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Evidence-based Clinical Practice Guidelines for

Acute Nontraumatic RLQ Abdominal Pain and Tenderness and

Acute Appendicitis

 

Clinical Issue/Question
 

What are reliable clinical parameters that we can use to make a confident primary clinical diagnosis of acute appendicitis in patients presenting with an acute nontraumatic right lower quadrant (RLQ) abdominal pain and tenderness?

 

In other words, with what clinical parameters can we say that we are quite certain that the diagnosis is acute appendicitis that we do not have to go through the paraclinical diagnostic process?

 

Format of Guidelines Development

 

 

 

Clinical Scenario and Issue

 

In a non-immunocompromised patient of any age, any gender, communicative, coherent, with stable vital signs with acute nontraumatic right lower quadrant abdominal pain and tenderness,

 

What are reliable clinical parameters that we can use to make a confident primary clinical diagnosis of acute appendicitis in patients presenting with an acute nontraumatic right lower quadrant (RLQ) abdominal pain and tenderness?

 

In other words, with what clinical parameters can we say that we are quite certain that the diagnosis is acute appendicitis that we do not have to go through the paraclinical diagnostic process?

 

 

Statement of Premises:

 

In all patients presenting with an acute onset of nontraumatic right lower quadrant (RLQ) abdominal pain, acute appendicitis is always one of the considerations.

 

The first cue for the diagnosis of acute appendicitis is RLQ abdominal pain.

 

Not all patients with RLQ abdominal pain has acute appendicitis. Other causes consist of urinary tract infection, gastroenteritis, pelvic inflammatory disease, twisted ovarian cyst, to mention a few specific disorders. Majority of RLQ abdominal pain has a nonspecific cause, conveniently labeled as "nonspecific RLQ abdominal pain."

 

There is a need for a structured evidence-based data collection and processing in order to improve the accuracy and efficiency of the clinical diagnosis of acute appendicitis.

 

 

Operational Definition of Terms in the Issue/Question:

 

·        Clinical parameters - data from history and physical examination or symptoms (from history) and signs (from physical examination)

 

·        Acute appendicitis - appendicitis with localized right lower quadrant irritation or peritonitis

 

·        Patients - all ages; both genders

 

·        Reliability - more than 1 likelihood ratio or 90% or more post-test probability

 

·        Primary diagnosis - most likely diagnosis

 

·        Right lower quadrant abdominal pain - acute onset of RLQ abdominal pain, within 7 days

 

 

Evidence Appraisal Plan:

 

End-points in answering the question:

 

·        Signs and symptoms that will lead to a primary diagnosis of 90% or more probability of acute appendicitis which may serve as the pretreatment diagnosis without going through paraclinical diagnostic procedures

 

·        Signs and symptoms that will lead to a primary diagnosis of less than 90% probability of acute appendicitis which may need paraclinical diagnostic procedures.

 

Note: The end-point is clinical diagnosis, that is derived from history taking and performance of physical examination. This excludes all paraclinical diagnostic procedures except repeated history and physical examination.

 

Statistical Formulas

 

LR(+) = sensitivity/ (1-specificity)

LR(-) = (1-sensitivity)/specificity

Prevalence = pretest probability

Pretest odds = prevalence/ (1-prevalence)

Posttest odds = pretest odds x LR

Posttest probability = posttest odds/(posttest odds+1)

 

 

 

Search Methodology:

 

 Tracking:

            Medline – for international journal publications

            Herdin – for local journal publications

            Internet using various search engines such as AltaVista, Infoseek, Lycos, etc.

 

Retrieval:

 

Retrieval of whole journal article was done through the various libraries of the Metro Manila medical schools, Department of Science and Technology (DOST), and acquaintances.

 

Appraisal (Inclusion Criteria):

 

·        Focus of paper on clinical diagnosis

·        With gold standard (intraoperative findings, histopathological results, follow-up)

·        More than 50 subjects

·        With reliability data (sensitivity and specificity rates; likelihood ratios; odd ratios)

 

 

Search and Tracking Outcome:

 

·        Total no. of papers and abstracts appraised: At least 60

 

·        Level of evidences: All were of Level III Evidence (case series)

 

Tracking and Retrieval Results:

 

Database

Search engine

Search span

Search words

No. of titles

Relevant abstracts/

papers

Medline

1966-1999 (July)

Ap + Dx by Hx and PE only

50

5

 

 

Ap +Clin Dx

520

35

 

1966-1999 (March)

Ap +Dx

192

10

 

 

RLQ Abdo. Pain +Evaluation

13

2

Herdin

 

Appendicitis

107

2

AltaVista, Infoseek, Lycos, etc

 

Appendicitis

tntc

5

Total :

59

 

 

 

 

 

Presentation of Primary Evidences:

 

Primary Evidence 1

 

There is only one meta-analysis paper on the clinical diagnosis of acute appendicitis, that of Wagner.

 

·        Wagner JM, Mckinney WP, Carpenter JL.

Does this patient have appendicitis?

JAMA 1996;276:19, 1589-1594.

 

·        Wager JM.

Summary of Clinical Examination Operating Characteristics for Appendicitis.

      http://www.amaassn.org/scipubs/journals/archive/jama/vol_278/no_10/71076t1.htm

 

·        It is a study of more than 4,000 patients with likelihood ratios for important clinical diagnostic cues tabulated.

 

·        It is a meta-analysis of 11 case series studies.

 

·        The search strategy of Wagner yielded about 300 articles since 1966. The titles and abstracts were reviewed and chosen if adequate detail of the outcomes and aspects of the clinical examination allowed construction of 2x2 tables and subsequent calculation of likelihood ratios.

 

Procedure

Sensitivity

Specificity

LR+

(95%CI)

LR-

(95% CI)

**RLQ pain

0.81

0.53

7.31-8.46

0-0.28

**Rigidity

0.27

0.83

3.76

(2.90-4.78)

0.82

(0.79-0.85)

**Migration

0.64

0.82

3.18

(2.41-4.21)

0.52

(0.42-0.59)

Pain before vomiting

1.00

0.64

2.76

(1.94-3.94)

NA

Psoas sign

0.16

0.95

2.38

(1.21-4.67)

0.90

(0.83-0.98)

Fever

0.67

0.79

1.94

(1.63-2.32)

0.58

(0.51-0.67)

Rebound tenderness test

0.63

0.69

1.10-6.30

0-0.86

Guarding

0.74

0.57

1.65-1.78

0-0.54

No similar pain previously

0.81

0.41

1.50

(1.36-1.66)

0.32

(0.25-0.42)

Rectal tenderness

0.41

0.77

0.83-5.34

0.36-1.15)

Anorexia

0.68

0.36

1.27

(1.16-1.38)

0.64

(0.54-0.75)

Nausea

0.58

0.37

0.69-1.20

0.70-0.84)

Vomiting

0.51

0.45

0.92

(0.82-1.04)

1.12

(0.95-1.33)

Wagner, 1996

 

·        RLQ pain                                                 (LR+=8.0)

·        Rigidity                                                     (LR+=4.0)

·        Migratory pain                                         (LR+=3.1).

 

These three findings can be recommended as cues for a clinical diagnosis of acute appendicitis.

 

 

Guarding and Rebound Tenderness

 

Procedure

Sensitivity

Specificity

LR+

(95%CI)

LR-

(95% CI)

 

Rebound tenderness test

0.63

0.69

1.10-6.30

0-0.86

Guarding

0.74

0.57

1.65-1.78

0-0.54

 

Rigidity

0.27

0.83

3.76

(2.90-4.78)

0.82

(0.79-0.85)

 

·        Guarding and rebound tenderness tests have a little more than one LR.

·        The LR+ of rebound tenderness varied too much to allow a statistical estimate of its effect (LR+= 1.1 to 6.30).

 

·        Difficult to make any conclusions as to which one is more reliable because of the wide range of positive LR for the former sign.

 

Primary Evidence 1

(Wagner, 1996)

 

Appraisal Notes:

 

·     Lot of case series studies on reliability of clinical parameters. All of them can be subsumed by the analysis of Wagner, unless there are studies that have as large a number of patient population as 4,000 and that have better study designs, in which the clinical parameters are well-defined and interrater variabilities are minimized.

 

·        Limitations of the Wagner's analysis:

 

·        Parameters evaluated are poorly defined in the text of  studies

·        Single signs, rather than combined signs, are used

 

 

Primary Evidence 2

 

Note:

Papers on active observation relied on clinical parameters. Thus, these papers could be good sources of information for our question. We tried looking for specific description of the clinical parameters used in the papers advocating observation in the diagnosis of acute appendicitis.

We were able to find only one paper, that of Joson.

 

 

Joson RO.

Active observation in the evaluation of patients with possible acute appendicitis.

Phil J Surg Special  1990; 45:3, 108-111

(Age: 7-71; Sex: 262 - females; 242 - males)

 

·        Signs of peritoneal irritation:

definite, persistent, and increasing direct RLQ tenderness with guarding*

*rebound tenderness was not elicited anymore because of the author’s belief

that rebound tenderness is nonspecific; eliciting it is cruelty; and that

rebound tenderness is assumed to be present when a patient is guarding

his/her RLQ because of pain.

 

Signs of Peritoneal Irritation

Appendicitis

Not Appendicitis

Total

Positive

247

  12

259

Negative

0

245

245

 

247

257

504

 

 

Sensitivity

Specificity

(+) LR

Signs of peritoneal irritation without cue for other specific condition

 

100%

 

~95%

 

21.38

 

 

 

Distillation of all available evidences to come out with recommendations or answers to the clinical issue/question:

 

We thought of starting the analysis with the pathophysiology of acute appendicitis and enumerating the expected symptoms and abdominal signs. Then, we tried differentiating acute appendicitis from other common specific causes of acute nontraumatic RLQ abdominal pain. Then, we tried coming out with an approach in the clinical evaluation of patients with acute RLQ abdominal pain with acute appendicitis as one of the considerations.

 

Pathophysiology and Expected  Symptoms and Abdominal Signs of the Common Specific Causes of

Acute Nontraumatic RLQ Abdominal Pain

(For Pattern Recognition Use)

 

1. Acute Appendicitis

 

Pathophysiology

Expected Symptoms

Expected Abdominal Signs

Distention of appendix

(for obstructive ones only -30% of cases)

Periumbilical pain

With or without

Anorexia, nausea, vomiting

No significant findings

Inflammation of the appendix

(minimal peritonitis)

RLQ pain

With or without fever

Minimal signs of RLQ peritoneal

irritation 

Inflammation of the appendix

(moderate peritonitis)

RLQ pain

With or without fever

Moderate signs of RLQ peritoneal irritation

 

Inflammation of the appendix

(severe peritonitis- still localized at  RLQ)

      gangrene

      perforation

RLQ pain

Usually with fever

 

 

Frank or severe signs of RLQ peritoneal irritation

 

If there is irritation of the urinary tract

Dysuria

NA

If there is irritation of the adjacent bowels

Diarrhea

NA

 

Note 1: The more full-blown or advanced in the pathophysiology of the disease is, the more reliable are the clinical parameters present. For example, rigidity will be most likely present during the severe inflammatory phase and direct tenderness without rigidity in the earlier phases. Rigidity as a clinical parameter to suspect acute appendicitis will, therefore,be expected to be more reliable than direct tenderness without rigidity.

 

 

Differentiating Acute Appendicitis from the Other More Common Specific Causes of Acute Nontraumatic RLQ Abdominal Pain

 

 

RLQ direct tender

ness

Migratory pain -

epigastric  to RLQ

RLQ

perito-nitis

Anorexia

Nausea

Vomi-ting

Fever

Dys-uria

Diar-rhea

Clinical Cues

Appendicitis

+

+/-

(+)

+/-

 

+/-

+/-

+/-

RLQ peritonitis

No alternative diagnosis

Acute gastroenteritis

+

+/-

x

+

+/-

x

+

diarrhea

anorexia,

nausea, vomiting

Urinary tract

Infections

+

X

x

+/-

+/-

+

x

dysuria

Ureteral  stone,

Right

+

X

x

+/-

+/-

+/-

x

severe colic,  right

flank

Pelvic  inflammatory disease

+

X

(+/-)

+/-

 

+/-

+/-

+/-

vaginal discharge

Ruptured right cctopic pregnancy

+

X

(+)

+/-

+/-

x

x

pregnant suspect

vaginal bleeding

intraperitoneal bleed

Twisted right ovarian tumor

+

X

(+/-)

+/-

 

+/-

x

x

mass

 

Note 2: The reliability of the clinical parameters for acute appendicitis present during the time of evaluation will be dependent primarily on the phase of the pathophysiology of the disease the patient is in.

 

From the above table, after RLQ direct tenderness, one can use presence or absence of RLQ peritonitis as the parameter to group the various disorders into 2 categories:

 

RLQ direct tenderness with RLQ peritonitis

Acute appendicitis

Pelvic inflammatory disease

Ruptured right ectopic pregnancy

Twisted right ovarian tumor

 

RLQ direct tenderness without RLQ peritonitis

Acute gastroenteritis

Urinary tract infection

Ureteral stone

 

For the category with RLQ peritonitis, one can use specific cues to suspect a particular disease outside of acute appendicitis, example, purulent vaginal discharge for pelvic inflammatory disease; pregnant suspect and vaginal bleeding, for ectopic pregnancy; an intraabdominal mass, for twisted ovarian tumor.  In the presence of RLQ peritonitis, acute appendicitis should be the primary suspect or diagnosis if there are no cues to suggest another disease. If there are, the other disease is the primary suspect and acute appendicitis is just a differential or secondary diagnosis.

 

What constitute signs of RLQ peritonitis?

 

How reliable are the following possible RLQ signs in patients with acute appendicitis?

 

·        Direct tenderness only

·        Direct tenderness with rebound tenderness

·        Direct tenderness with guarding

·        Direct tenderness with rigidity

·        Definite, persistent, and increasing direct tenderness with guarding

 

Based on evidences (Wagner and Joson) and our computations,

Premise: Direct tenderness has a Pretest Probability at 30% *

 

 

(+) LR

Posttest Probability

Direct tenderness with guarding/rebound

~2

46%

Direct tenderness with rigidity

~4

63%

Definite, persistent, and increasing direct tenderness with guarding

 

~21

 

90%

*Wagner (see also References)

 

 

 

 

 

 

 Summary of Answer to Question or Recommendations:

 

In a non-immunocompromised patient of any age, any gender, communicative, coherent, with stable vital signs with acute nontraumatic right lower quadrant abdominal pain and tenderness,

 

What are reliable clinical parameters that we can use to make a confident primary clinical diagnosis of acute appendicitis in patients presenting with an acute nontraumatic right lower quadrant (RLQ) abdominal pain and tenderness?

 

In other words, with what clinical parameters can we say that we are quite certain that the diagnosis is acute appendicitis that we do not have to go through the paraclinical diagnostic process?

 

The reliable clinical parameters that we can use for making a primary clinical diagnosis of acute appendicitis (of 90% or more probability) in patients with acute RLQ abdominal pain consist of the following:

 

RLQ abdominal pain and tenderness with signs of peritoneal irritation

No alternative diagnosis of the RLQ signs of peritoneal irritation

 

RLQ Signs of Peritoneal Irritation:

·        Definite (persistent progressive) direct tenderness with at least guarding

·        Rigidity

 

 

 

 

Future Research Issues/Questions Arising from Attempts to Answer Issue:

 

RLQ rebound tenderness and guarding, which is a more reliable cue for peritoneal irritation?

 

 

 

References:

 

·        Wagner JM, Mckinney WP, Carpenter JL. Does this patient have appendicitis? JAMA 1996;276:19, 1589-1594.  Pretest probability of acute appendicitis is 12 to 26%

·        Wager JM. Summary of Clinical Examination Operating Characteristics for Appendicitis. http://www.ama-assn.org/sci-pubs/journals/archive/jama/vol_278/no_10/71076t1.htm

·        Leopando ZE, Ulanday JB. Acute appendicitis: Toward a better diagnosis. Fil Fam Phy 1980;13:3,1-5.

·        Hale DA, Molloy M, Pearl RH, Schutt DC, Jaques DP. Appendectomy: A contemporary appraisal. Ann Surg 1997; 225:3, 253-61.

·        Hale DA, Jaques DP, Molloy M, Pearl RH, Schutt DC, dAvis JC. Appendectomy. Improving care through quality improvement. Arch Surg 1997; 132:2, 153-7.

·        Condon RE, Relford GL. Appendicitis. In Sabiston DC, editor. Textbook of Surgery: the biological basis of modern surgical practice. Philadelphia: WB Saunders Co, 1991:884-98.

Classic pain sequence may be elicited in only 55% of patients with appendicitis.

·        Poole GV. Appendicitis. The diagnostic challenge continues. Am Surg 1988;54:609-612.

Classic presentation is seen in less than half.

·        Joson RO. Active observation in the evaluation of patients with possible acute appendicitis. Phil J Surg Special 1990; 45:3, 108-111

 

 

 

Quick Reference Guide or Algorithm:

 

In a non-immunocompromised patient of any age, any gender, communicative, coherent, with stable vital signs with acute nontraumatic right lower quadrant abdominal pain and tenderness,

 

What are reliable clinical parameters that we can use to make a confident primary clinical diagnosis of acute appendicitis in patients presenting with an acute nontraumatic right lower quadrant (RLQ) abdominal pain and tenderness?

 

In other words, with what clinical parameters can we say that we are quite certain that the diagnosis is acute appendicitis that we do not have to go through the paraclinical diagnostic process?

 

 

The reliable clinical parameters that we can use for making a primary clinical diagnosis of acute appendicitis (of 90% or more probability) in patients with acute RLQ abdominal pain consist of the following:

 

RLQ abdominal pain and tenderness with signs of peritoneal irritation

No alternative diagnosis of the RLQ signs of peritoneal irritation

 

RLQ Signs of Peritoneal Irritation:

·        Definite (persistent progressive) direct tenderness with at least guarding

·        Rigidity