effective pain management with opioids in this population.³⁶ Until such time, a reasonable approach is to start with a lower dose of opioids and then frequently reassess and readminister as indicated. This approach allows for appropriate analgesia and also will help reduce the likelihood of some adverse side effects.

Review of Selected Causes of Acute Abdominal Pain

Cholecystitis

Acute cholecystitis is an acute inflammatory process of the gallbladder. In more than 90% of cases, the cause of acute cholecystitis is obstruction of the cystic duct by a gallstone. The other causes are known collectively as acalculous cholecystitis. Gallstones are present in 10% to 15% of the adult population, but most of those are asymptomatic.³⁶ The prevalence of gallstones increases with age. In an Italian study of adults 60 years of age and older, 13.9% had gallstones and an additional 12.8% previously had a cholecystectomy performed, for an overall rate of 26.7%.³⁷ The Group for Epidemiology and Prevention of Cholelithiasis (GREPCO) in Rome, Italy, followed 151 subjects who were identified as having gallstones. Initially, only 33 (22%) were symptomatic. At 10-year follow-up, the cumulative probability of developing biliary colic was 25% for the 118 patients who were initially asymptomatic.³⁸

In adult ED patients with acute abdominal pain, acute cholecystitis is the causative diagnosis in 2.5% to 9.3% of cases.^39,40 However, for adults older than the age of 50 years, the percentage has been reported as high as 20.9%.⁴¹

The classic presentation of acute cholecystitis is a female patient in her 40s with fever, right upper quadrant abdominal pain, nausea, and vomiting. However, these characteristics are not replicated in older adults. Most patients in this age group still have the typical right upper quadrant abdominal pain, but vomiting may be present in only 25% of patients.⁴² Laboratory evaluation also may be similarly unreliable, with hallmark leukocytosis and abnormal liver function tests often normal in cases of acute cholecystitis in older adult patients.⁴³

A systematic review and meta-analysis that included studies published through August 2023 found that the pooled sensitivity of ultrasound for the diagnosis acute cholecystitis was 71% while the specificity was 85%, positive likelihood ratio was 4.8, and negative likelihood ratio was 0.33.⁴⁴ In a study of 475 patients older than 64 years with the diagnosis of acute cholecystitis made by composite criterion standard of clinical, laboratory, and radiographic findings, there were 168 patients who had both a CT and ultrasound performed. There was no difference between CT and ultrasound in the ability to diagnose gallstones. Inflammation was seen on more ultrasound than CT studies (52.3% vs. 30.3%). The authors suggest that ultrasound and CT may be complementary diagnostic tools in the evaluation of older adults with concern for acute cholecystitis.⁴⁵ The Tokyo Guidelines 2018 (TG18) for the diagnosis of acute cholecystitis are presented in Table 1.⁴⁶

Management of acute cholecystitis in the ED begins with supportive care, including IV hydration, analgesia, correction of electrolyte abnormalities, management of associated symptoms such as nausea and vomiting, and the administration of antibiotics. Although acute cholecystitis is primarily an inflammatory process, bile cultures have been positive in more than 50% of cases.⁴⁷ The TG18 make recommendations for antimicrobial treatment based on severity grade.⁴⁸ (See Table 2.) Antibiotic selection should be based on the commonly isolated organisms, which include gram-positive, gram-negative, and anaerobic organisms. The most commonly isolated organism from the bile of patients with an acute biliary infection are Escherichia coli, which is present in 31% to 44% of bile cultures, followed by Klebsiella spp. (9% to 20%) and Enterococcus spp. (3% to 34%). In bacteremic patients, E. coli is present in 35% to 62% of blood cultures, followed by Klebsiella spp. (12% to 28%) and Enterococcus spp. (10% to 23%).⁴⁹

Further definitive management includes surgical removal of the gallbladder. Advanced age often is noted as a reason to defer surgery in cases of acute cholecystitis, with preference for medical management alone.⁵⁰ Multiple studies have shown reasonable outcomes with surgical management of acute cholecystitis, even in octogenarians and older.^51,52 A study by Escartin et al also found that age was not an independent predictor of poor surgical outcomes. They found that disease severity and poor physical status were the best predictors of complications and suggested deferring surgical management in patients with an American Society of Anesthesiologists (ASA) classification of IV (severe systemic disease that is a constant threat to life).⁵³

Ascending Cholangitis

Ascending cholangitis is a serious life-threatening infection due to obstruction of the biliary tree. The most common cause is choledocholithiasis, a gallstone trapped in the common bile duct, followed by malignant steatosis of the bile duct.⁵⁴ Patients with asymptomatic gallstones have a 0.3% to 1.6% five- to 10-year risk of developing ascending cholangitis.⁵⁵ Cholangitis also can complicate endoscopic retrograde cholangiopancreatography (ERCP) procedures. A systematic review of post-ERCP complications published in 2007 analyzed 16,855 cases and found the incidence of cholangitis to be 1.44%.⁵⁶ The average age of patients diagnosed with ascending cholangitis frequently is reported to be 50 to 60 years; however, in a study of 260 cases from Korea by Lee et al, the average age was 72.3 ± 14.4 years.⁵⁷

The biliary tree is normally a low-pressure system with continual forward flow of bile preventing bacterial colonization. When there is an obstruction of the bile duct, the pressures rise, leading to loss of innate defenses against infection.⁵⁸ Coliform bacteria are the most frequently isolated pathogens in cases of acute cholangitis, similar to the organisms associated with acute cholecystitis.

The diagnosis of ascending cholangitis can be complicated by other potential pathologic conditions that have overlapping features, such as acute cholecystitis, gallstone pancreatitis, and acute hepatitis. The classic presentation of ascending cholangitis is described by Charcot’s triad, which includes fever, right upper quadrant abdominal pain, and jaundice. The sensitivity of this triad for the diagnosis has been reported to be 21.2%, with increasing sensitivity with more severe cases (Grade 1, 14.2%; Grade II, 25.2%; Grade III, 27.4%).⁵⁹ The TG18 Diagnostic Criteria uses a combination of clinical findings, laboratory assessments, and radiographic imaging to diagnose acute cholangitis.⁶⁰ (See Table 3.) The sensitivity of these newer criteria was 82% with 60% specificity in an external validation study.⁶¹

Laboratory evaluation may demonstrate leukocytosis and elevated liver enzymes. However, one study showed that only 26% of patients with ascending cholangitis had a white blood cell count < 4 or > 10 × 10³/μL.⁶¹ Inflammatory markers, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), are included in the TG18 diagnostic criteria.⁶⁰ One study found that the inflammatory markers with the best discriminatory power for the diagnosis of acute cholangitis were the lymphocyte count, neutrophil-to-lymphocyte ratio (NLR), and CRP.⁶²

The Surgical Infection Society and the Infectious Diseases Society of America guidelines from 2010 and 2017 recommend against routine blood cultures for most community-acquired intra-abdominal infections. However, these guidelines do suggest acquiring blood cultures if there is > 10% to 20% resistance in common bacterial isolates and in higher-risk patients. A recent study by Otani et al demonstrated that bacteremia frequently was present in all severity grades of cholangitis and that the rates of positivity increased with increasing severity of illness (Grade I, 35%; Grade II, 59%; Grade III, 74%). This led the authors to advocate for blood culture collection in all cases of cholangitis.⁶³

There is considerable debate regarding the imaging study of choice for the diagnosis of acute cholangitis. The TG18 diagnostic criteria recommend the use of abdominal ultrasound first because of its lack of invasiveness, widespread availability, and cost effectiveness. A 2015 Cochrane review found that abdominal ultrasound had a summary sensitivity of 73% and specificity of 91% for the diagnosis of choledocolithiasis.⁶⁴ However, it should be noted that a normal ultrasound does not rule out ascending cholangitis.

Multidetector CT imaging with IV contrast may have increased accuracy compared to ultrasound. In addition, it has the advantage of potentially identifying other causes of intra-abdominal pathology beyond what may be seen on ultrasound. In 2012, Kim et al evaluated CT imaging and a novel scoring system that used extent of transient hepatic attenuation differentiation (THAD), biliary dilatation, and presence of an obstructive lesion for the diagnosis of acute cholangitis. They reported that using an optimal cutoff for the score resulted in a sensitivity of 84.6% and specificity of 83.7%.⁶⁵

The TG18 diagnostic criteria provide recommendations for the initial management of patients with ascending cholangitis. These include IV fluids, electrolyte repletion, analgesics, and the administration of broad-spectrum antibiotics.⁶⁶ The choice of antibiotics previously was determined based on the biliary penetration of the antimicrobial. As of the Tokyo Guidelines 2013 Diagnostic Criteria, this consideration has been removed because of evidence that secretion into the bile ceases in the setting of obstruction.⁴⁹ The TG18 diagnostic criteria provide initial antimicrobial recommendations based on the severity grade and community resistance rates. Choices include penicillins, cephalosporins with or without metronidazole, and carbapenems. Monobactam-based treatment coupled with metronidazole is reserved for Grade III and for healthcare-associated ascending cholangitis. Also, in Grade III or healthcare-associated cases, vancomycin should be added to monotherapy for Enterococcus coverage. Treatment with fluoroquinolones is only recommended in some cases of Grade I or II severity.⁴⁸

Patients may respond to medical therapy alone, but a substantial proportion will require decompression of the obstruction. The American Society for Gastrointestinal Endoscopy (ASGE) recommends ERCP over percutaneous transhepatic biliary drainage (PTBD) due to lower rates of adverse events and duration of hospitalization. They found no difference in rates of successful decompression or mortality. The ASGE also recommends that ERCP should be performed within the first 48 hours based on very low quality of evidence.⁶⁷ Patients may require transfer to an institution capable of performing ERCP.

Since the introduction of techniques to decompress the biliary tree, the mortality associated with acute cholangitis has decreased to 10% to 30% from previously reported rates of 50% to 100%.⁵⁴ A 2006 study by Agarwal et al reported a higher mortality rate for patients aged 60 years and older compared to younger patients (9.6% vs. 0%). Acute cholangitis also was found to be caused more often by malignancy in older patients (65.4% vs. 2.4%). Older adults also were more likely to have hypotension, peritonitis, and altered mental status and were more likely to fail conservative treatment. Older adults were less likely to have fever (34.6% vs. 96%).⁶⁸

Biliary Colic

A non-infectious complication of gallstones that can cause post-prandial right upper quadrant abdominal pain is commonly referred to as biliary colic. The pain is brought on by a previously formed gallstone becoming lodged and irritating the lining of the bile ducts, leading to pain.⁶⁹ The pain typically is intermittent, commonly is exacerbated by eating a large fatty meal, and often radiates to the back. It is important to differentiate biliary colic from cholecystitis. An absence of leukocytosis, elevated aspartate aminotransferase (AST), alanine aminotransferase (ALT), or alkaline phosphatase lowers the suspicion of a more significant pathology such as cholecystitis or ascending cholangitis.⁷⁰ Ultrasound is the recommended first test for suspected biliary pathology, with magnetic resonance cholangiopancreatography (MRCP) a consideration if it is available. Once diagnosed, patients should be counseled to avoid high-fat foods and consider surgical management for definitive treatment. Without evidence of infection, manageable pain, and ability to tolerate eating and drinking, patients may be discharged from the ED with close outpatient surgical follow-up.

Acute Mesenteric Ischemia

Acute mesenteric ischemia (AMI) is a potential catastrophic illness that primarily affects older adults. The median age in one meta-analysis of 1,970 patients with AMI was 67 years.⁷¹ Risk increases with increasing age. For a 65-year-old patient, the incidence of AMI is similar to that of ruptured aortic aneurysm but increases to be four-fold higher by the age of 90 years. A 75-year-old patient has a similar incidence of AMI as for appendicitis, and by the age of 90 years, the incidence of AMI is seven-fold higher than appendicitis.⁷²

AMI results from either impaired delivery to or inadequate outflow of blood from the intestines, which are primarily supplied by the celiac artery, the superior mesenteric artery (SMA), and the inferior mesenteric artery (IMA). Circulation to the gastrointestinal organs is referred to as splanchnic circulation and receives 20% to 25% of the total cardiac output. The splanchnic circulation contains up to one-third of the total blood volume, making it the largest store of blood in the body.⁷³ There are four subtypes of AMI based on the underlying pathophysiology of the reduced blood flow. (See Table 4.)

Embolic acute mesenteric ischemia (EAMI) is the most common subtype, accounting for 40% to 50% of cases of AMI.⁷⁴ The SMA is the most commonly involved vessel because of its relatively large caliber allowing entry of an embolus and the oblique angle that it forms from the proximal portion of the aorta. In approximately half of the cases of EAMI, the embolus lodges distal to the middle colic artery, leading to sparing of the small intestine and ascending colon. Risk factors for EAMI are those frequently seen with older age, such as atrial fibrillation and severe congestive heart failure with reduced ejection fraction. Up to one-third of patients will have had a preceding embolic event, such as a stroke.⁷⁴

Thrombotic acute mesenteric ischemia (TAMI) accounts for 25% to 30% of cases of AMI.⁷⁴ With advancing age and progressive atherosclerosis, there is narrowing of the mesenteric arteries, increasing the risk of occlusion due to thrombotic events. In addition to dyslipidemia and atherosclerosis, risk factors for TAMI include hypercoagulable states, vasculitis, mesenteric artery dissection, and mycotic aneurysms.⁷⁵ Patients may present acutely or with a more insidious course, reporting development of postprandial pain, sitophobia (i.e., food fear), and weight loss. The abdominal pain that develops after eating is sometimes called “intestinal angina.”

Venous acute mesenteric ischemia (VAMI) accounts for approximately 10% of cases of AMI. Patients with VAMI frequently are younger than those with other subtypes of AMI, often < 50 years of age.⁷⁶ Risk factors include hypercoagulable states; injury or inflammation, such as pancreatitis, inflammatory bowel disease, trauma, and abdominal surgery; and conditions that result in venous stasis, such as CHF and cirrhosis.⁷⁵ Many patients will present within the first few days of symptoms, which often include diarrhea (40% of cases), nausea and vomiting (33%), and gastrointestinal bleeding (10%).⁷⁷ The abdominal pain frequently is reported in the mid-abdomen and often will be out of proportion to the physical exam, although frequently less intense than that seen with TAMI.^76,78

Non-occlusive mesenteric ischemia (NOMI) typically occurs in patients experiencing a low-flow state, such as during a critical illness requiring vasopressor use. Other scenarios where NOMI may be encountered include CHF and septic shock.⁷⁵ Abdominal pain that develops in the setting of hypotension should alert the clinician to the possibility of NOMI. Critically ill patients who develop an unexplained lactic acidosis or worsening lactic acidosis in the setting of appropriate treatment also should raise concern for the possibility of NOMI. Risk factors for the development of NOMI include older age, end-stage renal disease requiring hemodialysis, low cardiac output, and the use of medications such as vasopressors that reduce splanchnic blood flow.^79,80

Laboratory testing is used to assess for severity of illness and to help guide therapy, but no laboratory test can definitively rule in or rule out AMI. A complete blood count can be useful to help guide the use of blood products in the setting of acute anemia. The white blood cell count has limited utility because of insufficient sensitivity and poor specificity.^81,82 An electrolyte panel can be used to guide the need for electrolyte repletion, presence of acute kidney injury, and presence of metabolic acidosis. A serum lactate level frequently is used in the workup of patients being evaluated for AMI. Cudnik et al found the sensitivity to be 86% and specificity to the 44% in a systematic review and meta-analysis.⁷¹ The lactate level can be used as a prognostic marker in cases where AMI has been diagnosed. Ritz et al found that a lactate level of 2 mmol/L or greater was associated with increased mortality.⁸³

Historically, the gold standard test for the diagnosis of AMI was angiography. CT angiography of the abdomen and pelvis now largely has replaced angiography as the study of choice and is recommended by the American College of Radiology (ACR) as the initial imaging study for cases of suspected AMI.⁸⁴ Plain film AXRs have a very low yield and may be normal in up to 25% of cases.⁷⁹ Findings on AXR may include paucity of intestinal gas, portal venous gas, pneumatosis intestinalis, and free air underneath the diaphragm.⁸⁵ While ultrasound is not the study of choice, it sometimes may be ordered if AMI is not strongly suspected. Ultrasound is useful for detecting SMA or celiac artery stenosis and mesenteric venous thrombosis. Sartini et al found duplex ultrasound to have a 100% sensitivity and a 100% negative predictive value for AMI.⁸⁶

Treatment of AMI in the ED focuses on patient stabilization and engaging appropriate consultation services. Broad-spectrum antibiotics should be initiated.^75,78 Anticoagulation may be started in most cases; however, it is not indicated in NOMI, which is associated with low flow rather than thromboembolic disease.⁷⁶ Vasopressor use should be avoided because these agents lead to mesenteric hypoperfusion.⁷⁶ Patients should be kept nil per os (NPO), and most will need a nasogastric tube for gastric decompression. A multidisciplinary approach to patients with AMI includes the combined input from gastroenterology, vascular surgery, intensive care, and palliative care.

Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a disease that primarily affects older adults. The aorta is made of three layers. The adventitia is a thin outer layer that surrounds the media, the thick central layer. The intima is the innermost layer. The media is comprised of layers of smooth muscle cells and elastic fibers known as the elastic lamellae.⁸⁷ Degeneration of this layer leads to the formation of an AAA. An aneurysm was defined by the Society for Vascular Surgery and the North American Chapter of the International Society for Cardiovascular Surgery in 1991 as a permanent localized dilation of an artery that is at least 50% larger than the expected normal diameter.⁸⁸ An AAA usually is defined as having a diameter of 3.0 cm or larger.⁸⁹ (See Figure 1.)

Males develop AAAs with a prevalence three to four times greater than females.⁹⁰ The prevalence of AAA in older male adults has decreased from approximately 3.9% to 7.2% in the 1990s to 1.2% to 3.3% in more recent years.^91-94 AAAs usually are asymptomatic until they rupture.⁹⁵ The mortality rate of a ruptured AAA is very high, with estimates as high as 80% to 90%. Many patients with a ruptured AAA do not reach the hospital prior to death. Of those who do reach the hospital and undergo operative repair, the mortality remains high at 20% to 40%.^96,97

In 2019, the United States Preventive Services Task Force recommended one-time AAA screening for men aged 65 to 75 years who had ever smoked, while recommending against screening for women who never smoked. Selective screening was recommended for men aged 65 to 75 years who never smoked.⁹⁸ The American College of Cardiology and American Heart Association (ACC/AHA) also recommends screening men or women aged 65 years or older who are first-degree relatives of patients with AAA.⁹⁹

Patients with unruptured AAA present most commonly with pulsatile abdominal pain (27%) and back pain (25%).¹⁰⁰ When an AAA ruptures, the classic triad is the presence of a pulsatile abdominal mass, hypotension, and flank or back pain, but the presence of all three usually is not seen.¹⁰¹ Less common presenting symptoms of a ruptured AAA include nausea and vomiting, groin pain, dizziness, dyspnea, and chest pain.¹⁰²

Although abdominal ultrasound has excellent sensitivity for detecting the presence of an AAA,¹⁰³ it is less accurate at detecting a ruptured AAA because of the frequency with which the rupture occurs in the retroperitoneal space.¹⁰⁴ CTA of the abdomen and pelvis is the preferred diagnostic imaging test because of its high accuracy and its ability to characterize the anatomic characteristics of the aneurysm and surrounding structures.

Patients with a ruptured AAA have a critical, time-sensitive diagnosis. The Society for Vascular Surgery recommends a door-to-intervention time of < 90 minutes. Within the first 30 minutes, the patient should have their initial assessment and diagnosis made, with consideration for transfer to an appropriate facility if the treating facility does not have the resources to manage the patient.¹⁰⁵ Patients with a ruptured AAA should have adequate venous access. Blood products should be made available because transfusion is required in 71% of cases.¹⁰⁶ Permissive hypotension is preferred to maintain a systolic blood pressure (SBP) of 70 mmHg to 90 mmHg.¹⁰⁵ Consultation with vascular surgery should occur as soon as the diagnosis is made, or when AAA is strongly suspected. Patients may undergo open surgical repair (OSR) or endovascular repair (EVAR) for a ruptured AAA. EVAR has better in-hospital mortality rates than OSR, but the 30-day and one-year mortality rates are similar for the two approaches.¹⁰⁷

Small Bowel Obstruction

Small bowel obstruction (SBO) is a relatively common diagnosis and reason for patients to present to the ED. SBOs most commonly are caused by intra-abdominal adhesions, followed by hernias and neoplasms.¹⁰⁸ Behman et al, using an administrative database from Ontario, Canada, found that the average age of the first episode of SBO was 68.5 years and that 55% were male.¹⁰⁹ Unfortunately, older adult patients are at especially high risk for both diagnosis and complications from an SBO. Up to 12% to 25% of older adult patients presenting with abdominal pain ultimately are diagnosed with an SBO and have mortality rates of 7% to 14%, as compared to < 3% for the general population.¹¹⁰

Patients with an SBO typically will present with abdominal pain, distension, nausea and vomiting, and obstipation (i.e., inability to pass flatus or stool).^111–113 Despite the presence of a complete obstruction, flatus and stool still may pass from the more distal portion of the bowel for 12 to 24 hours after the onset of symptoms. Physical exam may reveal a distended abdomen with generalized tenderness and abnormal bowel sounds.

Radiographic evaluation of a patient with possible SBO may include plain-film radiographs (X-ray), ultrasound, and CT scan. X-rays frequently are ordered as the initial imaging because of the low cost, universal availability, and ease of acquisition. Findings of SBO on X-ray include dilation of the small bowel to > 3 cm, paucity of bowel gas, and multiple air-fluid levels.¹¹⁴ In 2013, Taylor and Lalani performed a systematic review and meta-analysis finding that X-ray had a summary sensitivity of 75% and specificity of 66%.¹¹⁵

The ACR states that X-ray imaging for suspected SBO usually is appropriate but notes that there is disagreement.¹¹⁶ CT of the abdomen and pelvis with IV contrast is the preferred imaging test according to the ACR, owing to its high degree of accuracy, ability to distinguish obstruction from adynamic ileus, and for identifying the cause of the obstruction. Oral contrast is not recommended because it delays the imaging, it rarely reaches the transition point due to the obstruction, and it can interfere with the identification of bowel wall ischemia.¹¹⁶

In a recent meta-analysis that included 15 studies, ultrasound was shown to have a sensitivity of 92% and specificity of 93%. The authors did note that in sub-group analyses, sensitivities were similar, but specificities were lower when the studies were done in North America and when the ultrasounds were performed in the ED.¹¹⁷ Abnormal ultrasound findings that suggest SBO include changes in intestinal peristalsis, increased bowel wall thickness, and dilation of small bowel loops.¹¹⁸

Patients with an SBO should be made NPO. Hydration should be initiated with IV crystalloids. Placement of a nasogastric tube (NGT) is a procedure associated with substantial discomfort, and evidence for its use is very limited. A single-center, retrospective study by Shinohara et al found no benefit to NGT placement regarding the incidence of vomiting, development of pneumonia, or need for surgery.¹¹⁹ Hemodynamic instability or the presence of peritonitis suggests bowel perforation or the translocation of bacteria across the gut wall. Patients with these findings should be given broad-spectrum antibiotics. A surgical consultation should be obtained to determine the need for operative management. In the case of nonoperative management, admission to a surgical service as opposed to a medical service results in reduced costs, hospital length of stay, readmissions, and mortality.^120-123

Acute colonic pseudo-obstruction (ACPO) or Ogilvie syndrome is a form of obstruction that occurs when there is acute colonic dilation in the absence of intrinsic mechanical obstruction or an extrinsic inflammatory process. Although the exact cause is not understood clearly, the leading theory focuses on an imbalance of sympathetic and parasympathetic tone.¹²⁴ However, risk factors include advanced age, polypharmacy, poor functional status, and immobility.¹²⁵ While considered rare, a national survey found the incidence of this disease to be approximately 100 cases out of 100,000 inpatient admissions per year.¹²⁶

Patients presenting with ACPO may have similar symptoms as those with a more traditional obstruction, including nausea, vomiting, and abdominal distension. Diagnosis is made with CT imaging with IV contrast and after other etiologies are ruled out. Management is focused on conservative management, bowel rest, and pharmacological therapy with neostigmine.¹²⁶ The mortality rate of this diagnosis was as high as 30%, with complications including colonic perforation and ischemia occurring in 10% to 20%.¹²⁷

Diverticulitis

Diverticulitis indicates inflammation of colonic diverticula. A diverticulum is a pouchlike protrusion of the colon wall where the mucosa and submucosa herniate through the smooth muscle. In a study by Peery et al, the proportion of patients with more than 10 diverticula seen on colonoscopy increased with age: < 50 years = 8%, 51-60 years = 15%, and > 60 years = 30%.¹²⁸ About 4% of patients diagnosed with diverticula will go on to develop diverticulitis.¹²⁹ In addition to age, risk factors for the development of diverticulitis include increased body mass index, smoking, use of NSAIDs, and sedentary lifestyle.¹³⁰

Patients with acute diverticulitis classically present with pain the left lower quadrant of the abdomen since this is the most common location for diverticula. However, in patients of Asian decent, the most common location for diverticula is in the ascending colon, so they may present with right-sided abdominal pain.¹³¹ Patients may report either constipation or diarrhea as well as fever, nausea, and vomiting. On exam, the presence of guarding or rebound suggests perforation.

The European Association for Endoscopic Surgery (EAES) and Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) collaborative guideline recommends ordering a CRP based on evidence that a CRP > 50 mg/L is associated with the presence of diverticulitis.¹³² However, in a study by Laméris et al, the sensitivity of CRP at that level was only 79%, making it unreliable to rule out diverticulitis.¹³³

CT of the abdomen and pelvis with IV contrast is recommended for the evaluation of patients suspected of having diverticulitis because of its high sensitivity (94%) and specificity (99%).^134,135 Findings on CT imaging that are consistent with diverticulitis include colonic wall thickening, pericolonic fat stranding, abscess formation, localized air bubbles, peritoneal fluid, and free air.¹³⁰

Graded compression ultrasound reportedly has 77% to 98% sensitivity with 80% to 99% specificity.¹³⁶ In a study by van Randen et al comparing transabdominal ultrasound to CT for the diagnosis of diverticulitis, the authors reported a sensitivity of only 61% but a specificity of 99%.¹³⁷

One of the most commonly used classification systems for acute diverticulitis is the Modified Hinchey Classification, which uses findings of CT imaging.¹³⁸

The management of patients with diverticulitis has changed in recent years, with several quality studies demonstrating that for patients with uncomplicated diverticulitis, antibiotics do not reduce length of stay, complications, pain, or the need for surgical intervention.^139-142 The American Gastroenterological Association Institute recommends that antibiotics should be used selectively rather than routinely for acute uncomplicated diverticulitis.¹⁴³ The American College of Physicians recommends that most patients with uncomplicated diverticulitis can be managed in the outpatient setting.¹⁴⁴

Patients with complicated diverticulitis should have prompt administration of broad-spectrum antibiotics. A surgical consultation is recommended since some patients may require surgery, such as those with perforation or obstruction. Approximately 16% to 32% of patients hospitalized for diverticulitis will undergo surgery.^145,146 Patients with an abscess > 3 cm or those who fail to improve with antibiotics alone may have percutaneous abscess drainage performed by interventional radiology.¹⁴⁷

Colonic Volvulus

Colonic volvulus occurs when a mobile portion of the colon twists around a fixed portion, leading to possible obstruction and ischemia of the affected bowel. There are geographic differences in the proportion of cases of large bowel obstruction that is caused by volvulus. In a Polish study from 2012, for patients admitted between 2000 and 2003, volvulus was the second leading cause of large bowel obstruction (LBO) at 10.7%. The most common inciting factor was malignancy at 80.4%, whereas inflammatory conditions such as diverticulitis only caused 3.6% of LBOs.¹⁴⁸ A 2023 study from Iran reported that tumors were the cause of 33.9% of LBOs, while volvulus caused 29.7%.¹⁴⁹ A study using a U.S. database of more than 3 million cases of LBO found that only 1.9% were due to volvulus.

Volvulus can occur to any structure that is not tethered within the abdomen. The most common sites of colonic volvulus are the sigmoid (60.9%), the cecum (34.5%), the transverse colon (3.6%), and the splenic flexure (1%).¹⁵⁰ While both sigmoid and cecal volvulus frequently occur in older adults, sigmoid volvulus commonly is associated with bedbound nursing home patients who often are on psychotropic medications. Chronic constipation and diabetes also have been associated with development of volvulus.¹⁵¹

Patients with volvulus may present with acute generalized abdominal pain and distention. There may be reduced bowel sounds because of cessation of normal peristalsis.¹⁵² The coffee bean and bird beak signs on plain films have been described for both cecal and sigmoid volvulus, respectively. The inverted “U” sign extending into the right upper quadrant is specific to sigmoid volvulus.¹⁵² Plain film studies may demonstrate classic findings of sigmoid volvulus in about two-thirds of all cases.¹⁵³ CT of the abdomen and pelvis with IV contrast is the preferred imaging study. CT signs of volvulus include absence of rectal gas (90%), inverted “U” sign (86%), coffee bean sign (76%), disproportionate sigmoid enlargement (76%), and northern exposure sign (57%).¹⁵⁴ (See Figure 2.)

Management of patients with colonic volvulus begins with hydration with IV crystalloids, electrolyte repletion, pain management, and consultation with surgical and gastroenterology services. Patients should be kept NPO, and there should be consideration for NGT placement if there is persistent vomiting. If there are concerns for intestinal necrosis or bowel perforation, then broad-spectrum antibiotics should be administered.

According to guidelines from the American Society of Colon and Rectal Surgeons (ASCRS) as well as those published by the ASGE, when signs of intestinal gangrene or perforation are absent, the initial treatment of choice for sigmoid volvulus is endoscopic detorsion, which is effective in 60% to 95% of cases.^155,156 If there are signs of gangrene or perforation or if there is failure to endoscopically detorse the colon, the patient should undergo operative intervention.

The long-term risk of recurrence is very high, with reports of rates as high as 43% to 75%.^155,156 Patients should be considered for elective sigmoidectomy during the index hospitalization.^155,156 Patients with cecal volvulus generally are not candidates for endoscopic treatment, and the ASCRS and ASGE recommend resection as the preferred treatment.^155,156

Appendicitis

Appendicitis is a common diagnosis for patients presenting with abdominal pain to the ED and carries a lifetime risk of 8.6% for males and 6.7% for females.¹⁵⁷ While there is a reduction in the incidence following adolescence, acute appendicitis in the older adult is not uncommon, and it is the second most common reason for acute surgical intervention.¹⁵⁸ Adults age 65 years and older account for 6.2% of all appendectomies.¹⁵⁹ Rates of complicated appendicitis also are higher in older adults.¹⁶⁰ Malignant tumors also are found at a higher rate in older adults (2.7% vs. 1.0%).¹⁵⁹ Postoperative complications occur more commonly in older adults — 19.3% to 46.2% compared to 5.06% to 9.3% for younger patients.¹⁶¹ Mortality also is higher for older adults compared to younger patients (0.74% to 6.1% vs. 0.04% to 0.21%).¹⁶¹

There is increased complexity for making the correct diagnosis in older patients as evidenced by longer delays to appendectomy in this age group. In one study, the time to surgery was > 12 hours for 67.2% of patients 68 years of age and older and 71.4% of patients 80 years of age and older as compared to just 34.4% of patients younger than 68 years of age.¹⁶²

Symptoms are similar across age groups, with right-sided lower abdominal pain, anorexia, nausea, and vomiting. Fever may be absent in an older adult patient with appendicitis due to a lower basal temperature and diminished thermoregulatory response. The sensitivity of fever for appendicitis has been reported to be between 23% to 31%.^163,164 Laboratory tests may reveal an elevated white blood cell count; however, as with younger patients, a leukocytosis may not always be present. Bayrak et al found that using a white blood cell count of > 11.9 x 10³/µL had a positive predictive value of 92%.¹⁶⁵ The combination of elevated white blood cell count and elevated CRP has improved sensitivity for the diagnosis of appendicitis.¹⁶⁶

According to the ACR guidelines, the initial imaging study that is most appropriate for a patient with suspected appendicitis is a CT scan of the abdomen and pelvis with IV contrast.¹⁶⁷ In a 2019 Cochrane review, Rud et al reported that CT imaging had a summary sensitivity of 95% and specificity of 94% for the diagnosis of appendicitis. The sensitivity for CT with IV contrast was 96%, while CT without IV contrast had a sensitivity of 91%.¹⁶⁸ A noncontrast CT scan may have reasonable sensitivity; however, it has limited use for operative planning, identification of complications such as the presence of a phlegmon, and identification of alternative diagnoses. Ultrasound has been shown to have a sensitivity of 85% and specificity of 90%.¹⁶⁶ The use of ultrasound also is limited by availability and patient tolerance of the compression required to make the diagnosis.

All older adult patients diagnosed with appendicitis should receive antibiotics and have a surgical consult. Recent clinical trials have provided support for medical management with antibiotics alone in select patients. The APPendicitis ACuta (APPAC) multicenter, open-label, noninferiority randomized clinical trial randomized patients to early appendectomy or antibiotic therapy alone with a one-year follow-up; however, this study excluded patients older than 60 years of age.¹⁶⁹ The Comparison of Outcomes of Antibiotic Drugs and Appendectomy (CODA) trial included older adults, but only 7.6% of the study population was 60 years of age or older. Complications were more common in the antibiotics alone group (8.1 vs. 3.5 per 100 participants), and 29% of patients in the antibiotics alone group had an appendectomy by 90 days. The rates of complications and failure of medical management for different age groups were not made available.¹⁷⁰ A small retrospective study by Park et al evaluated 26 patients 80 years of age and older who received antibiotics alone for uncomplicated appendicitis. Of the 26 patients, only five (19%) experienced symptom recurrence during a mean follow-up duration of 17 months.¹⁷¹

Peptic Ulcer Disease

Peptic ulcer disease (PUD) is a common etiology for abdominal pain with a lifetime risk of development ranging from 5% to 10% in the global population.¹⁷² The underlying causes of PUD include not only Helicobacter pylori and use of NSAIDs, but also diabetes, coronary artery disease, hypertension, and concomitant drug use for multiple medical comorbidities.¹⁷³ Older adults also have increased risk of development of PUD because there is decreased gastric and duodenal barrier protection with increasing age.¹⁷⁴ The major complications of PUD include upper gastrointestinal bleeding, gastric outlet obstruction, and perforation.

Presenting symptoms of older adult patients with PUD may differ than those in a younger patient, with the traditional epigastric pain found in only one-third of patients in a prospective study of patients undergoing upper endoscopy. The remainder of these patients reported vague abdominal pain.¹⁷⁵ Other symptoms include gastric bleeding, made more common by use of aspirin and non-aspirin antithrombotic drugs.¹⁷⁶ PUD is the leading cause of non-variceal upper gastrointestinal bleeding (UGIB).¹⁷²

Diagnosis of PUD includes screening for H. pylori, but the ultimate diagnosis will be made via endoscopy. Interestingly, epidemiologic studies found approximately 70% of older adult patients with diagnosed PUD test positive for H. pylori.¹⁷⁷ Treatment is focused on the treatment of the underlying etiology of the ulcer, with acid suppression and eradication of H. pylori the mainstay of management.

Perforation of PUD is a feared disease complication that has high morbidity and mortality. Patients with a perforated ulcer present in acute pain, often worse than what was experienced previously with the unperforated ulcer.¹⁷³ However, as can be common in the older adult, pain and symptoms may not be reflective of the severity of disease. Once the diagnosis of a perforated peptic ulcer is made, management requires emergent surgical consultation for definitive repair.

Postoperative mortality of a ruptured peptic ulcer is high, with substantial variation in the rates reported. However, 30-day mortality frequently is cited to be between 10% and 25%.¹⁷⁸ The World Society of Emergency Surgery provides a weak recommendation for the use of clinical risk scores in the evaluation of patients with perforated peptic ulcers. The Boey, Peptic ULcer Perforation (PULP), and American Society of Anesthesiologists (ASA) scores are among some that have been developed and used to predict mortality.¹⁷⁹

Pancreatitis

Pancreatitis is the acute or chronic inflammatory process of the pancreas. Using data from the National Inpatient Sample (NIS), Peery et al determined that pancreatitis is the third leading gastrointestinal cause of hospitalization in the United States.¹⁸⁰ Gallstones and alcohol use are the two most common causes of acute pancreatitis, accounting for approximately 45% and 20% of cases, respectively.¹⁸¹ Other causes include toxins, medications, trauma, infection, hypertriglyceridemia, hypercalcemia, autoimmune disease, and recent ERCP.¹⁸¹

Older adults have a greater burden of disease, with conventional regression analysis showing a linear increase in the incidence of severe pancreatitis for the ages of younger than 20 years to the ages of 70 years and older. The highest incidence of severe pancreatitis was seen in the 60-to-69-year age group (16.6%) and the lowest incidence was in the age group younger than 20 years (4.2%).¹⁸²

In older adults, the clinical presentation can differ from younger patients, as with many other causes of abdominal pain. In one study, abdominal pain was present in only 61.3% of patients aged 60 to 79 years and in only 46.3% of patients older than 80 years of age.¹⁸³ Nausea and vomiting usually are associated with acute pancreatitis. However, in older adults these symptoms may be absent. In a single center study of 500 patients, nausea was present in approximately two-thirds of patients and vomiting was present in just more than half.¹⁸⁴

The diagnosis of acute pancreatitis is made by the fulfillment of the Revised Atlanta Criteria, which require two of the three following findings: abdominal pain consistent with acute pancreatitis, elevation of either amylase or lipase to greater than three times the upper limit of normal, and imaging findings consistent with the diagnosis.¹⁸⁵ Both serum amylase and lipase measurements rise within hours of developing acute pancreatitis, but lipase elevations persist longer. The American College of Gastroenterology (ACG) recommends the use of lipase rather than amylase for the diagnosis of acute pancreatitis because of better sensitivity and specificity.¹⁸⁶

Patients with suspected pancreatitis should have routine electrolytes and blood counts measured. Older patients with pancreatitis tend to have lower hemoglobin and hematocrit levels, blood urea nitrogen, and creatinine levels.¹⁸⁷ In general, most patients with acute pancreatitis do not require imaging to make the diagnosis of pancreatitis. Despite having greater than 90% sensitivity and specificity for acute pancreatitis, routine contrast-enhanced CT imaging is not recommended by the ACG because most patients are diagnosed based on history, physical, and laboratory values. CT imaging is recommended in patients who are critically ill, fail to improve, or when the diagnosis is in doubt.¹⁸⁶

The management of patients with pancreatitis focuses on identifying and treating the underlying cause, supportive care through adequate fluid and electrolyte repletion, and pain control. The practice of early and aggressive administration of IV fluids has been called into question with the publication of the WATERFALL trial,¹⁸⁸ an international, multicenter, open-label randomized trial that compared aggressive vs. moderate administration of lactated Ringer’s (LR) solution. This study was stopped early because of increased rates of volume overload in the aggressive group (21% vs. 6%) and fewer complications found in the moderate group, although this did not meet statistical significance.

The ACG guidelines recommend 1.5 mL/kg of LR in patients with no evidence of hypovolemia and 10 mL/kg if hypovolemia is present. Caution is advised for older patients because of the higher risk of developing fluid overload due to comorbid conditions.¹⁸⁶ Older patients with acute pancreatitis are at moderate to high risk of malnutrition and, therefore, should be admitted for serial laboratory studies, and encouragement of enteral feeding as soon as possible.¹⁸⁹

In patients with diagnosed gallstone etiology of their pancreatitis, early ERCP should be considered if indicated. One study found an improvement in outcomes of patients aged > 80 years who underwent early ERCP.¹⁹⁰

Unfortunately, mortality in older adult patients diagnosed with acute pancreatitis is higher than in the general population. A linear relationship was found between mortality and age, with mortality rate increasing by 0.08% per year between 20 and 59 years of age and growing to 0.76% per year between ages 59 and 70 years of age.¹⁹¹

Drug-Induced Ileus

A variety of drugs can alter intestinal motility, producing ileus and presenting as intestinal obstruction.¹⁹² The most commonly reported drugs are listed in Table 5. The onset of ileus typically is eight to 20 days after drug initiation. There is some evidence that older adults are more susceptible to drug-induced ileus.¹⁹²

Patients present with symptoms of abdominal distension, pain, and constipation. Like other patients with a bowel obstruction, laboratory tests and CT imaging are recommended. The patient’s medication list should be carefully reviewed and administration of a possible offending agent discontinued. Treatment is supportive with IV fluids, bowel rest, and gastrointestinal decompression.

Disposition

Older adults presenting to the ED with abdominal pain frequently are admitted to the hospital because of the higher rate of pathological processes found on diagnostic workup. The workup leading to this disposition frequently is time-intensive, requiring laboratory testing, imaging, and specialty consultation. EDs and hospitals need to be prepared to accommodate this growing population, with one in five Americans expected to be older than age 65 years by 2030.¹⁹³ Older adults with abdominal pain presenting to the ED have a high rate of admission — 49% to 58%.^194,195 Early diagnosis and disposition, whether surgical or medical admission, are important. Even when the correct diagnosis is made promptly with appropriate intervention, mortality is high in this group. A prospective observational study found a 5% mortality rate for patients older than the age of 60 years who presented with abdominal pain during a two-week follow-up period. This is likely an underestimate since patients needed to be well enough to provide consent to be included in the study and follow-up data were unavailable for 4.8% of the study population.¹⁹⁵ Part of this increased mortality may be related to frailty, as a prospective observational study found this feature was a significant predictor for mortality for older adult patients undergoing emergency abdominal surgery.¹⁹⁶

While admission of older adults with abdominal pain is common, certain conditions may make discharge possible if no pathologic conditions are found on a thorough workup: documentation of a benign repeat physical exam, demonstration that the patient can tolerate oral intake, and assurance that the patient will be looked after by family or caregivers with close outpatient follow-up.¹⁹⁷ CT imaging in this patient population assists in the final disposition, as one study found that 63% of discharges had a negative CT study.¹⁷

Conclusion

As the U.S. population ages, an increased number of older adults likely will present to the ED with abdominal pain. A history and physical exam are important in the initial evaluation; however, a normal, reassuring abdominal exam is not necessarily indicative of a lack of intra-abdominal pathology. The differential must remain broad during the initial workup, since sometimes catastrophic pathologies can have minimal symptoms. (See Table 6.) Reliance on laboratory testing and imaging, specifically CT imaging, is important to make a timely diagnoses and initiate therapy. Special attention should be paid to the type and dose of analgesia, since unfortunately this patient population often is under-treated. Lastly, disposition for older adults with acute abdominal pain often is admission. However, with appropriate follow-up, reassuring repeat examinations, and ability to tolerate oral intake, discharge may be possible.

Benjamin Cornwell, MD, is an emergency physician with Osler Drive Emergency Physician Associates, University of Maryland St. Joseph Medical Center, Towson, MD.
R. Gentry Wilkerson is Associate Professor, Department of Emergency Medicine, University of Maryland School of Medicine, Baltimore.

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