AUTHOR AND EDITOR INFORMATION

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INTRODUCTION

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Background

Appendicitis is a common and urgent surgical illness with protean manifestations, generous overlap with other clinical syndromes, and significant morbidity, which increases with diagnostic delay. No single sign, symptom, or diagnostic test accurately confirms the diagnosis of appendiceal inflammation in all cases.

The surgeon's goals are to evaluate a relatively small population of patients referred for suspected appendicitis and to minimize the negative appendectomy rate without increasing the incidence of perforation. The emergency department clinician must evaluate the larger group of patients who present to the ED with abdominal pain of all etiologies with the goal of approaching 100% sensitivity for the diagnosis in a time-, cost-, and consultation-efficient manner.

Pathophysiology

Obstruction of the appendiceal lumen is the primary cause of appendicitis. Obstruction of the lumen leads to distension of the appendix due to accumulated intraluminal fluid. Ineffective lymphatic and venous drainage allows bacterial invasion of the appendiceal wall and, in advanced cases, perforation and spillage of pus into the peritoneal cavity.

Frequency

United States

Appendicitis occurs in 7% of the US population, with an incidence of 1.1 cases per 1000 people per year. Some familial predisposition exists.

International

Incidence of appendicitis is lower in cultures with a higher intake of dietary fiber. Dietary fiber is thought to decrease the viscosity of feces, decrease bowel transit time, and discourage formation of fecaliths, which predispose individuals to obstructions of the appendiceal lumen.

Mortality/Morbidity

• The overall mortality rate of 0.2-0.8% is attributable to complications of the disease rather than to surgical intervention.
• Mortality rate rises above 20% in patients older than 70 years, primarily because of diagnostic and therapeutic delay.
• Perforation rate is higher among patients younger than 18 years and patients older than 50 years, possibly because of delays in diagnosis. Appendiceal perforation is associated with an increase in morbidity and mortality rates.

Sex

The incidence of appendicitis is approximately 1.4 times greater in men than in women. The incidence of primary appendectomy is approximately equal in both sexes.

Age

• Incidence of appendicitis gradually rises from birth, peaks in the late teen years, and gradually declines in the geriatric years.
• Although rare, neonatal and even prenatal appendicitis have been reported.
• The emergency department clinician must maintain a high index of suspicion in all age groups.

CLINICAL

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History

• Variations in the position of the appendix, age of the patient, and degree of inflammation make the clinical presentation of appendicitis notoriously inconsistent.
• In addition, patients with many other disorders present with symptoms similar to those of appendicitis. Examples include the following:
• • Pelvic inflammatory disease (PID) or tubo-ovarian abscess
  • Endometriosis
  • Ovarian cyst or torsion
  • Ureterolithiasis and renal colic
  • Degenerating uterine leiomyomata
  • Diverticulitis
  • Crohn disease
  • Colonic carcinoma
  • Rectus sheath hematoma
  • Cholecystitis
  • Bacterial enteritis
  • Mesenteric adenitis
  • Omental torsion
• The classic history of anorexia and periumbilical pain followed by nausea, right lower quadrant (RLQ) pain, and vomiting occurs in only 50% of cases.
• Migration of pain from the periumbilical area to the RLQ is the most discriminating feature of the patient's history. This finding has a sensitivity and specificity of approximately 80%.
• When vomiting occurs, it nearly always follows the onset of pain. Vomiting that precedes pain is suggestive of intestinal obstruction, and the diagnosis of appendicitis should be reconsidered.
• Nausea is present in 61-92% of patients; anorexia is present in 74-78% of patients. Neither finding is statistically different from findings in ED patients with other etiologies of abdominal pain.
• Diarrhea or constipation is noted in as many as 18% of patients and should not be used to discard the possibility of appendicitis.
• Duration of symptoms is less than 48 hours in approximately 80% of adults but tends to be longer in elderly persons and in those with perforation. Approximately 2% of patients report duration of pain in excess of 2 weeks.
• A history of similar pain is reported in as many as 23% of cases. A history of similar pain, in and of itself, should not be used to rule out the possibility of appendicitis.
• An inflamed appendix near the urinary bladder or ureter can cause irritative voiding symptoms and hematuria or pyuria. Cystitis in male patients is rare in the absence of instrumentation. Consider the possibility of an inflamed pelvic appendix in male patients with apparent cystitis.

Physical

• Male infants and children occasionally present with an inflamed hemiscrotum due to migration of an inflamed appendix or pus through a patent processus vaginalis. This is often initially misdiagnosed as acute testicular torsion.
• RLQ tenderness is present in 96% of patients, but this is a nonspecific finding. Rarely, left lower quadrant (LLQ) tenderness has been the major manifestation in patients with situs inversus or in patients with a lengthy appendix that extends into the LLQ.
• The most specific physical findings are rebound tenderness, pain on percussion, rigidity, and guarding.
• The Rovsing sign (RLQ pain with palpation of the LLQ), the obturator sign (RLQ pain with internal rotation of the flexed right hip), and the psoas sign (RLQ pain with hyperextension of the right hip) are present in a minority of patients with acute appendicitis. Their absence never should be used to rule out appendiceal inflammation.
• A positive cough sign (sharp pain in the RLQ elicited by a voluntary cough) may be helpful in making the clinical diagnosis of localized peritonitis. Similarly, RLQ pain in response to percussion of a remote quadrant of the abdomen, or to firm percussion of the patient's heel, suggests peritoneal inflammation. The Markle sign, pain elicited in a certain area of the abdomen when the standing patient drops from standing on toes to the heels with a jarring landing, is stated in DeGowin's Diagnostic Examination to be very sensitive for localizing true peritonitis.
• The literature is inconsistent as to whether rectal examination is helpful in making the diagnosis; however, failure to perform a rectal examination is frequently cited in successful malpractice claims.

Causes

• Obstruction of the appendiceal lumen usually precipitates appendicitis.
• The most common causes of luminal obstruction are fecaliths and lymphoid follicle hyperplasia.
• • Fecaliths form when calcium salts and fecal debris become layered around a nidus of inspissated fecal material located within the appendix.
  • Lymphoid hyperplasia is associated with a variety of inflammatory and infectious disorders including Crohn disease, gastroenteritis, amebiasis, respiratory infections, measles, and mononucleosis.
  • Obstruction of the appendiceal lumen has less commonly been associated with parasites (eg, Schistosomes species, Strongyloides species), foreign material (eg, shotgun pellet, intrauterine device, tongue stud, activated charcoal), tuberculosis, and tumors.

DIFFERENTIALS

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Other Problems to be Considered

Appendiceal stump appendicitis
Typhilitis
Epiploic appendagitis
Mesenteric adenitis
Omental torsion
Psoas abscess

WORKUP

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Lab Studies

• Complete blood cell count
• • Studies consistently show that 80-85% of adults with appendicitis have a WBC count greater than 10,000 cells/mm³. Neutrophilia greater than 75% occurs in 78% of patients. Fewer than 4% of patients with appendicitis have a WBC count less than 10,000 cells/mm³ and neutrophilia less than 75%.
  • CBC tests are inexpensive, rapid, and widely available; however, the findings are nonspecific, and 4% of cases are missed.
  • The literature is inconsistent with regard to WBC counts in children and elderly patients with appendicitis.
• C-reactive protein test
• • C-reactive protein (CRP) is an acute-phase reactant synthesized by the liver in response to bacterial infection. Serum levels begin to rise within 6-12 hours of acute tissue inflammation. A rapid assay is widely available.
  • Several prospective studies have shown that in adults who have had symptoms for longer than 24 hours, a normal CRP level has a negative predictive value of approximately 100% for appendicitis.
  • Specificity is 50-87% in several series.
  • Three studies in adults showed that the combination of a WBC count of less than 10,500 cells/mm³, neutrophilia less than 75%, and a normal CRP level had 99-100% negative predictive value for acute appendicitis (Yang, 2006). One retrospective study of 77 patients older than 60 years found that only 2 had a normal "triple screen" (Yang, 2005).
  • In 1989, Thimsen et al noted that a normal CRP level after 12 hours of symptoms was 100% predictive of benign, self-limited illness.
  • CRP results do not distinguish between various types of bacterial infection.
• Urinalysis: One study of 500 patients with acute appendicitis revealed that approximately one third reported urinary symptoms, most commonly dysuria or right flank pain. One in 7 patients had pyuria greater than 10 WBC per high power field, and 1 in 6 patients had greater than 3 RBC per high power field. Thus, the diagnosis of appendicitis should not be dismissed due to the presence of urologic symptoms or abnormal urinalysis (Tundidor, 2005).

Imaging Studies

• Computed tomography
• • Abdominal CT has become the most important imaging study in the evaluation of patients with atypical presentations of appendicitis. Studies have found a decrease in negative laparotomy rate and appendiceal perforation rate when pelvic CT was used in selected patients with suspected appendicitis (Rao, 1999; McGory, 2005; Harswick, 2006).
  • Note that one study of asymptomatic volunteers undergoing pelvic CT found that 42% had an "abnormal" appendiceal diameter of greater than 6 mm and 78% of appendices did not fill after oral contrast. Thus, findings on CT must be correlated with the clinical scenario (Tamburrini, 2005).
  • Advantages of CT scanning include its superior sensitivity and accuracy compared with those of other imaging techniques, ready availability, noninvasiveness, and potential to reveal alternative diagnoses. Disadvantages include radiation exposure, potential for anaphylactic reaction if intravenous contrast agent is used, lengthy acquisition time if oral contrast is used, and patient discomfort if rectal contrast is used.
  • Initial studies evaluated sequential (nonhelical) CT in the diagnosis of appendicitis. In 1993, Malone evaluated nonenhanced, sequential CT in 211 patients and reported a sensitivity of 87% and a specificity of 97%. The addition of intravenous and oral contrast agent increased sensitivity to 96-98%. Thus, sequential CT with oral and intravenous contrast enhancement is highly accurate but time consuming and expensive; it is best used for equivocal presentations when helical CT is not available.
  • In 1997, Lane et al evaluated helical CT without contrast enhancement and found a sensitivity of 90% and specificity of 97%. More recent studies of noncontrast helical CT in adults with suspected appendicitis showed a sensitivity of 91-96% and a specificity of 92-100% (Lane, 1999; Ege, 2002; Hof, 2004; Yuksekkaya, 2004; Ashraf, 2006).
  • In a 2004 study of pediatric patients, Kaiser et al found that nonenhanced CT was 66% sensitive. Sensitivity increased to 90% with the use of intravenous contrast material. In a 2005 study of 112 pediatric patients, Hoecker and Bilman found that unenhanced CT achieved a sensitivity of 87.5%, specificity of 98.7%, positive predictive value of 91.3%, and negative predictive value of 90.8%.
  • In 1997, Rao et al found that focused (lower abdominal and upper pelvic) helical CT with 3% Gastrografin instilled into the colon (without intravenous contrast agent) had a superior sensitivity of 98% and specificity of 98%. Focused helical scanning without intravenous contrast agent eliminates the risk of anaphylaxis and reduces the cost to about $230. Acquisition time is less than 15 minutes. Radiation exposure is less than that of a standard obstruction series. Alternative diagnoses are revealed in up to 62% of patients and include diverticulitis, nephrolithiasis, adnexal pathology, RLQ tumor, small-bowel hernias, and ischemia.
  • The literature suggests that limited helical CT with rectal contrast enhancement is a highly accurate, time-efficient, cost-effective way to evaluate adults with equivocal presentations for appendicitis. Two studies of focused helical CT with rectal contrast in children suggest a sensitivity of 95-97%. This is an excellent diagnostic approach in patients with equivocal presentations who are poor candidates for intravenous contrast.
  • One recent retrospective study of 173 adults found that helical CT with intravenous contrast only has a sensitivity of 100%, specificity of 97%, positive predictive value of 97%, and negative predictive value of 100% (Mun, 2006). An earlier study of 78 patients with appendicitis found sensitivity of 91.9%, specificity of 87.5%, and accuracy of 91% (Iwahasi, 2005). In a 2005 retrospective review of 23 published reports, Anderson et al found that CT without oral contrast was at least as accurate as CT with oral contrast, achieving sensitivity of 95%, specificity of 97%, positive predictive value of 97%, and negative predictive value of 96%. Elimination of oral contrast reduces emergency department length of stay and delay to operative intervention.
  • Continued improvements in helical CT technology may allow nonenhanced helical CT to be the imaging test of choice for adults with suspected appendicitis. Additional studies are needed to identify subgroups that derive the most benefit from diagnostic imaging.
• Ultrasonography
• • In 1986, Puylaert described a graded compression technique for evaluating the appendix with transabdominal sonography. A 5-MHz transducer is used. Gentle but firm pressure is applied on the RLQ to displace intervening bowel gas and to decrease the distance between the transducer and the appendix, improving image quality. An outer diameter of greater than 6 mm, noncompressibility, lack of peristalsis, or periappendiceal fluid collection characterizes an inflamed appendix. The normal appendix is not visualized in most cases. A posterolateral approach is suggested to evaluate the retrocecal area. Scattered case reports endorse transvaginal sonography in women with low pelvic tenderness if the appendix is not visualized on transabdominal scans.
  • Numerous studies have documented a sensitivity of 85-90% and a specificity of 92-96%. Five studies of graded compression ultrasonography in children showed overall sensitivities of 85-95% and specificities ranging from 47-96%. One study found sensitivity of 35% and specificity of 98% in pediatric patients with perforated appendicitis. The cost is approximately $225.
  • Advantages of sonography include its noninvasiveness, short acquisition time, lack of radiation exposure, and potential for diagnosis of other causes of abdominal pain, particularly in the subset of women of childbearing age. Many authorities believe that ultrasonography should be the initial imaging test in pregnant women and in pediatric patients because radiation exposure is particularly undesirable in these groups.
  • The principal disadvantage is that ultrasonography is operator dependent. Because nonvisualization is interpreted as a noninflamed appendix, technical expertise and commitment to a thorough examination are essential in obtaining maximum sensitivity.
  • If graded compression sonogram of the RLQ is positive for appendicitis, appendectomy should be performed. If negative, this finding is not sufficiently sensitive to rule out the possibility of appendicitis. Consideration should be given to further observation and focused helical CT with rectal contrast enhancement.
• Abdominal radiography
• • The kidneys-ureters-bladder (KUB) view is typically used. Visualization of an appendicolith in a patient with symptoms consistent with appendicitis is highly suggestive of appendicitis, but this occurs in fewer than 10% of cases.
  • The consensus in the literature is that plain radiographs are insensitive, nonspecific, and not cost-effective.
• Barium enema study
  • A single-contrast study can be performed on an unprepared bowel. Absent or incomplete filling of the appendix coupled with pressure effect or spasm in the cecum suggests appendicitis. The cost is approximately $420.
  • Multiple studies have found that the sensitivity of a barium enema study is in the range of 80-100%. However, as many as 16% of studies in adults (22-39% in children) were technically unsuitable for interpretation and excluded from data analysis.
  • Advantages of barium enema study are its wide availability, use of simple equipment, and potential for diagnosis of other diseases (eg, Crohn disease, colon cancer, ischemic colitis) that may mimic appendicitis.
  • Disadvantages include its high incidence of nondiagnostic results, radiation exposure, insufficient sensitivity, and invasiveness. These disadvantages make barium enema study a poor screening examination for use by emergency departments.
  • Barium enema study has essentially no role in the diagnosis of acute appendicitis in the era of ultrasonography and CT.
• Radionuclide scanning
• • Whole blood is withdrawn for radionuclide scanning. Neutrophils and macrophages are labeled with technetium-99m albumin and administered intravenously. Images of the abdomen and pelvis are obtained serially over 4 hours. Localized uptake of tracer in the RLQ suggests appendiceal inflammation.
  • Four early studies in adults with suspected appendicitis showed a sensitivity of 80-90% and specificity of 92-100% (Navarro, 1987; Henneman, 1988; DeLaney, 1989; Foley 1992). Two studies of newer labeling techniques achieved sensitivities of 98% for the presence of appendicitis (Kipper, 1999; Rypins, 1997).
  • Although future studies may confirm sensitivity as high as 98%, the acquisition time of 5 hours and the lack of availability are disadvantages to its use as a high-sensitivity ED screening test for appendicitis.
• MRI: A single retrospective study assessed the accuracy of MRI in 51 pregnant patients with suspected appendicitis in whom ultrasonography was nondiagnostic. Sensitivity, specificity, positive and negative predictive values, and accuracy for MRI was 100%, 93.6%, 91.4%, 100%, and 94.0%, respectively (Pedrosa, 2006).

Other Tests

• Clinical diagnostic scores
• • Several investigators have created diagnostic scoring systems in which a finite number of clinical variables is elicited from the patient and each is given a numerical value. The sum of these values is used to predict the likelihood of acute appendicitis.
  • The best known of these is the MANTRELS score, which tabulates migration of pain, anorexia, nausea and/or vomiting, tenderness in the RLQ, rebound tenderness, elevated temperature, leukocytosis, and shift to the left (Table).

    MANTRELS score

    Characteristic	Score
    M = Migration of pain to the RLQ	1
    A = Anorexia	1
    N = Nausea and vomiting	1
    T = Tenderness in RLQ	2
    R = Rebound pain	1
    E = Elevated temperature	1
    L = Leukocytosis	2
    S = Shift of WBC to the left	1
    Total	10

    Source.—Alvarado, 1986.
  • Clinical scoring systems are attractive because of their simplicity; however, none has been shown prospectively to improve on the clinician's judgment in the subset of patients evaluated in the ED for abdominal pain suggestive of appendicitis. The MANTRELS score, in fact, was based on a population of patients hospitalized for suspected appendicitis, which differs markedly from the population seen in the ED.
  • More recently, Tzanakis and others proposed a clinical scoring system that assigns 6 points if appendiceal ultrasonogram is positive, 4 points for RLQ tenderness, 3 points for rebound tenderness, and 2 points for WBC count greater than 12,000. In their prospective study of 303 adults using a total score cut-off of 8 points or greater, they found sensitivity, specificity, and accuracy of 95.4%, 97.4%, and 96.5%, respectively. These findings should be confirmed by additional studies before routine clinical use.
• Computer-aided diagnosis
• • A retrospective database of clinical features of patients with appendicitis and other causes of abdominal pain is entered into a computer. It is then used in prospectively assessing the risk of appendicitis.
  • Computer-aided diagnosis can achieve a sensitivity greater than 90% while reducing rates of perforation and negative laparotomy by as much as 50%.
  • The principle disadvantages are that each institution must generate its own database to reflect characteristics of its local population. Specialized equipment and significant initiation time are required.
  • Computer-aided diagnosis is not widely available in US EDs.

TREATMENT

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Emergency Department Care

• Treatment guidelines for patients with suspected acute appendicitis
• • Establish intravenous access and administer aggressive crystalloid therapy to patients with clinical signs of dehydration or septicemia.
  • Patients with suspected appendicitis should not receive anything by mouth.
  • Administer parenteral analgesic and antiemetic as needed for patient comfort.
  • At least 8 randomized controlled studies show that administering opioid analgesic medications to adult and pediatric patients with acute undifferentiated abdominal pain is safe; no study has shown that analgesics adversely affect the accuracy of physical examination. Formerly, the administration of analgesics to patients with acute undifferentiated abdominal pain has historically been discouraged and criticized because of concerns that they render the physical findings less reliable.
  • Consider ectopic pregnancy in women of childbearing age and obtain a qualitative beta–human chorionic gonadotropin (beta-hCG) measurement in all cases.
  • Administer intravenous antibiotics to those with signs of septicemia and to those who are to proceed to laparotomy.
• Nonsurgical treatment of appendicitis
• • Anecdotal reports describe the success of intravenous antibiotics in treating acute appendicitis in patients without access to surgical intervention (eg, submariners, individuals on ships at sea).
  • In one prospective study of 20 patients with sonography-proven appendicitis, symptoms resolved in 95% of patients receiving antibiotics alone, but 37% of these patients had recurrent appendicitis within 14 months (Eriksson, 1995).
  • Nonsurgical treatment may be useful when appendectomy is not accessible or when it is temporarily a high-risk procedure.
• Preoperative antibiotics
  • Preoperative antibiotics have demonstrated efficacy in decreasing postoperative wound infection rates in numerous prospective controlled studies.
  • Broad-spectrum gram-negative and anaerobic coverage is indicated.
  • Preoperative antibiotics should be given in conjunction with the surgical consultant.

Consultations

• Consult a general surgeon.

MEDICATION

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The goals of therapy are to eradicate the infection and to prevent complications.

Drug Category: Antibiotics

These agents are effective in decreasing the rate of postoperative wound infection and in improving outcome in patients with appendiceal abscess or septicemia. The Surgical Infection Society recommends starting prophylactic antibiotics before surgery, using appropriate spectrum agents for less than 24 hours for nonperforated appendicitis and for less than 5 days for perforated appendicitis. Regimens are of approximately equal efficacy, so consideration should be given to features such as toxicity and cost.

Drug Category: Analgesics

These agents can be used to relieve acute undifferentiated abdominal pain in patients presenting to the ED.

FOLLOW-UP

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Further Inpatient Care

• Open versus laparoscopic appendectomy
• • Initially performed in 1987, laparoscopic appendectomy has been performed in thousands of patients and is successful in 90-94% of attempts. Recent experience has also demonstrated that laparoscopic appendectomy is successful in approximately 90% of cases of perforated appendicitis.
  • Advantages of laparoscopic appendectomy include increased cosmetic satisfaction and a decrease in the postoperative wound-infection rate. Some studies show that laparoscopic appendectomy shortens the hospital stay and convalescent period compared with open appendectomy.
  • Disadvantages of laparoscopic appendectomy are increased cost and an operating time approximately 20 minutes longer than that of open appendectomy. The latter may resolve with increasing experience with laparoscopic technique.
  • Laparoscopic appendectomy is contraindicated in patients with significant intra-abdominal adhesions.
• Emergent versus urgent appendectomy
• • One retrospective study suggests that the risk of appendiceal rupture is minimal in patients with less than 24-36 hours of untreated symptoms (Bickell, 2006). Another recent retrospective study suggests that appendectomy within 12-24 hours of presentation is not associated with an increase in hospital length of stay, operative time, advanced stages of appendicitis, or complications compared to appendectomy within 12 hours of presentation (Abou-Nukta, 2006).
  • Additional studies are needed to demonstrate whether initiation of antibiotic therapy followed by urgent appendectomy is as effective as emergent appendectomy for patients with unperforated appendicitis.
• Immediate versus interval appendectomy for appendicitis with perforation
• • Historically, immediate (emergent) appendectomy was recommended for all patients with appendicitis, whether perforated or unperforated.
  • Recent clinical experience suggests that patients with perforated appendicitis with mild symptoms and localized abscess or phlegmon on abdominopelvic CT scans can be initially treated with intravenous antibiotics and percutaneous or transrectal drainage of any localized abscess. If the patient's symptoms, WBC count, and fever satisfactorily resolve, therapy can be changed to oral antibiotics and the patient can be discharged home. Delayed (interval) appendectomy can then be performed 4-8 weeks later. This approach is successful in the vast majority of patients with perforated appendicitis and localized symptoms. Some have suggested that interval appendectomy is not necessary unless the patient presents with recurrent symptoms. Further studies are needed to clarify whether routine interval appendectomy is indicated.
  • Further studies are necessary to identify the optimal treatment strategy in patients with perforated appendicitis.

Complications

• Wound infection
• Dehiscence
• Bowel obstruction
• Abdominal/pelvic abscess
• Stump appendicitis - Although rare, approximately 36 reported cases of appendicitis in the surgical stump after prior appendectomy exist (Liang, 2006).
• Death (rare)

Prognosis

• The prognosis is excellent.

Patient Education

• For excellent patient education resources, visit eMedicine's Esophagus, Stomach, and Intestine Center. Also, see eMedicine's patient education articles, Appendicitis and Abdominal Pain in Adults.

MISCELLANEOUS

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Medical/Legal Pitfalls

• For approximately 10% of adults with appendicitis, the condition is not diagnosed correctly on their first visit to the health care provider.
• Failure to diagnose appendicitis is the leading cause of successful malpractice claims and the fifth most expensive source of claims against emergency physicians.

Special Concerns

• Pregnant women
• • The incidence of appendicitis is unchanged in pregnancy, but the clinical presentation is more variable than at other times.
  • During pregnancy, the appendix migrates in a counterclockwise direction toward the right kidney, rising above the iliac crest at about 4.5 months' gestation.
  • RLQ pain and tenderness dominate in the first trimester, but in the latter half of pregnancy, right upper quadrant (RUQ) or right flank pain must be considered a possible sign of appendiceal inflammation.
  • Nausea, vomiting, and anorexia are common in uncomplicated first trimester pregnancies, but their reappearance later in gestation should be viewed with suspicion.
  • Physiologic leukocytosis during pregnancy makes the WBC count less useful in the diagnosis than at other times, and no reliable distinguishing WBC parameters are cited in the literature.
  • One study of 22 pregnant women in the first and second trimesters showed that graded compression ultrasonography had a sensitivity of 66% and specificity of 95% (Barloon, 1995).
  • Diagnostic laparoscopy has also been suggested for pregnant patients in the first trimester with suspected appendicitis.
  • Although negative appendectomy does not appear to adversely affect maternal or fetal health, diagnostic delay with perforation does increase fetal and maternal morbidity. Therefore, aggressive evaluation of the appendix is warranted in this group.
• Nonpregnant women of childbearing age
• • Appendicitis is misdiagnosed in 33% of nonpregnant women of childbearing age. The most frequent misdiagnoses are PID, followed by gastroenteritis and urinary tract infection.
  • In distinguishing appendiceal pain from that of PID, anorexia and onset of pain more than 14 days after menses suggests appendicitis. Previous PID, vaginal discharge, or urinary symptoms indicates PID.
  • On physical examination, tenderness outside the RLQ, cervical motion tenderness, vaginal discharge, and positive urinalysis support the diagnosis of PID.
• Children
• • Appendicitis is misdiagnosed in 25-30% of children, and the rate of initial misdiagnosis is inversely related to the age of the patient.
  • The most common misdiagnosis is gastroenteritis, followed by upper respiratory infection and lower respiratory infection.
  • Children with misdiagnosed appendicitis are more likely than their counterparts to have vomiting before pain onset, diarrhea, constipation, dysuria, signs and symptoms of upper respiratory infection, and lethargy or irritability.
  • Physical findings less likely to be documented in children with a misdiagnosis than in others include bowel sounds; peritoneal signs; rectal findings; and ear, nose, and throat findings.
• Elderly patients
• • Appendicitis in patients older than 60 years accounts for 10% of all appendectomies.
  • The incidence of misdiagnosis is increased in elderly patients.
  • In patients with comorbid conditions, diagnostic delay is correlated with increased morbidity and mortality.
  • Older patients tend to seek medical attention later in the course of illness; therefore, a duration of symptoms in excess of 24-48 hours should not dissuade the clinician from the diagnosis.

MULTIMEDIA

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Media file 1:  CT scan reveals an enlarged appendix with thickened walls, which do not fill with colonic contrast agent, lying adjacent to the right psoas muscle.
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Media type:  CT

Media file 2:  Sagittal graded compression transabdominal sonogram shows an acutely inflamed appendix. The tubular structure is noncompressible, lacks peristalsis, and measures greater than 6 mm in diameter. A thin rim of periappendiceal fluid is present.
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Media type:  Photo

Media file 3:  Transverse graded compression transabdominal sonogram of an acutely inflamed appendix. Note the targetlike appearance due to thickened wall and surrounding loculated fluid collection.
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Media type:  Photo

Media file 4:  Kidneys-ureters-bladder (KUB) radiograph shows an appendicolith in the right lower quadrant. An appendicolith is seen in fewer than 10% of patients with appendicitis, but, when present, it is essentially pathognomonic.
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Media type:  X-RAY

Media file 5:  Technetium-99m radionuclide scan of the abdomen shows focal uptake of labeled WBCs in the right lower quadrant consistent with acute appendicitis.
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Media type:  Photo

REFERENCES

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• Authors and Editors
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• Abou-Nukta F, Bakhos C, Arroyo K, et al. Effects of delaying appendectomy for acute appendicitis for 12 to 24 hours. Arch Surg. May 2006;141(5):504-6; discussioin 506-7. [Medline].
• Albu E, Miller BM, Choi Y, et al. Diagnostic value of C-reactive protein in acute appendicitis. Dis Colon Rectum. Jan 1994;37(1):49-51. [Medline].
• Alvarado A. A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med. May 1986;15(5):557-64. [Medline].
• Anderson BA, Salem L, Flum DR. A systematic review of whether oral contrast is necessary for the computed tomography diagnosis of appendicitis in adults. Am J Surg. Sep 2005;190(3):474-8. [Medline].
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Article Last Updated: Oct 24, 2006