Relative Value of Clinical, Laboratory and Imaging Tools in Diagnosing Pediatric Acute Appendicitis

Abstract

Objective: Aim of the study was to evaluate the relative value of the tools used to diagnose suspected acute appendicitis (AA) in children.

Methods: A retrospective review of data from 1 848 children admitted to the Pediatric Surgery Department between 2004 and 2008 in our university-affiliated medical center was conducted. A total of 780 children underwent appendectomy at first presentation. Of these patients, 75 children required removal of their appendix during laparotomy for other reasons and 19 had appendectomy following peri-appendicular abscess and were excluded from the study. The study included 686 children (2–16 years of age) with presumed AA managed by appendectomy. Clinical, laboratory, and imaging data were collected and compared to pathology results.

Results: Of the 686 children who underwent surgery for suspected AA, 34 (5%) had a normal appendix (negative appendectomy rate). No statistical differences were found between normal and AA groups with regard to vomiting, diarrhea, pain duration, and peritoneal signs on admission. Children in the AA group were younger (10.9±3.2 vs. 12.1±2.3 years, p=0.004), had higher fever (36.9±0.7°C vs. 37.4±0.8°C, p=0.004), WBC (14.8±4.8 vs. 10.5±4.6×103/mL, p<0.0005), and neutrophil counts (77.2±11.1% vs. 64.0±15.9%, p<0.0005) on admission, and larger appendicular diameters on ultrasound (US) examination (0.9±0.2 cm vs. 0.7±0.08 cm, p<0.0005). The parameters with the highest positive predictive values for AA were WBC (>10×10³/mL), neutrophil (>66%) count on admission (positive predictive value [PPV]=0.971 and 0.975, respectively), and appendicular diameter on US (>6 mm; PPV=0.968). These 3 parameters combined had a PPV of 0.991.

Conclusions: The results of laboratory tests (WBC, neutrophils) and imaging (US) contributed far more than clinical signs and symptoms (pain duration, vomiting, diarrhea, fever, and peritoneal signs at first physical examination) to the correct diagnosis of AA in children. When these 3 parameters were positive, the probability of a false positive (normal appendix) was only 1%. The contribution of US was particularly high as it was used primarily in patients in whom the diagnosis was in doubt and its results matched the final diagnosis better than diagnoses based on clinical signs and symptoms alone. It provides the additional benefit of no radiation exposure.

acute appendicitis - appendectomy - pediatric diagnosis - imaging tools - predictive value

References

• 1 Sakellaris G, Tilemis S, Charissis G. Acute appendicitis in preschool-aged children.  Eur J Pediatr. 2005;  164 80-83
• 2 Doria AS, Moineddin R, Kellenberger CJ. et al . US or CT for diagnosis of appendicitis in children and adults? A meta-analysis.  Radiology. 2006;  241 83-94
• 3 Tseng YC, Lee MS, Chang YJ. et al . Acute abdomen in pediatric patients admitted to the pediatric emergency department.  Pediatr Neonatol. 2008;  49 126-134
• 4 Siegel MJ. Acute appendicitis in childhood: the role of US.  Radiology. 1992;  185 341-342
• 5 Wong KK, Cheung TW, Tam PK. Diagnosing acute appendicitis: are we overusing radiologic investigations?.  J Pediatr Surg. 2008;  43 2239-2241
• 6 Garcia Peña BM, Cook EF, Mandl KD. Selective imaging strategies for the diagnosis of appendicitis in children.  Pediatrics. 2004;  113 24-28
• 7 Brennan GD. Pediatric appendicitis: pathophysiology and appropriate use of diagnostic imaging.  CJEM. 2006;  8 425-432
• 8 Newman K, Ponsky T, Kittle K. et al . Appendicitis 2000. Variability in practice outcomes and resource utilization at thirty pediatric hospitals.  J Pediatr Surg. 2003;  38 372-379
• 9 Henry MC, Walker A, Silverman BL. et al . Risk factors for the development of abdominal abscess following operation for perforated appendicitis in children.  Arch Surg. 2007;  142 236-241
• 10 Flum DR, Morris A, Koepsell T. et al . Has misdiagnosis of appendicitis decreased over time? A population-based analysis.  JAMA. 2001;  286 1748-1753
• 11 Smink DS, Finkelstein JA, Garcia Peña BM. et al . Diagnosis of acute appendicitis in children using a clinical practice guideline.  J Pediatr Surg. 2004;  39 458-463
• 12 Flum DR, Koepsell T. The clinical and economical correlates of misdiagnosed appendicitis: Nationwide analysis.  Arch Surg. 2002;  137 799-804
• 13 Kosloske AM, Love CL, Rohrer JE. et al . The diagnosis of appendicitis in children: outcomes of a strategy based on pediatric surgical evaluation.  Pediatrics. 2004;  113 29-34
• 14 Zampieri N, Corroppolo M, El Dalati G. et al . Correlation between high-resolution ultrasound and surgical/pathological findings in patients with suspected appendicitis.  Minerva Chir. 2008;  63 469-474
• 15 Samuel M. Pediatric appendicitis score.  J Pediatr Surg. 2002;  37 877-881
• 16 Schneider C, Kharbanda A, Bachur R. Evaluating appendicitis scoring system using a prospective pediatric cohort.  Ann Emerg Med. 2007;  49 778-784
• 17 Bhatt M, Joseph L, Ducharme FM. et al . Prospective validation of the pediatric appendicitis score in a Canadian pediatric emergency department.  Academic Emerg Med. 2009;  16 591-596
• 18 Lycopoulou L, Mamoulakis C, Hantzi E. et al . Serum amyloid A protein levels as a possible aid in the diagnosis of acute appendicitis in children.  Clin Chem Lab Med. 2005;  43 49-53
• 19 Gronroos JM, Forsstrom JJ, Irjala K. et al . Phospholipase A2, C reactive protein, and white blood cell count in the diagnosis of acute appendicitis.  Clin Chem. 1994;  40 1757-1760
• 20 Eriksson S, Granstrom L, Olander B. et al . Leukocyte elastase as a marker in the diagnosis of acute appendicitis.  Eur J Surg. 1995;  161 901-905
• 21 Dalal I, Somekh E, Bilker-Reich A. et al . Serum and peritoneal inflammatory mediators in children with suspected acute appendicitis.  Arch Surg. 2005;  140 169-173
• 22 Stefanutti G, Ghirardo V, Gamba P. Inflammatory markers for acute appendicitis in children: are they helpful?.  J Pediatr Surg. 2007;  42 773-776
• 23 Kim E, Subhas G, Mittal VK. et al . C-reactive protein estimation does not improve accuracy in the diagnosis of acute appendicitis in pediatric patients.  Int J Surg. 2009;  7 74-77
• 24 Wang LT, Prentiss KA, Simon JZ. et al . The use of white blood cell count and left shift in the diagnosis of appendicitis in children.  Pediatr Emerg Care. 2007;  23 69-76
• 25 Beltrán MA, Almonacid J, Vicencio A. et al . Predictive value of white blood cell count and C-reactive protein in children with appendicitis.  J Pediatr Surg. 2007;  42 1208-1214
• 26 Johansson EP, Rydh A, Riklund KA. Ultrasound, computed tomography, and laboratory findings in the diagnosis of appendicitis.  Acta Radiol. 2007;  48 267-273
• 27 Yang HR, Wang YC, Chung PK. et al . Laboratory tests in patients with acute appendicitis.  ANZ J Surg. 2006;  76 71-74
• 28 Sengupta A, Bax G, Paterson-Brown S. White cell count and C-reactive protein measurement in patients with possible appendicitis.  Ann R Coll Surg Engl. 2009;  91 113-115
• 29 Amalesh T, Shankar M, Shankar R. CRP in acute appendicitis – is it a necessary investigation?.  Int J Surg. 2004;  2 88-89
• 30 Schwartz DM. Imaging of suspected appendicitis: appropriateness of various imaging modalities.  Pediatric Annals. 2008;  37 433- 438
• 31 Vissers RJ, Lennarz WB. Pitfalls in appendicitis.  Emerg Med Clin N Am. 2010;  28 103-118
• 32 Toorenvliet BR, Wiersma F, Bakker RF. et al . Routine ultrasound and limited computed tomography for the diagnosis of acute appendicitis.  World J Surg. 2010;  34 2278-2285
• 33 Brenner D, Elliston C, Hall E. et al . Estimated risks of radiation induced fatal cancer from pediatric CT.  Am J Roentgenol. 2001;  176 289-296
• 34 Chodick G, Ronckers CM, Shalev V. et al . Excess lifetime cancer mortality risk attributable to radiation exposure from computed tomography examinations in children.  Isr Med Assoc J. 2007;  9 584-587

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