Makindo Medical Notes

Related Subjects: |Chronic liver disease |Cirrhosis |Alkaline phosphatase (ALP) |Liver Function Tests |Ascites Assessment and Management |Budd-Chiari syndrome |Autoimmune Hepatitis |Primary Biliary Cirrhosis |Primary Sclerosing Cholangitis |Wilson disease |Hereditary Haemochromatosis |Alpha-1 Antitrypsin (AAT) deficiency |Non alcoholic steatohepatitis (NASH) |Spontaneous Bacterial Peritonitis |Alcoholism and Alcoholic Liver Disease

Spontaneous Bacterial Peritonitis

Spontaneous bacterial peritonitis (SBP) should be suspected in any patient with symptoms such as unexplained encephalopathy, renal dysfunction, or gastrointestinal hemorrhage. A diagnostic paracentesis is recommended in all patients with new-onset ascites or when signs of SBP are present.

About

• SBP is an infection of the peritoneal fluid without an apparent intra-abdominal source.
• It is most commonly seen in patients with advanced liver disease and cirrhosis.
• Occurs in approximately 8-10% of cirrhotic patients with ascites and can recur.

Aetiology

• Impaired immune function in liver disease leads to a higher risk of SBP.
• Portosystemic shunting reduces the liver’s ability to filter bacteria, allowing transient bacteremia to colonize ascitic fluid.

Microbiology

• Gram-negative organisms:
  • Escherichia coli (E. coli)
  • Enterobacteriaceae (e.g., Klebsiella)
• Gram-positive organisms:
  • Streptococcus (e.g., viridans group)
  • Enterococcus species
  • Pneumococcal species

When to Suspect SBP: Ascites +

• Gastrointestinal bleeding or shock
• Fever or systemic inflammatory signs
• New or worsening gastrointestinal symptoms
• Hepatic encephalopathy
• Deteriorating liver or renal function

Precipitating Factors

• Other infections (e.g., UTI, pneumonia, sepsis)
• Gastrointestinal hemorrhage
• Delayed gut transit or constipation
• Certain medications (e.g., opioids, benzodiazepines)
• Renal or cardiac impairment
• Active liver damage or alcohol consumption
• Idiopathic (no obvious cause identified)

Clinical Presentation

• May cause acute decompensation, leading to hepatic encephalopathy.
• Common symptoms include fever, jaundice, abdominal pain, vomiting, and confusion.
• Classical signs like fever and abdominal pain may be absent, making diagnosis challenging.

Investigations

• Microscopy: Neutrophil count > 250/mm³ in ascitic fluid is diagnostic.
• Ascitic Albumin Gradient: Calculate serum-ascites albumin gradient (SAAG) to determine the cause of ascites.
• Culture: Inoculate ascitic fluid directly into blood culture bottles at bedside to improve sensitivity.
• pH: Low pH in ascitic fluid may indicate infection.
• Rapid Tests: Leukocyte esterase strip tests may help quickly identify elevated white cells in ascitic fluid, aiding in diagnosis.

Management

• Empirical Antibiotic Therapy: Initiate if ascitic neutrophil count > 250 cells/mm³. Use intravenous third-generation cephalosporins like cefotaxime (2 g tds) or ceftriaxone. Consult local guidelines for antibiotic choices.
• Albumin Administration: For patients with SBP and renal dysfunction, administer albumin 1.5 g/kg on day 1 and 1 g/kg on day 3 to reduce the risk of hepatorenal syndrome.
• Prophylactic Antibiotics: In patients with a history of SBP, consider norfloxacin (400 mg daily), ciprofloxacin (500 mg daily), or co-trimoxazole (800 mg sulfamethoxazole/160 mg trimethoprim daily) to prevent recurrence.
• Referral for Transplant Assessment: In patients with SBP being evaluated for liver transplant, consult a regional liver center for early guidance.
• Prophylaxis Post-GI Bleed: Prophylactic antibiotics can reduce the risk of SBP in patients with cirrhosis who have experienced a GI bleed.

References

• Guidelines on the Management of Ascites in Cirrhosis (BMJ, 2020)
• EASL Clinical Practice Guidelines on the Management of Ascites, SBP, and Hepatorenal Syndrome in Cirrhosis