Appendicitis: Sensitivity and Specificity

Introduction: RLQ pain

nausea

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Tags: Gastrointestinal Problem Infection Physical Exam Tag this Diagnosis.

Differential Diagnoses include: Urinary Tract Infection

Prevalence

Population / Calculator	Prevalence	Comments / Study / Link
Adults >60 years old, abdominal pain in the ED	4%	http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
Adults, abdominal pain in ambulatory setting	1%	http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
Adults <60 years old, abdominal pain in ED	25%	http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
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The sensitivity and specificity of findings for Appendicitis are listed below. See the left navigation bar to change the display.

Sensitive and Specific Findings

Abdominal CT

94%

95%

Usually radiologists like the CTs to be done with rectal contrast. However, there may not be a sensitivity difference between with and without contrast; see PMID: 17456874, PMID: 16105539, though other studies disagree PMID: 17566826.

Study: Ann Intern Med 2004 Oct 5;141(7):537-46. PMID 15466771

Specific Findings

Psoas sign

16%

95%

With the patient in the supine position, ask the patient to lift the right thigh against your hand placed just above the knee. With the patient in left lateral decubitus position, extend the right leg at the hip.

Study: JAMA. 1996;276(19):1589-1594

http://jama.ama-assn.org/cgi/content/abstract/276/19/1589

Appendicolith

65%

86%

By CT. In children

Study: AJR Am J Roentgenol. 2000 Oct;175(4):981-4. PMID: 11000148

Sensitive Findings

Pain preceeding vomiting

100%

64%

Based on only one study

Study: JAMA. 1996;276(19):1589-1594

http://jama.ama-assn.org/cgi/content/abstract/276/19/1589

Abdominal US

86%

81%

Study: Ann Intern Med 2004 Oct 5;141(7):537-46. PMID 15466771

Negative Findings

Emesis

51%

45%

Study: JAMA. 1996;276(19):1589-1594

http://jama.ama-assn.org/cgi/content/abstract/276/19/1589

Poorly Diagnostic Findings

Finding	Sensitivity	Specificity	Comments, Study
Abdominal Rigidity	27%	83%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
Migration of Pain	64%	82%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
hearing loss Duplicate	67%	79%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
Rectal tenderness	41%	77%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
Rebound	63%	69%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
hearing loss Duplicate	47%	64%	>99F Study: Acad Emerg Med. 2004 Oct;11(10):1021-7. PMID: 15466143
Guarding	74%	57%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
RLQ Pain Duplicate	81%	53%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
Leukocytosis	76%	52%	>10k Study: Acad Emerg Med. 2004 Oct;11(10):1021-7. PMID: 15466143
No similar pain previously	81%	41%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589
Anorexia	68%	36%	Study: JAMA. 1996;276(19):1589-1594 http://jama.ama-assn.org/cgi/content/abstract/276/19/1589

Findings With Unspecified Accuracy

Finding	Sensitivity	Specificity	Comments, Study
Obturator sign	No accuracy specified.		Passively flex the right leg at the hip and knee and internally rotate the leg at the hip. Study: No studies but thought to be equivalent to psoas sign in accuracy.
Rovsing's Sign	No accuracy specified.		palpation of the lower left quadrant of a person's abdomen results in more pain in the right lower quadrant Study: no study specified.
RLQ Pain Duplicate	No accuracy specified.		Differential Diagnosis: Urinary Tract Infection Study: no study specified.