The evaluation of patients presenting with abdominal pain poses a difficult challenge for the emergency physician. It will become an increasingly common problem because the elderly population in the United States is growing rapidly. The definition of elderly varies among authors, but for the purpose of this subject, age 60 years is a reasonable starting point.
Previous studies demonstrated that among elderly patients presenting to the ED with abdominal pain, at least 50% were hospitalized and 30-40% eventually had surgery for the underlying condition. These studies also showed that approximately 40% of these patients were misdiagnosed, contributing to an overall mortality of approximately 10%. However, note that no study examining the epidemiology of abdominal pain in elderly patients has been published since 1998 and that data was collected in 1994 (Marco, 1998).
In the period of time since the last of these studies was published, the availability and accuracy of emergency diagnostic techniques have improved dramatically. Computed tomography and ultrasonography were not widely used in most EDs before the mid 1990s. Today, it is relatively rare for a patient with significant abdominal pain to leave the ED without some type of advanced imaging. Diagnostic accuracy and presumably short-term mortality very likely have improved since the bulk of the studies on this subject were published.
Immune function tends to decrease with advancing age. Many elderly patients have underlying conditions such as diabetes or malignancy, further suppressing immunity. Elderly patients often have underlying cardiovascular and pulmonary disease, which decreases physiologic reserve and predisposes them to conditions such as abdominal aortic aneurysm (AAA) and mesenteric ischemia. Elderly patients also have a high incidence of asymptomatic underlying pathology. Up to one half of elderly patients have underlying cholelithiasis, one half have diverticula, and 5-10% have AAA.
Understanding that elderly patients may present very differently than their younger counterparts also is important. Elderly patients are more likely than younger patients to present with vague symptoms and have nonspecific findings on examination. Many elderly patients have a diminished sensorium, allowing pathology to advance to a dangerous point prior to symptom development. Elderly patients with acute peritonitis are much less likely to have the classic findings of an acute abdomen. They are less likely to have fever or leukocytosis. In addition, their pain is likely to be much less severe than expected for a particular disease. Because of these factors, many elderly patients with serious pathology initially are misdiagnosed with benign conditions such as gastroenteritis or constipation. They also are at greater risk of being admitted to the wrong service (eg, internal medicine when a surgeon may be required).
A careful history and physical examination as well as a high index of suspicion are crucial to prevent missed diagnoses.
Pathophysiology: Abdominal pain may be the presenting symptom in a wide range of diseases in elderly patients. Note that elderly patients with intra-abdominal pathology are more likely to present with symptoms other than abdominal pain, such as fever, fatigue, chest pain, or altered mental status.
Biliary tract disease
Biliary tract disease includes symptomatic cholelithiasis, choledocholithiasis, calculus and acalculous cholecystitis, and ascending cholangitis.
In some studies, biliary tract disease is the most common diagnosis among elderly patients presenting with abdominal pain.
Approximately 30-50% of patients older than 65 years have gallstones.
The mortality rate of elderly patients diagnosed with cholecystitis is approximately 10%. Cholecystitis is acalculous in approximately 10% of elderly patients with the condition. Classically, the diagnosis requires the presence of right upper quadrant pain associated with fever and leukocytosis. Unfortunately, 25% of elderly patients may have no significant pain, and less than one half have fever, vomiting, or leukocytosis. The diagnosis therefore can be difficult in this age group, requiring a high index of suspicion.
Complications of biliary tract disease include gallbladder perforation, emphysematous cholecystitis, ascending cholangitis, and gallstone ileus, which is responsible for approximately 2% of cases of small bowel obstruction in elderly patients.
Appendicitis
Appendicitis is a less common cause of abdominal pain in elderly patients than in younger patients, but the incidence among elderly patients appears to be rising. Only approximately 10% of cases of acute appendicitis occur in patients older than 60 years, whereas one half of all deaths from appendicitis occur in this age group.
The rate of perforation in elderly patients is approximately 50%, 5 times higher than in younger adults. This is largely because 75% of elderly patients wait more than 24 hours to seek medical attention.
The diagnosis can be difficult to make, since more than one half of patients in this age group do not present with fever or leukocytosis. Further confusing the picture, approximately one third do not localize pain to the right lower quadrant, and one fourth do not have appreciable right lower quadrant tenderness.
Only 20% of elderly patients present with anorexia, fever, right lower quadrant pain, and leukocytosis. The initial diagnosis is incorrect in 40-50% of patients in this age range.
All of the above factors contribute to delayed diagnosis and high complication rates. A 10-year retrospective review found that the diagnosis was delayed in 35% of patients (Lee, 2000). Again, a high index of suspicion is necessary to avoid missing this diagnosis.
Diverticulitis
The formation of diverticula in the colon is largely a product of diet and age and is relatively rare in those younger than 40 years. In the United States, diverticula are present in approximately 50-80% of patients older than 65 years.
Diverticulitis results when diverticula become obstructed by fecal matter, resulting in lymphatic obstruction, inflammation, and perforation. By definition, diverticulitis involves at least microperforation of the colon.
Approximately 85% of cases occur in the left colon. Right-sided diverticulitis is often more difficult to diagnose and generally is more benign.
Elderly patients with diverticulitis are often afebrile, and an elevated WBC count is observed in less than one half. Only approximately 25% of patients have guaiac positive stool.
Mesenteric ischemia
Including mesenteric ischemia in the differential is important, even though it accounts for less than 1% of cases of abdominal pain in elderly patients.
Mortality ranges from 70-90%, and any delay in diagnosis increases the risk of death.
Patients classically present with severe abdominal pain despite having little tenderness on examination. Vomiting and diarrhea are often present.
Risk factors for the development of mesenteric ischemia include atrial fibrillation, atherosclerotic disease, and low ejection fraction.
Occasionally patients may present with recurrent episodes of postprandial abdominal pain, sometimes termed intestinal angina.
Bowel obstruction
Bowel obstruction accounts for approximately 12% of cases of abdominal pain in elderly patients. Obstruction is classified as blockage of either the small bowel or the large bowel, although the distinction can be difficult to make clinically.
Cecal volvulus is relatively rare and typically presents clinically as small bowel obstruction. Sigmoid volvulus is much more common and often can be identified by plain abdominal radiography.
Distension of the colon of more than 9 cm can signal impending perforation.
Risk factors for sigmoid volvulus include inactivity and laxative use, both of which are common in elderly patients.
Abdominal aortic aneurysm
AAA is observed almost exclusively in elderly patients. Approximately 5% of men older than 65 years have AAA. The male-to-female ratio is 7:1.
If the diagnosis of ruptured AAA is made in the hemodynamically stable patient, the mortality is approximately 25%. In patients presenting in shock, the mortality is 80%.
Maintain a high index of suspicion, since many patients present with a clinical picture suggestive of renal colic or musculoskeletal back pain. Approximately 30% of patients with ruptured AAA are misdiagnosed initially.
Peptic ulcer disease
Peptic ulcer disease (PUD) deserves special mention, since the incidence among elderly patients is increasing. This may be due in part to the increasing availability and use of nonsteroidal anti-inflammatory drugs (NSAIDs). Users of NSAIDs are 5-10 times more likely to develop PUD than nonusers.
Mortality of elderly patients with PUD is approximately 100 times higher than that of younger patients with PUD.
Diagnosis of PUD in elderly patients can be difficult. Approximately 35% of elderly patients with PUD have no pain. The most common presenting symptom is melena.
Complications include hemorrhage and perforation. In elderly patients perforation is often painless, and free air may be absent on plain radiographs in more than 60% of patients.
Malignancy
Among elderly patients discharged from the ED with a diagnosis of nonspecific abdominal pain, approximately 10% eventually are diagnosed with an underlying malignancy.
Gastroenteritis
Consider gastroenteritis a diagnosis of exclusion in elderly patients with vomiting and diarrhea. Vomiting and diarrhea can be caused by many illnesses. Reviews of cases of missed appendicitis reveal that approximately one half of patients initially were diagnosed with gastroenteritis.
Even when more dangerous conditions have been excluded, realize that gastroenteritis can cause serious morbidity in elderly patients. Of all deaths due to gastroenteritis, approximately two thirds occur in patients older than 70 years.
History: Obtaining a careful history is especially important in elderly patients complaining of abdominal pain. Elderly patients are often less likely to volunteer key points in their symptom development and their medical history. Unfortunately, many elderly patients may be unable to give an adequate history due to predisposing conditions such as dementia or prior stroke.
Key points in the history include the following:
Time of onset and course of the pain
Sudden or gradual onset
Location, quality, and severity of pain
Radiation (eg, to back, groin, shoulder)
Aggravating or precipitating factors (eg, food, position, medication)
Physical: A thorough physical examination can help to identify the underlying cause of abdominal pain. In general, findings on abdominal examination tend to be less pronounced than in younger patients. Give special attention to the following systems:
Vital signs
Tachycardia or hypotension may be signs of ruptured AAA, septic shock, GI hemorrhage, or volume depletion.
Take a rectal temperature to detect fever or hypothermia.
Pulmonary: Pneumonia occasionally may cause abdominal pain without respiratory symptoms.
Cardiovascular
Acute myocardial infarction can present as epigastric pain with or without nausea and vomiting.
The finding of atrial fibrillation or signs of diminished cardiac output should raise the consideration of mesenteric ischemia.
Hypotension, even if transient, is an ominous sign and should elicit consideration of ruptured AAA, acute myocardial infarction, or septic shock.
Abdominal examination
High-pitched bowel sounds often are associated with bowel obstruction. Absent bowel sounds may indicate adynamic ileus or advanced bowel obstruction.
A tympanitic abdomen may be observed with bowel obstruction.
Elderly patients with peritonitis may lack classic peritoneal signs of rebound and guarding.
A palpable mass may indicate malignancy or phlegmon from ruptured appendix or diverticulitis. A pulsatile mass should raise the consideration of AAA.
Carefully look for the presence of hernia at the umbilicus, in the groin, or near the site of prior surgical incisions.
Genitourinary examination
Perform a rectal examination to identify tenderness, fecal impaction, and the presence of gross or occult blood. Failure to perform a rectal examination in patients with abdominal pain may be associated with an increased rate of misdiagnosis and should be considered a medicolegal pitfall.
Perform a pelvic examination in women regardless of whether the patient may have had a hysterectomy or is postmenopausal.
Causes: Causes of abdominal pain in elderly patients are as follows (see Pathophysiology for more information):
Biliary tract disease
Appendicitis
Diverticulitis
Mesenteric ischemia (risk factors include atrial fibrillation, atherosclerotic disease, and low ejection fraction)
Bowel obstruction
Small bowel obstruction most often is caused by adhesions from previous surgery. In elderly patients, an incarcerated hernia causes approximately 30% of cases, and approximately 20% are caused by gallstone ileus.
Large bowel obstruction most often is caused by malignancy or volvulus.
Abdominal aortic aneurysm
Peptic ulcer disease
Malignancy
Gastroenteritis
Lab Studies:
Complete blood count
Generally perform a complete blood count (CBC).
Although an elevated white blood cell (WBC) count may indicate infection or inflammation, it has poor sensitivity and specificity. Do not make treatment decisions based on a normal WBC count in elderly patients.
Serum chemistries
Comprehensive metabolic panel or basic metabolic panel with liver function tests can be useful in assessing renal function, diabetes, acidosis, biliary tract disease, and liver dysfunction.
An anion gap may be an indication of a serious intra-abdominal process; look for a gap and other signs of acidosis particularly with concern for ischemic bowel.
Again, maintain caution despite the presence of normal results of liver function tests, since elderly patients with acute cholecystitis may not demonstrate elevations.
Serum lipase or amylase: These studies are useful as screening tests for pancreatitis. Little evidence supports obtaining both, and lipase is the superior test.
Urinalysis
Urinalysis is essential to aid in excluding urinary tract infection and detecting the presence of hematuria. Hematuria can have many causes in elderly patients, including ruptured AAA.
In female patients, a catheterized specimen has higher specificity when evaluating for urinary tract infection.
Blood cultures: Blood cultures are recommended for elderly patients presenting with abdominal pain associated with either fever or hypothermia or when sepsis is suspected.
Prothrombin time (PT) and activated partial thromboplastin time (aPTT): Obtain these in patients in whom liver disease, sepsis, or GI bleeding is suspected and in those expected to require operative intervention.
Arterial blood gases
This is indicated for patients in whom bowel ischemia, diabetic ketoacidosis, or sepsis is suspected.
Arterial blood gas also is a rapid method of determining hematocrit in patients with GI bleeding or if ruptured AAA is suggested.
Serum lactate: This is helpful in sepsis or unexplained high anion gap acidosis.
Type and crossmatch: This is indicated in patients with GI bleeding, ruptured AAA, or in unstable patients.
Imaging Studies:
Imaging plays a larger role in the workup of elderly patients with abdominal pain than in younger patients. Preference of imaging modality may vary among institutions according to what is available.
Plain film radiography
Although of limited utility in younger patients, an abdominal series may be helpful in elderly patients because of the wide differential diagnosis.
Plain film radiography can be useful in detecting bowel obstruction, adynamic ileus, nephrolithiasis, and perforation. Occasionally, gallstones may be observed, as well as late findings of mesenteric ischemia (ie, pneumatosis intestinalis). However, the overall sensitivity is very low and a negative abdominal series should not influence management.
Abdominal ultrasonography
Generally, this is the initial study of choice when evaluating for biliary tract disease because of availability and speed.
Bedside ultrasonography is an excellent rapid screening test for AAA.
Some studies report that it is reasonably sensitive in detecting hydronephrosis and nephrolithiasis, but it is highly operator dependent and not considered the optimal test for urolithiasis.
CT scan
CT plays an increasingly important role in the evaluation of elderly patients with abdominal pain, especially when the diagnosis is unclear.
CT scan is the study of choice for suspected diverticulitis, having a sensitivity of 93%, and is very sensitive in patients with possible appendicitis when the diagnosis is not clear.
When performing CT scan to exclude diverticulitis, allow enough time for the oral contrast to reach the distal colon (usually 2-3 h).
One study demonstrated that using CT scan with only water-soluble contrast administered by enema without intravenous (IV) or oral contrast had a sensitivity for diverticulitis of 99% and appeared to be safe.
Avoid barium enema in patients with suspected diverticulitis.
In stable patients with suspected AAA, CT scanning with IV contrast is approximately 100% sensitive.
Noncontrast helical CT scan is reported to be 95-100% sensitive in detecting nephrolithiasis and ureterolithiasis. Unfortunately, many elderly patients have vascular calcifications in the pelvis, making interpretation more difficult. The presence of ureteral dilatation or perinephric stranding can help establish the diagnosis.
CT scanning combined with CT angiography is increasingly used in the evaluation of suspected mesenteric ischemia. In a 2000 position statement by the American Gastrointestinal Society, it was stated that CT was of limited use in the diagnosis of mesenteric ischemia. Subsequent studies have strongly advocated for the use of multidetector-row CT in the evaluation of mesenteric ischemia (Fleischmann, 2003; Cademartiri, 2004), including one prospective study that found an overall sensitivity of 96%, with specificity of 94% (Kirkpatrick, 2003). Multidetector-row CT scanning had the additional advantage of identifying an alternate diagnosis in 58% of patients without mesenteric ischemia.
Chest radiography
Chest radiography is helpful in excluding pneumonia, which is a cause of abdominal pain.
It may demonstrate free intraperitoneal air under the diaphragm in patients with ruptured viscus. The lateral chest radiography has been demonstrated to be more sensitive in detecting free air.
Angiography: Although this is difficult to obtain on an emergency basis in some institutions, angiography remains the study of choice for mesenteric ischemia.
Nuclear medicine imaging (hepatic 2,6 dimethyliminodiacetic acid [HIDA] scan or diisopropyl iminodiacetic acid [DISIDA] scan): This is helpful for patients in whom cholecystitis is suspected when the diagnosis is not clear. HIDA and DISIDA scanning both provide a very high negative predictive value.
Other Tests:
Electrocardiogram: Perform an ECG in all elderly patients with upper abdominal pain and in
Prehospital Care: Patients with severe pain, abnormal vital signs, or altered mental status should undergo the following:
Large-bore IV placed with either normal saline or lactated Ringer solution (gauge fluid resuscitation by vital signs)
Cardiac monitor and pulse oximetry
Oxygen by nasal cannula or 100% face mask, depending on vital signs and pulse oximetry
Emergency Department Care:
Care in the emergency department is dictated by the severity of presentation. Assess ABCs and vital signs immediately. Place patients on a monitor and start an IV or heparin lock. Administer oxygen to patients who appear to be seriously ill.
If the diagnosis of AAA is suggested, perform a rapid bedside ultrasound, if available.
Administer IV boluses of normal saline or lactated Ringer solution to patients with suspected volume loss. Carefully hydrate patients with a history of renal disease or congestive heart failure to avoid volume overload.
A Foley catheter may be helpful as a guide for volume resuscitation in patients who are sicker. Incontinence is not an indication for a Foley catheter.
Keep all patients with abdominal pain as nothing by mouth (NPO) until surgical pathology is excluded.
Place a nasogastric tube in patients in whom bowel obstruction, ileus, or upper GI bleeding is suspected.
Maintain a low threshold for ordering additional tests such as CT scan or ultrasound.
If biliary disease is suggested, dicyclomine (Bentyl) or glycopyrrolate (Robinul) may be administered for pain. NSAIDs are very effective for biliary colic but should be administered with caution to elderly patients.
In patients with undifferentiated abdominal pain, administering small doses of opioids is reasonable. Several studies have demonstrated this to be safe and effective without decreasing diagnostic accuracy.
Morphine administered IV in doses of 2-4 mg is inexpensive and effective. Morphine has been demonstrated to cause spasm of the sphincter of Oddi and should be avoided in patients in whom biliary disease is suspected.
Meperidine (Demerol) has been the traditional opioid of choice in biliary tract disease because it causes less sphincter of Oddi spasm.
Depending on the practice environment, contacting the on-call surgeon prior to administering opioids may be reasonable.
Initiate appropriate antibiotic coverage for patients in whom sepsis, cholecystitis, appendicitis, diverticulitis, or perforated viscus is suspected. Please refer to the article on the specific diagnosis for choice of antibiotics for a specific disease process (see Differentials).
Consultations:
In patients in whom ruptured AAA or mesenteric ischemia is suspected, consult a surgeon immediately.
Consult a gastroenterologist immediately for patients with significant GI bleeding.
When the diagnosis is uncertain, obtain surgical consultation. Discharge of an elderly patient with abdominal pain should be the exception rather than the rule.
