1. An Evidence Based ApproachAn Evidence Based Approach
in the Diagnosis ofin the Diagnosis of
Acute AppendicitisAcute Appendicitis
Dr. Rashidi Ahmad
MD USM, Mmed USM, FADUSM,
AM (Mal), Clinical Fellow (Cardiology)

2. The failure to diagnoseThe failure to diagnose
appendicitis is routinely listedappendicitis is routinely listed
among the top five reasons for aamong the top five reasons for a
malpractice suite.malpractice suite.
Reigelman R, Minimizing medical mistakes : The Art of Medical Decision Making
Fact of lifeFact of life

3. Diagnostic challengesDiagnostic challenges
Poor specificity and sensitivity of the historical
data, the physical findings, and the laboratory tests
currently available.
Wagner JM, et al. JAMA 1996;276:1589-94
The American Journal of Emergency Medicine
Volume 23, Issue 4 , July 2005, Pages 483-487

4. Diagnostic challengesDiagnostic challenges
• Causes of appendicitis – varies in
presentation
• Position of the appendix
• In pediatric and pregnancy
• Mimics
Goal to diagnose before peritonitis sets inGoal to diagnose before peritonitis sets in

5. Acute appendicitisAcute appendicitis
• Disease of civilization
• The commonest acute surgical condition.
• Approximately 7 – 12% of the population will have
appendicitis in their lifetime (1 in 6).
• Peak incidence: between the ages of 10 - 30 years.
• Misdiagnosis: 15 – 20% .
• Rate of “negative” appendicectomy: 20 – 40%.
• Removing normal appendix is a an economic burden to
patients and health resources
Am JAm J EpidemiolEpidemiol 1990;132:9101990;132:910--25.25.
Ann R Coll Surg 1994;76:418-9
J Pediatr Surg 2000;35:1320-2

6. •• The incidence of perforated appendicitis in relation toThe incidence of perforated appendicitis in relation to
time of abdominal pain till surgerytime of abdominal pain till surgery
-- 24 hours:24 hours: 20%20% perforationperforation
-- 36 hours:36 hours: 50%50% gangrenous/perforatedgangrenous/perforated
-- 48 hours:48 hours: 80%80% perforated with peritonitisperforated with peritonitis
•• < 4 years of age: perforation rate< 4 years of age: perforation rate -- 95%95%
•• 44 –– 19%19% in non pregnant,in non pregnant, 57%57% in pregnant womanin pregnant woman
BrenderBrender, Journal of Pediatrics, August 1985, Journal of Pediatrics, August 1985
AcadAcad EmergEmerg Med.Med. 2000 Nov;7(11):12442000 Nov;7(11):1244--5555
Tracey & Fletcher,2000
Perforated acute appendicitisPerforated acute appendicitis

7. Final diagnosis for 303 subjects with suspected appendicitisFinal diagnosis for 303 subjects with suspected appendicitis
Operated patients (n: 161) No.
Diagnosis
Positive appendectomy 130 (80.8%)
SIMPLE 30
SUPPURATIVE 23
ABSCESSED 2
GANGRENOUS 14
PERFORATED
Negative appendectomy 31 (19.2%)
NSAP 16
ACUTE MESENTERIC ADENITIS 4
ACUTE GYNECOLOGICAL DISEASE 4
DIVERTICULITIS 2
OMENTAL TORSION 2
PGU 2
UTI 1
Tzanakis et al.World J. Surg. Vol. 29, No. 9, September 2005Tzanakis et al.World J. Surg. Vol. 29, No. 9, September 2005
mimicsmimics

9. Common symptomsCommon symptoms
Common symptomsCommon symptoms Frequency (%)Frequency (%)
Abdominal pain 100
Anorexia 100
Nausea 90
Vomiting 75
Pain migration 50
Classic symptom sequence 50
Graffeo CS, Counselman FL. Appendicitis. Emerg Med Clin North Am 1996;14:653-71

10. Procedure Sensitivity Specificity
RLQ 0.81 0.53
Rigidity 0.27 0.83
Migration 0.64 0.82
Pain before vomiting 1.00 0.64
Psoas sign 0.16 0.95
Fever 0.67 0.79
Wagner J,Does this patient have appendicitis? JAMA 1996;276(19):Wagner J,Does this patient have appendicitis? JAMA 1996;276(19):589589--594594

11. Procedure Sensitivity Specificity
Rebound 0.63 0.69
Guarding 0.74 0.57
No similar pain 0.81 0.41
Rectal tenderness 0.41 0.77
Anorexia 0.68 0.36
Nausea 0.58 0.37
Vomiting 0.51 0.45
Cough test 0.78 0.79
Wagner J,Does this patient have appendicitis? JAMA 1996;276(19):Wagner J,Does this patient have appendicitis? JAMA 1996;276(19):589589--594594

13. Appendicitis Perforated Normal
Duration 1.3 ± 0.7 3.1 ± 1.9 1.9 ± 2.2
Vomiting 60% 69% 31%
Diarrhea 0% 25% 10%
Fever 80% 88% 71%
RLQ T 88% 100% 82%
Diffuse P 12% 44% 0%
Temp 38.4 ± 0.9 38.4 ± 0.64 37.9 ± .8
Paajanen H,Paajanen H, ActaActa PaediatrPaediatr, 1996;85:459, 1996;85:459--6262

14. Madan samuel. J Pediatr Surg. Vol 37, No 6 (June) 2002:877-881..

15. • Alternative method for rebound
tenderness detection
LTC Bruce. Southern Medical Journal, Jan 2006, Jan 2006

16. Per Rectal ExaminationPer Rectal Examination
Your opinionYour opinion……

17. Paajanen H, Acta Paediatr 1995; 85:459-62 *P<.001
Test Appendicitis Perforated Normal
WBC 16 ± 4.6 16 ± 6.9 16 ± 5.1
CRP* 37 ± 36 92 ± 50 35 ± 44
Urinalysis
WBC >3 32% 19% 10%
RBC >3 0% 13% 10%
Bacteria 0% 6% 0%

18. Role of Leukocyte Count,Role of Leukocyte Count, NeutrophilNeutrophil Percentage, and CPercentage, and C--Reactive Protein in the acuteReactive Protein in the acute
appendicitis in elderly.appendicitis in elderly. HorngHorng--RenRen Yang, et alYang, et al The American Surgeon;The American Surgeon; Apr 2005; 71, 4;Apr 2005; 71, 4;
Health Module pg. 344Health Module pg. 344

19. The American Surgeon;The American Surgeon; Apr 2005; 71, 4; Health Module pg. 344Apr 2005; 71, 4; Health Module pg. 344

20. Tzanakis et al.: Diagnosis of Acute Appendicitis.Tzanakis et al.: Diagnosis of Acute Appendicitis.
World J.World J. SurgSurg. Vol. 29, No. 9, September 2005. Vol. 29, No. 9, September 2005

21. Serial CRP measurementSerial CRP measurement
The American Surgeon;The American Surgeon; Apr 2005; 71, 4; Health Module pg. 344Apr 2005; 71, 4; Health Module pg. 344

22. Serial CRP measurementSerial CRP measurement
The American Surgeon;The American Surgeon; Apr 2005; 71, 4; Health Module pg. 344Apr 2005; 71, 4; Health Module pg. 344

23. Urine 5-hydroxyindoleacetic acid and
5-hydroxytryptamine
• Ongoing inflammatory process of the appendix -
elevated blood serotonin level.
• Upon release, 5-hydroxytryptamine (5-HT) is rapidly
metabolized in the liver by the monoamine oxidase
(MAO) system to 5-hydroxyindoleacetic acid (5-
HIAA) and, thereafter, is secreted in the urine

24. • These results demonstrated that the increase of 5-
HIAA level in urine could be a warning sign of AA.
• Require further study.
No obvious differenceNo obvious difference
P value > 0.05P value > 0.05
H. Xu et al. / J. Chromatogr. (2006)

26. Scoring system used in HUSMScoring system used in HUSM
• Alvarado Scoring system
SNS: 89.7%SNS: 89.7%
SPC: 76.3%SPC: 76.3%
PPV: 74.3%PPV: 74.3%
NPV: 90.6%NPV: 90.6%
Tzanakis et al.: Diagnosis of Acute Appendicitis.Tzanakis et al.: Diagnosis of Acute Appendicitis.
World J.World J. SurgSurg. Vol. 29, No. 9, September 2005. Vol. 29, No. 9, September 2005

27. Application of Alvarado ScoreApplication of Alvarado Score
• Aggregate score 7-10: emergency appendicectomy.
• Aggregate score 5-6: kept under observation for 24
hours with frequent re-evaluation of the clinical data
and reapplication of the score.
• Aggregate score 1-4: discharged with symptomatic
treatment and proper instructions.

28. Proposed ScoreProposed Score
Tzanakis et al.: Diagnosis of Acute Appendicitis.Tzanakis et al.: Diagnosis of Acute Appendicitis.
World J. Surg. Vol. 29, No. 9, September 2005World J. Surg. Vol. 29, No. 9, September 2005

29. 6 points: appendiceal ultrasonogram is positive
4 points: RLQ tenderness
3 points: rebound tenderness
2 points: WBC count greater than 12,000

30. •1-year Observational study
•Small sample size
•PAR helped clinicians diagnosis AA in < 10% in
which mostly in those with perforations.
CURRENT SURGERY • Volume 60/Number 3 • May/June 2003

32. • Meta-analysis, 17 studies, 3,358 patient
• Overall sensitivity 84.7% (81.0 to 87.8%)
• Overall specificity 92.1% (88.0 to 95.2%)
• PPV 87.3%, NPV 89.9%
• Most useful in equivocal group
** limitation: negative USG and yet acute appendicitis,
Academic emergency medicine, 2(7):644-50, 1995

33. USGUSG
Non-compressible, > 6 mm in diameter, fluid, mass,
tender with focal compression

34. Appendiceal CTAppendiceal CT
• … is a focused, helical, appendiceal CT after a
Gastrografin-saline enema (with or without oral
contrast)
• If appendiceal CT is not available, standard
abdominal/pelvic CT with contrast remains highly
useful and may be more accurate than
ultrasonography.
Gupta H, Dupuy DE. Advances in imaging of the acute abdomen.
Surg Clin North Am 1997;77: 1245-63

35. IV contrast-enhanced helical CT without oral contrast
Sensitivity 85% 90 to 100%
Specificity 92% 95 to 97%
SNS: 90SNS: 90 –– 100%100%
SPS: 95SPS: 95 –– 97%97%
Rao PM, et al. Helical CT technique for the diagnosis of appendicitis:
prospective evaluation of a focused appendix CT examination.
Radiology 1997;202:139-44

36. CT ScanCT Scan
Distention of appendix, thickened > 5-7 mm walls, target sign

37. Inflamed appendix (A) with
appendicolith (a).
Enlarged and inflamed appendix (A)
extending from the cecum (C).

38. Sensitivity Specificity PPV NPV
USG 76 91 95 76
CT 96 89 96 95
Balthazan E, Radiology 1994;190:31-35

39. USGUSG vsvs CTCT
• USG
• Safe, inexpensive, can
rule out pelvic disease in
females, better for
children
• Operator dependent,
technically inadequate
studies due to gas and
painful
• CT
• More accurate than USG
• Better identifies phlegmon
and abscess
• Better identifies normal
appendix
• Operator dependent,
ionizing radiation, contrast

40. 60 CONSECUTIVE CASES
Sensitivity Specificity PPV NPV
USG 76 88 90 74
MRI 97 92 94 96
IncesuIncesu L, American Journal of Radiology. 168(3):669L, American Journal of Radiology. 168(3):669--74, 199774, 1997

41. • Very careful history and physical exam especially in
high risk patients.
• High sensitivity (history): pain before vomiting
• High specificity (PE): cough & hoping tenderness in
children
• Serial CRP as objective measurement is valuable –
high specificity and conclusive (+ ve LR > 10)

42. • Alvarado scoring system is easy, cheap and
reliable
• Proposed score is a new challenge for EP
• Appendiceal CT – high accuracy but costly
• High index of suspicious, close observation,
appropriate follow up are also as good as
surgeon’s hand.