Appendicitis

 

Etiology

Ischemic necrosis of appendix and infection of devitalized tissue with bacteria

Simple>gangrenous>perforated

 

Back to top  

Signs/Symptoms

No individual sign has adequate accuracy in the diagnosis

(NEJM 348:3, 2003, p. 236)(JAMA. Volume 276 (19) 20 November 1996 pp 1589-1594.)

McBurney’s Point 1 1/2 – 2 inches from anterior spinous process of ilium on a straight line from that process to umbilicus

Psoas Sign-flex thigh against resistance or passive extension of hip

Obdurator sign-rotate flexed thigh internally and externally

Rovsing sign-pain in RLQ with palpation of LLQ

PID more likely if history of PID, vaginal d/c on exam or by history, urinary sx, abnormal UA, tender outside the RLQ, CMT

Adler’s Sign-to differentiate between appendicitis and tuboovarian pathology in RLQ pain.  Find point of maximal tenderness while the patient is supine.  Have them roll onto left side.  If pain shifts towards center then may be tubo-ovarian.

 

Back to top  

Laboratory

Brown and Reeves reported likelihoods for various intervals of the WBC count for patients suspected of appendicitis.

WBC Count (x103/ml)

Likelihood Ratio

4-7

0.1

7-9

0.52

9-11

2.8

13-15

1.7

15-17

2.8

17-19

3.5

It can be seen that the WBC count has very little diagnostic effect unless it is <7 or >17. This makes the WBC a less than optimal test for appendicitis. If interval likelihoods are not used and an arbitrary cutoff such as >11 is used, the test is even less functional. (Snyder BK, Hayden SR. Accuracy of leukocyte count in the diagnosis of acute appendicitis. Ann Emerg Med 1999;33:565-574.  Anderson RE. et al. Diagnostic value of disease history, clinical presentation, and inflammatory parameters of appendicitis. World J Surg. 1999;23:133-140.)

May cause pyuria, hematuria, or bacteriuria in up to 40% of cases.  If erythrocytes are greater than 30 per HPF or leukocytes>20 more likely true urinary etiology. (NEJM 348:3, 2003, p. 236)

 

Elderly (>60!) with appendicitis: normal white cell count 45% of time Freund HR, et al. Am Surg. 1984 Oct;50(10):573-6. Triple test …if white cell count <9000 / mm3 AND …if neutrophils <75% of total white cells AND …C-reactive protein <0.6 mg/dL, THEN Negative predictive value approaches 100% Dueholm S, et al. Dis Colon Rectum. 1989 Oct;32(10):855-9.

 

more on lack of utility of WBC or fever (Acad Emerg Med 2004;11:1021)

 

 

Journal of Gastrointestinal Surgery Volume 11, Number 6 / June, 2007 714-718Hyperbilirubinemia in Appendicitis: A New Predictor of Perforation On logistic regression the only significant relationship between the presence or absence of appendiceal gangrene and perforation was the presence of hyperbilirubinemia (p = 0.031, 95% confidence interval 1.11–7.6). The odds of appendiceal perforation are three times higher (odds ratio 2.96) for patients with hyperbilirubinemia compared to those with normal bilirubin levels. Hyperbilirubinemia is frequently associated with appendicitis. Elevated bilirubin levels have a predictive potential for the diagnosis of appendiceal perforation.

 

 

 

Seems it is safe to wait up to 24 hours before appie (Arch Surg. 2010 Sep;145(9):886-92.)

 

 

Back to top  

Imaging

UTS

good 1st choice to check appie (Orr RK, Porter D, Hartman D. Ultrasound to evaluate adults for appendicitis: decision making based on meta-analysis and probabilistic reasoning. Acad Emerg Med 1995;2:644-650.) Helpful if positive, but cannot exclude diagnosis

Accuracy in expert hands 83%-96% Can diagnose other important diseases in differential diagnosis – especially female pelvic disorders. Especially helpful in Pregnant patients (42 patient study by Lim found it 100% sensitive and 96% specific in 15 cases with 3 non-dx).

CT Scan

ABD CT good in ABD pain. (Br Med J 325:1, December 14, 2002)

Adding contrast did not add much to diagnostic ability of CT scans (J Clin Imag 26:405, 2002)

Need to use thin cuts (5mm cuts lead to an accuracy of 99% versus 89% for 10mm cuts, Diagnosis of acute appendicitis: comparison of 5- and 10-mm CT sections in the same patient. Radiology 2000;216:172-177.). b. Rectal Contrast : highest sensitivity and specificity if done without IV contrast (AJR 1999;1447-1448, AJR 1998;171:997-1001..) c. Recent study compares different CT sequences in 100 ED patients. (AJR 2001;176:933-941) i. No significant difference between standard abdominal/pelvic helical CT with IV contrast and focused study w or w/o rectal contrast ii. All patients had P.O. contrast iii. Limited sample size iv. 18 pts refused study due to rectal contrast v. Discomfort with rectal contrast (6.7) versus (5.3) with IV contrast on 10 point scale vi. Suggests standard CT with IV and PO contrast as initial approach with rectal contrast reserved for questionable cases Focus CT with rc can also safely be used in pregnant patients using 300mrads (Castro, The use of helical CT in pregnancy for the diagnosis of acute appendicitis. Amer Jo Obstet Gyn 2001;184:954-957.).

 

 

Incidence of acute appendicitis in patients with equivocal CT findings. Daly CP. Cohan RH, Francis IR, et al. AJR Am J Roentgenol 2005; 184:1813–1820. Objective: The purpose of our study was to determine the incidence of acute appendicitis in patients for whom the CT interpretation is deemed equivocal. Materials and methods: Of 1,344 patients referred for CT with suspected appendicitis between January 1998 and December 2002, 172 were identified in whom the radiographic findings were equivocal. Two radiologists reviewed the equivocal CT cases, reassessing appendiceal size and the presence of right lower quadrant stranding, fluid, or an appendicolith. The reviewers’ findings were correlated with surgical pathology reports and clinical follow-up. Results: Fifty-three (31%) of 172 patients with indeterminate findings on CT scans were subsequently diagnosed with appendicitis. For reviewers 1 and 2, respectively, appendicitis was present in five (14%) of 36 and six (13%) of 47 patients who had isolated appendiceal diameter less than 9 mm, and in 11 (52%) of 21 and in 10 (50%) of 20 patients who had isolated appendiceal dilatation equal to or greater than 9 mm. If a normal diameter appendix (<6 mm) was visualized in a patient who had right lower quadrant stranding or fluid, appendicitis was present in only one (17%) of six and in four (27%) of 15 patients for reviewers 1 and 2, respectively. If the appendix could not be identified but there was right lower quadrant stranding or fluid, appendicitis was present in seven (37%) of 19 and in eight (53%) of 15 patients. Conclusion: Appendicitis is encountered in about 30% of patients with equivocal findings on CT, and the diagnosis should be considered in most of these patients if they are appropriately symptomatic. However, when the appendix measures less than 9 mm alone, the likelihood of appendicitis is much smaller. Go to source: 10.1007/s10140-006-0521-9

 

 

Jeff Mann’s Discussion of interpreting CT scans in Appendicitis

 

If the appendix is not visualized, but there is a sufficient amount of fat, then most likely negative (AJR:183, October 2004)

 

 

When surgeons said it was definitely appie, they were right only ~80% of the time (22% negative lap rate)

(Rao N Engl J Med 1998;338:141-6.)

 

Use CT in high and moderate prob patients

Using it in low prob is begging for false positives

 

 

(J Comput Assist Tomogr. – 01-Sep-1997; 21(5): 686-92)

 

Mann’s Sheet for ct

 

The accuracy of a CT scan to diagnose appendicitis depends on optimal ileocecal opacification and thin collimation helical scanning. The results will be less accurate if a contrast agent is not used, or if older generation CT scanners are used. Some radiologists achieve significant success using a non-contrast CT scan, but the degree of success apparently depends on the radiologist’s experience and skill. Rao uses oral and rectal contrast in his CT scan studies, and he does not use IV contrast. Therefore, he does not mention radiological signs such as appendiceal wall thickening and appendiceal wall enhancement, which can only be readily seen when using IV contrast. Rao thinks that the risks of IV contrast (allergy) outweigh the small additional diagnostic benefits achieved by using IV contrast in addition to oral/rectal contrast.

 

CT scan signs suggestive of appendictis include an abnormal appendix (enlarged appendix and/or appendicolith); RLQ inflammatory changes (fat stranding, fluid, phlegmon, abscess, extraluminal air, adenopathy, adjacent bowel wall thickening) and cecal apical changes (focal cecal apical thickening, arrowhead sign, cecal bar). An enlarged appendix is defined as >6mm in diameter. The distended appendix doesn’t opacify with contrast in appendicitis because the appendiceal lumen is usually proximally occluded. Extensive fat stranding or fluid can occasionally obscure a distended appendix. A distended appendix may also not be seen if a phlegmon or abscess is present. Usually additional radiological signs of appendicitis are present when the phlegmon or abscess obscures the distended appendix eg. appendicolith or arrowhead sign. Remember that an inflammed appendix can also lose its rounded or distended appearance if it perforates, and it may therefore not be visisble on the CT scan. Appendicoliths are visible in roughly 25-50% of CT scans that are positive for appendicitis. Although the presence of appendicoliths were 100% specific for appendicitis is Rao’s study, other CT scan studies have shown a normal appendix in the presence of appendicoliths, so always look for additional radiological signs of appendicitis to confirm the presence of appendicitis. RLQ adenopathy is defined as a cluster of three or more nodes of at least 5mm in diameter in the smallest dimension. Adenopathy is not a highly specific sign of appendicitis and it may also be seen in mesenteric adenitis, and occasionally in ileiltis or colitis. Focal cecal wall thickening (not apical) is a rare, but highly specific radiological sign of appendicitis. Diffuse cecal wall thickening is not usually seen in patients with appendicitis. Diffuse cecal wall thickening was seen in 9% of Rao’s patients who had a normal appendix, and was usually due to other RLQ diseases eg. colitis or right sided diverticulitis. Focal cecal apical thickening is a localised thickening of the cecal wall at the origin of the appendix, often seen with appendicitis at CT scan if good cecal distention is present. The arrowhead sign is a triangle-shaped collection of contrast material seen at the cecal apex when contrast meaterial funnels symmetrically to the point of appendiceal occlusion. The cecal bar is a straight or slightly curved band of inflammed soft tissue that can separate proximal calcified appendoliths from similarly dense contrast material.

appendicitis appie with perf is probably a different disease process than non-perf appie.

The former is usually associated with obstruction. Non-perf appie probably does not progress to perforation just as a result of observation non-perfed appie will probably resolve with antibiotic treatment alone

Myth

1 rate of perf reflects quality of surg care

2 clinical observation increases number of perfs

3 simple appie, if untreated progresses to perforation

4 early use of imaging improves results

5 non-localized findings demand a “formal” lap

6 the stump needs to be cauterized, inverted, or touched with antiseptic

7 wound has to be lef topen for complicated appie

8 prolonged course of abx is needed for complicated appie

9 drains are necessary if there is periappie pus

10 an interval appie is always necessary after conservative management of appie phlegmon/mass/abscess

 

 

Non-contrast had adequate accuracy SR (Ann Emerg Med 2010;55(1):51)

Back to top  

Antibiotics

ABX-2nd gen

If going to surg for perf, use amp/gent/flagyl or Unasyn 3g IVPB

 

Post-Appie Stump Phlegmon

fever, wbc a week after appie, but wound looks good. CT will demonstarte phlegmon of cecum

 

Stump Appendicitis

an time after appie; especially after lappie appie

 

Appendiceal Mass

late presenters or smoldering presentation

can be managed with antibiotics and interval appendectomy

use perc drainage

 

Back to top  

Primary Epiploic Appendagitis

Torsion of epiploic appendage.  Tend to be younger than diverticulitis pts (35 vs. 55), pain was rapid onset, constant, localized to LLQ (or right iliac fossa).  Usually presents s rebound c normal labs.  Diverticulitis is usually much more diffuse and has rebound.

 

Back to top  

Stump Appendicitis

Stump appendicitis is a real entity, the frequency of which may be increasing due to the great increase in laparoscopic appendectomies, which leave bigger stumps with a greater chance of becoming inflamed again (J of EM, published online 10/1807).

 

 

 

RLQ Pain in Pregnancy (the sequel)

|      |      |

Back to top