Diagnosis of Acute Appendicitis in Children Clinical Trial
Official title:
BUILDING UP A DIAGNOSTIC MODEL OF ACUTE APPENDICITIS IN CHILDREN USING URINARY 5-HYDROXY INDOL ACETIC ACID
it is randomized control study. two groups of children (n=191) were divided into two groups A and B. Group A included children subjected to the classical protocol of diagnosis of acute appendicitis. this protocol consisted of pediatric appendicitis score evaluation, pelvi abdominal ultrasound and measurement of serum CRP. Group B, children had the same previous assessment plus measurement of urinary 5-HIAA.
1.1- Study design: Patients were randomly categorized into two groups A and B. Randomization
was achieved using closed envelop method.
Group A (n= 95) included patients that were evaluated using our institutional protocol. This
protocol consists of assessment of children using PAS, ultrasound of abdomen and pelvis and
serum levels of C-reactive protein.
Group B (n= 96) included children that were evaluated by our institutional protocol. In
addition, all children gave a mid- stream urine sample for spot urinary 5-HIAA detection.
Detailed history was taken. This mainly was to exclude cases with history of foods or drugs
that may affect level of serotonin in urine such as mono amino oxidase inhibitors.
All related clinical data and laboratory investigations were recorded. 1.2- Quantitation of
urinary 5-HIAA level: From each participant, a random urine sample was obtained to assess the
urinary 5-HIAA level using a solid phase competitive enzyme-linked immunosorbent assay
(ELISA) technique. The commercial kit was purchased and provided by LDN, DN Labor Diagnosika
Nord GmbH & Co. Nordhorn, Germany; Catalog #: BA E-1900. As stated by the manufacturer, the
urine samples were methylated to derivatize the 5-HIAA. On the provided microtitre plate, the
methylated standards, controls and samples are added. 5-HIAA antiserum was then added and
incubated for 1 hour. After equilibration, excess free antigen and antigen-antibody complexes
are washed out. The affixed bounded antibodies to the solid phase were detected by an
anti-rabbit IgG-peroxidase conjugate using TMB as a substrate. The reaction is measured on a
microplate reader (Tecan Spectra II, Switzerland), at 450 nm. Quantification of unknown
sample concentration is processed by drawing a standard curve with known standard
concentrations. The results of 5-HIAA were divided by urinary creatinine and expressed as
mg/g creatinine. The inter-assay and intra-assay coefficient of variation were 10.8% and 8.6%
respectively.
1.3- Clinical outcome: Diagnosis of acute appendicitis was confirmed by histopathological
examination of resected appendix. According to operative findings and pathological reports,
the condition ranged from negative appendix to different types of acute appendicitis
(catarrhal, suppurative, perforated or gangrenous).
Children did not full filling the requirements for diagnosis as acute appendicitis were
discharged on symptomatic treatment or after referral to pediatric emergency department.
Readmitted cases were recorded. 1.4- Statistical analysis: Statistical analysis was done
using IBM SPSS V. 24 (IBM, NY, USA). A descriptive analysis was obtained for patients
included in the study. Shapiro-Wilk test was conducted to check for normal distribution of
dependent variables, such as urinary 5-HIAA, CRP and histopathological findings. X2 test was
used to compare the categorical data. Student T-test was used to compare the normally
distributed variable between two groups. Mann-Whitney U test and Kruskal-Wallis test were
used for comparing the non-normally distributed variables of two and more than two groups,
respectively. Binary logistic regression was performed to determine the independent
predictors for acute appendicitis and to combine 5-HIAA and PAS results in both groups.
Pearson correlation was used for correlating the urinary 5-HIAA with other acute appendicitis
predictors. Receiver operating characteristic (ROC) curve was constructed to assess the
diagnostic efficacy of acute appendicitis predictors. The optimal cutoff value for each
predictor was assessed via the Youden index. The value of AUC ranged from 0.5 to 1.0. The
ability of a diagnostic test to identify patients with appendicitis was considered optimal as
AUC value reached closer to 1.0. P-value <0.05 was considered significant
;