Noon Conference November 3, Appendicitis. Brad Sobolewski, MD Pediatric Emergency Medicine Fellow

Transcription

1 Noon Conference November 3, 2010 Appendicitis Brad Sobolewski, MD Pediatric Emergency Medicine Fellow

2 Appendicitis is the most common reason for emergency surgery in children

3 Missing appendicitis leads to perforation

4 Perforation = bad

5 Appendicitis is a clinical diagnosis

6 Signs & Symptoms Labs Imaging Making the diagnosis And more! Overview

7 What is appendicitis?

8 A graphical tale depicting the pathophysiology of appendicitis

9 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!

10 Unfortunately mean Mr. Fecalith arrives to ruin the peritoneal party, and occludes Mr. Appy s lumen. Oh crap!

11 Mr. Appy s wall dilates, and leads to poorly localized colicky belly pain. Ouch!

12 Sadly Mr. Appy s mucosal barrier breaks down, and bacteria invade his wall. I m E.coli! Say hello to little Peptostreptococcus! Anaerobes rule!

13 Mr. Appy becomes ischemic and intensely inflamed. He causes localized pain then fever. What a tragedy. This looks like the end!

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

15 Don t forget little Peptostreptococcus! HE DIED SO THAT YOU MIGHT LEARN

16 Could we please include EBM in this conference?

17 EBM Disclaimer This talk includes Sensitivity, Specificity and Likelihood Ratios No math required Refer to The Pocket TM pages for more information

18 EBM Disclaimer Sensitivity Proportion of patients with disease that correctly have positive test Screen (-) rules out SNOUT Specificity Proportion of healthy patients that correctly have a negative test result Confirm (+) rules in SPIN

19 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

20 Likelihood ratios Likelihood of positive test in patient with disease Likelihood of positive test in patient without disease 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

21 Likelihood ratios Helps assess the strength of a diagnostic test (+) LR >10 (-) LR < 0.1 very strong (+) LR 5-10 (-) LR moderate (+) LR 2-5 (-) LR small LR = 1 equivocal

22 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%

23 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%

24 How does appendicitis present?

25 The classic presentation Periumbilical pain Migration to RLQ Nausea and vomiting Fever up to 101.0ºF (38.3ºC)

26 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

27 Babies Vomiting, pain, fever Look out for Irritability Grunting Right hip complaints Fun fact: Less common because the appendix is funnel shaped

28 Vomiting and pain Preschoolers Many have anorexia Most have >2 days of symptoms

29 School age All have vomiting and pain May have migration of pain to the RLQ

30 Adolescents Often have the classic history (50%) Pain before vomiting Always ask about LMP and sexual history

31 Classic signs + LR - LR Sens Spec Fever % 78% Rebound % 76-86% RLQ pain Migration to RLQ % 5-64% % 76-78% Bundy JAMA, 2007

32 Other symptoms/signs Vomiting and diarrhea (O Shea - Pediatric Emergency Care, 1988) Vomiting LR+ 2.2 LR 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%

33 Other exam findings (adults) Rovsing s LR+ 1.9 LR Obturator LR+ 2.2 LR Psoas LR+ 2.5 LR Wagner JAMA, 1996

34 Duration of pain > or <24 hours Anorexia Nausea Constipation Lethargy Dysuria Uncertain diagnostic value

35 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

36 What labs should I get?

37 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

38 CBC Different WBC cut offs examined >10,000 LR+ 2.0 (95% CI ) LR (95% CI ) summary of 4 studies >15,000 LR+ 1.7 (95% CI ) LR (95% CI ) summary of 3 studies ANC >6750 (Kharbanda Pediatrics, 2005) LR+ 2.0 Sens 0.97 LR Spec 0.51

39 CRP Acute phase reactant Above normal within 6 hours Peaks at 48 hours CRP LR+ LR- SENS SPEC > % 80% > % 33-82% > % 44% All have wide 95% CI Serial measurements may be more useful

40 ESR >20 LR+ 3.8 Normal LR Other labs Calprotectin (Academic Emerg Med, 2010) Sens 93% Spec 54% Lactate not useful in children Procalcitonin no evidence yet

41 I like adding Can t I calculate a score for appendicitis?

42 Pediatric Appendicitis Score 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 > Max 10 2 Low likelihood 3-6 Equivocal 7 High likelihood PAS 6 LR+ 2.4 LR Sens 82% Spec 65% Samuel - J of Pediatr Surg, 2002

43 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 Compatible 7-8 Probable 9-10 Very probable Alvarado 7 LR+ 4.0 LR Sens 72-93% Spec 81-82% Alvarado Annals of Emerg Med, 1986

44 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

45 Just tell us already, Ultrasound or CT!

46 Plain radiographs Insensitive Not specific Stool load Appendicolith AP Bottom line: You don t need it 2x

47 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

48 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

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50 Ultrasound Up to 10% inconclusive Use to confirm, not exclude appy

51 CT Findings Diameter >6mm Wall >1mm thick Periappendiceal inflammatory changes: Fat streaks Phlegmon Fluid collection Extraluminal gas Other: adenopathy, appendicolith, abscess

52 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

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55 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

56 The evidence CT scans have a better ability to correctly identify and to rule out acute appendicitis U/S LR+ LR- Sens Spec % 94% CT % 95% Doria - Radiology, 2006

57 Sample cost of select studies Ultrasound Single quad: $540 + $350 for Radiology read Abdomen: $540 + $260 for Radiology read CT Abdomen: $ $550 for Radiology read Pelvis: $ $521 for Radiology read

58 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

59 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

60 What if the appy is perforated?

61 Complicated appendicitis 1/3 overall (17-42%) <4 years old % years old 10-20% More Medicaid patients have complicated appy OR=1.3 (Bratton Pediatrics, 2000)

62 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

63 Symptoms of perforated appy Generalized peritonitis Fever o C WBC high w/ left shift Younger kids have less omentum = widespread pus Overall appy mortality % Fun fact: #2 missed diagnosis malpractice claims

64 Management Henry - J Pediatr Surg, 2007 Case-control of immediate surgery vs. nonoperative 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%)

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66 You got anything else?

67 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

68 Ultimately it s the surgeons choice Antibiotics No difference between single and dual/triple drug regimens

69 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

70 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 years are 2.5x times more likely than same-age males

71 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?

72 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)

73 References Alvarado A. A Practical Score for the Early Diagnosis of Acute Appendicitis. Annals of Emerg Med. 1986; 15; 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 Oct;50(4): 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 Bundy, D. G. et al. Does this child have appendicitis? JAMA 2007; 298: Doria, A S et al. US or CT for diagnosis of appendicitis in children and adults? A meta-analysis. Rad 2006; 241: Henry MC, Gollin G, Illam S, et al. Matched analysis of nonoperative management vs immediate appendectomy for perforated appendicitis. J Pediatr Surg. 2007,42: Jo, Y. H. The accuracy of emergency medicine and surgical residents in the diagnosis of acute appendicitis. Am J Emerg Med Sep;28(7): 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 Kharbanda, AB, Taylor, GA, Bachur, RG. Comparison of rectal and IV conrast CT with IV contrast CT for the diagnosis of appendicitis. Radiology Kutasy, B. et al. Is C-reactive protein a reliable test for suspected appendicitis in extremely obese children? Pediatr Surg Int Jan;26(1): Nelson textbook of Pediatrics 17 th Edition. Samuel, M. Pediatric appendicitis score. J Pediatr Surg 37: , Wagner, J. M. et al.does This patient Have Appendicitis? JAMA. 1996;276(19): Up To Date online: Acute appendicitis in children: Clinical manifestations and diagnosis. accessed 10/29/2010.

74 Noon Conference Appendicitis Brad Sobolewski, MD Pediatric Emergency Medicine Fellow