Streptococcal Toxic-Shock Syndrome

Streptococcal toxic-shock syndrome (streptococcal TSS) is an acute disease mediated by the production of superantigenic toxins characterized by the sudden onset of fever and other febrile symptoms, pain, multisystem organ involvement and potentially leading to coma, shock and death due to a Streptococcus pyogenes infection.

Epidemiology

The annual incidence is estimated to range between 1/300,000 - 1/1,000,000.

Clinical description

Streptococcal TSS usually presents with a sudden onset of pain, often mimicking peritonitis or located in the extremities in previously healthy adults. General flu-like symptoms such as high fever, myalgia, nausea, diarrhea and vomiting are signs of streptococcal TSS and most patients develop hypotension soon after hospital admission. Signs of soft tissue infection can also be present manifesting with localized erythema and swelling which can lead to necrotizing fasciitis in some cases. A diffuse scarlatina-like erythema occurs in about 10% of cases. Other serious manifestations include confusion, shock, renal dysfunction, acute respiratory distress syndrome (ARDS; see this term) and coma. In some cases streptococcal TSS can be associated with acute adrenal insufficiency (see this term).

Etiology

Streptococcal TSS is caused by an infection with Streptococcus pyogenes, also known as group A streptococcus (GAS), and is usually associated with skin infections, child birth, and surgeries. Infection occurs at a site of trauma or can follow viral infections (influenza or varicella). Streptococcal TSS is the result of toxins released by the bacteria that cause a massive immune reaction involving mainly cytokines and chemokines. This reaction is related to the activation of T cells by the production of superantigens that circumvent the normal pathway of antigen presentation. Group C and G Streptococcus are also rarely associated.

Diagnostic methods

Clinical symptoms along with laboratory analysis are the basis for diagnosis of streptococcal TSS. Patients with fever, multisystem organ failure and shock are tested for GAS in their blood or a normally sterile site (e.g. cerebrospinal, pleural or peritoneal fluid) and those who test positive are given a diagnosis of streptococcal TSS. Bacteremia is present in most patients with streptococcal TSS (approximately 60%) which is not the case in staphylococcal TSS (see this term) where it is seen in approximately 5% of cases.

Differential diagnosis

Differential diagnoses include staphylococcal TSS, septic shock, typhoid fever, Rocky Mountain spotted fever, leptospirosis (see these terms), peritonitis, pneumonia, pelvic inflammatory disease, pericarditis, acute myocardial infarction, meningococcemia, viral/ drug/ allergic rash.

Management and treatment

The onset of streptococcal TSS is sudden and requires immediate medical treatment in an intensive care setting. Treatment involves antibiotics (beta-lactam antibiotics and clindamycin) along with supportive therapy (fluid resuscitation, inotropes and vassopressors) and intravenous immunoglobins that block superantigens. Corticosteroids and recombinant activated protein C (derotrecogin-alpha) can also be helpful in some cases. Dialysis may be necessary for those with renal dysfunction and oxygen supplementation along with mechanical ventilation is required for patients with ARDS. Suspected necrotizing fasciitis may require debridement.

Prognosis

The prognosis varies, with streptococcal TSS having a mortality rate of 30-80% in adults and 5-8% in children.