Mean platelet volume indicator for systemic inflammation in cirrhotic patients with spontaneous bacterial peritonitis

Abstract

Introduction: spontaneous bacterial peritonitis (SBP) is the most common infection in patients with cirrhosis [1] .Spontaneous bacterial peritonitis is found in patients where besides the increase of polymorphonuclear counting, they present a positive result of culture [2] . The BMN count as not always quickly available in clinical practice and the culture result usually takes 72 hours or more [3] .The use of additional markers that are rapidly and easily applicable, may add significant benefit for predicting the development of spontaneous bacterial peritonitis and achieving diagnostic accuracy [4] .Platelet size is a determinant factor of platelet proinflammatory functions. Several studies have found relationship between the mean platelet volume (MPV) and pro-inflammatory conditions, particularly acute infections [5]. Aim: to identify a mean platelet volume (MPV) cutoff value which should be able to predict the presence of sponataneous bacterial peritonitis. Settings and designs: a cross sectional observational study, carried out on 40 patients with AFI and 40 patients without AFI. Methods: Patients were classified into two groups, group A (SBP) which included 40 patients with ascetic fluid PMN count ≤ 250 cells / mm3 and group B (non/SBP) which included another 40 patients with ascetic fluid PMN count < 250 cells / mm3. All studied patients were subjected to history taking, Clinical examination and routine laboratory investigations including: CBC including platelet number and MPV, liver function test including (ALT, AST, albumin, and direct & total bilirubin), kidney function test including (BUN &creatinine), PT, PTT, INR, ESR and CRP .Abdominal-pelvic ultrasonography was done for all patients. Aspirated ascetic fluid samples were immediately examined for bacteriological cultures. Statistical analysis used: Statistical presentation and analysis of the present study was conducted, using the mean, standard deviation, independent samples t-test, Chi-square, Mann-Whitney U test and Analysis of variance [ANOVA] tests by SPSS version 22 software .Tukey test was used .Receiver operating characteristic (ROC) curve analysis was used to identify optimal cut-off values of MPV and with maximum sensitivity and specificity for differentiation of cirrhotic patients with SBP from those without SBP. Spearman’s correlation analysis was done. Results: MPV was significantly higher in SBP-patients (Group A) than that of non-SBP patients (Group B) (11.6820±1.19303 fL versus 9.0325±1.12441 fL) (P-value = 0.001) .MPV has positive correlation with Ascitic sample TLC and Ascitic sample PMNC in Group A. ROC curve shows that MPV cut off value is10.25with 85% sensitivity and 75% specificity .Conclusion: MPV may serve as a non-invasive, cheap and rapid test for detection and diagnosis of spontaneous bacterial peritonitis (SBP) with a sensitivity and specificity of 85% and 75% respectively.