Spontaneous bacterial peritonitis (SBP)

SBP should be suspected in a patient with ascites and any of the following:

1.     Temperature greater than 37.8ºC (100ºF)

2.     Abdominal pain and/or tenderness

3.     A change in mental status

4.     Ascitic fluid PMN count ≥250 cells/mm

Most cases of SBP are due to gut bacteria such as Escherichia coli and Klebsiella, though streptococcal and staphylococcal infections can also occur.

For patients with suspected SBP, while awaiting culture results, treat with a third-generation cephalosporin:

-Cefotaxime (2 g intravenously every eight hours) or a similar third-generation cephalosporin provides appropriate microbial coverage and attains good ascitic fluid levels.

-A fluoroquinolone (eg, levofloxacin) is an alternative in patients who are allergic to penicillin.

Antibiotic therapy should be tailored once the results of sensitivity testing are available. (See 'Choice of antibiotic' above.)

After five days of treatment, reassess the patient:

-Treatment is discontinued if there has been the usual dramatic improvement.

-If fever or pain persists, paracentesis is repeated, and the decision to continue or discontinue treatment is determined by the PMN response:

·      If the PMN count is  more than 250 cells/mm3, treatment is stopped

·      If the PMN count is greater than the pretreatment value, a search for a surgical source of infection is undertaken

·      If the PMN count is elevated but less than the pretreatment value, antibiotics are continued for another 48 hours, and the paracentesis is repeated

Patients at high risk for SBP include:

-Patients with cirrhosis and gastrointestinal bleeding.

-Patients who have had one or more episodes of SBP (among whom recurrence of SBP within one year has been reported to be close to 70 percent)

-Patients with cirrhosis and ascites if the ascitic fluid protein is less than 1.5 g/dL (15 g/L) along with either impaired renal function or liver failure.

-Patients with cirrhosis who are hospitalized for other reasons and have an ascitic protein concentration of less than 1 g/dL (10 g/L)

Prophylaxis:

For patients with a history of SBP, use prolonged outpatient fluoroquinolone therapy (norfloxacin 400 mg/day).

In settings where norfloxacin is unavailable, ciprofloxacin (500 mg orally once daily) or trimethoprim-sulfamethoxazole (one double-strength tablet daily) is an acceptable alternative.

In patients with cirrhosis who are hospitalized for other reasons and have an ascitic protein concentration of less than 1 g/dL (10 g/L), use oral norfloxacin (400 mg per day) ortrimethoprim-sulfamethoxazole (one double-strength tablet once daily) with discontinuation of the drug at the time of discharge.

In patients with cirrhosis and gastrointestinal bleeding, we use intravenous ceftriaxone 1 g intravenously daily and switch to oral norfloxacin (400 mg orally twice daily) once bleeding has been controlled and the patient is stable and eating. Seven days of total antibiotic treatment are given.