European Journal of Cardiovascular Medicine

Acute appendicitis is one of the most common causes of abdominal pain and is the most frequent cause of emergency abdominal surgery in children. It is common between the ages of 7–15 years but can occur at any age.¹ The diagnosis of acute appendicitis is mainly based on clinical assessment, and this involves the use of well-known symptoms and signs such as right lower quadrant abdominal pain, fever, vomiting, and McBurney's point tenderness.¹ Despite its high prevalence, the diagnosis of appendicitis remains challenging. The diagnosis of appendicitis embodies Sir William Osler‘s spirit when he stated, “Medicine is a science of uncertainty and an art of probability.” The clinical presentation is often atypical and the diagnosis is especially difficult because symptoms often overlap with other conditions.² It has been estimated that the diagnostic accuracy of acute appendicitis is between 70 and 85%, and that up to 50% of patients hospitalized for possible appendicitis have normal appendices.³ Misdiagnosing acute appendicitis is responsible of two types of outcomes: in one hand, a delay in surgical treatment can lead to perforation and peritonitis in up to 15% of the cases and, in the other hand, negative appendectomy which is associated with postoperative complications such as wound infection and adhesions.³ The rate of negative appendectomies in countries, where CT Abdomen is not a recommended diagnostic method, is reported to be between 21% to 26%.⁴ The high rate of negative explorations for appendicitis is a burden faced not only by the surgeons but also by the patients and society as a whole. This is because, like any other operation appendectomy results in socioeconomic impacts in the form of hospital expense, lost working days and delayed productivity.⁵ Equally distressing is the fact that perforation may occur in up to 39% of cases.⁶ So traditionally, surgeons have accepted a high incidence of negative appendectomies in order to decrease the incidence of perforation. This approach is increasingly questioned in today‘s era of evidence-based medicine. The meaningful evaluation of acute appendicitis balances early operative intervention in hopes of preventing perforation against a more restricted approach with the hope of reducing the risk of unnecessary surgery.² Different diagnostic modalities have been developed to facilitate surgical decisions and avert negative appendectomy. To date, many inflammatory markers have been used for the diagnosis of acute surgical conditions, including acute appendicitis.  Leucocyte count and C-reactive protein (CRP) are the most commonly used laboratory tests.⁷ CRP is an acute phase protein that is often relied-on by many surgeons as a diagnostic marker of acute appendicitis.³ The laboratory predictors are not constant and their accuracy is questionable, especially the leucocyte count and C-reactive protein (CRP), which are sensitive tests but are not specific for acute appendicitis. However, a combination of both tests in the presence of symptoms and signs seems to increase their specificity significantly, but the diagnosis of acute appendicitis is unlikely when both investigations are normal.¹ Hence, it was decided to conduct this study to find out the efficacy of the serum levels of CRP, WBC count, and raised neutrophil count as a diagnostic tool for acute appendicitis in order to avoid negative appendectomies. 

AIM:

To evaluate the diagnostic accuracy of C-reactive protein (CRP) and leucocyte count in operated cases of suspected acute appendicitis.

This is a prospective observational study that consists of 50 patients operated on an emergency basis for suspected acute appendicitis admitted in the Department of General Surgery, Mamata General Hospital. The study was conducted from October 2020 – September 2022. A series of 50 cases were compiled for this study during this period, after obtaining clearance from the ethical committee. Analytical data obtained were compared and discussed with data available in the literature.

Inclusion Criteria: 

1. All patients irrespective of sex, admitted with acute abdomen, clinically diagnosed as acute appendicitis and posted for appendectomy.
2. Age group above five years.
3. Patients willing to participate in the study.

Exclusion Criteria:

1. Acute appendicitis patients with associated diseases like: Rheumatoid arthritis, Systemic lupus erythematosus, Gout, Glomerular nephritis, Inflammatory bowel disease, Myocardial infarction, Malignant neoplasm.
2. Any other inflammatory conditions where CRP would be raised .
3. Patients who came for Interval appendicectomy.
4. Patients not willing for surgery.
5. Patient not willing to participate in the study.

METHOD OF COLLECTION OF DATA:

Informed written consent was obtained from the patients after a full explanation of the details of the disease process, options of treatment, possible side effects, and complications of surgery. They were informed of their right to withdraw from the study at any stage. Institutional ethical committee clearance was obtained for the study. Once the patients are admitted, a detailed history was taken along with any comorbidity if present. A general physical examination was done. Per abdomen along with other systemic examinations were carried out and a clinical diagnosis was made. Specific relevant investigations for confirmation of diagnosis like ultrasonography of the abdomen were carried out. CECT of the abdomen was done only in selected cases when indicated. Patients were subjected to routine investigations like complete blood picture, C-reactive protein (CRP) levels, biochemical parameters, serum electrolytes, and viral markers. Rhelax CRP slide test is done for detection of CRP and it is based on the principle of agglutination. The test specimen (serum) was mixed with Rhelax CRP latex reagent and allowed to react for 2 minutes after mixing. The appearance of macroscopic agglutination was taken as positive. The absence of visible agglutination and the presence of opaque fluid constituted a negative reaction. When CRP levels were more than 6mg/dl, agglutination occurs and it was taken as a positive result. WBC counts of more than 11,000/mm3 were considered positive and neutrophil count of more than 75% was considered positive. After pre-anaesthetic evaluation, patients were posted for surgery and various intraoperative parameters like total blood loss, peritonitis, and presence of any other pathology were recorded. Postoperatively clinical diagnosis was compared with that of histopathological examination (HPE). Leucocyte count and C-Reactive Protein levels were correlated with the histopathological diagnosis to determine their diagnostic accuracy in acute appendicitis. The relevant statistical analysis was done using SPSS software version 24.

In the present study out of 50 cases of acute appendicitis, it was observed that 52% were male patients and 48% were female patients. The maximum number of cases were in the age group of 11-29 years (62%). Out of 50 cases in the study group, histopathology confirmed acute appendicitis in 41 cases (82 %). Normal appendices were removed in nine cases (18%). Negative appendectomy rate in this study group was 18%.

TABLES AND FIGURES

Table-1: Correlation of CRP, TLC, Neutrophil percentage with respect to HPE positive and negative cases

Table-2: Statistical data from CRP level, TLC, Neutrophil count in acute appendicitis

*Positive predictive value, **Negative predictive values

Table-3: Correlation of CRP and TLC in acute appendicitis by various authors

Fig-1: Correlation of C - reactive protein in acute appendicitis by various authors.

Fig-2: Correlation of leucocyte count in acute appendicitis by various authors.

Fig-3: Correlation of Neutrophilia in acute appendicitis by various authors.

Correlation of CRP, TLC, Neutrophil percentage with respect to HPE positive and negative cases were shown in table-1.

Statistics from CRP level, TLC, Neutrophil count in acute appendicitis in this study were shown in table-2.

Acute appendicitis is the most common surgical emergency and the most common source of community-acquired intra-abdominal infections. Clinical diagnosis of acute appendicitis is still difficult. Several approaches have been introduced to improve the diagnostic accuracy of acute appendicitis and therefore to reduce complications.

In Acute appendicitis, with the initiation of symptoms, serum inflammatory markers begin to appear in bloodstream within hours. 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 the severity of acute appendicitis.6 C-reactive protein is an abnormal serum glycoprotein produced by the liver during the acute inflammation. Because it disappears rapidly when the inflammation subsides its detection signifies the presence of a current inflammatory process.

CRP production is a non-specific response to disease and it can never on its own be used as a diagnostic test. However, if CRP results are interpreted in the light of full clinical information on the patient, then it can provide exceptionally useful information. Levels of CRP increase very rapidly in response to trauma, inflammation and infection and decrease rapidly with the resolution of the condition. Since an elevated CRP level is always associated with pathological changes, determination of CRP is of great value in diagnosis, treatment and monitoring of inflammatory conditions.7

A complete blood count (CBC), is a very common blood test performed in laboratories, and is performed in emergency room surgeons as part of a preoperative evaluation to determine inflammatory lesions. Increased white blood cell count (WBC) and neutrophil count are the first signs of inflammation in acute appendicitis; nevertheless, the sensitivity and diagnostic value vary broadly, depending on the study population, the duration of symptoms, and laboratory results.8

In the study period from October 2020 – September 2022, around 200 cases were operated on for appendicitis in this institution. Patients who came for interval appendicectomy and patients with other conditions raising CRP values were excluded from the study. 50 patients who fulfilled the criteria and operated for suspected acute appendicitis were taken into this study. The discussion is based on the observations and analysis of the results in the study of 50 cases with regard to age, sex, histopathological positive and negative cases and efficacy of CRP, total leucocyte count (TLC) and differential count (DC) in acute appendicitis.

There was a male predominance (52%) in this study which is comparable with the studies conducted by Al-gaithy 9(59.86%), Rudiman R, et al10 (56.52%), Pinate AR, et al11 (56%) and Halbhavi SN, et al12 (60.66%).

In the present study, it was observed that appendicitis is common in age groups of 20 – 29 years (32%) and 11 – 19 years (30%). Appendicitis reaches peak incidence in the teens and early 20s. These findings were comparable with studies conducted by Halbhavi SN, et al12 and Dimic S, et al.13 In the study conducted by Bilal M, et al14, 75% of study participants were below 25years of age, which is not comparable to present study.

In the present study, clinical diagnosis was found to be confirmed with HPE in 41 patients (82%). This is comparable with the studies done by Al-gaithy, et al9 (93.6%), McGowan DR, et al15 (85.3%) and Bilal M, et al14 (83.2%). Panagiotopoulou IG, et al.16 in their study reported that HPE was confirmed in 64.6 % of cases.

The rate of negative appendectomy in this study was 18%. This is comparable with the studies conducted by Daldal E, et al17 (13.7%) and Maghsoudi LH, et al18(15%).

In 1984, for the first time, studies on the relation of acute appendicitis with serum C-reactive protein were reported. In several studies, the sensitivity of C-reactive proteinfor the diagnosis of acute appendicitis was 40-87%, the specificity was 53-82%, and diverse results were reported.19 In the present study, out of the 41 HPE positive patients, 30 (73.18 %) patients had raised CRP and 11 (26.87%) patients had normal CRP. Out of the nine HPE negative patients, all nine (100%) had normal CRP. The sensitivity and specificity of CRP in case of acute appendicitis were 73.18 % and 100% respectively in this study. This is comparable to the results of various authors as shown in figure-1.

Out of 50 study cases, 41 cases were HPE positive. Among them 31 (75.6 %) cases had raised TLC and 10 (24.3%) cases had normal TLC. Out of the 9 HPE negative cases, all 9 (100%) had normal TLC. On correlating TLC with HPE positive and negative cases, it was found that the sensitivity and specificity of the WBC count was 75.6 % and 100 % respectively. It is comparable with the studies done by various authors as shown in figure-2.

Out of 41 HPE positive cases, 36 cases (87.89%) had raised neutrophil counts and five (12.11 %) had normal neutrophil counts. Out of nine HPE negative cases, all the nine (100%) had normal neutrophil counts. In this study, Neutrophilia of more than 75% was seen in 72 % of cases. It is comparable with other studies as shown in figure-3.

In this study, total leucocyte count and CRP in combination were correlated with histopathological positive and negative cases. The sensitivity and specificity when combined in acute appendicitis was 63.5 % and 100 % respectively. None of the cases with HPE negative results had increase in CRP, WBC count or Neutrophilia. Same observations were found by many authors as shown in table-3. When the combined value of CRP, WBC and raised neutrophil count is taken into consideration negative value was important. In this study, negative appendectomy rate was 18%. All the cases with negative HPE had normal C reactive protein, total leucocyte count, and neutrophil count. Avoiding surgery in these cases could have reduced the negative appendicectomy rate considerably. This is particularly useful in rural areas where access to imaging modalities is limited.

One limitation of this study was its small study group. However, the parameters used are accessible anywhere, suitable for use in multiple settings, cost-effective and applicable to patients on whom some advanced imaging techniques cannot be used, such as pregnant women and in rural set ups where ultrasound imaging is not available.

It was concluded from this study that normal preoperative serum CRP levels, TLC & DC in patients with clinically suspected acute appendicitis are most likely associated with a normal appendix. By avoiding surgeries in such cases, we can avoid negative appendectomy rates. Hence, it is recommended that the inclusion of CRP along with TLC and DC as an investigative protocol in clinically suspected cases of acute appendicitis will definitely help in reducing negative appendectomy rates.

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