The Role of C-Reactive Protein , Granulocyte Colony Stimulating Factor and Total Antioxidant Capacity in Diagnosis of Acute Appendicitis

Background and Aim: Despite the fact that acute appendicitis is the most common surgical emergency all around the world, its diagnosis is still based on clinical evaluation and accuracy of the diagnosis depending on experience. The aim of this study is to evaluate the role of inflammatory markers in diagnosis of acute appendicitis. Material and Method: The study includes 77 cases with histopathologically proven acute appendicitis and 17 control cases. Blood samples were obtained from all cases and C-reactive protein (CRP), Granulocyte Colony Stimulating Factor (G-CSF) and Total Antioxidant Capacity (TAC) were measured. Findings: In cases with acute appendicitis, CRP and G-CSF levels were found to be related to acute appendicitis; however, TAC was not affected by the disease process. Moreover, CRP and G-CSF levels were correlated with the disease severity. Conclusion: Both CRP and G-CSF can be used in diagnosis of acute appendicitis. Furthermore, increased CRP level can be a marker to show advanced cases. However, G-CSF is not an effective marker to show disease severity.


Introduction
Despite the fact that acute appendicitis (AA) is the most common surgical emergency all around the world, its diagnosis is still based on clinical evaluation and accuracy of the diagnosis depending on experience [1]- [4].
In AA, with the initiation of symptoms, serum inflammatory markers begin to appear in blood stream within hours [5].
C-reactive protein (CRP) as a nonspecific indicator of inflammation is shown to be an indicator of acute appendicitis and reported to be a reliable indicator of severity of AA [6] [7].Besides mobilizing neutrophils from bone marrow, Granulocyte colony stimulating factor (GCSF) is known to have inflammatory effects.
Increased G-CSF levels are shown in inflammatory disorders [8].There is little data about the use of G-CSF in diagnosis of AA [9].In a study, it is found to be useful in staging of AA [10].
The role of free oxygen radicals in inflammatory status is well known.Plasma total antioxidant status (TAS) is an indicator of anti-oxidant defense status and a well-established marker of oxidative stress [11].
The aim of this study is to evaluate the role of inflammatory markers (CRP, G-CSF and TAS) in diagnosis of AA.

Material and Method
After approval from University Ethical Committee, the study was conducted in between January 2013 and January 2014.In this period serum samples of the patients with diagnosis of acute appendicitis were collected.For the control group, blood samples were taken from healthy volunteers who did not have any inflammatory disorder.An informed consent was obtained from all the cases.All serum samples were stored at −80 Celsius.
After the operation all specimens were histopathologically examined and only the cases with histopathologically proved diagnosis of acute appendicitis were included in the study group.
From the blood samples CRP, G-CSF and AC were measured.

Statistical Analysis
Statistical analysis was performed by IBM SPSS Statistics version 20.Data were presented as mean ± standard deviation.Chi square and Student T tests were used and statistical significance was accepted as 0.05.

Results
There were 94 patients included in the study.The mean age of the patients was 30.6 ± 12.9.There were 77 cases in study group (60 cases with simple appendicitis and 11 cases with perforated appendicitis) and 17 cases in control group.Mean CRP level was significantly higher in appendicitis group (0.53 for controls and 36.12 in study group) (p < 0.001).Moreover, mean CRP level was significantly higher in perforated cases compared to simple appendicitis (57.68 vs. 33, respectively) (p < 0.001).According to the ROC curve the optimal CRP value for discrimination of perforated appendicitis from uncomplicated appendicitis was found to be 15.3 with a sensitivity of 63.6% and specificity of 43.4% (AUC: 0.572, p < 0.001).
Mean G-CSF levels were also higher in appendicitis group than controls (1.11 vs. 0.26, respectively) (p < 0.05).According to the ROC curve the optimal GCSF value for acute appendicitis was found to be 0.4 with a sensitivity of 71.4% and specificity of 76.5% (AUC: 0.837, p < 0.001) In terms of TAC there was no significant difference between any groups.Mean CRP, G-CSF and TAS levels were presented in Table 1 and Table 2.

Discussion
Although AA is the most common emergency surgical condition the accuracy of clinical diagnosis is still between 71% -97% [4].This report reveals that serum CRP and G-CSF levels are increased in AA and this increase is more relevant in perforated cases.However, serum TAS has no difference between AA and control patients.
The increase in CRP levels in AA cases has shown in several studies.Xharra et al., in a prospective study, reported increased CRP levels in AA [12].Moreover, they reported a positive correlation between CRP levels  and AA severity.Furthermore, Erkasap et al. reported sensitivity and specificity of CRP as 96% and 78%, respectively and positive predictive value as 100% [13].However, according to Shakhatreh et al.CRP is not superior to white blood cell count in diagnosis of AA [14].In our study CRP levels are found to be elevated in AA, moreover, it correlates with severity of the disease.Granulocyte colony stimulating factor is produced in inflammatory site and transported to bone marrow to stimulate granulocyte synthesis [15].There are little and controversial data about the use of G-CSF in AA diagnosis.Dalal et al. reported that there is not any significant increase in levels of G-CSF in AA [9].In contrast, Allister et al. found that when compared to normal population, in AA G-CSF levels increase significantly [10].Moreover, they concluded that, G-CSF can be useful adjunctive test in diagnosis and staging of AA.Similarly in our study G-CSF levels are found to increase in AA.However, there is no significant difference in perforated cases, compared to simple AA.
Total anti-oxidant status is a well known marker of oxidative stress.There are several clinical and experimental studies showing the role of reactive oxygen species in acute inflammation [16]- [18].Furthermore, these studies reported that the activity of those reactive oxygen species is correlated with the severity of AA.However, in a prospective study, Özdoğan et al concluded that, TAS is decreased advanced AA cases; however, it cannot be used in diagnosis of acute appendicitis.In our study, there is no significant correlation between AA and TAS.TAS level was similar in both AA and control groups.

Conclusion
Both CRP and G-CSF can be used in diagnosis of acute appendicitis.Furthermore, increased CRP level can be a marker to show advanced cases.However, G-CSF is not an effective marker to show disease severity.TAC is useless both in diagnosis and estimating the progression of acute appendicitis.

Table 1 .
CRP, G-CSF and TAS levels compared to control group.* Appendicitis indicates all cases with simple and perforated cases; *** Values are compared to control group.CRP: C-reactive protein, G-CSF: Granulocyte colony stimulating factor, TAS: total antioxidant capacity. *

Table 2 .
Comparison of CRP, G-CSF and TAS levels in Simple appendicitis and perforated cases.