Appendicitis in the Elderly
Appendicitis in the Elderly
Authors: Robert D. Sidman, MD, Director, Brown University Program in Emergency Medicine, Rhode Island Hospital, Department of Emergency Medicine, Providence, RI; Colleen N. Roche, MD, Rhode Island Hospital, Department of Emergency Medicine, Providence, RI; Sandeep Duggal, MD, Rhode Island Hospital, Department of Internal Medicine, Providence, RI.
Peer Reviewer: Albert C. Weihl, MD, FACEP, Assistant Professor of Surgery and Medicine, Section of Emergency Medicine, Yale University School of Medicine, New Haven, CT.
Acute abdominal pain is one of the most common presenting complaints in older emergency department (ED) patients.1,2 Evaluation of these patients remains a daunting and complex task. The number of conditions that can cause acute abdominal pain in this group is extensive and the etiologies differ compared to those seen in a younger cohort. Although acute appendicitisis is less common than other intra-abdominal surgical emergencies, such as choleycystitis, it remains an important cause of abdominal pain in the elderly.
This issue examines acute appendicitis in the older patient. Clinical features, including atypical presentation and differences between older and younger patients, will be emphasized. The curent role of diagnostic studies is discussed and a management algorithm based on the diagnostic likelihood of appendicitis is presented.
— The Editor
Definition of the Problem
In the United States, abdominal complaints account for nearly 5 million ED visits annually.3 Approximately 250,000 of these visits are due to acute appendicitis, incurring costs of $1.5 billion.4 Of particular interest is the elderly population, age 65 and older, for whom the complication rate approaches 50%.5 This complication rate is caused by multiple factors but is most commonly secondary to the delayed diagnosis of appendicitis, which has been shown to increase mortality from 8% to 19%.6 The emergency physician can play a crucial role in the prompt diagnosis and treatment of this disease.
Initially described by Fitz in 1884 as a disease of young healthy males, appendicitis is now known to afflict both sexes and people of all ages.7 The diagnosis of appendicitis should be entertained in any patient with poorly defined abdominal pain. In fact, appendicitis is the most common surgical emergency in childhood and pregnancy, comprising more than 50% of the cases, with peak incidence in patients ages 10-20.8-11 Of particular interest, appendicitis also is the third most common cause of abdominal pain requiring surgical intervention in the elderly, behind biliary tract disease and intestinal obstruction.12,13
Right lower quadrant pain in elderly patients with appendicitis is elicited in more than three-fourths of patients at some point during their exams, but it may not be apparent upon initial evaluation in the ED.13 The classic history of periumbilical pain that localizes to the right lower quadrant as the disease progresses, is seen in fewer than one-third of these elderly patients.15,16 Therefore, although common, the diagnosis of acute appendicitis is sometimes difficult for the emergency physician. Approximately one-fourth of elderly patients with proven appendicitis who are initially evaluated in an ED are misdiagnosed and discharged home.17
Diagnosing appendicitis in the elderly patient is even more challenging. Elderly persons represent the fastest growing segment of the population in this country and account for more than 20% of all ED visits, thereby increasing the number of cases of appendicitis in this cohort.18 As patients age, there also is an increase in general medical problems. One study reported an average of three medical problems for independently living elderly persons. This number increased to 10 for patients living in nursing homes and other long-term care facilities.19 Concomitant diseases can both obscure the presentation and complicate the hospital course in patients with acute appendicitis. A better understanding of the progression of the disease process in this age group is necessary to improve patient outcome.
Relevance to the Geriatric Population
Older patients who present to the ED with abdominal pain may be difficult to evaluate. They are more likely to have significant pathology despite a physical exam that may not correlate well with the severity of disease. This is commonly a result of physiological changes, and is influenced by concomitant diseases and chronic medications that obscure normal physiological responses. This is evidenced by the delay in seeking emergency care, the higher proportion of ruptured visci on presentation, and the relative lack of correlation of symptoms and signs to findings at surgery and autopsy. Lack of recognition of these limitations and the resulting delay in diagnosis contribute to the mortality rate from appendicitis (more than 50%) in this age group.20,21
Diagnosing and treating elderly patients with appendicitis is a particularly challenging problem for emergency physicians. The reasons can be divided broadly into three categories: delays in seeking medical care; delays in making the diagnosis; and the typically more complicated course these patients experience compared to the younger cohort once the diagnosis is established.
Delays in seeking medical care may in part be due to decreased pain perception but also may have to do with problems in communication, transportation, economic factors, dislike of hospitals, and/or the belief that pain and decline in function are an inevitable part of aging.22,23 Most patients older than age 65 present to the ED more than 24 hours after symptom onset.23-26
There are multiple factors that contribute to the delay in the diagnosis of appendicitis in the elderly. These include, but are not limited to, limitations in the history, physician bias, and the physiologic changes of the elderly.
Obtaining a medical history from an elderly patient can be difficult and requires patience on the part of the emergency physician. As a consequence of cognitive defects, elderly patients exhibit poor recall of their subjective complaints. The history may be unobtainable in the unresponsive patient and in those with severe cognitive impairment. Communication with the elderly may be impeded by impaired hearing, stroke, or dementia. These conditions impair the ability of the patient to give his or her history and list past medical problems and current medications. Although family members or nursing homes may not always provide accurate histories, these sources should be interviewed since the information provided is often valuable. When available, additional history should be garnered by early acquisition of the patient’s medical records and discussion with the patient’s primary care physician.
Another obstacle to overcome is the emergency physician’s bias toward elderly diseases—for example, most emergency physicians think of appendicitis as a disease of the young. With these factors in mind, abdominal pain may be one of the most difficult complaints to evaluate in this patient population. Despite these difficulties, three-fourths of patients will have a specific diagnosis made in the ED, with more than 60% of those cases admitted.12
The elderly have been shown to have a higher threshold to pain than do the young. Sherman and Robillard illustrated in 1960 that pain sensitivity decreased with age.27 They studied two groups of individuals, one included patients ages 20-30 and another included those ages 65-97. A thermal stimulus was used (i.e., a light beam on the India ink blackened forehead of the test subject). Uniformity of the stimulus was guaranteed by measurement with an instrument called a thermophile. Both perception thresholds and reaction thresholds were found to be significantly higher in the older group.27 Although threshold differences to abdominal pain have not been objectively studied, these findings are observed clinically.
Fewer than one-third of elderly patients will present "classically," exhibiting all of the following features: anorexia, right lower quadrant pain, nausea or vomiting, temperature greater than 38.6°C (101.5°F), and elevated white blood cell count (WBC) and/or left shift.23 More often than not, the clinical scenario is confusing: Right lower quadrant pain is absent in 20-50% of these cases; 75% of patients will have WBC counts less than 15,000;28 and elevation in temperature is noted in only approximately 50% of these patients.23 Of note, nausea and vomiting occur less commonly in the elderly than the general population presenting with appendicitis.5,23,25,28 For these reasons, the diagnosis of appendicitis is not clear-cut and can have misleading laboratory and roentographic findings.
Various physiologic changes seen in the elderly make the diagnosis of appendicitis both confusing and challenging. With age, the abdominal musculature decreases, and peritoneal irritation is less likely to manifest itself as guarding or rebound. It has been shown that approximately one-fifth of elderly patients do not even exhibit right lower quadrant pain.23,28 Therefore, despite the occurrence of catastrophic processes, the elderly are more likely to present with vague complaints and a paucity of alarming signs and symptoms. It also has been speculated that the appendiceal wall in the elderly is weaker and more prone to perforation. Atherosclerotic disease, which is by nature more advanced in the elderly, leads to decreased appendiceal blood flow. This results in a vicious cycle of appendiceal infarction and increased bacterial invasion, until perforation ultimately occurs. These factors, combined with the fact that the omentum in the elderly is less able to limit the spread of intra-abdominal processes, lead to considerably higher complication rates in this age group.
Considering that the elderly with abdominal pain have twice the rate of surgical intervention than that of younger patients, it is clear why prompt diagnosis and treatment are paramount.29 Approximately 30% of ED patients older than age 65 who were taken to the operating room with a preoperative diagnosis other than appendicitis were later found to have appendicitis.23 Misdiagnosis and delays to diagnosis of appendicitis contribute to the increase in morbidity and mortality seen in the elderly.
Epidemiology
In one series, abdominal pain was the chief complaint in 5% of all patients presenting to the ED.29 Fifty to 60% of elderly patients who present with abdominal pain are admitted. Approximately one-third of these patients will undergo a surgical procedure during their initial hospitalization.12,29 Appendicitis comprises 14% of all abdominal emergencies in elderly patients, compared to 80% in patients younger than age 50.13 As the population older than age 65 increases, the number of cases of appendicitis will as well. One in 35 females and one in 50 males older than age 50 will develop appendicitis during the remainder of their lives.23,30
The percentage of patients with co-morbid conditions greatly increases with age. As many as one-third of elderly patients with appendicitis will have three or more co-morbid conditions and will be taking three or more chronic medications.31 Concurrent illnesses, such as diabetes, atherosclerosis, renal failure, and hypothyroidism, may inhibit patients from tolerating appendicitis effectively. Moreover, many concurrent illnesses may be adversely affected by the physiological stress of appendicitis, thereby placing this cohort at greater risk for morbidity and mortality. In elderly patients with more than one chronic condition, mortality from all abdominal etiologies has been found to double from 7% to 15% with acute abdominal disorders.18 Factors associated with increased mortality included the presence of intra-abdominal malignancy, multisystem involvement, and the presence of generalized peritonitis.13
Delays in seeking medical treatment may be secondary to psychological stressors related to hospital admission, cognitive dysfunction (either preexisting or due to the disease process itself), and/or the physiologic changes of aging that limit pain perception. As stated in the previous section, many patients older than age 60 were found to wait more than 24 hours before presenting to a physician. Delays in seeking treatment, as well as physician misdiagnosis, increase the time to definitive treatment. In conjunction with co-morbid diseases, this increases the rate of appendiceal perforations in the elderly (33-72%) compared to the general population (12-20%) and contributes to an increase in morbidity to greater than 30%.13,20,23,28 Overall mortality from appendicitis in this age group is around 8%.14
Etiology
The function of the appendix remains a mystery, and no deficits can be found in patients after appendectomy. Yet, it has been a source of illness to man since early in our history. In Egypt, a mummy dating from the times of the Byzantine Empire was found with adhesions in the right lower quadrant. The first anatomic drawings of the worm-like organ came from Leonardo DaVinci. In 1554, Frenchman Jean Fernel was credited with the first clinical description of a 7-year-old girl who suffered from perityphlitis, derived from the Greek typhlon or cecum. The autopsy determined that luminal obstruction of the appendix led to inflammation, perforation, and necrosis.
The appendix, a blind pouch arising anatomically from the inferior border of the cecum in the right lower quadrant, is generally 6-10 cm in length.32 It has its own meso-appendix and derives its blood supply from branches of the ileocolic artery. Lymphoid tissue is present in the submucosal layer of the appendix. At birth there is relatively little lymphoid tissue; it subsequently peaks between the ages of 10 and 20. Interestingly, the organ is devoid of lymphoid tissue by the age of 60.32
The chain of events responsible for acute appendicitis is initiated by luminal obstruction of the appendix. The most common etiology for obstruction is hyperplasia of lymphoid follicles (60%), followed by the presence of an appendicolith (35%).32,33 Considering that lymphoid hyperplasia often occurs concurrently with other diseases, such as measles, mononucleosis, or gastroenteritis, it is easy to see why appendicitis is sometimes difficult to differentiate. Numerous other factors can cause obstruction, including parasites, foreign bodies, tumors, inflammatory bowel disease, barium, appendiceal lymphadenopathy, and carcinomas.32,34 Although lymphoid hyperplasia also is thought to represent a major causative role in appendiceal obstruction in children, the appendix in the elderly is markedly atrophic with decreased lymphadenopathy. The elderly appendix is predisposed to obstruction and inflammation because of other factors, including a narrow or obliterated lumen, mucosal thinning and fibrosis, and fatty infiltrates.32 These characteristics, along with atherosclerosis, lead to more rapid progression of the disease.
Pathophysiology
Once obstruction has occurred, the appendix will secrete mucus until intraluminal pressure reaches 85 cm of water.33 This fluid accumulation causes an increase in pressure, resulting in edema and stretching of the muscular layer. Venous stasis allows for increased bacterial growth, most commonly Bacteroides spp. or Escherichia coli, and the subsequent increased production of endotoxins and exotoxins. These toxins lead to mucosal ulceration, allowing bacteria to translocate into the muscular layers of the appendix. Polymorphonuclear cells invade the appendiceal wall as well. The increasing inflammation leads to a further increase in appendiceal pressure, which impedes arterial, venous, and lymphatic flow. Tissue infarction results.
Visceral autonomic nerves entering the spinal cord at the levels of T8 to T10 are stimulated by stretch fibers located in the muscular layer of the appendix. Patients then perceive pain as poorly localized to the periumbilical region, as referred by these dermatomes.8
The disease process then spreads to adjacent intra-abdominal structures and organs. Once the inflammation contacts the parietal peritoneum, somatic pain develops, and patients experience more localized pain, classically in the right lower quadrant. If the disease process is allowed to continue, perforation ensues with a release of pressure, and patients often experience a brief respite of symptoms. Perforation generally takes 24-36 hours to occur.8,33 Most commonly, perforation results in localized peritonitis and abscess formation. Pneumoperitoneum or bowel obstruction has been found in some cases.
Clinical Features
In most cases of acute appendicitis, a good clinician needs only to conduct a thorough history and physical examination to make the diagnosis. Most patients seek care 12-48 hours into the course of the illness, although this often is delayed in the elderly. This, in addition to the fact that elderly patients often present with less reliable signs and symptoms and have atypical presentations, maks appendicitis difficult to distinguish from other disease states.
In several series, more than 90% of elderly patients with appendicitis presented with a chief complaint of abdominal pain.14,28 Any abnormal findings must be addressed carefully in relation to the chief complaint. The increased number of underlying medical problems and medication side effects with which the aged contend complicate the picture. Symptoms such as nausea, vomiting, anorexia, abdominal pain, diarrhea, and constipation are all encountered less commonly in the aged than what is expected for the general population.5 Yet, in a case-control study of 300 elderly patients with appendicitis, no significant differences were found when compared to the younger control cohort.30 This has been confirmed by others.28 Temperature elevations, frequent in the acute abdomen and appendicitis, may be normal or decreased in the elderly.14
The classic sequence of events of acute appendicitis begins with abdominal pain and is followed by anorexia, nausea, and vomiting, followed by pain in the right lower quadrant and fever. Many patients will not exhibit every symptom. Most elderly patients exhibit anorexia, nausea, or vomiting.14 Constipation or diarrhea may be present. Constipation motivates many to use laxatives or enemas, without relief.33 Abdominal pain precedes vomiting by several hours. Protracted vomiting is unlikely, and its presence should make the clinician question the diagnosis of appendicitis. Patients report the initial pain as dull, mid-epigastric, peri-umbilical in nature, often awakening them from sleep. Although abdominal pain usually is a chief complaint of patients, some only perceive mild gastrointestinal upset. Men may report testicular pain. This initial pain is visceral and often somewhat subsides, only to reappear in the right lower quadrant as a severe ache that often increases with peritoneal irritation. The movement of pain is important to note. Unfortunately, the classic presentation of acute appendicitis occurs in less than one-third of cases in the elderly.6,23
Physical findings usually coincide with the course of disease, depending on the degree of inflammation. On physical exam, 75% of patients will have temperatures greater than 37.7°C (99.9°F), but temperatures greater than 38°C (100.4°F) usually occur after transmural inflammation has occurred.14,24 Slight elevation in heart rate and blood pressure may occur in the apprehensive patient, but vital signs are often normal in simple cases or if the patient is on certain medications that blunt the sympathetic response, such as beta-blockers. Elevations in temperature in excess of 38°C (100.4°F) are rare until transmural inflammation has occurred.8 Abdominal tenderness does occur in more than 95% of all patients at some point during this disease process.5,8
The variable location of the appendix can be responsible for atypical presentations of acute appendicitis. The appendix can be located at any point 360 degrees around the cecum. Therefore, the variation of positions may account for atypical presentations. Consequently, the time to make the diagnosis may be significantly delayed or missed altogether. With a pelvic appendicitis, the pain may begin in the epigastrium but quickly settles into the lower abdomen. Some patients present with only minimal abdominal pain, and local tenderness can be found on rectal or pelvic exam.32 With a high retrocecal or retroiliac appendicitis, the inflamed structure is shielded from the anterior abdominal wall by the overlying cecum or ileum. The pain is, therefore, perceived as less intense in nature to the patient, with less discomfort when ambulating.33 Sometimes patients will present with urinary frequency due to proximity to the ureter, with flank pain on the right. In these cases, abdominal wall rigidity is usually absent and abdominal discomfort minimal.33 Rovsing’s sign, right lower quadrant pain elicited by palpation in the left lower quadrant, however, is often present. A positive psoas sign is somewhat specific but is insensitive. It is elicited by extension of the right hip or by flexion against resistance. A similar maneuver, the obturator sign, is performed by passive rotation of the hip, with the leg mid-flexed. Pain in response to the maneuver is considered positive. Either sign, when positive, represents irritation in the involved areas.32
The rectal exam, once a reflex of the examining physician when the diagnosis of appendicitis is suspected, has been challenged for its limited utility. In patients with signs and symptoms consistent with the classic presentation, this exam may be deferred.8 However, as is often the case in this population, many presentations are not classic. In those cases, the rectal exam may offer additional information about another diagnosis that may be in question or help confirm the diagnosis of appendicitis.
Duration of symptoms correlates directly with incidence of perforation and mortality in elderly patients.14,24 One study found that at the time of operation, fewer than 10% had simple, noncomplicated appendicitis, and most (85%) presented after 24 hours of pain.35 Another study concluded that the elderly have a more rapidly progressive course with earlier abscess formation and rupture.28 This accounts, in part, for the observed increase in mortality.28 A summary of the clinical findings is provided in Table 1.
| Table 1. Comparison of Clinical Features | ||
| Young | Elderly | |
| Time to presentation | usually < 24 hours | often > 24 hours |
| Abdominal pain | + + + | + + + |
| Associated symptoms (N/V, anorexia) |
+ + + | + + |
| Fever and leukocytosis | + | +/- |
| Classic presentation* | + + | less than one-third |
| Perforation on presentation | + | + + + |
| Morbidity and mortality | + | + + + |
| * = periumbilical pain which migrates to the RLQ as the disease progresses |
||
Diagnostic Studies
When approaching an elderly patient with undifferentiated abdominal pain, the emergency physician must cast a wide diagnostic net, considering that this particular patient population seldom presents "typically" with intra-abdominal pathology, as previously discussed.
Appendicitis is classically thought to be a clinical diagnosis, but it is sometimes very difficult to make in the elderly. It is important to entertain this diagnosis in any elderly patient presenting with abdominal complaints, because the longer it takes to diagnose appendicitis, the greater the risk for perforation and concomitant increase in morbidity and mortality. There are multiple diagnostic studies to aid the emergency physician in the work-up of suspected appendicitis, some of which (i.e., ultrasound [U/S] and computed tomography [CT]) are more appropriate when the etiology seems less clear.
Laboratory Investigations. A complete blood count (CBC) and urinalysis (UA) are appropriate first-line studies. A serum electrolyte panel may be indicated if the patient is to receive intravenous contrast material. If the clinical picture warrants (i.e., upper abdominal pain on exam), amylase, lipase, and liver function tests may add useful information. Lactate is often utilized in this clinical situation, and although it is a non-specific, it is a sensitive indicator of poor tissue perfusion. Elderly patients often present with a history of abdominal pain not elicited on physical exam. In such cases, a chest roentogram and electrocardiogram should be obtained to evaluate for the possibility of referred cardiopulmonary pathology.
The WBC count, although limited by a lack of sensitivity and specificity, has some value when evaluating an elderly patient with undifferentiated abdominal pain. The WBC count may be normal in many elderly patients with infection, although in most of those patients neutrophilia is present. An elevated WBC count is not specific for appendicitis, but because WBC count increases after 4-8 hours in patients with appendicitis, serial elevations of the WBC count may increase sensitivity to 92%, with a specificity that approaches 100%.34 The mean WBC count is 14,000-15,000.12,19,23 Multiple studies have found the WBC count to be greater than 10,000 in 70-90% of all patients with appendicitis at some point during the disease process.12,19,26,35 One study found neutrophilia in elderly patients that ranged from 59% to 96%.12 Of elderly patients with appendicitis, 12% presented only with immature forms (> 10% bands in this study) on their WBC and another 8% had a normal WBC count and differential.19 A manual differential should be requested at institutions where the manual differential is only performed if the total WBC count is elevated. Therefore, as an emergency physician, it is important not to rule out the possibility of appendicitis in an elderly patient based solely on an initially normal WBC count. Conversely, leukocytosis in the setting of abdominal pain, while not diagnostic, should increase the index of suspicion for surgical pathology.
UA should be obtained in elderly patients with abdominal pain in order to evaluate the genitourinary system. It has been shown to be abnormal in 19-40% of patients with appendicitis.5 These patients often are found to have mild pyuria, bacturia, and/or hematuria, often due to direct contact between the inflamed appendix and the ureter. Alternatively, false-positive findings can occur secondary to poor collection technique in patients with indwelling catheters, and in elderly women, who often have asymptomatic bacteruria and pyuria. If the physician is not considering appendicitis, it may be easy to attribute these laboratory abnormalities to a urinary tract infection or nephrolithiasis. Conversely, greater than 20 WBCs per high powered field generally implies the patient has a genitourinary infection.5
C-reactive protein (CRP) is an acute phase reactant synthesized by hepatocytes, and although it is not often obtained in the emergent work-up of the patient with abdominal pain, its role has been studied in patients suspected of having appendicitis. The CRP level is often very high with bacterial infections, and only minimally elevated in viral infections.27 An elevated CRP level has a sensitivity of 47-75% and a specificity of 56-82% and is therefore not a very helpful measurement when used alone for making the diagnosis of appendicitis.34,38,39 Additionally, it is more likely to be elevated in acute appendicitis when symptoms have persisted more than 12 hours.27 However, elevation of the WBC, neutrophilia greater than 75%, or an elevated CRP has a sensitivity of 97-100% for appendicitis with a specificity around 50%.40 One group specifically looked at CRP levels and WBC counts in elderly patients and found that if both the CRP and the WBC count are not elevated, appendicitis could be effectively ruled out.41
Radiographic Investigations. An emergency physician often will obtain plain radiographs in elderly patients with abdominal pain. This is often done to evaluate for radiographic evidence of certain disease processes, such as lower lobe infiltrates, hollow viscus perforation, intestinal obstruction, appendicolith, or ureteral stone. Plain radiographs, although still commonly obtained, are not currently recommended in the work-up of suspected appendicitis, owing to the lack of sensitivity and the presence of better diagnostic tests. There are many abnormalities on abdominal radiographs in patients with documented appendicitis.42 These findings include the presence of an appendicolith, gas in the appendix, air-fluid levels, or distention of the terminal ileum, cecum, or ascending colon secondary to ileus, which is the most common finding.23,42-44 An appendicolith is reported to be radiographically present on plain film in only about 1% of cases,23,43 and in our experience this seems accurate. When an appendicolith is actually present, it is considered pathognomonic for appendicitis, although that is not always the case.23 Additional non-specific findings include loss of the cecal shadow, blurring or obliteration of the right psoas muscle, rightward scoliosis of the lumbar spine, density or haziness over the right sacroiliac joint, and free intraperitoneal air or fluid.42,44 It has been shown that of patients presenting with abdominal symptoms, more than 60% had normal radiographs. Only 7% of the time did they offer any positive information, and this information did not change the diagnosis.11
When working-up an elderly patient with abdominal pain, it may be more prudent to order a CT scan of the abdomen and pelvis initially, circumventing plain abdominal radiographs altogether. CT scan of the abdomen and pelvis reveals the same diagnoses that are occasionally visualized on plain films, with improved sensitivity and specificity (i.e., bowel perforation and obstruction), and provides more complete information (i.e., hydroureter/hydronephrosis with nephrolithiasis). It is thereby more cost effective to utilize CT scan in patients suspected of having appendicitis. Rao et al found that the cost per specific and correct diagnosis of an abnormality was more than five times greater with plain x-rays than with appendiceal CT scan alone.45
CT scans of the abdomen and pelvis on patients with suspected appendicitis have been found to be 96-98% sensitive and 83-89% specific.46,47 Findings specific for appendicitis include a visualized abnormal appendix (dilated and/or thickened wall) or an appendicolith with pericecal inflammation or abscess. Findings suggestive of appendicitis include periappendiceal fat stranding, fluid collection in the right lower quadrant, abscess, adenopathy, and cecal apical changes. Rao et al found that because of the accuracy of CT scan, the rate of negative appendectomies in all patient populations decreased from 20% to 7%, and decreased to 3% in those patients who actually underwent appendectomies in the face of a positive CT scan.48 In patients in which appendicitis was not diagnosed, an alternative diagnosis was discovered in 50-80% of all cases.46,47,49 Figures 1, 2, 3a, and 3b are examples of CTs in patients with radiographic evidence of appendicitis.
There are some risks to CT scan that should be considered. Oral contrast may present an aspiration risk in the pre-operative patient who will undergo anesthesia. Intravenous contrast may elicit renal insult or allergic reactions. There also may be site extravasation of contrast. Therefore, the physician needs to be aware these possibilities, and a serum creatinine level should be checked prior to infusing intravenous contrast.
Other diagnostic studies that have been studied and are used clinically in cases of suspected appendicitis include U/S, barium enema, and radioactive isotope imaging.
U/S often is utilized when a patient is suspected to have appendicitis. It is advantageous in that it allows for visualization of other pathologic processes in the abdomen/pelvis, and for this reason it may be most useful in evaluating a woman of child-bearing age. It is readily accessible in most ED and is relatively inexpensive. The diagnosis of appendicitis is made by U/S if a non-compressible, aperistaltic appendix with a diameter greater than 6-7 mm is seen, or if an appendicolith is visualized.46,50,51 Additional findings suggestive of appendicitis include gas in the appendiceal lumen, the presence of loculated or focally organized fluid collection, and loss of the echogenic submucosal ring. False positives occur when there is a dilated fallopian tube, muscle fibers from the psoas muscle mimic appendicitis, periappendiceal inflammation secondary to inflammatory bowel disease is present, or if intussipated stool is present.51
Sensitivity of graded compression U/S is reported between 76% and 85% and the specificity between 84% and 92%.46,50,52 Because findings suggestive of appendicitis more commonly are present with an intact appendix, the sensitivity of U/S has been found to decrease with perforation.50,51 Additionally, false negatives may occur if the appendix is not visualized, when inflammation is confined to the appendiceal tip, with retrocecal appendicitis, or if the appendix is markedly enlarged and, therefore, misconstrued as small bowel.50,51 Factors limiting the adequacy of the study include obesity, tense ascites, or pain. If the U/S is reported as sub-optimal, indeterminate, or normal, or if perforation is suspected, CT scan is recommended. U/S should be employed primarily in the elderly when pathology of the biliary tree also is considered in the differential diagnosis.
Barium enhanced radiographs have been utilized in the evaluation of appendicitis. Barium enemas are utilized to evaluate for pathology of the colon and distal ileum. Findings suggestive of appendicitis include a non-visualized or partially filled appendix, irregularities of the appendiceal lumen, and/or mass effect on the cecum/terminal ileum.53 Accuracy rates have been reported to be less than that with CT or U/S and limit its utility at present.53-56
Radioactive isotope imaging has been studied in the diagnosis of appendicitis, based on the observation that there is an influx of leukocytes to the appendix during this pathologic state. Technitium-99m-albumin-colloid labeled leukocytes (TAC-WBC) has been shown to yield the most promising results to date.57,58 Yet isotope imaging is not readily accessible to most emergency physicians, is expensive, and delivers a relatively large radiation dose to the patient. These factors limit their clinical usefulness in the management of acute appendicitis.
Management
If the diagnosis of appendicitis is high in the emergency physician’s differential diagnosis, the patient should receive intravenous access, be kept nothing per os (NPO), and a surgeon should be consulted. The patient should receive intravenous antibiotics with aerobic and anaerobic coverage, such as cefotetan (1-2 g IV q 12h) or cefoxitan (1-2 g IV q 6-8h).59 This has been shown to reduce postoperative wound infections in patients both with and without perforations and will decrease the incidence of postoperative abscesses in patients with perforations.60 Judicious use of analgesics, once the diagnosis is suspected, should not be withheld until a surgeon is present in the ED. The patient should then be taken promptly to the operating room to minimize the chance of perforation.
However, most older patients with acute appendicitis will not be so clear cut. If the diagnosis is still considered after the initial evaluation (careful history, complete physical examination, and lab tests), the patient should be evaluated with a CT scan of the abdomen and pelvis. Findings consistent with acute appendicitis warrant an urgent surgical consult.
If the ED work-up of an elderly patient with abdominal pain is inconclusive, the patient should be admitted for observation, with both serial abdominal exams and WBC counts. The admitting physician, whether surgeon, internist, hospitalist, or family practitioner, must maintain a high index of suspicion, as the longer the delay to an accurate diagnosis of appendicitis, the higher the risk of perforation and subsequent morbidity and mortality. A management algorithm based on the clinical likelihood for the diagnosis of appendicitis is shown in Table 2.
| Table 2. ED Work-up of Elderly Patients with Possible Appendicitis | ||
| High Suspicion | ||
| • History and physical examination | ||
| • NPO | ||
| • Intravenous fluid resuscitation | ||
| • CBC and urinalysis | ||
| • Antibiotics (cefotetan or cefoxitin) | ||
| • Pain control | ||
| • Surgical consultation | ||
| • Appendectomy | ||
| Moderate Suspicion | ||
| • History and physical examination | ||
| • NPO | ||
| • Intravenous rehydration as needed | ||
| • CBC and urinalysis (lipase, LFTs, lactate and electrolytes as indicated) | ||
| • U/S if biliary pathology suspected | ||
| • Plain radiographs of the abdomen if perforation or obstruction is suspected |
||
| • CT scan of the abdomen/pelvis | ||
| —If positive, appendectomy or treat other pathology as indicated |
||
| —If negative, admit for observation and serial examinations and WBCs |
||
| • Surgical consultation | ||
Additional Aspects
The majority of younger patients diagnosed with undifferentiated abdominal pain have a benign course, with quick resolution of symptoms (1-2 weeks) and very low morbidity.61 In contrast, the elder patient presenting with undifferentiated abdominal pain should, under most circumstances, be observed in the hospital setting. When the emergency physician is unable to identify the etiology of a patient’s abdominal complaints, such caution should be exercised before sending that patient home. If sent home, the patient should have a plan in place for re-check, usually within 24 hours. Emergency physicians must be patient advocates when discussing cases with a patient’s primary caregiver or surgeon. Consultation with a surgeon should not be delayed, and narcotics not withheld. Failure to consider appendicitis or any potentially life-threatening abdominal condition in this population not only will result in a poor patient outcome, but also may prompt medicolegal consequences. Several clinical pearls related to appendicitis in the elderly are listed in Table 3.
| Table 3. Pearls in Elderly Patients Suspected of Having Appendicitis | ||
| • Greater than 95% of elderly patients will report abdominal pain at some point during their illness. |
||
| • Less than one-third will exhibit the "classic" presentation of vague periumbilical pain shifting to the RLQ. |
||
| • A normal WBC count is common during the first 4-8 hours of the patient's illness. |
||
| • Serial WBC's have sensitivity and specificity in appendicitis of greater than 90%. |
||
| • CT should be performed on all elderly patients when the diagnosis of abdominal pain is uncertain. |
||
| • Never send an elderly patient home with undiagnosed abdominal pain. |
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Disposition
Any patient suspected of having an appendicitis must be admitted to the care of a surgeon. The patient’s primary care provider and specialists (cardiologist, pulmonologist, nephrologist, etc.) should be notified to maximize their preoperative and post-operative resuscitative efforts. The role of the emergency physician is to rapidly facilitate and coordinate the patient’s emergency care. To stop at the point of diagnosis, without ensuring that the proper consultants are activated in a timely manner, will hinder the patient’s ability to weather this disease process and, thus, limit the effectiveness of the emergency physician as caregiver.
Summary
When evaluating elder patients presenting with abdominal pain, emergency physicians must maintain a high index of suspicion for all potentially life-threatening conditions, including appendicitis. An understanding of the presentation of appendicitis in the elderly, along with the atypical presentations often encountered in this population, is paramount. CT of the abdomen and pelvis should be utilized often in the evaluation of undiagnosed abdominal pain in the elderly, as delay to diagnosis and management significantly increases mortality.
Once the diagnosis of appendicitis is suspected, prompt consultation with a surgeon and the patient’s primary care physician should be initiated to facilitate rapid surgical intervention. Antibiotics, fluid resuscitation, and adequate analgesia should be given. When the diagnosis of appendicitis seems less likely, yet the etiology of the patient’s abdominal complaints remains unclear, the patient should be admitted for observation.
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