Noon Conference November 3, 2010

Appendicitis

Brad Sobolewski, MD Pediatric Emergency Medicine Fellow

Appendicitis is the most common reason

for emergency surgery in children

Missing appendicitis leads to perforation

Perforation = bad

Appendicitis is a clinical diagnosis

Overview

Signs & Symptoms

Labs

Imaging

Making the diagnosis

And more!

What is appendicitis?

A graphical tale depicting the pathophysiology of appendicitis

Here’s Mr. Appy. He’s a normal, healthy, albeit useless appendix. He’s just hanging out with friendly Mr. Cecum minding his business.

Hey yinz!

Unfortunately mean Mr. Fecalith arrives to ruin the peritoneal party, and occludes Mr. Appy’s lumen.

Oh crap!

Mr. Appy’s wall dilates, and leads to poorly localized colicky belly pain.

Ouch!

Sadly Mr. Appy’s mucosal barrier breaks down, and bacteria invade his wall.

I’m E.coli!

Say hello to little Peptostreptococcus! Anaerobes rule!

Mr. Appy becomes ischemic and intensely inflamed. He causes localized pain then fever. What a tragedy.

This looks like the end!

Party!

Mr. Appy is now gangrenous. He perforates and the bacteria run free. It is a sad, sad end to our once healthy friend.

HE DIED SO THAT YOU

MIGHT LEARN

Don’t forget little Peptostreptococcus!

Could we please include EBM in this

conference?

EBM Disclaimer

This talk includes Sensitivity, Specificity and Likelihood Ratios No math required

Refer to ‘The PocketTM’ pages 88-89 for

more information

EBM Disclaimer

Sensitivity – Proportion of patients with disease that correctly have positive test Specificity – Proportion

of healthy patients that correctly have a negative test result

Screen - - - - - - - - - - (-) rules out ‘SNOUT’

Confirm - - - - - - - - - -(+) rules in ‘SPIN’

EBM Disclaimer

Positive predictive value – Proportion of patients with positive test that have disease Negative predictive value – Proportion of

patients with negative test who are healthy

Tells you how likely a diagnosis is after getting your test result (or negative test result for a negative LR)

Start with a “pre-test” probability The % chance you think that the patient has the

disease before getting the test Based on experience, disease prevalence, clinical

prediction rules

Likelihood ratios

Likelihood of positive test in patient with disease

Likelihood of positive test in patient without disease

Likelihood ratios

Helps assess the strength of a diagnostic test

(+) LR >10 (-) LR < 0.1 very strong

(+) LR 5-10 (-) LR 0.1-0.2 moderate

(+) LR 2-5 (-) LR 0.2-0.5 small

LR = 1 equivocal

Likelihood ratios

Pre-test probability of boring lecture = 50% If I include more EBM the LR of it being more boring = 10 New post-test probability of a boring lecture is = 90%

Likelihood ratios

Pre-test probability of boring lecture = 50% If I include many ridiculous cat pictures the LR of it being more boring = 0.01 New post-test probability of a boring lecture is now = 1%

How does appendicitis present?

The “classic” presentation

Periumbilical pain

Migration to RLQ

Nausea and vomiting

Fever up to 101.0ºF (38.3ºC)

Epidemiology

Most common in teens Lifetime risk 7% girls and 9% boys

Delayed diagnosis in 3/5 <6 years old

70% of those <4 years old perforate

Babies

Vomiting, pain, fever Look out for Irritability Grunting Right hip complaints

Fun fact: Less common because the appendix is “funnel” shaped

Preschoolers

Vomiting and pain Many have anorexia

Most have >2 days

of symptoms

School age

All have vomiting and pain May have migration

of pain to the RLQ

Adolescents

Often have the “classic” history (50%) Pain before vomiting

Always ask about LMP

and sexual history

Classic signs

+ LR - LR Sens Spec

Fever 3.4 0.32 75% 78%

Rebound 3 0.28 53-88% 76-86%

RLQ pain 1.2 0.56 62-96% 5-64%

Migration to RLQ 1.9–3.1 0.41-0.72 45-76% 76-78%

Bundy – JAMA, 2007

Other symptoms/signs

Vomiting and diarrhea (O’Shea - Pediatric Emergency Care, 1988) Vomiting LR+ 2.2 LR- 0.57 Diarrhea LR+ 2.6 LR- 1.0

Samuel – J Peds Surg, 2002 Cough/percussion tenderness

Sens 93% Spec 100% PPV 100% NPV 88% Hopping tenderness

Sens 93% Spec 100% PPV 100% NPV 88%

Other exam findings (adults)

Rovsing’s LR+ 1.9 LR- 0.83

Obturator LR+ 2.2 LR- 0.82

Psoas LR+ 2.5 LR- 0.75

Wagner – JAMA, 1996

Uncertain diagnostic value

Duration of pain > or <24 hours

Anorexia

Nausea

Constipation

Lethargy

Dysuria

Summary of the evidence

No individual symptom makes the diagnosis

The most useful sign is fever (LR+ 3.4)

Fever usually comes after pain

Appendicitis is more likely to “classicly” present in older children/teens

What labs should I get?

Urine

U/A UTI/pyelo, cervicits, kidney stones You can have pyuria/bacteriuria in appy Insufficient data

βhCG in ALL postpubertal females What’s the one life threatening cause of abdominal pain in a post pubertal patient with a +βhCG that you should not miss

Ectopic pregnancy

CBC

Different WBC cut offs examined

ANC >6750 (Kharbanda – Pediatrics, 2005)

>15,000 LR+ 1.7 (95% CI 0.83-3.4) LR- 0.77 (95% CI 0.52-1.1) summary of 3 studies

>10,000 LR+ 2.0 (95% CI 1.3-2.9) LR- 0.22 (95% CI 0.17-0.30) summary of 4 studies

LR+ 2.0 Sens 0.97 LR- 0.06 Spec 0.51

CRP

Acute phase reactant Above normal within 6 hours Peaks at 48 hours

CRP ≥ 25 >17 >10 >8

LR+ 5.2 2.9 1.3-3.6 1.4

LR- 0.53 0.44-0.45 0.47

SENS 58% 64-85% 79%

SPEC 80% 33-82% 44%

All have wide 95% CI Serial measurements may be more useful

Other labs

ESR >20 LR+ 3.8 Normal LR- 0.68

Calprotectin (Academic Emerg Med, 2010) Sens 93% Spec 54%

Lactate – not useful in children

Procalcitonin – no evidence yet

I like adding… Can’t I calculate a score for

appendicitis?

Pediatric Appendicitis Score

Samuel - J of Pediatr Surg, 2002

Anorexia 1 Nausea/vomiting 1 Migration of pain 1 Fever >38 1 Pain w/ cough, percussion, hopping 2 RLQ tenderness 2 WBC >10,000 1 ANC >7500 1

Max 10

≤2 Low likelihood 3-6 Equivocal ≥7 High likelihood

PAS ≥6 LR+ 2.4 LR- 0.27 Sens 82% Spec 65%

Alvarado (MANTRELS) Score

Migration of pain to RLQ 1 Anorexia 1 Nausea/Vomiting 1 Tenderness RLQ 2 Rebound pain 1 Elevated temperature(>37.3) 1 Leukocytosis (>10K) 2 Shift (>75% Neutrophils) 1

Max 10

5-6 Compatible 7-8 Probable 9-10 Very probable

Alvarado ≥ 7 LR+ 4.0 LR- 0.20 Sens 72-93% Spec 81-82%

Alvarado – Annals of Emerg Med, 1986

Is one score better?

Alvarado is more statistically powerful but… Weighs wbc and fever higher

Both have low Positive Predictive Value in those

<10 years (Schneider – Annals of Emerg Med, 2007)

PAS >6 - PPV 58% Alvardao >6 - PPV 45%

Take home point: These scoring systems are good adjuncts, though they don’t make the diagnosis for you

Just tell us already, Ultrasound or CT!

Plain radiographs

Insensitive Not specific Stool load Appendicolith

Bottom line: You

don’t need it

2x

AP

Ultrasound

Graded compression technique

Signs of appendicitis Non compressible Diameter >6mm Wall thickness >2mm Target sign Distention/obstruction of the lumen Fluid surrounding the appendix Calcified fecalith

Ultrasound

Great for female patients Improving success Also scan pelvis (need full bladder)

Limitations Fat absorbs ultrasound beam Hard to see focally inflamed (tip) appy Limited access

Ultrasound

Up to 10% inconclusive Use to confirm,

not exclude appy

CT

Findings Diameter >6mm

Wall >1mm thick Periappendiceal inflammatory changes: Fat streaks Phlegmon Fluid collection Extraluminal gas

Other: adenopathy, appendicolith, abscess

CT

Contrast IV and enteral (oral preferred over rectal by patients)

Kharbanda – Radiology, 2007 – found that

noncontrast and IV/rectal contrast CT had similar sensitivity

Limitations A normal appendix is harder to see in skinny kids Fluid filled bowel or Meckel’s may be mistaken for

appy

CT

Radiation exposure risk 1 fatal cancer per 1000 CT scans (Brenner -

Pediatr Radiol, 2002) Based on atomic bomb survivors More radiation per organ over a longer

lifespan ALARA

The evidence

CT scans have a better ability to correctly identify and to rule out acute appendicitis

Doria - Radiology, 2006

LR+ LR- Sens Spec

U/S 14.7 0.13 88% 94%

CT 18.8 0.06 94% 95%

Sample cost of select studies

Ultrasound Single quad: $540 + $350 for Radiology read Abdomen: $540 + $260 for Radiology read

CT Abdomen: $1558 + $550 for Radiology read Pelvis: $1385 + $521 for Radiology read

So, which do I choose?

Per National Guideline Clearinghouse No Level A recommendations

Level B recommendations U/S to confirm but not exclude CT to confirm and exclude

Level C recommendations Use U/S to avoid ionizing radiation Uncertain after U/S – get a CT

National Guideline Clearinghouse

So, which do I choose?

Go with ultrasound first No radiation Still OK with “larger” kids Cheaper

If the U/S is negative – discharge home

If indeterminate consult surgery

What if the appy is perforated?

Complicated appendicitis

1/3 overall (17-42%) <4 years old 80-100%

10-17 years old 10-20%

More Medicaid patients have complicated

appy OR=1.3 (Bratton – Pediatrics, 2000)

Complicated appendicitis

When does it happen? Onset of symptoms to perforation over

36-48hrs Perf rate >2/3 if diagnosis made >48hrs

½ of perforated appys have been seen by

a physician prior to diagnosis

Symptoms of perforated appy

Generalized peritonitis Fever 39-41oC WBC high w/ left shift Younger kids have less omentum =

widespread pus Overall appy mortality 0.2-0.8%

“Fun” fact: #2 missed diagnosis malpractice claims

Management

Henry - J Pediatr Surg, 2007 Case-control of immediate surgery vs. non-

operative management Immediate surgery group had; Shorter duration of pain (3 vs 7d) Lower post-treatment recurrent abscess

rate (4% vs 24%) Shorter LOS (6.5 vs 8.8 days) Fewer complications (19% vs 43%)

You got anything else?

Pain meds

Numerous studies support giving pain medicines before surgery arrives No change in Time to diagnosis Perforation rate ED length of stay

Bailey – Ann Emerg Med, 2007

Antibiotics

Ultimately it’s the surgeons choice No difference

between single and dual/triple drug regimens

Surgery

Lap vs open Laparoscopic had decr LOS, pain, scar, and

faster return to work New single port techniques

Immediate vs delayed It’s OK to wait until the morning – similar

morbidity and mortality

Negative appendectomy rate?

Between 5-12% 11.5% even with in hospital observation

(Surana - Pediatr Surg Int, 1995)

Obese children could be as high as 25% (Kutasy - Pediatr Surg Int, 2010)

Adults as low as 6.8% (Jo - Am J Emerg Med, 2010)

Females 15-24 years are 2.5x times more likely than same-age males

What if it’s not an appy (yet)

What should you tell the patient who you discharge home, and it’s unlikely that they have an appy, but could have an appy in the near future?

The big 5

Take home points about appendicitis

Young patients perforate more often

Fever is the most predictive symptom (LR+ 3.4)

Useful labs include CBC, U/A, and βhCG

Ultrasound is the first choice for imaging

Appendicitis is a clinical diagnosis (really)

References

Alvarado A. A Practical Score for the Early Diagnosis of Acute Appendicitis. Annals of Emerg Med. 1986; 15; 557-564.

Bailey, B. et al. Efficacy and impact of intravenous morphine before surgical consultation in children with right lower quadrant pain suggestive of appendicitis: a randomized controlled trial. Ann Emerg Med. 2007 Oct;50(4):371-8. Epub 2007 Jun 27.

Bratton, S. L. et al. Acute Appendicitis Risks of Complications: Age and Medicaid Insurance. Pediatrics Vol. 106 No. 1 July 2000, pp. 75-78.

Bundy, D. G. et al. Does this child have appendicitis? JAMA 2007; 298:438-451. Doria, A S et al. US or CT for diagnosis of appendicitis in children and adults? A meta-analysis.

Rad 2006; 241:83-94. Henry MC, Gollin G, Illam S, et al. Matched analysis of nonoperative management vs immediate

appendectomy for perforated appendicitis. J Pediatr Surg. 2007,42:19–24. Jo, Y. H. The accuracy of emergency medicine and surgical residents in the diagnosis of acute

appendicitis. Am J Emerg Med. 2010 Sep;28(7):766-70. Epub 2010 Mar 25. Kharbanda, A. B. A Clinical Decision Rule to Identify Children at Low Risk for Appendicitis.

Pediatrics Vol. 116 No. 3 September 2005, pp. 709-716. Kharbanda, AB, Taylor, GA, Bachur, RG. Comparison of rectal and IV conrast CT with IV contrast

CT for the diagnosis of appendicitis. Radiology 2007. Kutasy, B. et al. Is C-reactive protein a reliable test for suspected appendicitis in extremely obese

children? Pediatr Surg Int. 2010 Jan;26(1):123-5. Nelson textbook of Pediatrics 17th Edition. Samuel, M. Pediatric appendicitis score. J Pediatr Surg 37: 877-881, 2002. Wagner, J. M. et al.Does This patient Have Appendicitis? JAMA. 1996;276(19):1589-1594 Up To Date online: Acute appendicitis in children: Clinical manifestations and diagnosis. accessed

10/29/2010.

Noon Conference

Appendicitis

Brad Sobolewski, MD Pediatric Emergency Medicine Fellow