Toxic shock syndrome (TSS) is a potentially fatal illness caused by a bacterial toxin. Different bacterial toxins may cause toxic shock syndrome, depending on the situation. The causative bacteria include Staphylococcus aureus and Streptococcus pyogenes. Streptococcal TSS is sometimes referred to as toxic shock-like syndrome (TSLS) or streptococcal toxic shock syndrome (STSS).
In contrast, TSS caused by the bacterium Streptococcus pyogenes, or TSLS, typically presents in people with pre-existing skin infections with the bacteria. These individuals often experience severe pain at the site of the skin infection, followed by rapid progression of symptoms as described above for TSS. In contrast to TSS caused by Staphylococcus, streptococcal TSS less often involves a sunburn rash.
In either case, diagnosis is based strictly upon CDC criteria modified in 1981 after the initial surge in tampon-associated infections.:
Signs and symptoms
Symptoms of toxic shock syndrome vary depending on the underlying cause. TSS resulting from infection with the bacterium Staphylococcus aureus typically manifests in otherwise healthy individuals with high fever, accompanied by low blood pressure, malaise and confusion, which can rapidly progress to stupor, coma, and multiple organ failure. The characteristic rash, often seen early in the course of illness, resembles a sunburn, and can involve any region of the body, including the lips, mouth, eyes, palms and soles. In patients who survive the initial onslaught of the infection, the rash desquamates, or peels off, after 10–14 days.In contrast, TSS caused by the bacterium Streptococcus pyogenes, or TSLS, typically presents in people with pre-existing skin infections with the bacteria. These individuals often experience severe pain at the site of the skin infection, followed by rapid progression of symptoms as described above for TSS. In contrast to TSS caused by Staphylococcus, streptococcal TSS less often involves a sunburn rash.
In either case, diagnosis is based strictly upon CDC criteria modified in 1981 after the initial surge in tampon-associated infections.:
- Body temperature > 38.9 °C (102.02 °F)
- Systolic blood pressure < 90 mmHg
- Diffuse rash, intense erythroderma, blanching with subsequent desquamation, especially of the palms and soles
- Involvement of three or more organ systems:
- Gastrointestinal (vomiting, diarrhea)
- Mucous membrane hyperemia (vaginal, oral, conjunctival)
- Renal failure (serum creatinine > 2 times normal)
- Hepatic inflammation (AST, ALT > 2 times normal)
- Thrombocytopenia (platelet count < 100,000 / mm³)
- CNS involvement (confusion without any focal neurological findings)
Pathophysiology
In both TSS (caused by S. aureus) and TSLS (caused by S. pyogenes), disease progression stems from a superantigen toxin that allows the nonspecific binding of MHC II with T cell receptors, resulting in polyclonal T cell activation. 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. By contrast, 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. 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.
Treatment
The severity of this disease frequently warrants hospitalization. Admission to the intensive care unit is often necessary for supportive care (for aggressive fluid management, ventilation, renal replacement therapy and inotropic support), particularly in the case of multiple organ failure. The source of infection should be removed or drained if possible: abscesses and collections should be drained. Anyone wearing a tampon at the onset of symptoms should remove it immediately. Outcomes are poorer in patients who do not have the source of infection removed.
Antibiotic treatment should cover both S. pyogenes and S. aureus. This may include a combination of cephalosporins, penicillins or vancomycin. The addition of clindamycin or gentamicin reduces toxin production and mortality.
Prognosis
With proper treatment, patients usually recover in two to three weeks. The condition can, however, be fatal within hours.
Epidemiology
Staphylococcal toxic shock syndrome is rare and the number of reported cases has declined significantly since the 1980s. Patrick Schlievert, who published a study on it in 2004, determined incidence at 3 to 4 out of 100,000 tampon users per year; the information supplied by manufacturers of sanitary products such as Tampax and Stayfree puts it at 1 to 17 of every 100,000 menstruating people per year. The CDC has stopped tracking TSS. However, there was a rise in reported cases in the early 2000s: eight deaths from the syndrome in California in 2002 after three successive years of four deaths per year, and Schlievert's study found cases in part of Minnesota more than tripled from 2000 to 2003. Schlievert considers earlier onset of menstruation to be a cause of the rise; others, such as Philip M. Tierno and Bruce A. Hanna, blame new high-absorbency tampons introduced in 1999 and manufacturers discontinuing warnings not to leave tampons in overnight.
