Running head: ACUTE APPENDICITIS: A LITERATURE REVIEW AND
Acute Appendicitis: A Review of the literature
Kimberly Henry
SUNY Institute of Technology
Family Primary Care Health I
Nur 652
1
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
2
Acute Appendicitis: A literature Review and Treatment Guidelines
Despite years of medical breakthroughs in preventing many diseases, acute
appendicitis (AA) still remains one of the most common acute abdominal surgery in both
adults and pediatrics (Yang et al. 2006; Morrow & Newman 2007; Nelson et al. 2013; Kwan
& Nager 2010; Stefanutti et al. 2007; Schneider et al. 2007; Schellekens et al. 2013 ).
Appendicitis is thought to be an obstruction of the appendiceal lumen leading to
inflammation and bacteria overgrowth of the appendix (Burns, Dunn, Brady, Starr, &
Blosser, 2013). If not treated, the appendix becomes ischemic leading to perforation and
peritonitis (Dunphy, Winland-Brown, Porter, & Thomas, 2011). Appendicitis can occur
anytime across the lifespan, but peak incidence is generally ages 10-30 (Baldor, Golding, &
Grimes, 2014). Risk factors for AA include adolescent males, abdominal neoplasms, and 1st
degree relatives. There is Speculation of recent roundworm or other parasitic infestations
causing appendicitis, yet this has not been proven (Dunphy et al., 2011; Burns et al., 2013).
In the United States, appendicitis will affect “10 in 100,000 people…with a lifetime risk for
individuals projected at 7 to 10 percent” (Dunphy et al., 2011, p. 555).
Due to the risk of perforation, diagnosing AA in a timely manner is essential. Most
authorities agree there are classic signs and symptoms indicating a strong clinical suspicion
of acute appendicitis in adult patients. Unfortunately, most patients, including the pediatric
population, do not have classic presumptive signs of AA (Huckins et al. 2013; Morrow &
Newman 2007). Classic adult presentation consists of vague periumbilical pain which later
migrates to right lower quadrant (RLQ) as inflammation progresses, anorexia, nausea, and
positive Rovsing sign (Palpating the left lower quadrant (LLQ) area and eliciting pain in the
RLQ) (Kwan & Nager 2010).
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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With growing concern of long-term effects of radiation exposure from computed
tomography (Brenner & Phil 2007; Wong et al. 2008), there appears to be much debate on
whether or not acute appendicitis can be clinically diagnosed without the routine use of
medical imaging.
To find current diagnoses, treatment , and management guidelines a search of
existing empirical research was conducted using the State University of New York Institute
of Technology Cayan library electronic database and the UpToDate evidence based clinical
decision database. PubMed, CINAHL, Medline, and EBSCHO catalog were the primary
database engines searched. Search terms including appendicitis, appendix, and
appendectomy were entered into the filter. In addition the words management, diagnosis,
treatment, medical imaging, clinical presentation, adult, and pediatric were added to the
primary terms to augment the literature search. Journal articles from the scholarly
disciplines and popular literature were reviewed. The literature was generally limited to
2005-2013, but literature published prior to these dates was also received for historical
purposes. Once the studies were identified and located, the articles were sorted. After
sorting and a review of relevance, the manuscripts were summarized with regard to
research methods and placed into tables (see appendices A and B).
Credible Authorities
A search for current treatment and management guidelines was conducted using the
National Guideline Clearinghouse of the Agency for Healthcare Research and Quality
(AHRQ). Additionally, the websites of the American College of Family Physicians (AAFP),
American College of Pediatrics (AAP), American College of Surgeons, American Pediatric
Surgical Association, and the American College of Emergency Physicians (ACEP) were
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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viewed for current AA treatment guidelines. Aside from the AHRQ, most websites require a
subscription for complete access to this valuable information. The lack of obtainable
information from these credible sources leads to confusion in clinical decisions and can
potentially create biases.
Themes
No one in the healthcare industry will dispute the gold standard of care in treating
appendicitis is surgery (Tsioplis et al. 2013; Goldman et al. 2008; Morrow & Newman
2007). Once AA is suspected or confirmed, referral to surgery should occur to prevent
perforation. As discussed prior, reaching a definitive diagnosis of AA is not always black
and white.
Medical Imaging
Several themes began to emerge while reviewing the literature. When to use
medical imaging in aiding diagnosis of AA versus clinical judgment alone overwhelmed the
literature. In medical facilities that have limited availability to medical imaging modalities,
clinical judgment of appendicitis did not increase the perforation rate (Nelson et al. 2013)
or negative appendectomy rate (Wong et al. 2008). In those facilities without the
impediment of limited medical imaging availability, clinical judgment alone could lead to
diagnosis in many cases (Wong et al 2008; McKay & Shepard 2007). Patient whom
presented with clinical features consistent with AA along with laboratory results indicating
a high likelihood of appendicitis, were still routinely sent for medical imaging (Unlu et al
2009). Two diagnostic medical imaging modalities available for AA is ultrasound and
computed tomography (CT). It appears from the research, CT is the preferred method of
diagnostic imaging. Several articles suggest CT is routinely used for diagnosis, regardless
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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of clinical suspicion for AA (Wong et al. 2008; Unlu et al. 2009). Gender also played a role
in medical imaging, with females more likely to undergo both modalities in the process of
ruling out gynecological RLQ issues (Saito et al. 2013). Body weight seems to also be a
factor medical imaging choices, with ultrasound use occurring more often in non-obese
patients than overweight patients (Davis & Yanchar 2007). Finally, several authors found
ultrasound rates decreased simply because the results are operator dependent (Mittal et al.
2013; Saito et al. 2012; Morrow & Newman 2007).
Routinely using CT for diagnosis of AA on all patients seemingly exposes patients to
unnecessary radiation (Wong et al. 2008). Meltzer et al. (2103) reported that between
2001 and 2005 “the use of computed tomography for abdominal pain had increased by
122%” (p.126). In 2013, Nelson et al. reported:
Over the years, as computed tomographic technology has improved, a school of
thought has emerged that advocates for the routine and liberal use of CT in
diagnosing suspected acute appendicitis, arguing that CT decreases the incidence of
negative appendectomy, improves patient care, and ultimately reduces the use of
hospital resources (p. 453)
Of particular concern is the use of computed tomography in the pediatric population. Not
only are children more radiosensitive than adults, their risk of developing a radiation
induced cancer is greater given that they have a larger availability of living years (Brenner
et al. 2007; Adibe et al. 2010; Morrow & Newman 2007). Research suggests, “one
abdominal CT is equal in radiation to 500 chest radiographs… [and] it is estimated that
approximately 500 children younger than 15 years will ultimately dies from a cancer
attributable to the radiation from CT” (Adibe et al., 2011, p. 194).
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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In 2010, The American College of Emergency Physicians released guidelines on the
evaluation of suspected AA. Although they supported performing ultrasonography before
CT, the article states “ultrasonography …. can confirm the diagnosis of acute appendicitis in
children, but it cannot definitely rule out the condition” (Armstong, 2010, p. 1044).
Recently the American College of Surgeons (n.d) issued an informational brochure inciting
not to “do computed tomography (CT) for the evaluation of suspected appendicitis in
children until after ultrasound has been considered an option” (figure 5).
Laboratory Markers
As previously eluded to, specific laboratory markers distinguishing appendicitis
versus other causes of abdominal pain was another theme appearing frequently in the
literature. Leukocytosis, defined as a total white blood cell count two standard deviations
above the mean, (Basow, 2013) occurs in the vast majority of patients with AA. However,
leukocytosis occurs in many other inflammatory disease processes, not just AA. As a result,
many attempts have been made to research other biomarkers in combination with an
increased white blood cell counts (WBC) to aid in diagnosing or excluding AA.
Several studies have tried to correlate an increase in WBC’s and C-reactive protein
(CRP) to AA. In the pediatric population, Stefanutti et al. (2007) found the sensitivity of
combining the tests results to be greater than 0.93 further suggesting results within normal
limits have a low likelihood of AA. Two other studies, one involving pediatric and adult
populations (Yang et al. 2006) and the other involving geriatric patients (Yang et al. 2005)
found the same results. However, in another pediatric study the researchers concluded
“white blood cell counts greater than >12 cells x 1000mm³ and CRP greater than 3mg/dL
increase the likelihood of appendicitis and helps to distinguish appendicitis for other
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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diagnoses that mimic appendicitis in pediatric subjects “ (Kwan & Nager, 2010, p. 1014).
The study does not, however, discuss which differential diagnoses can be excluded based
on the laboratory results. Additional laboratory markers, including calprotectin (CPT),
serum amyloid A (SAA), and d-lactate, were found to be inconclusive (Kwan & Nager, 2010;
Schellekens et al. 2013). Both studies did mention the fact that CPT, SAA, and d-lactate do
not have a standard measurement as the current assays are for laboratory research only.
Clinical Scoring System
Another topic emanating in the research involves using a clinical scoring system to
aid in diagnosing AA. The Alvarado score (table C1), Pediatric Appendicitis Score (table
C1), and the modified Alvarado scoring system (table C2) are three scoring systems
designed to evaluate a patient’s symptoms, laboratory results, and physical exam to
facilitate diagnosing AA. However, their usefulness in guiding clinical decisions is greatly
contended (McKay & Shepard 2006; Davies & Yancher 2007; Schneider et al. 2007). Many
authors believe a score greater than seven indicates a high probability of having
appendicitis and does not warrant medical imaging while a score less than three has a very
low likelihood of AA. Only those patients presenting with a score between three and six
(labeled as equivocal) need further medical imaging (Goldman et al. 2008).
Some authors report these scoring systems have either low sensitivity and
specificity or insufficient positive predictive value (PPV) thereby declaring these systems
unfavorable for sole diagnostic purposes (Morrow & Newman 2007; Meltzer et al. 2013;
Schneider et al. 2007; Nelson et al. 2013). Yet others will disagree (Adibe et al. 2011;
Goldman et al. 2008).
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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Gaps in the Literature
Throughout the literature the implication of accurately diagnosing AA using sound
clinical judgment is dependent on US technician competence and clinical expertise of the
physician. This is independent of geographical location or facility type (academia, rural, or
metropolitan) (Saito et al. 2013). If some authors report sonography has a high sensitivity
and specificity in diagnosing AA while others do not, one could assume this threat to
reliability would be critically appraised in the literature. Furthermore, most studies were
conducted retrospectively rather than prospectively. More prospective studies need to be
conducted to eliminate biases and other errors in physiological measurements. Lastly, in
two of the studies (Meltzer et al. 2013; Schneider et al. 2007) participants were captured
without regard to attending physician evaluation of the patient (clinical experience) nor
was timing of onset of symptoms documented as migratory pain and nausea/vomiting are
later sign of AA. These studies also captured some patients’ whom were missing
leukocytosis data.
Conclusion
No matter how hard we try, nothing in life is ever going to occur with 100%
accuracy. Human error does not have to equate to incompetence or negligence. Having the
confidence to make sound clinical decisions can take years to develop. That being said,
having the availability of reliable tools to aid in accurately diagnosing a patient with AA (or
any other acute medical problem for that matter) can help in the clinical decision process.
Misdiagnosing a patient is not the end of the world, so long as the provider accepts
accountability for the error and continues to do what is best for the patient.
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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ACUTE APPENDICITIS: A LITERATURE REVIEW AND
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Appendix A
STUDIES
FOCUS
POPULATION
AGE
METHOD
FINDINGS
McKay &
Shepard (2006)
Using the
Alvarado
scoring system
to perform CT
150 patients
who presented
with abdominal
pain
Patients older
than 7
Retrospective
study over 5
months
If the patient
scores 4-6, CT is
indicated to
confirm dx.
Wong, Cheung,
& Tam (2008)
Comparing
clinical dx to
using CT in
pediatrics
254 pediatric
patients
admitted with
acute
appendicitis
Only reported
mean age of
11.4
Retrospective
study over 120
months
In all patients a
clinical dx of
appendicitis
prior to CT
suggesting an
overuse of
medical imaging
Davis & Yanchar
(2007)
Does obesity in
children affect
presentation, dx,
surgery, and
post-op
treatment of
appendicitis?
Total of 56
patients
classified as
moderately or
very obese and
treated for
appendicitis
1 to 15
Retrospective
study over 71
months
Obesity only
affected length
of surgery,
length of
hospital stay
and increased
risk of post-op
infections
Tsioplis et al.
(2013)
To determine
predictive
factors for dx
and post-op
complications of
appendicitis
1,439 patients
who had an
appendectomy
due to primary
indication of
appendicitis
Reported 560
cases were
children (<18),
879 cases were
adults (>18)
Retrospective
study over 108
months
Gender, WBC,
CRP, and
Ultrasound are
important
indicators of
mild and severe
acute
appendicitis in
adults and
children
Kwan & Nager
(2010)
To determine if
CRP, PCT, and
WBC can
distinguish
appendicitis
from other dx in
pediatrics
209 patients
presenting to the
ED with
abdominal pain
suspicious for
appendicitis
1-18
Retrospective
study over 6
months
CPR with
elevated WBC is
useful in
determining
appendicitis
from other
diagnoses
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
15
Appendix B
STUDIES
FOCUS
POPULATION
AGE
METHOD
FINDINGS
Stefanutti,
Ghirardo, &
Gamba
(2007)
Determining
usefulness of
inflammatory to
diagnose AA in
children
100 children
diagnosed with AA
pathologically
0-14
Prospective study
over 21 months
Leukocytosis or
CRP value alone
is not predicative;
however together
the sensitivity is
high
Nelson, et al.
(2013)
Relevance of
clinical
assessment and
reliance of CT in
diagnosis AA
664 patients in a
military tertiary
care center
scheduled for
surgery for AA
>18
Retrospective study
over 72 months
CT has become
the common
modality in dx
AA, despite
clinical
assessment
Yang et al.
(2005)
Role of leukocyte
count, neutrophil
percentage, and
CRP to diagnosis
AA in the elderly
85 patients
operated on with a
preoperative dx of
AA
>60
Retrospective study
over 29 months
Patients with
normal results of
all three tests are
highly unlikely to
have AA
Meltzer et al.
(2013)
Using a low
modified
Alvarado score
(<4) to clinically
exclude dx of AA
261 patients
18-89
Prospective
observational study
over 12 months
12% of patients
with a Modified
Alvarado Score
<4 had AA,
confirmed by
pathology or CT
Yang et al.
(2006)
Role of leukocyte
count, neutrophil
percentage, and
CRP to diagnosis
AA
946 patients
2-100
Retrospective study
over 29 months
The lab tests can’t
be used alone for
dx purposes, but
can be used to aid
clinical judgment
ACUTE APPENDICITIS: A LITERATURE REVIEW AND
16
Appendix C
Table 1
The Alvarado and Pediatric Scoring System
The Alvarado Score
Pediatric Appendicitis Score
Note. Adapted from “Evaluating Appendicitis Scoring System Using a Prospective Pediatric Cohort”, by C. Schneider, A. Kharbanda, & R.
Bachur, 2007, Annals of Emergency Medicine, 49, p. 780. Copyright by The American College of Emergency Physicians.
Table 2
The Modified Alvarado Score
Note. Adapted from “Poor sensitivity of a modified Alvarado score in adults with suspected appendicitis” by A.C. Meltzer et al., 2013,
Annals of Emergency Medicine, volume 62, p. 129. Copyright 2013 by The American College of Emergency Physicians.