Presentations

Abstract

Introduction: Streptococcal toxic shock syndrome (STSS) is a severe, exotoxin-mediated complication of invasive Group A Streptococcus (GAS) infections, such as necrotizing fasciitis and bacteremia. While GAS commonly causes noninvasive infections such as pharyngitis and non-necrotizing skin and soft tissue infections, the incidence of invasive GAS cases has notably risen in recent years, from 3.8 per 100,000 persons annually (2005-2012) to 8.2 per 100,000 in 2022., Up to 30% of patients with invasive GAS infections develop STSS, with rates climbing to 50% among those with necrotizing fasciitis. Recent US data reports 556 cases of STSS in 2023 and 333 in 2022. Clinical manifestations of STSS commonly include renal failure, acute respiratory distress syndrome (ARDS), hepatic failure, and heart failure, with mortality rates estimated around 30%. The pathogenesis of STSS involves the release of superantigenic toxins that trigger a cytokine storm. Treatment typically includes intravenous immunoglobulin (IVIG) to neutralize toxins, along with bactericidal antibiotics (penicillin) and protein synthesis-inhibiting antibiotics (clindamycin, linezolid).,

Case Information: Our patient is a forty-five year male with past medical history of hypertension who presented following brushfire who was found to have deep partial thickness to full thickness burns to the left lower extremity, left upper extremity, and left axilla with TBSA ~ 9%. He underwent burn excision 7 days after the incident and was discharged home the next day. He went for graft check with autograft about a week later and was again discharged home post op day (POD) 1. Patient represented POD3 from the second operation to an outside hospital with one-day history of shortness of breath and persistent fevers. His initial workup revealed leukocytosis (20,000), elevated lactic acid (10 mmol/L), creatinine (5 mg/dL), BNP (7,800 pg/mL), and troponin (55 ng/mL), concerning for septic shock and prompting transfer to our hospital. Further evaluation revealed multiorgan involvement including biventricular heart failure with an ejection fraction (EF) of 27% and concern for pulmonary embolism in setting of tachycardia with a new oxygen requirement of high flow nasal cannula. Broad spectrum antibiotics (vancomycin and zosyn) were continued and a heparin drip was started empirically. Due to concern for acalculous cholecystitis in setting of elevated LFTs with unknown source of sepsis, the patient underwent percutaneous cholecystostomy tube placement. He was unable to have CTA done in setting of AKI, so we proceeded with a VQ scan to further assess for PE. This demonstrated low probability of PE and heparin drip was discontinued. Patient was placed on CRRT in setting of AKI with volume overload and lactic acidosis. He developed ARDS and was intubated within 48 hours of admission with transfer to the cardiac ICU for possible ECMO. Blood cultures resulted around this time and ID was consulted now with known strep pyogenes toxic shock syndrome. Speciation confirmed invasive GAS infection likely secondary to skin grafting, despite no overt signs of infection at the graft sites. The patient was started on a 21-day course of penicillin G and a 3-day course of linezolid and IVIG. He improved significantly with decreasing leukocytosis and pressor requirements, and was extubated 4 days later. He developed a pruritic maculopapular rash on his trunk on day 10 of penicillin therapy and was switched to cefazolin for the remainder of his antibiotic course. His recovery was prolonged by heart failure necessitating guideline-directed medical therapy (GDMT) and kidney failure requiring dialysis three times a week. Due to his renal dysfunction, his GDMT was limited. Despite not receiving full GDMT, his EF improved from 27% to 55% prior to discharge. He was discharged on hospital day 18 with a temporary dialysis catheter, which was removed 10 days later as dialysis was no longer needed.

Discussion/Clinical Findings: This case illustrates the rapid onset of STSS with multisystem organ failure and the critical importance of early identification and treatment. As the incidence of invasive GAS infections and STSS continues to rise, maintaining a high index of suspicion is crucial, even in the absence of overt signs of infection. In fact, up to 45% of invasive GAS infections lack a clear portal of entry as the anti-phagocytic M protein enables the bacteria to evade the host immune system during transient bacteremia. In our case, the patient's recent debridement and grafting procedures likely led to GAS bacteremia, precipitating STSS without evidence of skin and soft tissue infection. Renal impairment is a classic and early manifestation of STSS, occurring in over 50% of patients. Renal impairment often precedes hypotension; in fact, a a clinical picture of sepsis with or without cutaneous or soft tissue lesions with elevated creatinine at time of admission is highly suggestive of STSS.6 In our case, the patient's sepsis and elevated creatinine in the context of recent skin debridement and grafting should have raised suspicion for STSS. While initial broad-spectrum antibiotic coverage with vancomycin and Zosyn covered GAS, the lack of antitoxin therapy with linezolid or clindamycin and IVIG delayed optimal treatment. The patient's rapid recovery following the initiation of IVIG and linezolid suggests that earlier suspicion and intervention may have reduced morbidity. Reversible heart failure due to septic cardiomyopathy is a recognized complication of STSS. Although the exact mechanism is unknown, it is established that pore-forming toxin, Streptolysin O (SLO), and subsequent calcium influx mediates cardiotoxicity. As the infection progresses, superantigen mediated cytokine storm further diminishes cardiomyocyte contractility. Importantly, this septic cardiomyopathy is reversible, as SLO-mediated pores can be repaired via calcium and ATP-dependent endocytosis. Our patient initially presented with an EF of 27%, which markedly improved to 55% following resolution of STSS. This recovery corroborates the reversibility of STSS-induced heart failure. In all, this case upholds our current understanding of STSS of early renal impairment, reversible cardiomyopathy, and most importantly, the importance of early identification and treatment.

Conclusion: Although rare, STSS is a life-threatening condition with significant morbidity and mortality. Given the doubling incidence of invasive GAS infections in the US in recent years, clinicians must maintain a high level of suspicion for STSS in patients presenting with sepsis and acute kidney injury. Early treatment with penicillin, IVIG, and linezolid or clindamycin is essential for improving outcomes in STSS.