European Journal of Cardiovascular Medicine

Ascites is the most frequent complication seen in patients with decompensated cirrhosis, with approximately half of those with compensated cirrhosis developing ascites over a ten-year span. The accumulation of ascitic fluid significantly increases the risk of infections due to weakened host defense mechanisms, including immune system dysfunction and reduced bactericidal capacity of the ascitic fluid. The most severe and prevalent infection in this population is spontaneous bacterial peritonitis (SBP), which has a reported prevalence of up to 18% among cirrhotic patients with ascites. Despite improvements in diagnostic methods and therapeutic interventions, SBP continues to have a high mortality rate, ranging from 16% to 52%, highlighting the urgent need for more effective management strategies.SBP reflects the underlying immune dysfunction associated with cirrhosis. Patients with cirrhosis have impaired phagocytic function of the reticuloendothelial system, leukocyte dysfunction, and reduced serum complement levels, particularly of complement component C3. The bactericidal activity of ascitic fluid is also significantly decreased. The opsonic activity, which relies heavily on C3 concentration, is crucial for fighting infections in ascitic fluid. Reduced levels of ascitic fluid C3 and impaired opsonic function have been strongly associated with the development of SBP. Consequently, these deficiencies make patients more vulnerable to translocated bacteria from the gut, a process believed to play a central role in SBP pathogenesis. Bacterial translocation, driven by increased intestinal permeability, altered microbiota, and immune dysfunction, represents a key mechanism behind the development of SBP.The clinical management of SBP has become increasingly complex due to the growing problem of antibiotic resistance. Many commonly used antibiotics, such as third-generation cephalosporins, are losing their effectiveness due to the emergence of multidrug-resistant (MDR) organisms. This significantly limits treatment options and has led to the exploration of alternative therapies and prophylactic approaches. While efforts to reduce cirrhosis rates through antiviral therapies for hepatitis B and C have had some success, the increasing prevalence of non-alcoholic fatty liver disease (NAFLD) is expected to offset these gains, maintaining or even increasing the overall burden of cirrhosis-related complications, including SBP.In clinical practice, SBP is a major marker of disease progression and often indicates a turning point in the management of advanced liver disease. Its occurrence signals worsening liver function and often necessitates consideration for liver transplantation. Moreover, beyond classic SBP, there are recognized variants of ascitic fluid infections, including culture-negative neutrocytic ascites (CNNA), monomicrobial non-neutrocytic bacterascites (MNBA), polymicrobial bacterascites, and secondary bacterial peritonitis. These variants complicate diagnosis and require tailored treatment approaches.To improve diagnostic sensitivity and early detection of SBP, research has explored alternatives to the conventional polymorphonuclear neutrophil (PMN) count. Biomarkers such as high-sensitivity C-reactive protein (hsCRP), serum procalcitonin, urinary lipocalin, ascitic lactoferrin, homocysteine, and fecal or ascitic calprotectin are under investigation. These markers may help identify SBP earlier and more reliably, potentially improving outcomes through timely intervention. However, more studies are needed to validate these alternatives and integrate them into standard practice.

AIM

To study the diagnostic significance of Ascitic fluid lactate dehydrogenase (LDH) as a diagnostic marker of spontaneous bacterial peritonitis ( SBP).

This hospital-based prospective observational study will be conducted over a period of 18 months following approval from the Institute Ethics Committee (IEC) at Mahatma Gandhi Medical College & Hospital. Prior to enrolment, written and informed consent will be obtained from all participating patients. The study will include all newly diagnosed patients presenting with ascites admitted to the inpatient department (IPD) or emergency department of the hospital. The target sample size is 137 patients, calculated with a 95% confidence level, a 5% margin of error, and an assumed unlimited population. The inclusion criteria for the study consist of patients aged between 18 and 65 years who are admitted with ascites. Exclusion criteria include pregnant women and those who are within six months postpartum.

Table 1: Age wise distribution of the study

20-30 year age group cases were found 35.8%, 30-40 year age group cases were found 25.5%, 40-50 year age group cases were found 19.7% and 50-60 year age group cases were found 19%. Mean age was 47.87 year.

Table 2: Culture wise distribution of the study

Positive (Polymicrobial) cases were 38.7%

Table 3:SBP (Spontaneous Bacterial Peritonitis) wise distribution of the study

Positive cases were 32.1% and negative cases were 67.9% SBP (Spontaneous Bacterial Peritonitis) wise distribution of the study

Table 4 Comparison between SBP and SAAG (serum ascitic albumin gradient) and SBP and protein

In our study, the mean value in the SBP-negative group was 2.72 with a standard deviation of 0.707, while in the SBP-present group it was significantly lower at 0.93 ± 0.34, with a p-value of 0.001, indicating statistical significance. Similarly, for another measured parameter, the mean in the SBP-negative group was 2.01 ± 0.09, whereas it was significantly higher in the SBP-present group at 3.005 ± 1.28, also with a statistically significant p-value of 0.001. These findings support a strong association between these parameters and the presence of SBP.

Table 5: Comparison between SBP and LDH and SBP and Ratio of AFLDH / Serum LDH

The study revealed that the mean value in the SBP-negative group was 97.39 ± 35.11, while in the SBP-present group it was significantly higher at 519.55 ± 193.07, with a p-value of 0.001, indicating statistical significance. In another parameter, the mean for SBP-negative patients was 0.36 ± 0.27, compared to 2.12 ± 1.56 in SBP-positive patients, also with a statistically significant p-value of 0.001. These results demonstrate a strong correlation between elevated values and the presence of SBP.

Table 6: Comparison between SAAG and SBP

In our study, all 17 patients with a SAAG <1.1 g/dL were diagnosed with SBP, accounting for 100% of that group. Among patients with SAAG >1.1 g/dL, 27 (22.5%) had SBP while 93 (77.5%) did not. Overall, SBP was present in 44 out of 137 patients (32.1%), indicating a significant association between low SAAG levels and the presence of SBP.

Graph 1 :Comparison between SAAG and LDH and Ascites

In the comparison between SAAG groups, the mean LDH was slightly higher in the <1.1 group (279.00) than in the >1.1 group (226.45 ± 242.51), though not statistically significant (p = 0.37). Similarly, ascitic cell count and ascitic fluid LDH were slightly elevated in the <1.1 group compared to the >1.1 group, with p-values of 0.42 and 0.89 respectively, showing no significant difference. The ascitic fluid LDH/serum LDH ratio was also comparable between groups (1.04 vs. 0.91), with a non-significant p-value of 0.67.

Ascites according to a study is defined as the pathological accumulation of fluid in peritoneal cavity. Where, peritoneal fluid volume normally is around 5 ml in men while 518ml in women respectively. Thus, atleast 1,500 ml of fluid is needed to between detected clinically.⁹ Study have also shown that, mild ascites does not cause any symptoms on the other hand, moderate to massive ascites lead yo abdominal distension, development of abdominal hernias or respiratory distress.¹⁰

In our study we have found that, patient age between 20-30 years were in majority with 49 in number (35.8%) followed by 30-40 age group patient with 35 in number (25.5%) , then  40-50 years patient with 27 in number (19.7%) and finally, 50-60 years patient with 26 in number (19%) respectively In contrat to our study results done by Syed Faiz Ahmed et al., ¹¹found that majority of age group seen between 41 to 60 age range with 91 in number (43.33%) followed by >60 years group with 75 in number

(35.71%) and finally, between 19-40 years with 44 in number (20.95%) respectively.

In our study we also found that, there was no pus found in all the 137 patients on gram staining. On the other hand, after culturing we found agar plate to be sterile in majority of the cases i.e. 84 (61.3%) followed by polymicrobial colony was seen in 53 cases (38.7%) respectively. In our study, positive cases were 44 in number for SBP (32.1%) while negative cases were 93 in number (67.9%) respectively. In a study done by Reginato TJ et al., ¹²found that upon gram staining pus cells were found in 17 patients. While upon bacterial culture 63 patients agar plate noted bacterial presence respectively. In a study done by Salehi S et al.,¹³ found that, upon bacterial culture, out of 18 ascites fluid samples from patients with peritonitis, 12 ascites fluid samples were positive, and the frequency of Gram-positive bacteria was higher than gram-negative bacteria. Meanwhile, the highest frequency was related to gram-positive coagulase-negative staphylococci (25%), followed by E. coli with a frequency of 16.7%.

In our study we have found that, comparison was statistically significant as the p value was 0.001 respectively. The research undertaken by Lichoska-Josifovikj F et al,¹⁴included a cohort of 70 patients, divided into two separate groups: 35 patients diagnosed with SBP and 35 patients without SBP. It was found that the average SAAG for people with SBP was 19.0±4.6, while it was 23.2±5.5 for people who did not have SBP. The analysis of mean values demonstrated a statistically significant outcome with p<0.05 (t-test = 3.46512; p=0.000992). The univariate analysis of the SAAG in predicting SBP demonstrated that a SAAG level below 20 g/L significantly increased the risk of SBP by five times.Krastev et al., found that patients with SBP frequently have ascitic fluid LDH greater than that of non-SBP group.

 Banerjee et al.,¹⁵in their study found that, the sensitivity and specificity of ascitic fluid LDH at a cut-off of 422 U/L were 74% and 60%, respectively. When compared to cytology, which has a sensitivity of just 40%, ascitic fluid LDH is a stronger indicator for screening for malignancy as a cause of ascites. In their study, one of the two instances with questionable cytology had an ascitic fluid LDH level of 614 U/L. Kounturas et al.,¹⁶ did a study where they looked at how well serum-ascites albumin gradient (SAAG) and ascitic fluid ferritin levels could identify cancer in sixty patients with ascites. Out of these sixty patients, thirty-one had different types of cancer, while the other twenty-nine had only chronic liver disease. Thirty-one of these sixty patients were diagnosed with various carcinomas, whereas the other thirty-nine were diagnosed with chronic liver disease alone. His data analysis revealed that ascitic ferritin is a more accurate indicator of malignant ascites than SAAG. This was the conclusion reached by the researcher. When it comes to distinguishing between non-malignant ascites that are brought on by chronic liver disease alone and malignant ascites that are associated with hepatocellular carcinoma and metastatic liver disease, this innovative metric is very helpful. The examination of ascitic fluid revealed markedly elevated neutrophil counts and LDH levels, whereas total protein, albumin, and glucose levels were significantly reduced in patients of group I in comparison to those in group II. A higher neutrophil count in ascitic fluid is considered an important factor for diagnosing SBP.¹⁴ The higher level of LDH found in infected ascitic fluid might come from the blood or from dying neutrophils in the fluid.¹⁵

Furthermore, studies indicate that tuberculous peritonitis, when compared to SBP, is characterized by higher white blood cell counts in ascitic fluid, an increased proportion of mononuclear leukocytes (including lymphocytes and monocytes), and higher adenosine deaminase (ADA) concentrations.¹⁶ However, the ability to find acid-fast bacilli using a direct microscopic smear in ascitic fluid ranges from 0% to 6%, while testing the ascitic fluid in a mycobacterial culture has a sensitivity of 20% to 35%. In addition, patients who suffer from tuberculous peritonitis, as well as those who suffer from other medical problems such as cirrhosis, renal failure, diabetes mellitus, and cancer, have a high death risk. The usefulness of these tests for figuring out the cause of ascites is limited because it takes a long time to get results from mycobacterial cultures of the fluid.Recent developments in molecular methods have presented a new approach for the rapid diagnosis of bacterial diseases, such as TB. This method makes use of polymerase chain reaction (PCR) in tiny amounts of ascitic fluid (50 ml).

Ascitic fluid infection is the most common complication in liver disease patients. If untreated, it may lead to serious complications like Hepato – renal syndrome, hepatic encephalopathy and finally results in death. So, by identifying ascitic fluid infection early, we can reduce the mortality rate. The diagnostic criteria for ascitic fluid infection requires ascitic fluid PMN count and culture, of which ascitic fluid culture will take atleast 3 days to have a report. So, by using leukocyte esterase reagent strip kit in the bedside to diagnose SBP (purple or pink), a cheaper and non invasive method, we can diagnose ascitic fluid infection early and treat the patient at the earliest, so that morbidity and mortality can be prevented. Henceforth, we come to conclude that, ascitic fluid lactate dehydrogenase (LDH) act as a diagnostic marker of SBP due to presence of polymicrobial colony in culture. Furthermore studies should be done to validate our results.

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