Polymicrobial PID Presenting as Primary Peritonitis in a Young Immunocompetent Patient—Case Report and Disease Perspectives

Background and Clinical Significance: Pelvic inflammatory disease represents a multifaceted sexually transmitted disease affecting women of reproductive age, beginning in adolescence. Clinical presentation ranges from asymptomatic patients to acute abdominal pain in the setting of tubo-ovarian abscesses; however, presentation as primary peritonitis with seemingly intact fallopian tubes is exceptional. Primary peritonitis in the absence of other comorbid conditions (e.g., liver cirrhosis and nephrotic syndrome) in healthy, immunocompetent women is rare and typically occurs without an identifiable intra-abdominal source. The diagnosis can be challenging due to its mild-to-moderate, nonspecific symptoms. Case Presentation: We report the case of a 21-year-old immunocompetent woman who presented with lower abdominal and left iliac fossa pain with hyperleukocytosis. Laparoscopic exploration confirmed the diagnosis of primary peritonitis. Following diagnosis, she underwent peritoneal lavage and was started on empiric broad-spectrum parenteral antibiotic therapy. Cervico-vaginal cultures established the diagnosis of PID following identification of Chlamydia trachomatis, Mycoplasma hominis, and Ureaplasma parvum. The clinical course was favorable. Conclusions: An early multidisciplinary approach, including consultation with an infectious disease specialist and clinical pharmacologist, is recommended in cases of peritonitis with an unclear source. PID may present as primary peritonitis and this clinical scenario should be considered in sexually active young women with unexplained peritoneal infection when no gastrointestinal or gynecologic source is evident intraoperatively.