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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