Is the acidity of ascitic fluid a reliable index in making the presumptive diagnosis of spontaneous bacterial peritonitis?

The role of microvascular thrombosis in sepsis

The acute inflammatory response to sepsis gives rise to significant morbidity and mortality. The mechanisms underlying this form of tissue injury are poorly understood. This review examines the evidence that tissue ischaemia due, to generalized microvascular thrombosis may play an important role. Microvascular thrombosis is probably an adaptive response that prevents bacteria in the tissues reaching the systemic circulation via the capillaries. In time, a definitive response by leucocytes removes the bacteria and repairs the damaged tissues. There is however evidence that if microvascular thrombosis becomes generalized, then extensive tissue ischaemia may precipitate organ failure and death. Post-mortem studies of patients with sepsis demonstrate microvascular thrombi in many organs including the kidney, liver, lung, gut, adrenals and brain, and the degree of organ injury is related to the quantity of thrombi. Furthermore studies in human and animal models of sepsis demonstrate therapies that inhibit coagulation or promote fibrinolysis reduce organ failure and mortality. In view of the personal and economic burdens that tissue injury associated with the acute inflammatory response places on the community, further studies to establish the role of microvascular thrombosis are clearly required. Such studies may lead to new therapies to limit or prevent this form of injury.

Validation of automated blood cell counter for the determination of polymorphonuclear cell count in the ascitic fluid of cirrhotic patients with or without spontaneous bacterial peritonitis

OBJECTIVES

Polymorphonuclear (PMN) cell count in ascitic fluid is the most useful test for the diagnosis of spontaneous bacterial peritonitis (SBP). We evaluated the validity of an automated blood cell counter for the PMN determination in ascitic fluid by comparing it with the traditional hematologic method with a light microscope in a manual counting chamber.

METHODS

A total of 130 ascitic fluid samples were collected from 74 consecutive cirrhotics. The agreement between the two techniques was assessed according to Bland and Altman's method. The sensitivity, specificity, and positive and negative predictive values of the automated blood cell counter were calculated by considering the diagnosis of SBP as a PMN count > or = 250 cells/mm(3), determined by the manual method as the "gold standard."

RESULTS

The mean PMN counts assessed by the manual method and the automated blood cell counter were 124 +/- 301 cells/mm(3) and 130 +/- 339 cells/mm(3), respectively (p = 0.89, ns). The mean +/- SD of the difference between manual and automated measurements was 6 +/- 61 cells/mm(3), whereas the limits of agreement were +127 cells/mm(3) (95% CI = +108 to +147) and -115 cells/mm(3) (95%CI = -96 to -135). SBP was diagnosed in 11 patients. All but one were correctly identified with the automated blood cell counter, with a sensitivity of 94% and a specificity of 100%; positive and negative predictive values were 100% and 99.1%, respectively.

CONCLUSIONS

The manual method and the automated blood cell counter have a good agreement in the PMN determination in ascitic fluid, and the automated blood cell counter is a reliable tool for rapid diagnosis of SBP.

Tuberculous peritonitis: diagnostic value of ascitic fluid pH and lactate

BACKGROUND

The analytical pattern of ascitic fluid in peritoneal tuberculosis is frequently similar to that found in other causes of ascites. The diagnostic value of the ascitic fluid pH and lactate in cases of tuberculous peritonitis has not yet been established.

METHODS

Ascitic fluid pH, lactate, total proteins, cell count, lactate dehydrogenase, glucose, and their blood-ascitic gradients were determined in 10 patients with tuberculous peritonitis (group I). These results were compared with those obtained from 40 patients with cirrhotic sterile ascites (group II), 16 patients with spontaneous bacterial peritonitis (group III), and 18 patients with malignant ascites (group IV).

RESULTS

A decreased pH and an elevated lactate level in ascitic fluid were found in patients in group I in comparison with those in group II (p < 0.001). No significant differences were found between group I and groups III and IV. The arterial blood-ascitic fluid pH gradient was more than 0.10 (p < 0.001), and the ascitic fluid-serum lactate gradient was greater than 15 mg/dl (p < 0.001) in group I when compared with group II. No significant differences were found between group I and groups III and IV.

CONCLUSIONS

Ascitic fluid pH and lactate are useful markers in differentiating tuberculous peritonitis from cirrhotic sterile ascites. However, these variables lack specificity, as they are also decreased and increased, respectively, in cases of malignant ascites and spontaneous bacterial peritonitis.

Ascitic fluid analysis in hepatocellular carcinoma

BACKGROUND

Ascites in patients with hepatocellular carcinoma (HCC) is a poorly characterized subgroup of malignancy-related ascites. Not only the underlying liver disease, but also the tumor growth and spread contributes to the ascites formation. The authors differentiated ascites in HCC from other types of ascites.

METHODS

The authors analyzed the ascitic fluid of 185 consecutive patients (89 liver cirrhosis, 33 HCC, 31 peritoneal carcinomatosis, 22 liver metastases, 10 spontaneous bacterial peritonitis).

RESULTS

Each subgroup showed a typical pattern. Compared with the cirrhotic patients, those with HCC showed a higher frequency of positive cytologic findings (4 of 33 versus 0/89, P < 0.004), elevated fibronectin concentration (10/33 versus 8/89, P < 0.004), and elevated polymorphonuclear cell count (10/33 versus 5/89 P < 0.004).

CONCLUSIONS

A significant number of patients with ascites and HCC patients showed signs of peritoneal infiltration with positive cytologic findings and increased concentration of fibronectin. Moreover, neutrocytic ascites without signs of superinfection is relatively common (30%).

Ascitic fluid polymorphonuclear cell count and serum to ascites albumin gradient in the diagnosis of bacterial peritonitis

The analysis of ascitic fluid has been complicated by several recently reported new tests. To simplify this assessment, we evaluated nine parameters prospectively and simultaneously in blood and ascitic fluid from 285 patients with ascites to determine which were the most reliable for immediate diagnosis of the etiology of the ascites and of its complications. Subjects were first divided into four groups: sterile cirrhotic ascites (n = 201), spontaneous bacterial peritonitis (n = 41), malignant ascites (n = 34), and miscellaneous ascites (n = 9). An ascitic fluid polymorphonuclear count greater than 500/microliters was the test with the greatest accuracy (96%) for the diagnosis of spontaneous bacterial peritonitis. Neither the most precise cutoff values for ascitic fluid pH (less than 7.32) and ascitic fluid lactate (greater than 32 mg/dl), nor their respective blood-ascitic fluid gradients (greater than 0.11 and less than -20 mg/dl) were more reliable indexes of spontaneous bacterial peritonitis, mainly due to the decreased ascitic fluid pH and increased ascitic fluid lactate observed in malignant ascites, tuberculous peritonitis, and pancreatic ascites. A blood-ascitic fluid albumin gradient less than 1.1 g/dl was the most accurate parameter for the diagnosis of malignant ascites (diagnostic efficacy, 93%). Therefore, the etiologic analysis of ascitic fluid might be simplified and the single practice of two tests, ascitic fluid polymorphonuclear cell count and blood-ascitic fluid albumin gradient, provides immediately useful information.

Recurrence of spontaneous bacterial peritonitis in cirrhosis: frequency and predictive factors

We investigated whether spontaneous bacterial peritonitis in cirrhosis is a recurrent process and attempted to identify possible predictors of recurrence in 75 consecutive cirrhotics who had recovered from a first episode of spontaneous bacterial peritonitis between January, 1981 and December, 1984 and who were followed closely throughout their illness (follow-up period 10 +/- 13 months; mean +/- S.D.). Thirty-eight patients (51%) developed one or more episodes of spontaneous bacterial peritonitis during follow-up, the probability of recurrence (Kaplan-Meier's method) being 43% at 6 months, 69% at 1 year and 74% at 2 years. Twenty-three variables (age, sex, etiology of cirrhosis, standard liver and renal function tests and characteristics of the first spontaneous bacterial peritonitis) were analyzed as possible predictors of recurrence of spontaneous bacterial peritonitis. In univariate analysis (curves of Kaplan-Meier compared with Mantel-Cox's method), serum bilirubin greater than 4 mg per dl, prothrombin less than or equal to 45% and protein concentration in ascitic fluid less than or equal to 1 gm per dl were significantly (p less than 0.05) associated with a high risk or recurrence of spontaneous bacterial peritonitis. In multivariate analysis (Cox multiple regression model), only ascitic fluid protein concentration (p = 0.005) and prothrombin activity (p = 0.009) were found to be independent predictors of recurrence of spontaneous bacterial peritonitis. Fifty-nine patients (79%) died during follow-up, 18 of them (31%) secondary to spontaneous bacterial peritonitis. The 1-year survival probability in the whole series of patients was 38%.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous bacterial peritonitis in cirrhosis. Incidence, diagnosis, and prognosis

Among 342 consecutive patients admitted to the hospital with cirrhosis of the liver 68 (17%) had ascites and had a diagnostic paracentesis performed. Fourteen episodes of peritonitis were diagnosed in 13 patients, which is an overall incidence of peritonitis of 19%. The incidence of peritonitis was 36% in patients with hepatic encephalopathy and 10% in patients without hepatic encephalopathy (P less than 0.01). In all except one case the infecting organism was most likely of enteric origin--that is, gram-negative or anaerobic species. The infected patients had lower mean ascites pH and higher mean ascites leukocyte and polymorphonuclear cell counts than non-infected patients. However, there was a considerable overlap between the two groups, and the diagnostic sensitivity did not exceed 65% for any of these three features. The survival of infected patients without encephalopathy was 33%, which was significantly lower (P less than 0.05) than that the 89% for non-infected patients. In patients with encephalopathy the survival was identical for infected and non-infected patients.