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Spontaneous bacterial peritonitis (SBP)
Discuss the pathogenesis of SBP?
What is SBP?
What is secondary bacterial peritonitis?
Discuss the incidence and prognosis of SBP?
SBP occurs in 10-30% of cirrhotic hospitalised patients
Untreated mortality is 90% which is reduced to 20% with early diagnosis and prompt treatment.
When to suspect SBP?
Any cirrhotic ascites on admission to hospital for any reason should have a diagnostic tap.
Any known cirrhotic with ascites with fever, abdominal pain, confusion, encephalopathy, abdominal tenderness or diarrhoea or developing renal failure should have diagnostic tap.
Risk factors for SBP in cirrhotic:
Low ascitic fluid protein
On PPI
Malnutrition
GI bleeding
Does it matter if fluid is sent in EDTA bottle or normal bottle for cell count?
Yes. The sample if clotted will give a false negative result if sent in a white top universal container.
How to diagnose by ascitic fluid analysis?
Does it matter if fluid is sent in blood culture bottle or normal bottle?
Yes, inoculation at bed side in blood culture bottle will yield positive culture in 72-90% of cases of SBP as opposed to only 40% if culture is sent in white topped sterile universal container (which is the common practice)
Is Gram stain necessary?
Rarely helpful in SBP and BSG does not recommend requesting it.
What is bacterascites?
Ascitic fluid which is culture positive but with normal neutrophil count.
What is CNNA?
Culture negative neutrocytic ascites should be treated exactly as SBP as they have similar morbidity and mortality.
Do they need repeat tap to make sure the count is improving?
If repeat tap after 48hrs does not show reduction in the neutrophil count to >25% of the pre-treatment value – implies treatment failure. Antibiotic should be changed. This is important particularly if patient is still symptomatic and not improving.
Why it is important to differentiate SBP from secondary BP?
The patients of secondary BP will die almost 100% in spite of antibiotic in absence of surgery
The patients of SBP will have 80% mortality if they have unnecessary laparotomy.
How to differentiate from secondary BP?
Neutrophil count: normally in hundreds in SBP and in thousands in Secondary BP
Sugar: <2.8 mmol/L in Secondary BP because high numbers of neutrophil consume sugar and in frank perforation sugar level can be zero
Protein: low (<10g/L) in SBP, higher in Secondary BP
LDH: High in secondary BP greater than the upper limit of normal for serum
Microbial flora on culture/Gram stain: polymicrobial in secondary BP. Gram stain is normally negative in SBP and shows polymicrobial flora in secondary BP. Even then Gram stain is not recommended.
CEA: High levels in secondary BP
ALP: High levels in secondary BP
Also Erect CXR shows gas under diaphragm/ gastrograffin enema shows extravasation of contrast into the peritoneum.
What are the differentials of Secondary BP?
Late presentation of SBP, SBP treated with resistant antibiotic, peritoneal carcinomatosis and tubercular peritonitis can masquerade as secondary BP with very high WBC count and low ascitic fluid sugar and high LDH.
What is the microbiological flora?
In 70% of cases it is – either E.Coli, Streptococcus or enterococcus
Which antibiotic to start treatment?
Any third generation antibiotic which is sensitive to the microbiological flora and good penetration to ascitic fluid is good. Most studied antibiotic is cefotaxime- 2g BD for 5days is the BSG recommendation.
Other alternatives are ceftriaxone, ceftazidime or co-amoxiclav.
Oral treatment works?
Asymptomatic patients with good bowel sound can be treated with oral ciprofloxacin (750mg BD) or co-amoxiclav (1.2g TDS)
Is there any role of primary prophylaxis?
Some centres suggest primary prophylaxis when ascitic fluid protein is lower than 10gm/L but no consensus and currently no good evidence to suggest its use.
Discuss secondary prophylaxis?
After first episode of SBP approx 70% of the patients will have recurrence at the end of one year.
Should be given secondary prophylaxis with Norfloxacin 400mg OD or ciprofloxacin 500mg OD- reduces the probability of recurrence of SBP from 68% to 20%
Does it precipitate renal failure?
Development of renal failure occurs in 30% of patients of SBP and is one of the strongest predictors of mortality in SBP.
Is there any use of albumin in SBP?
BSG supports the recommendations of the Barcelona group of infusing albumin (1.5gm /Kg on Day 1 and 1gm/Kg on Day 3) in SBP in patients with high creatinine or rising creatinine but does not support routine use.
Is it indication for referral to transplant centre?
Yes.
Probability of survival at one year after an episode of SBP is 30-50% which falls to 25-30% at two years. So patients recovering form SBP should be referred to transplant centre for consideration of liver transplant, if clinically appropriate.
Ref
British Society of Gastroenterology guidelines for the management of ascites in cirrhosis
Take home message:
Suspect SBP when—- ascites with cirrhosis
+ fever or
abdominal pain or
confusion or
abdominal tenderness or
diarrhoea or
renal failure
Ascitic tap-
Exclude secondary bacterial peritonitis
Start cefotaxime 2g bd x 5 days
Change later depending on sensitivities
Asymptomatic patients with good bowel sound can be treated with oral ciprofloxacin (750mg BD) or co-amoxiclav (1.2g TDS)
Prevention of ARF
BSG supports the recommendations of the Barcelona group of infusing albumin (1.5gm /Kg on Day 1 and 1gm/Kg on Day 3) in SBP in patients with high creatinine or rising creatinine but does not support routine use.
After an attack of SBP
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