A Minor Sports Injury with Major Consequences: Probable Streptococcal Toxic Shock Syndrome and Necrotizing Soft Tissue Infection in a Young Adult—A Case Report

Background and Clinical Significance: Streptococcus pyogenes (group A Streptococcus, GAS) can cause rapidly progressive invasive infections, including necrotizing soft tissue infection (NSTI) and streptococcal toxic shock syndrome (STSS). Although invasive GAS disease is often associated with skin barrier disruption, severe infection may also follow blunt trauma without visible skin injury. Case Presentation: A 22-year-old woman presented with persistent right hip and groin pain four days after a blunt fall during recreational sports activity, without disruption of skin integrity. On admission, she was hypotensive, tachycardic, and intermittently hypoxemic, with local hematoma, swelling, and inflammatory infiltration of the right groin. Laboratory tests showed marked inflammation, acidosis, acute kidney injury (AKI), elevated lactate, creatine kinase, and myoglobin levels. She was admitted to the intensive care unit with septic shock. Empirical antimicrobial therapy was initiated with piperacillin/tazobactam, clindamycin, and linezolid. Computed tomography showed inflammatory changes extending from the right groin to the thigh fascia. On day 3, the patient’s condition deteriorated with respiratory failure necessitating endotracheal intubation and mechanical ventilation. Surgical incision revealed inflamed and necrotic subcutaneous tissue with superficial muscle involvement. Deep tissue cultures yielded GAS, whereas blood and urine cultures remained negative; probable STSS was diagnosed. Therapy was de-escalated to penicillin plus clindamycin. Continuous renal replacement therapy with an adsorptive acrylonitrile 69 surface-treated (AN69ST) membrane was initiated for AKI. The patient gradually improved and was transferred to the surgical ward on day 16. Conclusions: Minor blunt trauma without skin disruption may precede life-threatening invasive GAS infection. Rapid recognition, surgical source control, antitoxin antimicrobial therapy, and intensive organ support are essential in suspected STSS.