Toxic shock syndrome laboratory findings
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1],Associate Editor(s)-in-Chief: Mahshid Mir, M.D. [2]
Overview:
Laboratory findings consistent with the diagnosis of toxic shock syndrome (TSS) include leukocytosis, anemia and thrombocytopenia.
A positive blood culture is diagnostic for Streptococcal TSS, although in other causes of TSS blood culture doesn't have a high value.
Laboratory Findings
The International Guideline Committee for diagnosis of septic shock recommends obtaining appropriate cultures that may include at least two blood cultures, urine, cerebrospinal fluid, wounds, respiratory secretions, or other body fluid cultures before antimicrobial therapy is initiated. In TSS patients, blood culture for staphylococcus is not diagnostic, although blood culture for streptococcal TSS is highly diagnostic.
Primary General Electrolyte and Biomarker Studies[1][2]
| Laboratory Exam | Result |
|---|---|
| Complete blood count (CBC) | Leukocytosis with a left shift |
| Hematocrit levels up to 80 percent have been reported | |
| Thrombocytopenia with platelets <100 x 10^3/microliter | |
| Anemia | |
| Blood culture | Bacteremia |
| Renal function tests | Elevated serum BUN and creatinine |
| Urine Analysis (UA): hemoglobinuria | |
| Liver Function Tests | Elevated transaminases and bilirubin |
| hypoalbuminemia | |
| Serum lactic acid | Elevated |
| Metabolic tests | hypocalcemia |
| hyponatremia | |
| hypophosphatemia | |
| Blood gas analysis:
Venous blood gas (VBG) and arterial blood gas analysis (ABG) |
Hypoxemia may be present as a result of pulmonary edema and pleural effusion |
| Metabolic acidosis and elevated pH | |
| Creatine phosphokinase (CPK) | Elevated |
Specialized Laboratory Tests
A diagnosis of probable GAS TSS can be made if GAS is isolated from a normally nonsterile site (eg, throat, vagina, skin lesion) but the patient fulfills the other criteria noted above and no other etiology for the illness is identified.
Recovery of the organism from blood cultures usually takes 8 to 24 hours. Gram stain of involved tissue demonstrating gram-positive cocci in pairs and chains can provide an early diagnostic clue in many cases
Cultures from mucosal and wound sites should be obtained because S. aureus isolates can be tested for toxin production in research laboratories.acute and convalescent serum can be analyzed for antibody responses to various S. aureus exotoxins. The presence of a strain of S. aureus that produces toxin in a patient who does not have acute phase antibody to the toxin is highly suggestive of TSS.[1][2]
| Exam | Result |
| Blood microscopy and culture (blood, wound, fluid, tissue) | Positive for group A streptococcus or Staphylococcus aureus |
| Prothrombin time | Prolonged in staphylococcal disease in conjunction with DIC |
| Partial thromboplastin time | Prolonged in staphylococcal disease in conjunction with DIC |
| Creatine kinase (CK) | Elevated in necrotizing fasciitis or myositis and in some staphylococcal disease |
| Polymerase chain reaction (PCR) | Protracted expansion of TSST-1–reactive Vβ2-positive T cells persisting for 4–5 weeks |
| Serotyping | Evidence of streptococcal exotoxins |
References
- ↑ 1.0 1.1 "Defining the group A streptococcal toxic shock syndrome. Rationale and consensus definition. The Working Group on Severe Streptococcal Infections". JAMA. 269 (3): 390–1. 1993. PMID 8418347.
- ↑ 2.0 2.1 Adams EM, Gudmundsson S, Yocum DE, Haselby RC, Craig WA, Sundstrom WR (1985). "Streptococcal myositis". Arch. Intern. Med. 145 (6): 1020–3. PMID 3890787.