What subgroups are created from the results of the ascitic fluid polymorphonuclear neutrophil (PMN) count and the ascitic fluid culture in the workup of spontaneous bacterial peritonitis (SBP)?

Updated: Nov 26, 2018
  • Author: Thomas E Green, DO, MPH, MMM, CPE, FACEP, FACOEP; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD  more...
  • Print
Answer

Combining the results of the ascitic fluid polymorphonuclear neutrophil (PMN) count and the ascitic fluid culture yields the following subgroups:

  • Spontaneous bacterial peritonitis

  • Culture-negative neutrocytic ascites (probable spontaneous bacterial peritonitis)

  • Monomicrobial nonneutrocytic bacterascites

Spontaneous bacterial peritonitis is noted when the PMN count is 250 cells/µL or higher, in conjunction with a positive bacterial culture result. As mentioned previously, one organism is usually identified on the culture in most cases. Obviously, these patients should receive antibiotic therapy.

Culture-negative neutrocytic ascites (probable spontaneous bacterial peritonitis) is noted when the ascitic fluid culture results are negative, but the PMN count is 250 cells/µL or higher. This may happen in as many as 50% of patients with SBP and may not actually represent a distinctly different disease entity. It may be the result of poor culturing techniques or late-stage resolving infection. Nonetheless, these patients should be treated just as aggressively as those with positive culture results.

Monomicrobial nonneutrocytic bacterascites exists when a positive culture result coexists with a PMN count of 250 cells/µL or fewer. Although this may often be the result of contamination of bacterial cultures, one study found that 38% of these patients subsequently develop spontaneous bacterial peritonitis. [18] Therefore, monomicrobial nonneutrocytic bacterascites may represent an early form of spontaneous bacterial peritonitis.

All study patients described that eventually developed spontaneous bacterial peritonitis were symptomatic. [18] For this reason, any patient suspected clinically of having spontaneous bacterial peritonitis in this setting must be treated.


Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!