Evidence Based Approach to AppendicitisEBM summary

Epidemiology• Males>Females @ 1.4:1 (lifetime risk 8.6%, 6.7% respectively)• Females have higher negative appendectomy rate

• Most common between the ages of 5-50 • Peak incidence 10-14yo (males) and 15-19yo (females)

• Risk factors: smoking, low fiber diet, Caucasian ethnicity, summer months

Anatomy• Retrocecal>pelvic>subcecal>preilial>postilieal

• 11% of retrocecal appendices extend into the retroperitoneum• Might present as R flank pain

• Obstruction causes inflammation in 50% of cases and can occur anywhere along the length of the appendix• Tip appendicitis is inflammation of the

distal-most aspect, common cause of false-negative CT scans

McBurney’s Point

Pathophysiology

5 Stages of Appendicitis1. Appendiceal obstruction, luminal distension

2. T8-T10 visceral afferent nerve irritation (periumbilical pain)• Lasts 4-6h classically

3. Intraluminal pressure>local venous pressure resulting in tissue ischemia and vascular congestion

4. Ischemia induces inflammation and local bacterial invasion

5. Inflammation extends extraluminally leading to parietal peritoneal inflammation and focal pain

Variations on Classic Presentation

• Perforation rate is 80% if diagnosis is delayed >48h from the onset of pain

• Recurrent Appendicitis• Patient with ≥1 episode of similar pain in the past

• Subacute/Chronic Appendicitis• Abdominal pain lasting days-weeks that is relieved post-

appendectomy

• Delayed presentations often have CT e/o inflammation

• History of prior abdominal pain has poor NPV for acute appy

Why do I need my appendix, doctor?

• You can tell your patient one of the following…

1. We really don’t know

2. It served its purpose when you were young helping develop your immune system, but it’s purpose greatly decreased after about the age of 5 years old

3. It acts as a reservoir for commensal bacteria, offering re-inoculation of the colon should all your normal flora be wiped out

Differential Diagnosis

1. Enteritis (Yersinia, Campylobacter, Salmonella)2. Omental infarction (NEC in kids)3. Epiploic appendigits (mesenteric adenitis in kids)4. UTI/pyelo5. Nephrolithiasis6. Hernia7. Bowel obstruction8. Cecal diverticulits (Meckel’s)9. Cecal volvulus (intuss in kids)10. Testicular/ovarian torsion11. PID/TOA12. Ruptured ovarian follicle/ectopic pregnancy

Physical Examination• RLQ TTP (specifically McBurney’s) and rigidity

are most predictive of acute appy• Rebound, guarding, fever, and psoas sign have additive value

• Pain on rectal exam, Rovsing’s sign, increased RLQ skin temperature have no diagnostic value

• Psoas (13-42% sens, 79-95% spec) if performed correctly!

• Obturator (8% sens, 94% spec)

History• “Classic” presentation is rare (~6%)• Anorexia is not a helpful marker• 2010 ACEP Clinical Policy on suggestive findings for acute appy• RLQ pain, pain migration, pain progression

ALVARADO/MANTREL SCORE• Migratory abdominal pain to RLQ (1)• Anorexia/ketonuria (1)• Nausea/vomiting (1) • TTP to RLQ (2)• Rebound tenderness (1)• Elevated temp >37.5C (1)• Leukocytosis >10 (2)

0-3: Low probability4-6: Moderate probability>7: High probability • 95% sens, 83% diag accuracy (M>F)

PEADIATRIC ASSESSMENT SCORE

• Anorexia (1)• Nausea/vomiting (1)• Migratory pain (1)• Fever > 38C (1)• RLQ pain w/ cough/hopping (2)• RLQ TTP (2)• WBC >10k (1)• Bandemia >7500 (1)

0-2: Low risk (2% false positive3-6: Inderterminant>7: High risk (96% specificity)

Appendicitis Inflammatory Response Score• Shows decent diagnostic value better than Alvarado• 73% true negatives and 67% true positives identified• Only 37% left indeterminant

• Alvarado -> 61%, 40%, 48%, respectively

Vomiting (1)RLQ Pain (1)RT or Guarding (light (1), medium (2), strong (3))Temp > 38.5C (1)PMN count (70-84% (1), ≥85% (2)) WBC count (10-14.9 (1), ≥15 (2))CRP (1-4.9 (1), ≥5 (2))• 0-4: Low Prob (o/p f/u supported)• 5-8: Indeterminate (serial exams or further testing required)• ≥9: High Prob (surgical exploration proposed)

Unique Workup Options• Stool guiac • Heme-positive diarrhea suggestive of enteroinvasive bacteria

• UA • >30RBC/hpf or >20WBC/hpf suggests UTI>appy

• Cervical motion tenderness• Can be seen with any peritoneal inflammation, non-specific• Significant if associated with pelvic discharge

• WBC + CRP (a fool makes a judgment based on WBC alone!)• WBC alone has low diagnostic value• WBC>10 and CRP>8 has notable predictive power• WBC>15 and PMN>85% is slightly useful

Treatment• IV opioids• DOES NOT mask physical exam findings

• Antibiotics vs placebo – no difference in post-op findings histologically• Augmentin, cefotetan, clindamycin should NOT be considered

(high resistance patterns in E.coli and B.fragilis)• MRSA coverage not necessary• FQs showing rapidly emerging E.coli resistance patterns

Patient Group Single-agent Multi-agent

Peds -penems, zosyn Flagyl+3rd gen Cef

Adults Cefoxitin, ertapenem, timentin

Flagyl+3rd gen Cef or Ancef

Hi-risk Adults Primaxin, -penems Flagyl+Cefepime