084. Acute Appendicitis


8-12% lifetime risk, 2/3 before age 30. Caused by obstruction of appendix lumen usually by fecalith (MCC, found in 11-52% on pathology)

Clinical Features

Classic: Anorexia with nonspecific abdominal symptoms. Periumbilical pain develops later with nausea w/wo emesis. Pain migrates to RLQ. 1/3 will have atypical symptoms.

McBurney’s point: 1/3 distance on a line traced superomedially from anterior superior iliac spine to umbilicus. Rovsing sign: palpation of LLQ worsens RLQ pain. Psoas sign: extension of R leg at the hip while pt lying on left side. Obturator sign: pain with internal and external rotation of the thigh at the hip. Adler’s sign: to differentiate appendicitis from tuboovarian pathology in RLQ: find point of maximal tenderness in supine position, then have pt roll onto left side and if pain shifts toward center, its tubo-ovarian.

LR: RLQ pain 7.3-8.4, rigidity 3.76, migration 3.18, pain before vomiting 2.76, psoas sign 2.38, fever 1.94. (Wagner, 1996)


WBC: basically useless. LR for WBC: < 7: 0.1, > 17: 3.5. Everything in-between has little diagnostic effect (Hayden, 1999). WBC < 9, neutrophils < 75%, CRP < 0.6, NPV close to 100% (Dueholm, 1989).

Hyperbilirubemia on labs has higher chance of perforation when in the setting of appendicitis (Estrada, 2007).

UA can have blood or pyuria in it due to close proximity, though > 30 RBCs or > 20 WBCs more likely true urinary (Paulson, 2003)

Ultrasound (83-96% in experts hand): preferred initially in children and pregnant women. Looking for thickened, non compressible appendix > 6mm in diameter.

CT: IV may not be needed. One study with unenhanced CT was 95% sens and 100% spec. A systemic review showed 93% sensitivity. If CT equivocal, 30% still have true appendicitis (Daly, 2005). ACR Appropriateness recommendations leave it up to institutional preference, though give CT without contrast a 7 rating.

Using Samuel’s Pediatric Score (PAS), one study placed children into low, moderate, or high risk. If low, they were discharge with f/u (no appys found). In high risk, all had appy in OR. Moderate risk were either admitted with most have ultrasound. 33 of 119 had positive US, positive OR. 5 with negative US were found later to have appy. Only 13 of the 196 kids had CT scans. (Saucier, 2014). PAS points: Anorexia, Nausea or Vomiting, Migration of pain, Fever > 100.5, Pain with cough, percussion, or hopping (2 points), RLQ tenderness (2 points), WBC > 10, Neutrophils > 75%.

Alvarado Score: 10 point scale; modified to take out left shift now. One ED study looking at score < 4 can rule out? 29% still had appendicitis. 50% spec, 70% sens (Meltzer, 2013). Alvarado points: Migratory right iliac fossa pain, Anorexia, Nausea/Vomiting, Fever > 99.5, Tenderness in right iliac fossa (2 points), rebound tenderness in right iliac fossa, leukocytosis (2 points).


Same rate of appendicitis as general population.

Do ultrasound first; if equivocal, get surgeon involved for MRI vs CT vs diagnostic lap. Fetal loss at lap appy 6%, WORSE than open appy; though fetal loss greatest in complex/perforated appy. Fetal loss same for simple appendicitis as the ‘negative’ appy group. (Walsh, 2007). Tetrogenic exposure threshold: 5 rads (<1% risk). CT appy protocol in first trimester 2.4 rads vs 3 rads in second/third. Still 99% chance nothing will happen with the fetus.

Can consider MRI without gadolinium (crosses placenta) in first trimester pregnancy.


Call surgeon, make NPO, start antibiotics.

IV antibiotics: Uncomplicated: Unasyn 3g or Cefoxitin 2g or Ertapenem 1g or Moxifloxacin 500mg + Cefuroxime 1.5g/Cefazolin 1g/Cipro 400mg/Levofloxacin 750mg. Complicated: Imipenem 500mg or Meropenem 1g or Doripenem 500mg or Moxifloxacin or Zosyn or Metro 500mg + Aztreonam 2g/Cefepime 2g/Cipro 400mg/Levofloxacin 750mg.

Non-surgical tx: 5 non-US trials: about 70% did not need surgery up to 1 year. 46% reduction in complications. Limitations: small size, no CT done, varied criteria for ‘rescue’ surgery. (Ericksson, 1995) (Styrud, 2006) (Hansson, 2009) (Malik, 2009) (Vons, 2011).

Vons, 2011: 239 pts diagnosed by CT. Augmentin vs surgery. Rate of peritonitis at 30d: Surgery 2% vs Augmentin 8%. In abx group, 12% had surgery within 30d & another 22% within a year.

Clinical Cases


Essentials of EM, 2013, Greg Moran – Appendicitis and Diverticulitis – Is it all the same thing in 2013!

Tintinalli, Seventh Edition, Chapter 84: Acute Appendicitis

Crashing Patient, Scott Weingart, Appendicitis, Reviewed on 4/15/14

EM Literature of Note, Ryan Radecki, Appendicitis Week Continues

EMRAP, December 2013, Paper Chase 5 – The Alvarado Score Sucks

ERCAST, Rob Orman, Nov 2011, RLQ pain in pregnancy

EMRAP, November 2011, RLQ pain in the Pregnant Patient

EB Medicine, Pediatric Emergency Medicine Practice, March 2012, An Evidence-Based Review of Acute Appendicitis in Childhood

084. Acute Appendicitis

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