Prevalence, clinical and laboratory characteristics of patients with spontaneous bacterial peritonitis in cirrhotic ascites at Mulago Hospital

Abstract

Introduction and rationale: Patients with cirrhosis and ascites show a higher susceptibility to bacterial infections. In these patients, spontaneous bacterial peritonitis may occur in up to 25% of the cases and is usually severe. The symptoms and signs of this complication are variable. SBP may be asymptomatic in about one-third of patients. In 65-70% of cases Gram-negative bacilli especially E. coli are involved, Gram-positive bacilli in 30% and anaerobes in a minority of patients. The magnitude of SBP and the best antibiotics to use in treating SBP in our setting are unknown. It is also important to identify cirrhotic patients who are likely to have an episode of SBP so that investigations and treatment are initiated in a timely manner. Objectives: To determine the prevalence and describe the clinical and laboratory characteristics of patients with Spontaneous Bacterial Peritonitis at Mulago hospital, Gastroenterology ward. Methods: This was a cross sectional study, which took place between October 2010 to February 2011. It was conducted in the gastroenterology ward of Mulago hospital on patients aged ≥13 years. 137 consecutive patients were screened and 108 patients with sonographically and clinically diagnosed cirrhosis, presenting with grade 2 or 3 ascites were recruited after informed consent. A pre-tested and standardized questionnaire was administered to obtain information on patients from whom a sample of ascitic fluid was drawn by the PI or a trained research assistant. Ascitic fluid was immediately inoculated at bedside into culture bottles and sent to the laboratory for aerobic cultures. Ascitic fluid was also analyzed for total and differential leukocyte count as well as albumin estimation. Culture positive ascitic fluid was morphologically determined and gram-stain done and subsequently subjected to an antibiogram to determine the antibiotic sensitivity of the identified organisms to the common antibiotics. Individual patients were identified using study numbers. Study tools were kept well for safety and confidentiality. Data was analyzed using SPSS version 11.0. Results: One hundred eight patients were recruited in the study. There were sixty seven (62%) males and 41 females (38%) with a mean age of 42.8(±15.5) years with a median of 39 years and a range of 17 – 89 years. A big proportion of the study participants 70 (64.8%) were < 45 years of age. There was one minor aged 17years.Thirty two (29.6%) of these were found to have SBP, with the majority being the Culture Negative Neutrocytic Ascites variant. Characteristics that were likely to be observed among SBP patients included; Secondary/tertiary education, (OR 2.64, p=0.032), a recent paracentesis (OR 4.91, p= 0.001), jaundice (OR 3.76, p=0.005), encephalopathy (OR 3.98, p=0.021), serum bilirubin≥2mg/dl (OR 3.01, p=0.010) and a serum creatinine >1.1mg/dl (OR 2.47, p=0.033). Klebsiella pneumoniae(ESBL) was isolated in two cultures, only sensitive to Imipenem. One culture grew Strep. pneumoniae that was sensitive to erythromycin and clindamycin. Conclusion: The prevalence of Spontaneous Bacterial Peritonitis among cirrhotic patients on the gastroenterology ward is 29.6%. Cirrhotic ascites patients admitted with features of upper GI bleeding, history of a paracentesis, hepatic encephalopathy, jaundice, high total bilirubin and a high serum creatinine are more likely to have an episode of SBP. Therefore clinicians should be on the look out for these features to help them raise their suspicion of the diagnosis of SBP.