What is the ascitic protein count in Spontaneous Bacterial Peritonitis (SBP)?

From the Guidelines

The ascitic fluid protein count is a significant risk factor for developing spontaneous bacterial peritonitis (SBP), with levels less than 1.5 g/dL indicating a higher risk. This is because proteins in ascitic fluid, particularly opsonins, play a crucial role in bacterial clearance, and their deficiency allows bacteria to proliferate more easily 1. When assessing the risk of SBP, the ascitic fluid protein count is valuable for guiding prophylaxis decisions.

Key Points to Consider

• The European Association for the Study of Liver (EASL) and the American Association for the Study of Liver Diseases (AASLD) recommend primary prophylaxis with norfloxacin in patients with Child-Pugh score ≥9 and serum bilirubin ≥3 mg/dL, with either impaired renal function or hyponatraemia and ascitic fluid protein lower than 15 g/L 1.
• However, the use of long-term oral antibiotic therapy is controversial due to concerns about resistance, increased risk of Clostridium difficile associated diarrhoea, adverse reactions, and drug interactions 1.
• Patients with cirrhosis who have low ascitic fluid protein levels, especially those with a prior episode of SBP, may benefit from antibiotic prophylaxis with medications like norfloxacin or trimethoprim-sulfamethoxazole to prevent recurrent episodes of this potentially life-threatening infection.

Diagnosis and Treatment

• The key laboratory finding for diagnosing SBP is an elevated polymorphonuclear leukocyte (PMN) count in ascitic fluid (≥250 cells/mm³), rather than the protein level itself 1.
• Immediate empirical antibiotic therapy should be determined with due consideration of the context of SBP, severity of infection, and local bacterial resistance profile 1.

From the Research

Ascitoc Protein Count in SBP

• The ascitic fluid total protein count is an important factor in determining the risk of Spontaneous Bacterial Peritonitis (SBP) in patients with cirrhosis and ascites 2.
• Individuals with low-protein ascites (ascitic fluid total protein < 1g/dL) are at higher risk of developing SBP and may benefit from selective intestinal decontamination (SID) with norfloxacin 2.
• The protein count in ascitic fluid is not directly related to the diagnosis of SBP, but rather to the risk of developing the infection 3, 4.
• The diagnosis of SBP is typically made by the presence of >250 polymorphonuclear leukocyte/mm3 in ascites after paracentesis 3, 5.
• The treatment of SBP involves the use of broad-spectrum antibiotics, such as cefotaxime or ceftriaxone, and may include the administration of albumin to reduce the risk of hepatorenal syndrome 2, 5, 6.

Risk Factors for SBP

• Advanced age, refractory ascites, variceal bleeding, renal failure, low albumin levels, and previous diagnosis of SBP are all risk factors for developing SBP 5.
• Patients with cirrhosis and upper gastrointestinal bleeding are at increased risk of developing SBP and may benefit from prophylactic antibiotic therapy 2.
• The use of acid suppressive medication and beta-adrenergic antagonist therapies may also increase the risk of SBP in at-risk individuals 4.

Treatment and Prophylaxis of SBP

• The treatment of SBP typically involves the use of broad-spectrum antibiotics, such as cefotaxime or ceftriaxone, and may include the administration of albumin to reduce the risk of hepatorenal syndrome 2, 5, 6.
• Prophylactic antibiotic therapy, such as norfloxacin, may be recommended for patients at high risk of developing SBP, including those with low-protein ascites or a history of SBP 2, 5.
• The use of selective intestinal decontamination (SID) with norfloxacin may also be beneficial in preventing the development of SBP in high-risk patients 2.