In this episode on Appendicitis Controversies, we have the continuation of our discussion on abdominal pain emergencies with Dr. Brian Steinhart & Dr. David Dushenski. We kick off the discussion with key clinical pearls and pitfalls in the history and physical exam with their respective liklihood ratios when assessing patients with abdominal pain for appendicitis – a diagnosis that is still sometimes missed despite its prevalence. Dr. Dushenski hacks apart the Alvarado and Appendicitis Inflammatory Response Scores and we discuss the value of WBC, CRP and urinalysis in the work-up of appendicitis. Next up are the controversies of imaging algorithms using ultrasound and CT abdomen, as well as the factors affecting which imaging algorithm you might pursue. We wrap up the discussion on Appendicitis Controversies with a critical look at the value of antibiotics in the ED for appendicitis and which patients might be appropriate for non-surgical management.
Written Summary and blog post by Claire Heslop, edited by Anton Helman April, 2014
Cite this podcast as: Steinhart, B, Dushenski, D, Helman, A. Appendicitis Controversies. Emergency Medicine Cases. April, 2014. https://emergencymedicinecases.com/episode-43-appendicitis-controversies/. Accessed [date].
History and Physical Examination Pearls for Appendicitis
The signs most likely to be associated with appendicitis in one meta-analysis were:
rigidity (+LR = 4)
positive psoas sign (+LR = 2.38)
fever (+LR = 1.94)
The positive LR of rebound tenderness varied too much to make definitive recommendations (+LR = 1.1-6.3)
Guarding and rectal tenderness were not found to be significant signs
The most predictive signs of appendicitis in another meta-analysis (Br J Surg, 2004) were those involving peritoneal irritation:
rebound tenderness (+LR = 1.99)
percussion tenderness (+LR = 2.86)
guarding (+LR = 2.48)
rigidity (+LR = 2.96)
Recurrent pain decreases the likelihood of appendicitis but does not rule it out (chronic recurrent appendicitis is a well known entity)
DRE has limited role in diagnosis of acute, undifferentiated abdominal pain
Important to consider pelvic exam in females with undifferentiated abdominal pain. Remember, cervical motion tenderness does not rule out appendicitis!
Atypical presentations: obese, immunocompromised, extremes of age, diabetics
Pain while traveling over speed bumps increased the likelihood of appendicitis in one study (BMJ 2012)
Does Delay in Diagnosis Increase the Rate of Appendix Perforation?
Delay in seeking care is a risk factor for perforation (time from symptom onset to ED)
Score 0-4 is low probability of appendicitis, 9-12 high probability
Expert interpretation of literature on AIP Score: No better than Alvarado score
Lab Values in Appendicitis Controversies
Despite the EM community’s general attitude that WBC is generally non-contributory for appendicitis, studies show WBC > 10 has a Positive Likelihood Ratio (+LR) = 2.4; Negative LR = 0.25 which is as good or better than any single clinical history/physical factor
Sensitivity of WBC increases with duration of illness, so that WBC may be more useful in late presenters
Combining WBC and CRP increases predictive power to both rule in and rule out appendicitis with very good sensitivity and specificity
Urinalysis – in appendicitis, inflamed appendix can abut the ureter and cause ureter inflammation, resulting in a significant WBC in the urine (don’t assume UTI!)
Imaging for Appendicitis
Factors Affecting Imaging in Appendicitis
1. Duration of Pain:
Ultrasound sensitivity increases with duration of pain (as does clinical exam & lab tests!)
CT sensitivity unchanged with duration of pain
2. Body Habitus:
Ultrasound accuracy is increased in slim patients
CT accuracy is increased in obese patients
3. Number of ultrasounds done at your institution for appendicitis – US sensitivity was 78% in centres that use it in 90% of cases, 52% in centres that use it in 50% of cases, 35% in centres that use it in 10% of cases
The Effect of Abdominal Pain Duration on the Accuracy of Diagnostic Imaging for Pediatric Appendicitis. Annals of Emergency Medicine. July 30th, 2012. (Free full pdf)
Abdominal pain duration impacts the accuracy of ultrasound for diagnosing pediatric appendicitis. Evid Based Med 2013 (Free full pdf)
Ultrasound for Appendicitis
First line in: young, non-obese patients with symptoms > 12h
Dependent on operator skill. More impact of patient’s body habitus. Bowel gas can hinder image acquisition
Diameter > 6mm
Other suggestive findings (secondary ultrasound signs can be helpful in your post-test probability):
Free fluid in males
Appendix ‘not visualized’
The NPV for ultrasound that reports ‘appendix not visualized’ is 85-95% (you don’t necessarily need to go onto to CT abdomen to rule out appendicitis (see alternate option below)
Consider your pre-test probability and secondary ultrasound findings (see above)
One option after equivocal ultrasound for appendicitis: observe patient for 8hrs, then re-examine +/- re-ultrasound (remember that ultrasound sensitivity increases with time).
US should/could be first line for most patients (esp young, slim, lat in presentation)
There is a low risk of appendicitis after equivocal US
Low risk slim pt + equivocal US = No CT
Low risk slim pt + equivocal US ?observe +/- repeat US as time from onset of pain improves sensitivity
For a dive into the role of POCUS for appendicitis in the ED visit Greg Hall’s post (EM Cases guest expert on Ep18 Utrasound Pearls, Pitfalls & Controversies) at theEDE blog.
CT Abdomen for Appendicitis
Contrast may increase sensitivity for appendicitis and may be more likely to rule in or out alternate diagnoses
IV contrast accentuates periappendiceal and luminal inflammation
Oral contrast demarcates appendix from surrounding structures, opacifies ileocecal portion of bowel in 45-60min
Rectal contrast: also helps demarcate appendix, can administer just prior to CT, thereby reducing time to wait for CT
CT non-contrast – sensitivity 93%, specificity 98%
CT with PO/IV contrast – sens 93%, spec 93%
CT with rectal contrast – sens 97%, spec 97%
Studies have failed to demonstrate reduction in negative appendectomy rate in men despite increased CT use
Treatment of Appendicitis Controversies: Antibiotic & Surgical Management
Which patients with Appendicitis Require Antibiotics in the ED?
No good evidence for routine administration of antibiotics in ED for appendicitis effecting clinical outcomes
Patients should receive prophylactic antibiotics within 60min window prior to surgical incision
Consider antibiotics if there is delay to OR
Medical vs Surgical Management
Oral antibiotics vs. immediate OR for acute, uncomplicated appendicitis – Amox-Clav found to be non-inferior to emergency appendectomy
However, associated with increased risk for recurrent disease
Candidates for medical management (decision best made in conjunction with surgical colleagues): Early, non-perforated, < 24h from onset of symptoms, no appendicolith or masses causing persistent obstruction of the appendix
Update 2014: The NOTA study (Non Operative Treatment for Acute Appendicitis) shows that antibiotics without surgery may be a viable option for simple appendicitis, although it showed a 12% treatment failure rate. See Ryan Radecki’s analysis on EM Literature of Note and the abstract.
Update 2015: Head over to the Skeptics Guide to EM for an analysis of two trials looking at the non-operative treatment of acute appendicitis.
Update 2021: A multi-center randomized clinical trial demonstrated that oral antibiotics alone are non-inferior to IV followed by oral antibiotics in the treatment of uncomplicated acute appendicitis. Abstract
Answer: Candidates for medical management (decision best made in conjunction with surgical colleagues): Early, non-perforated, < 24h from onset of symptoms, no appendicolith or masses causing persistent obstruction of the appendix.
Dr. Helman, Dr. Steinhart and Dr. Dushenski have no conflicts of interest to declare.
Mason RJ, Moazzez A, Sohn H, Katkhouda N. Meta-analysis of randomized trials comparing antibiotic therapy with appendectomy for acute uncomplicated (no abscess or phlegmon) appendicitis. Surg Infect (Larchmt). 2012;13:74-84.
Dr. Anton Helman is an Emergency Physician at North York General in Toronto. He is an Assistant Professor at the University of Toronto, Division of Emergency Medicine and the Education Innovation Lead at the Schwartz-Reisman Emergency Medicine Instititute. He is the founder, editor-in-chief and host of Emergency Medicine Cases.