Psoas Abscess of Rare Etiology in an Adult Patient with Human Immunodeficiency Virus and Nodal Tuberculosis

Abstract

Introduction: The Streptococcus anginosus group consists of three distinct species: S. anginosus, S. intermedius, and S. constellatus. These are found as commensals in the oral flora, gastrointestinal tract, and vagina of humans. They can spread to the bloodstream in individuals with poor oral hygiene or in cases of oral infections, such as gingivitis and dental abscesses, which develop following the loss of mucosal integrity. Case Presentation: We report the case of a 36-year-old male patient with a history of nodal tuberculosis and HIV, undergoing four and two months of treatment, respectively. He was admitted to the emergency department of the Hospital Hipólito Unanue in Tacna with a 7-day history characterized by fever and pain in the left inguinal region that prevented ambulation and extension of the left lower limb. Complementary examinations revealed leukocytosis and positive acute-phase reactants. Ultrasound and abdominal CT imaging showed a collection involving the left psoas-iliac muscle, extending to the left inguinal region with an approximate volume of 609 cc. Abscess drainage was performed, obtaining purulent fluid where Streptococcus anginosus was isolated. Antibiotic treatment was initiated with ampicillin according to the antibiogram, along with every-other-day abscess irrigation. The patient's evolution was favorable. Conclusion: Prompt microbiological identification and comprehensive management based on drainage and targeted antibiotic therapy are decisive in achieving a favorable outcome, even in complex clinical scenarios such as the one described.