Intravenous Immunoglobulin for Refractory Streptococcal Toxic Shock Syndrome With Purpura Fulminans: A Case Report and Literature Review

Streptococcal toxic shock syndrome (STSS) is a rare but life-threatening condition characterized by rapid progression to septic shock and multiorgan dysfunction driven by toxin-mediated immune activation. We report the case of a previously healthy 39-year-old man who presented with acute encephalopathy and rapidly deteriorated into refractory septic shock requiring mechanical ventilation, maximal vasopressor support, and continuous renal replacement therapy. Blood cultures identified Streptococcus pyogenes, and the clinical course was complicated by severe metabolic acidosis, acute liver injury, thrombocytopenia, and the development of purpura fulminans, consistent with STSS. Despite early broad-spectrum antimicrobial therapy transitioned to antitoxin-directed antibiotics and aggressive supportive management, the patient demonstrated persistent hemodynamic instability and progressive multiorgan failure. Adjunctive intravenous immunoglobulin (IVIG) was administered as part of a multidisciplinary treatment strategy in the setting of refractory shock and suspected ongoing toxin-mediated injury. Following IVIG therapy, the patient exhibited gradual hemodynamic improvement with decreasing vasopressor requirements and stabilization of organ function. This case illustrates the diagnostic and therapeutic uncertainty in toxin-mediated septic shock and demonstrates how IVIG was considered as a rescue adjunct in the setting of persistent hemodynamic instability despite optimal standard therapy. The report aims to contextualize clinical decision-making rather than attribute causality to a single intervention.