White count, pH and lactate in ascites in the diagnosis of spontaneous bacterial peritonitis

An exploratory study of ascitic fluid lactate as prognostic factor of mortality in cirrhotic patients with spontaneous bacterial peritonitis

BACKGROUND

The diagnostic value of ascitic fluid lactate (AF lactate) was previously evaluated in spontaneous bacterial peritonitis (SBP) but its prognostic value was not established.

AIM

To assess the prognostic value of AF lactate in SBP.

METHODS

We prospectively studied 63 consecutive patients with SBP. Fifty patients with acute-on-chronic liver failure (ACLF) or acute decompensation (AD) (ACLF/AD group) without SBP and 30 with stable decompensated cirrhosis (DC) were included as controls. In SBP, mortality was recorded at 30, 90 and 180 days.

RESULTS

Arterial and AF lactate were significantly higher in SBP compared to other groups. Analyzing the SBP group alone, AF lactate accurately differentiated survivors from nonsurvivors in all time points. The prognostic performance of AF lactate was improved over time, with the area under the receiver operating characteristic computed at 0.894, 0.927 and 0.934 at 30, 90 and 180 days, respectively. The cutoff level of 2 mmol/L was associated with 100, 100 and 94.7% sensitivity, 57.9, 73.3 and 80% specificity, 61, 80.5 and 87.8% positive predictive value and 100, 100 and 90.9% negative predictive value, respectively. Arterial lactate, neutrophil-to-lymphocyte ratio (NLR) and Model for End-Stage Liver Disease (MELD) score predicted outcomes less accurately than AF lactate. Patients with AF lactate >2 mmol/L had a worse prognosis compared to patients with ≤2 mmol/L (log-rank P < 0.001). No case with AF lactate ≤2 mmol/L died within 90 days postSBP diagnosis. In Cox multivariate analysis at all time points, only AF lactate and NLR were independent predictors of mortality.

CONCLUSION

An AF lactate level of 2 mmol/L has a high ability to differentiate survivors from nonsurvivors in the first 180 days postSBP. Its prognostic value outperformed arterial-lactate, NLR and MELD.

Use of a Variety of Biological Parameters in Distinguishing Cirrhotic from Malignant Ascites

Twenty-two different protein measurements were taken in the serum and ascitic fluid of fifty consecutive patients in an attempt to investigate which tests are the most reliable for the differential diagnosis of ascites. Serum and ascitic fluid total proteins (TPR), albumin (ALB), lactate (LAC), ferritin (FER), C3 and C4 complement factors, C-reactive protein (CRP), ceruloplasmin (CER), α2-macroglobulin (α2MG), haptoglobin (HAP), α1-antitrypsin (α1AT), α1-acid glycoprotein (α1AG), transferrin (TRF), immunoglobulins IgG, IgA, IgM and cytokines such as interleukin-1α (IL-1α), interleukin-1α (IL-1α), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α) were measured to distinguish between malignant and cirrhotic ascites. Correlations and non-parametric Mann-Whitney tests were used for ascitic fluid:serum ratio comparisons between the two groups. Multivariate analyses were used to determine the most significant biochemical ratio predictors for the differential diagnosis and a recursive partitioning model was constructed. Highly positive correlations (r>0.50) were found between the ratios IgA, IgG, IgM, CER, α2 MG, HAP, α1AT, α1AG and TRF. There was evidence that TPR, ALB, LAC, FER, IgG, CER, α2MG, α1AT, α1AG, TRF and IL-8 ascitic fluid:serum ratios are significnatly higher in patients with malignant neoplasms than in cirrhotics. In the recursive partitioning model the most significant parameters were found to be the ratios of albumin and IL-1a. The model fitted allowed for 100% correct classification of ascites. In conclusion, we have shown that a simple and very accurate model based on two ascitic fluid: serum measurements is able to differentiate between malignant and non-malignant ascites.

Clinical relevance and contemporary methods for counting blood cells in body fluids suspected of inflammatory disease

In many inflammatory diseases, the cellular components in body fluids [cerebrospinal fluid (CSF), serous fluids] are increased, rendering essential diagnostic information. The diagnostic value of the total white blood cell count (WBC) and differential count has been evaluated extensively over the years, and a remarkable amount of knowledge has been gained; yet, there is a great deal of clinical uncertainty whether the diagnosis should be based solely on these variables. In some diseases, such as peritonitis, the total WBC and differential count has high sensitivity; whereas, in differentiating pleural effusions, it lacks the sensitivity required to be clinically useful. Nevertheless, many guidelines consider these tests as cornerstone parameters, and in combination with clinical variables, they can successfully guide clinical decision making in initiating or postponing a treatment course for infection and/or inflammatory diseases while awaiting culture results. Although other methods are available for detecting and differentiating WBCs in body fluids, manual microscopy is still considered the gold standard despite its many limitations. During the last decade, automated analyzers have become a popular method for first line screening. Continued progress in their design has led to major improvements including their speed, improved accuracy and lower variability compared with microscopy. Disadvantages of this method include high imprecision in low ranges (depending on the method) and interfering factors. In a time where automation is at the front line in clinical laboratories, it is essential the results obtained are precise, accurate and reproducible. This review provides an overview of the relevance for cell counting in a variety of diagnostic body fluids, and highlights the current technologies used.

Diagnosis of spontaneous bacterial peritonitis and an in situ hybridization approach to detect an "unidentified" pathogen

Spontaneous bacterial peritonitis (SBP) is a frequent and severe complication in cirrhotic patients with ascites. Although identifying the pathogen(s) plays a major role in the management of infectious diseases, ascitic fluid cultures often show negative results in patients with clinical signs and symptoms of SBP, and ascitic fluid cell analyses are the gold standard method for diagnosing SBP. SBP is generally diagnosed based on an increased number of polymorphonuclear neutrophils in the ascitic fluid (>250/mm(3)), and the identification of the causal pathogen may not be given consideration. We newly developed an in situ hybridization (ISH) method to provide early and direct evidence of bacterial infection in ascites in patients with SBP. This paper will review the diagnosis of SBP, including our novel approach with ISH method to detect bacterial DNA in SBP ascitic fluid.

Ascites and spontaneous bacterial peritonitis: recommendations from two United States centers

Cirrhosis affects millions of people throughout the world. Two of the most serious complications of liver cirrhosis are ascites and spontaneous bacterial peritonitis (SBP). The development of ascites is related to the severity of portal hypertension and is an indicator of increased mortality. Although sodium restriction and diuretic therapy have proven effective, some patients may not respond appropriately or develop adverse reactions to diuretic therapy. In such cases, interventions such as transjugular intrahepatic portosystemic shunt (TIPS) placement are warranted. SBP is a complication of ascites that confers a very high mortality rate. Recognition and prompt treatment of this condition is essential to prevent serious morbidity and mortality. Initiation of prophylaxis in SBP remains controversial. Given the burden of liver cirrhosis on the health care system, ascites and SBP will continue to provide challenges for the primary care provider, hospitalist, internist, and gastroenterologist alike.

Diagnosis of spontaneous bacterial peritonitis and an in situ hybridization approach to detect an "unidentified" pathogen

Spontaneous bacterial peritonitis (SBP) is a frequent and severe complication in cirrhotic patients with ascites. Although identifying the pathogen(s) plays a major role in the management of infectious diseases, ascitic fluid cultures often show negative results in patients with clinical signs and symptoms of SBP, and ascitic fluid cell analyses are the gold standard method for diagnosing SBP. SBP is generally diagnosed based on an increased number of polymorphonuclear neutrophils in the ascitic fluid (>250/mm(3)), and the identification of the causal pathogen may not be given consideration. We newly developed an in situ hybridization (ISH) method to provide early and direct evidence of bacterial infection in ascites in patients with SBP. This paper will review the diagnosis of SBP, including our novel approach with ISH method to detect bacterial DNA in SBP ascitic fluid.

Measurement of calprotectin in ascitic fluid to identify elevated polymorphonuclear cell count

AIM: To evaluate the diagnostic capability of calprotectin in ascitic fluid for detecting a polymorphonuclear (PMN) cell count > 250/μL ascites.

METHODS: In this prospective observational study, a total of 130 ascites samples were analysed from 71 consecutive patients referred for paracentesis. Total and differential leukocyte cell counts were determined manually with a Neubauer chamber and gentian-violet stain. Calprotectin was measured in 1 mL ascetic fluid by enzyme-linked immunosorbent assay (ELISA) and a point-of-care (POC) lateral flow assay with the Quantum Blue^® Reader (Bühlmann Laboratories). All measurements were carried out in a central laboratory by senior personnel blinded to patient history. A PMN count > 250/μL was the primary endpoint of the study. The diagnostic value of ascitic calprotectin measurement was assessed by comparing to the final diagnosis of each patient that had been adjudicated by investigators blinded to calprotectin values.

RESULTS: The PMN count was > 250/μL in 19 samples (14.6%) from 15 patients (21.1%) and varied widely among the study population (range 10-19 800/mL and 1-17 820/mL, respectively). Spontaneous bacterial peritonitis (SBP) was the final diagnosis in four patients (5.6%). All patients with PMN ≤ 250/μL had negative bacterial culture. PMN count was elevated in five patients with peritoneal carcinomatosis, three with lymphoma, one with neuroendocrine carcinoma, and two with secondary peritonitis due to abdominal perforation. PMN cell counts correlated with ascitic calprotectin values (Spearman’s rho; r = 0.457 for ELISA, r = 0.473 for POC). A considerable range of ascitic calprotectin concentrations was detected by ELISA [median 0.43 μg/mL, interquartile range (IQR) 0.23-1.23 (range 0.10-14.93)] and POC [median 0.38 μg/mL, IQR 0.38-0.56 (range 0.38-13.31)]. Ascitic calprotectin levels were higher in samples with PMN > 250/μL, by both ELISA [median (IQR) 2.48 μg/mL (1.61-3.65) vs 0.10 μg/mL (0.10-0.36), P < 0.001] and POC [2.78 μg/mL (2.05-5.37) vs 0.38 μg/mL (0.38-0.41), P < 0.001]. The area under the receiver operating characteristics curve for identifying an elevated PMN count was 0.977 (95%CI: 0.933 to 0.995) for ELISA and 0.982 (95%CI: 0.942 to 0.997) for POC (P = 0.246 vs ELISA). Using the optimal cut-off value for ELISA (0.63 μg/mL), ascitic calprotectin had 94.8% sensitivity, 89.2% specificity, positive and negative likelihood ratios of 8.76 and 0.06 respectively, positive and negative predictive values of 60.0% and 99.0% respectively, and 90.0% overall accuracy. Using the optimal cut-off value for POC (0.51 μg/mL), the respective values were 100.0%, 84.7%, 6.53, 0.00, 52.8%, 100% and 87.7%. Correlation between ELISA and POC was excellent (r = 0.873, P < 0.001). The mean ± SD of the difference was -0.11 ± 0.48 μg/mL with limits of agreement of + 0.8 μg/mL (95%CI: 0.69 to 0.98) and -1.1 μg/mL (95%CI: -1.19 to -0.91).

CONCLUSION: Ascitic calprotectin reliably predicts PMN count > 250/μL, which may prove useful in the diagnosis of SBP, especially with a readily available bedside testing device.

Diagnosis and management of bacterial infections in decompensated cirrhosis

Bacterial infections are one of the most frequent complications in cirrhosis and result in high mortality rates. Patients with cirrhosis have altered and impaired immunity, which favours bacterial translocation. Episodes of infections are more frequent in patients with decompensated cirrhosis than those with compensated liver disease. The most common and life-threatening infection in cirrhosis is spontaneous bacterial peritonitis followed by urinary tract infections, pneumonia, endocarditis and skin and soft-tissue infections. Patients with decompensated cirrhosis have increased risk of developing sepsis, multiple organ failure and death. Risk factors associated with the development of infections are severe liver failure, variceal bleeding, low ascitic protein level and prior episodes of spontaneous bacterial peritonitis (SBP). The prognosis of these patients is closely related to a prompt and accurate diagnosis. An appropriate treatment decreases the mortality rates. Preventive strategies are the mainstay of the management of these patients. Empirical antibiotics should be started immediately following the diagnosis of SBP and the first-line antibiotic treatment is third-generation cephalosporins. However, the efficacy of currently recommended empirical antibiotic therapy is very low in nosocomial infections including SBP, compared to community-acquired episodes. This may be associated with the emergence of infections caused by Enterococcus faecium and extended-spectrum β-lactamase-producing Enterobacteriaceae, which are resistant to the first line antimicrobial agents used for treatment. The emergence of resistant bacteria, underlines the need to restrict the use of prophylactic antibiotics to patients with the greatest risk of infections. Nosocomial infections should be treated with wide spectrum antibiotics. Further studies of early diagnosis, prevention and treatment are needed to improve the outcomes in patients with decompensated cirrhosis.

The role of serum procalcitonin levels in predicting ascitic fluid infection in hospitalized cirrhotic and non-cirrhotic patients

OBJECTIVE

To determine the role of serum procalcitonin levels in predicting ascites infection in hospitalized cirrhotic and non-cirrhotic patients.

METHODS

A total of 101 patients (mean age: 63.4 ± 1.3, 66.3% were males) hospitalized due to cirrhosis (n=88) or malignancy related (n=13) ascites were included in this study. Spontaneous bacterial peritonitis (SBP, 19.8%), culture-negative SBP (38.6%), bacterascites (4.9%), sterile ascites (23.8%) and malign ascites (12.9%) groups were compared in terms of procalcitonin levels in predicting ascites infection. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic performance of procalcitonin levels and predicting outcome of procalcitonin levels was compared with C-reactive protein (CRP).

RESULTS

Culture positivity was determined in 26.7% of overall population. Serum procalcitonin levels were determined to be significantly higher in patients with positive bacterial culture in ascitic fluid compared to patients without culture positivity (median (min-max): 4.1 (0.2-36.4) vs. 0.4 (0.04-15.8), p<0.001). Using ROC analysis, a serum procalcitonin level of <0.61 ng/mL in SBP (area under curve (AUC): 0.981, CI 95%: 0.000-1.000, p<0.001), <0.225 ng/mL in culture-negative SBP (AUC: 0.743, CI 95%: 0.619-0.867, p<0.001), <0.42 ng/mL in SBP and culture-negative SBP patients (AUC: 0.824, CI 95%: 0.732-0.916, p<0.001), and <1.12 ng/mL in bacterascites (AUC: 0.837, CI 95%: 0.000-1.000, p=0.019) were determined to accurately rule out the diagnosis of bacterial peritonitis. Predictive power of serum procalcitonin levels in SBP + culture-negative SBP group (AUCs: 0.824 vs 0.622, p=0.004, Fig 4), culture-positive SBP (AUCs: 0.981 vs 0.777, p=0.006, Fig 5) and (although less powerfull) in culture-negative SBP (AUCs: 0.743 vs 0.543, p=0.02, Fig 6) were found significantly higher than CRP.

CONCLUSION

According to our findings determination of serum procalcitonin levels seems to provide satisfactory diagnostic accuracy in differentiating bacterial infections in hospitalized patients with liver cirrhosis related ascites.

Cytoreductive surgery and intraoperative administration of paclitaxel-loaded expansile nanoparticles delay tumor recurrence in ovarian carcinoma

BACKGROUND

Locoregional recurrence significantly impacts survival and quality of life in patients with ovarian carcinoma. We hypothesize that local administration of paclitaxel-loaded expansile nanoparticles (pax-eNP) at the time of cytoreductive surgery decreases local tumor recurrence.

METHODS

In vitro cytotoxicity of pax-eNP was assessed against both the OVCAR-3 human ovarian cancer cell line and tumor cells isolated from a malignant pleural effusion from a patient with multidrug-resistant ovarian cancer. A murine xenogenic model involving surgical cytoreduction of established OVCAR-3 intra-abdominal tumor was used to evaluate in vivo efficacy of intraoperative intraperitoneal (IP) injection of 10 mg/kg of paclitaxel either as pax-eNP or paclitaxel in Cremophor EL/ethanol solution (pax-C/E) versus empty eNP controls. Cytoreductive surgery and intraoperative treatment were performed 4 weeks after established tumor. All animals were sacrificed when empty eNP controls displayed extensive evidence of disease progression.

RESULTS

Labeled-eNP entered tumor cells in vitro within 4 h and specifically accumulated at sites of tumor in vivo. Pax-eNP exhibited dose-dependent cytotoxicity in both OVCAR-3 and patient tumor cells isolated from a malignant pleural effusion and effectively prevented tumor recurrence following debulking (p = 0.003 vs. empty eNP). Furthermore, pax-eNP-treated animals did not develop severe recurrent carcinomatosis compared with 43 % of the pax-C/E-treated cohort, suggesting that single-dose intracavitary pax-eNP is more effective than an equivalent dose of pax-C/E.

CONCLUSIONS

Expansile nanoparticles readily enter human ovarian tumor cells and localize to sites of tumor in vivo with pax-eNP cytotoxicity resulting in superior inhibition of locoregional tumor recurrence following cytoreductive surgery.

Spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis (SBP) is the infection of ascitic fluid in the absence of any intra-abdominal, surgically treatable source of infection. Despite timely diagnosis and treatment its reported incidence in ascitic patients varies between 7-30%. Ascitic paracentesis remains the chief diagnostic procedure. Automated cell counters have the same diagnostic accuracy as the manual measurement of white cells. Lately, the use of leucocyte reagent strips (dipsticks) has emerged as a useful alternative. Examination of the fluid is not complete unless the sample is inoculated in blood culture bottles. Treatment is currently with third-generation cephalosporins or oral quinolones. Following a single episode of SBP patients should have long term antibiotic prophylaxis.

Lactate as a Diagnostic Test for Septic Peritoneal Effusions in Dogs and Cats

Lactate concentration in peritoneal fluid was evaluated and compared to blood lactate concentration in dogs and cats with septic and nonseptic abdominal effusions. All dogs with septic effusions had a peritoneal fluid lactate concentration &gt;2.5 mmol/L and a peritoneal fluid lactate concentration higher than blood lactate, resulting in a negative blood to fluid lactate difference. In dogs, the diagnostic accuracy of the peritoneal fluid lactate concentration and the blood to fluid lactate difference in differentiating septic peritoneal effusion was 95% and 90%, respectively. Peritoneal fluid lactate concentration and blood to fluid lactate difference were not accurate tests for detecting septic peritoneal effusions in cats.

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.

Comparison of peritoneal fluid and peripheral blood pH, bicarbonate, glucose, and lactate concentration as a diagnostic tool for septic peritonitis in dogs and cats

OBJECTIVE

To establish a reliable diagnostic tool for septic peritonitis in dogs and cats using pH, bicarbonate, lactate, and glucose concentrations in peritoneal fluid and venous blood.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Eighteen dogs and 12 cats with peritoneal effusion.

METHODS

pH, bicarbonate, electrolyte, lactate, and glucose concentrations were measured on 1- to 2-mL samples of venous blood and peritoneal fluid collected at admission. The concentration difference between blood and peritoneal fluid for pH, bicarbonate, glucose, and lactate concentrations were calculated by subtracting the peritoneal fluid concentration from the blood concentration. Peritoneal fluid was submitted for cytologic examination and bacterial culture. Peritonitis was classified as septic or nonseptic based on cytology and bacterial culture results.

RESULTS

In dogs, with septic effusion, peritoneal fluid glucose concentration was always lower than the blood glucose concentration. A blood-to-fluid glucose (BFG) difference > 20 mg/dL was 100% sensitive and 100% specific for the diagnosis of septic peritoneal effusion in dogs. In 7 dogs in which it was evaluated, a blood-to-fluid lactate (BFL) difference < -2.0 mmol/L was also 100% sensitive and specific for a diagnosis of septic peritoneal effusion. In cats, the BFG difference was 86% sensitive and 100% specific for a diagnosis of septic peritonitis. In dogs and cats, the BFG difference was more accurate for a diagnosis of septic peritonitis than peritoneal fluid glucose concentration alone.

CONCLUSIONS

A concentration difference > 20 mg/dL between blood and peritoneal fluid glucose concentration provides a rapid and reliable means to differentiate a septic peritoneal effusion from a nonseptic peritoneal effusion in dogs and cats.

CLINICAL RELEVANCE

The difference between blood and peritoneal fluid glucose concentrations should be used as a more reliable diagnostic indicator of septic peritoneal effusion than peritoneal fluid glucose concentration alone.

Predicting infection in localized intraabdominal fluid collections: value of pH and pO2 measurements

PURPOSE

To evaluate the use of pH, pO2, and the subjective opinion of the radiologist compared with bacterial culture in accurate diagnoses of bacterial infection in intraabdominal fluid collections.

MATERIALS AND METHODS

Prospectively, 79 patients who were suspected of having an intraabdominal fluid collection underwent diagnostic fluid aspiration. The aspirate was cultured and measured for pH and pO2. A pH < or = 7.1 and a PO2 < or = 49 mm Hg were threshold values used to separate infected from sterile fluid collections.

RESULTS

pH alone had a 92% sensitivity and 79% specificity, whereas PO2 alone had a 51% sensitivity and 79% specificity. pH or pO2 combined yielded a 92% sensitivity and 60% specificity. The radiologist's opinion produced a 83% sensitivity and 92% specificity. pH and the radiologist's opinion combined produced a 78% sensitivity and 96% specificity. pH or the radiologist's opinion combined had a 95% sensitivity and a 63% specificity.

CONCLUSION

pH is the most sensitive indicator of infection and the radiologist's opinion is the most specific. We recommend proceeding to drainage if the radiologist believes the collection to be infected and performing pH analysis if not. If the pH < or = 7.04, proceed to drainage. If neither of the above criteria are met, drainage could be delayed, pending the results of culture.

An economic analysis of norfloxacin prophylaxis against spontaneous bacterial peritonitis

BACKGROUND/AIMS/METHODS

Spontaneous bacterial peritonitis (SBP) is a frequent complication of advanced liver disease and in high-risk patients, it is associated with a mean (per episode) mortality of 29% and a mean 1-year mortality of 82%. The 1-year recurrence rate of SBP can be as high as 30-70%. Selective intestinal decontamination with antibiotic prophylaxis has been shown to significantly reduce the incidence of recurrent SBP. The aim of this study was to perform an economic analysis of norfloxacin prophylaxis to prevent SBP recurrence.

RESULTS

This analysis showed that norfloxacin prophylaxis in high-risk patients with cirrhosis resulted in USD 4632 savings per patient per year by avoiding SBP and its associated expense. A sensitivity analysis showed that the norfloxacin prophylaxis remained cost-saving, even if it resulted in only a modest reduction in the SBP recurrence rate.

CONCLUSIONS

Selective gut decontamination with norfloxacin is not only efficacious in preventing SBP, but can also be cost-saving by avoiding the resource utilization associated with its treatment.

Prevalence and prognostic significance of bacterascites in cirrhosis with ascites

The prevalence and prognostic significance of bacterascites (BA) were prospectively studied in 443 predominantly HBsAg-positive cirrhotic patients with ascites. Spontaneous bacterial peritonitis (SBP), culture-negative neutrocytic ascites (CNNA), and BA were identified in 12.4%, 8.4%, and 10.8%, respectively. Of these, 67%, 70%, and 71%, respectively, had peritonitis-related signs or symptoms. Among patients with SBP or CNNA, the clinical and laboratory data showed no significant difference between the symptomatic and asymptomatic groups. In contrast, among the patients with BA, the symptomatic group had significantly higher levels of serum total bilirubin and prolonged prothrombin time and significantly lower levels of ascitic fluid total protein than the asymptomatic group. Furthermore, the clinical and laboratory data were relatively similar between patients with asymptomatic BA and those with sterile ascites. In contrast, patients with SBP, CNNA, or symptomatic BA exhibited significantly more severe degrees of liver disease and significantly lower levels of ascitic fluid total protein than those with sterile ascites. There was no statistically significant difference between SBP and bacterascites regarding flora. All patients with SBP, CNNA, or symptomatic BA received antibiotic treatment immediately after paracentesis, as did six of the 14 patients with asymptomatic BA for concurrent respiratory or urinary tract infection, while the remaining eight patients with asymptomatic BA were followed clinically without treatment. Repeated paracentesis in the latter revealed no evidence of SBP or CNNA. The in-hospital mortality for sterile ascites was 22.8%, significantly lower than the 54.5% for SBP, 43.2% for CNNA, and 50% for symptomatic BA, but similar to the 21.4% for asymptomatic BA.(ABSTRACT TRUNCATED AT 250 WORDS)

Malignancy-related ascites: a diagnostic pitfall of spontaneous bacterial peritonitis by ascitic fluid polymorphonuclear cell count

To define patients with an ascitic fluid polymorphonuclear cell count > or = 250 cells/mm3 or > or = 500 cells/mm3 but without spontaneous bacterial peritonitis, 166 patients with sterile cirrhotic ascites, 46 patients with spontaneous bacterial peritonitis, 123 patients with hepatocellular carcinoma, 67 patients with peritoneal carcinomatosis or massive liver metastasis and 12 patients with other miscellaneous diseases were studied. The sensitivity, specificity and accuracy of the diagnosis of spontaneous bacterial peritonitis were 100, 86 and 88% with the cut-off value of an ascitic fluid polymorphonuclear cell count > or = 250 cells/mm3; and were 93, 91 and 92% with that value > or = 500 cells/mm3, respectively. With the cut-off value > or = 250 cells/mm3 or > or = 500 cells/mm3, the prevalence was 18% or 14% in hepatocellular carcinoma; and 30% or 19% in peritoneal carcinomatosis or massive liver metastasis. The ascitic fluid lactate concentration was insensitive and nonspecific. Among the patients with an ascitic fluid polymorphonuclear cell count greater than the cut-off values, an ascitic fluid erythrocyte count > or = 10,000 cells/mm3, a ratio of ascitic fluid erythrocyte to total leukocyte count > or = 100, and the ratio of ascitic fluid polymorphonuclear cell to total leukocyte count < or = 75% indicated hepatocellular carcinoma, while serum to ascites albumin gradient < or = 1.1 g/dl and a ratio of ascitic fluid polymorphonuclear cell to total leukocyte count < or = 75% indicated peritoneal carcinomatosis or massive liver metastasis.

A prospective study of bacterial infections in patients with cirrhosis

One hundred and seventy hospitalized patients with cirrhosis were included in a prospective and sequential study, to verify the prevalence and most frequent causes of bacterial infection. The differences in clinical and laboratory data between the two groups were analyzed: group I--80 patients who developed bacterial infection and group II--90 patients without bacterial infection. The prevalence or cumulative frequency of the development of bacterial infection during one hospitalization was 47.06%. Among these, the most frequent types of infection were: spontaneous bacterial peritonitis (SBP): 31.07%, urinary tract infection (UTI): 25.24% and pneumonia: 21.37%. Community infections were more frequent (56.25%) than nosocomial infections (32.50%) and they occurred sequentially in 11.25% of the cases. The agents responsible were gram negative bacteria in 72.34% of the cases. Clinical and biochemical parameters in bacterial infection were generally correlated with the severity of liver disease. Child-Pugh classification showed a predominance of class C in infected cirrhotic patients compared to non-infected ones. During hospitalization, the mortality rate of group I was 30% whereas in group II it was 5.55% (P = 0.0001). SBP and pneumonia were the most severe types of infection, with high mortality rates, 31.25% and 40.91%, respectively. These results indicate that bacterial infection is a severe complication in the course of cirrhosis.

Serum-ascites albumin concentration gradient and ascites fibronectin in the diagnosis of malignant ascites

BACKGROUND

The differential diagnosis between malignant and nonmalignant ascites by using laboratory parameters has not been completely achieved so far.

METHODS

The authors studied serum-ascites albumin concentration gradients ([albumin]s - [albumin]a), ascites fibronectin and various parameters in 149 consecutive patients with ascites (including Group 1: 22 patients with intraabdominal malignant lesions; Group 2: 81 patients with chronic liver disease; and Group 3: 46 patients with hepatocellular carcinoma [HCC]).

RESULTS

The concentrations of fibronectin, albumin, protein, lactate dehydrogenase, and carcinoembryonic antigen in ascites were significantly higher in Group 1 than in Group 2 (P < 0.001). By contrast, the [albumin]s - [albumin]a was significantly lower in Group 1 than in Group 2 (P < 0.001). None of these parameters was useful in differentiating the ascites of chronic liver disease from that of HCC. In this study, to differentiate malignant ascites from the ascites caused by liver diseases, [albumin]s - [albumin]a (< 1.5 g/dl) and the fibronectin level in the ascites (> 100 micrograms/ml) provided diagnostic accuracy (96.8% and 95.9%, respectively) as precise as those of the levels of albumin (> 1.6 g/dl), protein (> 2.5 g/dl), and lactate dehydrogenase (> 60 U/l; 97.9%, 96.7%, and 94.8%, respectively) in ascites. These results were better than that of carcinoembryonic antigen level (> 1.5 ng/ml, 80.9%).

CONCLUSIONS

The authors concluded that [albumin]s - [albumin]a offered the best method to survey malignant ascites because of its sensitivity (100%).

The prevalence and prognostic significance of spontaneous bacterial peritonitis in severe acute hepatitis with ascites

The prevalence and prognostic significance of spontaneous bacterial peritonitis were prospectively studied in a series of 82 acute hepatitis patients decompensated with ascites. The in-hospital prevalence of spontaneous bacterial peritonitis was 31.7% (26 of 82 patients). Twenty cases were culture positive, including one with multiple isolates, and six cases were culture negative. E. coli and Klebsiella pneumoniae were the most common pathogens, accounting for 71.4% (15 of 21) of the total isolates, whereas only 9.5% were gram-positive organisms. No significant difference in the age, sex, cause of acute hepatitis, liver biochemistry, prothrombin time and ascites fluid concentration of total protein was noted between patients with spontaneous bacterial peritonitis and those without spontaneous bacterial peritonitis, except that bacteremia was recognized significantly more frequently in the former (57.7% or 15 of 26 patients) than in the latter (25.0% or 14 of 56 patients, p less than 0.005). In addition, patients with spontaneous bacterial peritonitis, when compared with those without spontaneous bacterial peritonitis, were more likely to have kidney failure (57.7% vs. 30.4%, p less than 0.05) and had a significantly higher mortality rate (73.1% vs. 39.3%, p less than 0.01). Among patients without spontaneous bacterial peritonitis, the prevalence of kidney failure and gastrointestinal hemorrhage and the mortality rate in patients with bacteremia (57.1%, 64.3% and 71.4%, respectively) were significantly higher than in those without bacteremia (21.4%, 19.0% and 28.6%, respectively; p less than 0.05, p less than 0.01 and p less than 0.01, respectively). In conclusion, 31.7% of severe acute hepatitis patients with ascites were recognized as having spontaneous bacterial peritonitis; the other 17.1% had bacteremia.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous bacterial peritonitis in patients with hepatitis B-related cirrhosis and hepatocellular carcinoma

To delineate the natural clinical course of spontaneous bacterial peritonitis in hepatitis B-related cirrhosis and to determine if it occurs in hepatocellular carcinoma, a prospective survey was conducted in 262 patients over 2 1/2 years. The in-hospital incidence and mortality rates of spontaneous bacterial peritonitis were 21.6% and 36.4%, respectively, in cirrhosis and 7.3% and 50% in hepatocellular carcinoma. In cirrhosis, the cumulative probability of annual recurrence of spontaneous bacterial peritonitis was 47.3%, which was significantly higher than the annual probability of occurrence of 11.3% in those with no previous attack (P less than 0.0001). The cumulative probability of annual survival was 27.6% in the spontaneous bacterial peritonitis patients, significantly lower than the probability of 64.0% in the control group (P = 0.0001). A univariate analysis, with Kaplan-Meier curves compared by the Mantel-Cox test, and subsequent multivariate analysis by stepwise Cox regression procedure were used to evaluate 37 variables recorded immediately after admission. Blood urea nitrogen concentration greater than 10.5 mmol/L urea (greater than 30 mg/dL) and ascitic fluid protein concentration less than 7.35 g/L (less than 735 mg/dL) were found to be the only significant predictors of lower annual survival; ascitic fluid protein concentration less than 7.50 g/L (less than 750 mg/dL) was the only significant predictor of higher annual recurrence. The authors conclude that spontaneous bacterial peritonitis has a high risk of recurrence in hepatitis B-related cirrhosis and that the same disease occurring in patients with hepatocellular carcinoma is related to the underlying cirrhosis rather than the hepatocellular carcinoma.

Determination of D-lactate concentration for rapid diagnosis of bacterial infections of body fluids

The value of determining D-lactate concentrations in body fluids for the rapid diagnosis of bacterial infections was investigated. A total of 336 body fluid samples were analyzed: 208 ascitic fluids, 57 synovial fluids, 40 cerebrospinal fluids and 32 pleural fluids. Using a cut-off value of 0.05 mM, the overall sensitivity was 0.96 and the specificity was 0.88. Therefore, the measurement of D-lactate concentration in body fluids offers a rapid (2-hour) and useful method of differentiating between infectious and non-infectious body fluid diseases.

Incidence of spontaneous bacterial peritonitis in patients with ascites. Diagnostic value of white blood cell count and pH measurement in ascitic fluid

During a 21-month period, 65 consecutive patients admitted with ascites were included in a prospective study of the incidence of spontaneous bacterial peritonitis, and paracentesis was performed on admission. The ascitic fluid was cultured, ascitic leucocytes were counted and pH was measured. Bacterial growth was found in five patients with chronic liver disease, who were diagnosed as having spontaneous bacterial peritonitis (SBP), since no intra-abdominal focus could be demonstrated. Thus, the incidence of SBP in this material was 7.7% (95% confidence limits: 2.5-17%). SBP was caused by Escherichia coli (n = 3), coagulase negative staphylococcus (n = 1), and Bacteroides species (n = 1). Abdominal tenderness, abnormal intestinal sounds, fever and hepatic encephalopathy were equally frequent in the group with SBP and in patients with sterile ascites. Infection was not anticipated in any of the patients with SBP. In contrast to several previous studies, neither ascites pH nor ascites leucocyte counts were any help in obtaining a rapid diagnosis. Survival time of patients with SBP was significantly shorter than of patients without SBP.

Spontaneous bacterial peritonitis: Analysis of treatment and outcome

Spontaneous bacterial peritonitis occurred on 44 separate occasions in 43 patients during a five year period, including 27 culture positive and 17 probable cases of spontaneous bacterial peritonitis. Alcoholic liver disease was the underlying cause of 72% of cases. Of the 27 culture positive cases, Escherichia coli was the most common isolate (14 cases), followed by Klebsiella pneumoniae (three cases), group G streptococci (three cases), group B streptococci (two cases) and one case each of five other organisms. Bacteremia occurred in 50% of cases and was the same as the peritoneal isolate 88% of the time. The overall mortality rate was 65% (66% culture positive and 60% probable spontaneous bacterial peritonitis). The mean interval between onset of symptoms and death was 10.2±8.6 days in fatal cases. Spontaneous bacterial peritonitis was felt to be a contributing cause of mortality in 70% of fatal cases. Survivors were younger (44±20 years versus 59±13, P<0.05) and less likely to develop renal insufficiency than nonsurvivors (38% versus 73%, P<0.05). Patients who were treated with an aminoglycoside were more likely to develop renal failure compared to those treated with nonaminoglycoside regimens (P<0.05). There was no difference in mortality rate between culture positive and culture negative spontaneous bacterial peritonitis, total peritoneal leukocyte counts, Gram-positive versus Gram-negative organisms, presence of bacteremia, or serum albumin or bilirubin levels. The mortality rate for this disease remains unacceptably high, indicating a need for the development of new strategies in the prevention, diagnosis and management of this disease.

Diagnosis and hemodynamic assessment of portal hypertension

Rational treatment of portal hypertensive complications requires a knowledge of the cause of portal hypertension and an assessment of the severity of liver disease. In the United States, chronic liver disease, usually due to alcohol, is the most common underlying cause. The history, physical examination, and laboratory analysis are usually sufficient to confirm the presence of underlying liver disease. If there is any question as to the etiology of portal hypertension, however, a more complete evaluation is required, whether the presenting complication is ascites, variceal bleeding, or hypersplenism. Usually, such an evaluation will require a liver biopsy, portal pressure measurement, and angiography. Occasionally, a noninvasive evaluation will be sufficient, but the value of these noninvasive parameters is still under investigation. Surgical mortality generally depends on the severity of the liver disease. Therefore, surgical intervention must be carefully considered in comparison to other therapeutic modalities depending on the patient's hepatic functional reserve. Secondary bacterial peritonitis due to perforation requires surgery regardless of the severity of the underlying liver disease.

Diagnostic and therapeutic challenges of intraabdominal infections

With the advances that are being made in many areas of medicine, the surgeon must be familiar with infectious diseases of the peritoneal cavity, which have increased in scope and complexity. In addition to the surgical management of secondary peritonitis resulting from perforation of the gastrointestinal tract, the practicing surgeon may be called on to manage patients with cirrhosis with infected ascitic fluid as well as patients undergoing peritoneal dialysis with infected dialysis fluid. In addition, there is increasing recognition of a group of patients with persistent intraabdominal sepsis or tertiary peritonitis in whom infection is associated with multiple systems organ failure and general depression of the immune system. This article endeavors to present an overview of the diagnostic and therapeutic approaches to these disease entities.

Diagnostic paracentesis. A potent clinical tool

Diagnostic paracentesis is a potent diagnostic tool capable of rapidly detecting portal hypertension and peritonitis. Gram's stain and chemical analysis of ascitic fluid add additional information by determining the predisposition to SBP, the presence of organisms, and the severity of peritonitis. In patients with a narrow A-GRAD, the chemical analysis, cell count and differential, and cytology will add direction for the work-up if the etiology is not apparent and confirmation if it is. This information should be available within a few hours of admission if the paracentesis and blood are obtained immediately. The results should optimize patient care and minimize costs.

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.

Optimization of ascitic fluid culture technique

The conventional method of ascitic fluid culture detects bacteria in only 42%-65% of patients who have neutrocytic ascites and suspected spontaneous bacterial peritonitis. In this study ascitic fluid was cultured by the conventional method as well as by a new method consisting of bedside inoculation of blood culture bottles with ascites. The conventional cultures grew bacteria in only 13 (43%) of 30 episodes of neutrocytic ascites, whereas the blood culture bottles grew bacteria in 28 (93%); this difference was significant (p less than 0.0001). The blood culture bottle method also resulted in more rapid detection of bacterial growth. The median concentration of bacteria in infected ascites was one organism per milliliter. Bedside inoculation of blood culture bottles with ascitic fluid is more sensitive than the conventional method in detecting bacterial peritonitis. The insensitivity of the conventional method is probably due to the low concentration of bacteria in infected ascites and the small volume of ascites cultured by this method.

Diagnosis of malignant ascites. Comparison of ascitic fibronectin, cholesterol, and serum-ascites albumin difference

The ascitic fluid concentrations of cholesterol and fibronectin and the serum-ascites albumin difference were compared with two conventional tests of ascitic fluid, total protein and LDH, in their diagnostic ability for detection of malignancy in ascitic samples from 69 patients with ascites: 54 with ascites due to liver disease and 15 whose ascites was caused by peritoneal metastases. Sixteen cirrhotic patients with superimposed hepatocellular carcinoma in whom ascites was of uncertain etiology were considered separately. The mean ascitic fluid total protein, LDH, cholesterol, and fibronectin values in the peritoneal metastases group were 3.70 +/- 1.20 g/dl, 247.26 +/- 148.14 units/liter, 109.06 +/- 29.85 mg/dl, and 91.57 +/- 41.52 micrograms/ml, respectively, and all were significantly higher than the corresponding values in the liver disease group (P less than 0.001), which were 1.37 +/- 0.59 g/dl, 75.40 +/- 110.70 units/liter, 23.75 +/- 11.22 mg/dl, and 31.86 +/- 10.51 micrograms/ml, respectively. Mean serum-ascites albumin difference in the peritoneal metastases group was 0.62 +/- 0.38 g/dl, which was significantly different from the corresponding value in the liver disease group (1.92 +/- 0.41 g/dl, P less than 0.001). Both ascitic cholesterol above 46 mg/dl and an ascitic fibronectin concentration greater than 50 micrograms/ml had high diagnostic accuracy (97%) for malignancy, being higher than that achieved using a serum-ascites albumin difference under 1.1 g/dl and an ascitic total protein above 2.5 g/dl, which had accuracies of 94% and 93%, respectively. Ascitic fluid LDH was the least reliable test. No differences in the ascitic fluid analysis were found between cirrhotic patients with and without hepatocellular carcinoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Finding the cause of ascites. The importance of accurate fluid analysis

Diagnostic paracentesis with ascitic fluid analysis is critical to the accurate diagnosis and management of ascites. Recent advances have improved the evaluation of ascitic fluid, among them the serum-ascites albumin difference for discriminating between ascites caused by liver disease and ascites due to malignancy. The ascitic fluid polymorphonuclear leukocyte concentration is the best index for the rapid presumptive diagnosis of spontaneous bacterial peritonitis. Familiarity on the part of the clinician with ascitic fluid interpretation and with ascitic fluid characteristics in various diseases will increase the chances of controlling ascites early.

Patients with deficient ascitic fluid opsonic activity are predisposed to spontaneous bacterial peritonitis

To assess the risk of development of spontaneous bacterial peritonitis in relation to ascitic fluid opsonic activity, routine admission abdominal paracentesis was performed on 119 patients during 141 hospitalizations. Paracentesis was repeated if evidence of peritonitis developed during the hospitalization. The ascitic fluid opsonic activity (0.2 +/- 0.5 log kill) of 24 spontaneously infected specimens was significantly (p less than 0.001) lower than that of the group with sterile portal hypertension-related ascites (0.8 +/- 1.1 log kill), and significantly lower than the group with ascites of miscellaneous type (2.4 +/- 1.0 log kill, p less than 0.001). The C3 and C4 concentrations of the spontaneous peritonitis specimens were also significantly lower than in the specimens from the other groups. Of the 55 patients whose initial sterile ascitic fluid opsonic activity was less than 0.2 log kill, 8 (14.5%) developed spontaneous bacterial peritonitis during the hospitalization; whereas none of the 70 patients with sterile ascitic fluid opsonic activity greater than or equal to 0.2 log kill developed spontaneous peritonitis. This difference in the risk of development of peritonitis was significant (p less than 0.01). Patients with deficient ascitic fluid opsonic activity are predisposed to spontaneous bacterial peritonitis.

Early diagnosis of spontaneous bacterial peritonitis: values of ascitic fluid variables

In a search for clinical and laboratory factors that would aid in early diagnosis of spontaneous bacterial peritonitis, we identified two groups of patients with chronic liver disease and ascites: 1) 38 patients with 40 episodes of spontaneous bacterial peritonitis, and 2) 39 randomly selected patients with 40 sterile paracenteses who were matched for severity of liver dysfunction as a reference group. A variety of clinical and laboratory features were examined. The absolute lymphocyte count in peripheral blood was lower for the spontaneous bacterial peritonitis group (mean = 703/mm3 vs. 1,212/mm3, p less than 0.005). Four ascitic fluid variables, i.e., a white blood cell count of greater than or equal to 300/mm3, a polymorphonuclear leukocyte count of greater than or equal to 240/mm3, an ascitic fluid/serum LDH ratio of greater than or equal to 0.4, or an ascitic fluid/serum glucose ratio of less than or equal to 1.0, could separate the spontaneous bacterial peritonitis and reference groups with both sensitivity and specificity of greater than 70%. Although ascitic fluid total leucocyte and polymorphonuclear leucocyte counts are appropriate indicators for the early diagnosis of spontaneous bacterial peritonitis, the possibility of their false positivity should be warranted. The use of multiple tests including ascitic fluid/serum LDH and glucose ratios has better positive predictive value than a single test alone.

Low-protein-concentration ascitic fluid is predisposed to spontaneous bacterial peritonitis

To assess the risk of development of spontaneous bacterial peritonitis in relation to the ascitic fluid total protein concentration, routine admission abdominal paracentesis was performed on a group of 107 patients during 125 hospitalizations. The paracentesis was repeated if evidence of peritonitis developed during hospitalization. Twenty-one episodes of spontaneous peritonitis (or its culture-negative variant) were documented in 17 patients. The ascitic fluid protein concentration in the spontaneous peritonitis group (0.72 +/- 0.53 g/dl) was significantly lower (p less than 0.001) than that in the group of patients with sterile portal hypertension-related ascites (1.36 +/- 0.89 g/dl) and was significantly lower than that of patients with ascites due to miscellaneous causes. Of the patients whose initial sterile ascitic fluid protein concentration was less than or equal to 1.0 g/dl, 7 of 47 (15%) developed spontaneous peritonitis during their hospitalization; whereas only 1 of 65 (1.5%) patients who had an initial sterile ascitic fluid protein concentration greater than 1.0 g/dl developed spontaneous peritonitis. This difference in risk of development of peritonitis in relation to initial ascitic fluid protein concentration was also significant (p less than 0.01). Low-protein-concentration ascitic fluid predisposes to spontaneous bacterial peritonitis.

Spontaneous bacterial peritonitis in the non-cirrhotic individual

A case of spontaneous bacterial peritonitis is reported. A methodical postmortem examination failed to disclose cirrhosis or other liver pathology; nor, was any anatomic alteration of the immune system noted. Acquired immunodeficiency syndrome was likewise discounted. A discussion ensues concerning recognition of this entity.

pH of ascitic fluid: diagnostic and prognostic value in cirrhotic and noncirrhotic patients

The pH measurements of 185 samples of ascitic fluid in 169 cirrhotic and 16 noncirrhotic patients were analyzed to assess their diagnostic and prognostic value. The 169 cirrhotic patients were divided into four groups: sterile ascites (group 1), spontaneous bacterial peritonitis (group 2), probable spontaneous bacterial peritonitis (group 3), and bacterascites (group 4). Mean ascitic fluid pH values were lower (p less than 0.001) in patients of groups 2 (7.24 +/- 0.17) and 3 (7.34 +/- 0.11) than in patients of groups 1 (7.44 +/- 0.06) and 4 (7.45 +/- 0.08), but there was an important overlap between these groups. Mean arterial-ascitic fluid pH gradient values were higher (p less than 0.001) in patients of groups 2 (0.21 +/- 0.16) and 3 (0.10 +/- 0.13) than in patients of groups 1 (0.02 +/- 0.05) and 4 (0.02 +/- 0.05). This gradient had a better discriminant power than ascitic fluid pH alone. Sensitivity, specificity, positive and negative predictive value, and diagnostic accuracy for the diagnosis of certain or probable spontaneous bacterial peritonitis were, respectively, 47%, 99%, 88%, 89%, and 89% for ascitic fluid pH values less than 7.32; 66%, 99%, 91%, 93%, and 92% for arterial-ascitic fluid pH gradient values greater than 0.10; and 97%, 96%, 86%, 99%, and 96% for polymorphonuclear cell count greater than 75/microliter. Ascitic fluid pH values appeared to have a high prognostic value, as 6 of 7 cirrhotic patients with ascitic fluid pH values less than 7.15 died rapidly. Low ascitic fluid pH values were found in patients with malignant and pancreatic ascites and tuberculous peritonitis but not in patients with cardiac ascites. We conclude that in cirrhotic patients with certain or probable spontaneous bacterial peritonitis (a) arterial-ascitic fluid pH gradient measurements had a slightly higher diagnostic value than ascitic fluid pH measurements but a slightly lower diagnostic value than polymorphonuclear cell count and (b) ascitic fluid pH measurements had a high prognostic value. In noncirrhotic patients, ascitic fluid pH and arterial-ascitic fluid pH gradient measurements had a poor diagnostic value.

Immediate diagnostic criteria for bacterial infection of ascitic fluid. Evaluation of ascitic fluid polymorphonuclear leukocyte count, pH, and lactate concentration, alone and in combination

We prospectively evaluated the ascitic fluid (AF) polymorphonuclear cell (PMN) count, pH, and lactate concentration in single ascitic fluids from 60 patients to determine their relative predictive values for the immediate diagnosis of ascitic fluid infection. Nine of the 60 ascitic fluids were malignant. Of the remaining 51 samples, nine from cirrhotic patients were infected. The mean AF pH, lactate concentration, and PMN count in the infected group were 7.20 +/- 0.19, 80 +/- 51 mg/dl, and 18,199 +/- 19,650 cells/mm3, respectively, and all were significantly different from the corresponding values in noninfected ascites. Mean arterial blood-ascitic fluid (B-AF) pH and lactate gradients in the infected group were 0.23 +/- 0.17 and -46 +/- 31 mg/dl, respectively, and were significantly different from the corresponding values in noninfected ascites (p less than 0.05). Significant differences were not found between infected and malignant ascites, except for the AF PMN count (p less than 0.001). In cirrhosis with ascites, an AF pH less than or equal to 7.34 was the most specific single test (100%) and had the highest diagnostic accuracy (98%). In the larger group of patients with ascites of diverse etiology, a B-AF pH gradient greater than or equal to 0.10 or an AF PMN count greater than or equal to 500 cells/mm3 were the single tests with the highest diagnostic accuracy (92%). Combining an AF PMN count greater than 500 cells/mm3 with any of the other diagnostic criteria increased the specificity and diagnostic accuracy (up to 98%) compared to the best single criterion. Although our data support the use of a number of different combinations of AF measurements for the immediate diagnosis of infection, the simplest and most readily obtainable measurements are the pH and PMN count. Therefore, in the clinical setting we recommend the use of either an AF pH less than or equal to 7.34 or a B-AF pH gradient greater than or equal to 0.10 in combination with an AF PMN count greater than 500 cells/mm3 to obtain the highest degree of accuracy in the immediate diagnosis of ascitic fluid infection.

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

Ascitic fluid pH and arterial-ascitic fluid pH gradient were compared to ascitic fluid polymorphonuclear cell count in 84 patients with cirrhotic ascites and in 12 with malignant ascites to assess their role as diagnostic tests for spontaneous bacterial peritonitis and to clarify the relationship between ascitic fluid pH and lactate. Ascitic fluid pH was significantly lower (pH 7.30) in spontaneous bacterial peritonitis (n = 18) and probable spontaneous bacterial peritonitis (n = 12) than in sterile ascites (pH 7.41; n = 54). Since blood pH levels were not different in the presence of infection, arterial-ascitic fluid pH gradient was significantly higher in spontaneous bacterial peritonitis and probable spontaneous bacterial peritonitis than in sterile ascites (0.12 vs. 0.02). The close correlations between arterial-ascitic pH gradient and lactate (r = 0.77, p less than 0.0001), lactate and bicarbonate gradient (r = 0.64, p = 0.003) and arterial-ascitic pH gradient and pCO2 gradient (r = -0.90, p less than 0.0001) suggest that the low ascitic fluid pH may be due to an increase in lactate and CO2. Patients with Escherichia coli-induced spontaneous bacterial peritonitis had significantly lower ascitic fluid pH and higher lactate than those with spontaneous bacterial peritonitis by other organisms. Values of ascitic fluid pH, lactate and arterial-ascitic fluid pH gradient in malignant ascites were similar to those of spontaneous bacterial peritonitis and probable spontaneous bacterial peritonitis. Cutoff points, selected by receiver operating characteristic curves analysis, of 450 per mm3 for polymorphonuclear cells and of 0.07 for arterial-ascitic fluid pH gradient, allow high positive and negative predictive values for spontaneous bacterial peritonitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Spontaneous bacterial peritonitis

Spontaneous bacterial peritonitis is an infection of the ascitic fluid of patients who, in general, have severe chronic liver disease. Several variants of this disease exist including bacterascites, culture-negative neutrocytic ascites, and secondary bacterial peritonitis. Spontaneous bacterial peritonitis is frequently manifested by signs and symptoms of peritonitis although the findings may be subtle; however, occasionally it may be completely without clinical manifestation. The clinician must have a high index of suspicion in order to make this diagnosis at a relatively earlier stage of infection. An abdominal paracentesis is required to make the diagnosis of spontaneous bacterial peritonitis. This paracentesis should be performed on all patients who are admitted to the hospital for ascites and should be repeated if there is any manifestation of bacterial infection during the hospitalization. Patients with severe intrahepatic shunting--as manifested by marked redistribution of activity from the liver to the spleen and to the bone marrow on liver-spleen scan as well as patients with an ascitic fluid total protein concentration of less than 1 g/dl--appear to be particularly susceptible to bacterial infection of their ascites. In order to optimize the yield of ascitic fluid culture, it is probably appropriate to inject blood culture bottles with ascites at the bedside immediately after the abdominal paracentesis. The mortality of spontaneous bacterial peritonitis continues to be very high. Perhaps routine admission paracentesis and prompt empiric antibiotic therapy with a third-generation cephalosporin will decrease the mortality of this infection if the Gram stain of the ascitic fluid demonstrates bacteria or the ascitic fluid neutrophil count is greater than 250 cells/cu mm. Repeating the paracentesis after 48 hours of treatment to reculture the fluid and reassess the ascitic fluid neutrophil count appears to be the best way to assess efficacy of treatment. After 48 hours of treatment the ascitic fluid neutrophil count should be less than 50% of the original value if the antimicrobial therapy is appropriate. The optimal duration of antibiotic treatment is unknown; however, until controlled trials provide data regarding duration of treatment it is appropriate to treat with parenteral antibiotics for 10 to 14 days. Research is also needed to determine if there are measures which can be taken to prevent the development of spontaneous peritonitis.