Group A Streptococci: A rare and often misdiagnosed cause of spontaneous bacterial peritonitis in adults.

Introduction: Acute primary peritonitis due to group A Streptococci (GAS) is a rare but life-threatening infection. Unlike other forms of primary peritonitis it affects predominantly young previously healthy individuals and thus is often confused with the more frequent secondary peritonitis. A case series of three patients is presented as well as a review of the literature focusing on pitfalls in the diagnose and therapy of GAS peritonitis.

Methods: A retrospective analysis of three patients with primary GAS peritonitis was performed. Furthermore a systematic review of all cases of primary GAS peritonitis published from 1990 to 2013 was performed comparing demographics and clinical presentation, as well as radiological imaging, treatment and outcome.

Results: All three female patients presented initially with high fever, nausea and severe abdominal pain. Radiological imaging revealed intraperitoneal fluid collections of various degrees, but no underlying cause of peritonitis. Broad antibiotic treatment was started and surgical exploration was performed for acute abdomen in all three cases. Intraoperatively fibrinous peritonitis was observed, but the correct diagnosis was not made until microbiological analysis confirmed GAS peritonitis. One patient died within 24h after admission. The other two patients recovered after multiple surgeries and several weeks on the intensive care unit due to multiple organ dysfunction syndrome. The fulminant clinical course of the three patients resembled those of many of the published cases: flu-like symptoms, high fever, severe acute abdominal pain and fibrinous peritonitis without obvious infectious focus were the most common symptoms reported in the literature.

Conclusion: GAS primary peritonitis should be considered in particular in young, previously healthy women who present with peritonitis but lack radiological findings of an infectious focus. The treatment of choice is immediate antibiotic therapy. Surgical intervention is difficult to avoid, since the diagnosis of GAS peritonitis is usually not confirmed until other causes of secondary peritonitis have been excluded.