Toxic shock syndrome (TSS) is a condition caused by bacterial toxins. Symptoms may include fever, rash, skin peeling, and low blood pressure. There may also be symptoms related to the specific underlying infection such as mastitis, osteomyelitis, necrotising fasciitis, or pneumonia. TSS is typically caused by bacteria of the Streptococcus pyogenes or Staphylococcus aureus type, though others may also be involved. Streptococcal toxic shock syndrome is sometimes referred to as toxic-shock-like syndrome (TSLS). The underlying mechanism involves the production of superantigens during an invasive streptococcus infection or a localized staphylococcus infection. Risk factors for the staphylococcal type include the use of very absorbent tampons, skin lesions in young children characterized by fever, low blood pressure, rash, vomiting and/or diarrhea, and multiorgan failure. Diagnosis is typically based on symptoms. Treatment includes intravenous fluids, antibiotics, incision and drainage of any abscesses, and possibly intravenous immunoglobulin. The need for rapid removal of infected tissue via surgery in those with a streptococcal cause, while commonly recommended, is poorly supported by the evidence. Some recommend delaying surgical debridement. The overall risk of death is about 50% in streptococcal disease, and 5% in staphylococcal disease. Death may occur within 2 days. TSS was first described in 1927, although this term was not applied then. In the United States, the incidence of menstrual staphylococcal TSS declined sharply in the 1990s, while both menstrual and nonmenstrual cases had stabilized at about 0.3 to 0.5 cases per 100,000 population by 2013. Streptococcal TSS (STSS) saw a significant rise in the mid-1980s and had remained stable at 2 to 4 cases per 100,000 population until 2013. In the developing world, the number of cases is usually on the higher extreme. It came to be associated with very absorbent tampons that were removed from sale soon after this discovery.
Signs and symptoms Both forms of toxic shock syndrome share rapid-onset fever, hypotension, and multiorgan dysfunction, but differ in their presentation and severity.
Staphylococcal TSS Staphylococcal TSS typically begins with influenza-like symptoms of fever, vomiting, diarrhea, and severe muscle pain, followed by rapid progression to low blood pressure. A characteristic rash appears early in the course of illness, beginning on the trunk and spreading to the extremities, peeling one to three weeks after onset. Blood cultures are positive in fewer than five percent of staphylococcal TSS cases, reflecting that the illness is driven by toxin production rather than bloodstream infection.
Streptococcal TSS Severe localized pain is typically the earliest and most prominent symptom. Common early stage symptoms include an influenza-like illness with fever, sore throat, and gastrointestinal upset. Up to fifty percent of cases have no identifiable site of bacterial entry, although soft-tissue infections are a common source. Unlike staphylococcal TSS, blood cultures are positive in 60 to 80 percent of streptococcal TSS cases. A scarlatiniform rash may be present but occurs less commonly than the erythroderma characteristic of staphylococcal disease.
Pathophysiology In both TSS (caused by S. aureus) and TSLS (caused by S. pyogenes), disease progression stems from a superantigen toxin. The toxin in S. aureus infections is TSS Toxin-1, or TSST-1. The TSST-1 is secreted as a single polypeptide chain. The gene encoding toxic shock syndrome toxin is carried by a mobile genetic element of S. aureus in the SaPI family of pathogenicity islands. The toxin causes the non-specific binding of MHC II, on professional antigen presenting cells, with T-cell receptors, on T cells. In typical T-cell recognition, an antigen is taken up by an antigen-presenting cell, processed, expressed on the cell surface in complex with class II major histocompatibility complex (MHC) in a groove formed by the alpha and beta chains of class II MHC, and recognized by an antigen-specific T-cell receptor. This results in polyclonal T-cell activation. Superantigens do not require processing by antigen-presenting cells but instead, interact directly with the invariant region of the class II MHC molecule. In patients with TSS, up to 20% of the body's T-cells can be activated at one time. This polyclonal T-cell population causes a cytokine storm, followed by a multisystem disease.
Risk factors Sources of toxic shock syndrome include postsurgical wounds, postpartum, postabortion, intrauterine device placement, soft tissue damage, and focal infections. Use of barrier contraceptives, including diaphragms and contraceptive sponges, has also been associated with TSS. Tampon use, particularly high-absorbency tampons left in place for longer than the recommended four to eight hours, is a risk factor during menstruation. Streptococcal TSS occurs more commonly after viral infections such as chickenpox, the flu, and sore throat. An inability to produce antibodies against TSST-1 after an episode of staphylococcal TSS predisposes patients to recurrent episodes.
Diagnosis For staphylococcal toxic shock syndrome, the diagnosis is based upon CDC criteria defined in 2011, as follows:
Body temperature > 38.9 °C (102.0 °F) Systolic blood pressure < 90 mmHg Diffuse macular erythroderma Desquamation (especially of the palms and soles) 1–2 weeks after onset Involvement of three or more organ systems: Gastrointestinal (vomiting, diarrhea) Muscular: severe myalgia or creatine phosphokinase level at least twice the upper limit of normal for laboratory Mucous membrane hyperemia (vaginal, oral, conjunctival) Kidney failure (serum creatinine > 2 times normal) Liver inflammation (bilirubin, AST, or ALT > 2 times normal) Low platelet count (platelet count < 100,000 / mm3) Central nervous system involvement (confusion without any focal neurological findings) Negative results of: Blood, throat, and CSF cultures for other bacteria (besides S. aureus) Negative serology for Rickettsia infection, leptospirosis, and measles Cases are classified as confirmed or probable as follows:
Confirmed: All six of the criteria above are met (unless the patient dies before desquamation can occur) Probable: Five of the six criteria above are met
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