Toxic Shock II Flashcards
What is Toxic Shock Syndrome?
Acute, systemic illness with fever and hypotension due to bacterial superantigen
– Occurs due to excessive activation of T-cells and APCs with subsequent cytokine storm causing:
Capillary leakage
Tissue Damage
Multiorgan Failure
Death
What are the most common bacterial causes of Toxic Shock Syndrome?
Staphylococcus aureus (TSST-1 (menstrual), Enterotoxins A-E (non-menstrual))
Streptococcus pyogenes (pyrogenic exotoxins, streptococcal superantigen)
What are the risk factors for staphylococcal toxic shock syndromes?
Menstrual: Associated with retention of high absorbancy tampons - causes excess TSST-1 production
Non-Menstrual:
post-surgical
skin infections
abscess
wounds (esp. burn victims)
post-influenza staphylococcal pneumonia
How is staphylococcal TSS diagnosed?
- *1. Fever > 102degF
2. Hypotension** (SBP < 90mmHg) - *3. Diffuse macular erythrodema
4. Desquamation at 1-2 weeks
5. 3 or more organ systems involved** (GI, renal, liver, muscular, CNS, mucous membranes, thrombocytopenia)
Does NOT require isolation of Staphylococcus aureus
+ negative serologies for measles, leptospirosis, rocky mt. spotted fever, and negative blood cultures for organisms other than S. aureus
What wounds are Streptococcal TSS associated with?
Invasive Strep infections, especially:
Invasive skin/soft tissue infections
Necrotizing Fasciitis
Myositis
Bacteremia
Patients often have extreme pain at the site of skin infections
What are the major risk factors for Streptococcal TSS?
Any disease compromising skin or mucosal surfaces
Wounds
Chickenpox
Use of NSAIDs
Pregnancy
Underlying comorbidities
How is strep TSS diagnosed?
1. Isolation of Streptococcus pyogenes from a normally sterile site (tissue bx, surgical wound, CSF, pleura, peritoneal fluid, blood)
2. Hyptension (SBP < 90mmHg)
AND
Two or more of the following:
Renal insufficiency
Coagulopathy
Increased liver enzymes
Adult respiratory distress syndrome (ARDS)
Erythematous macular rash (may desquamate)
Soft tissue necrosis
How do Strep and Staph TSS differ in presentation that makes strep TSS easier to identify?
Staphylococcal infection doesn’t always have an obvious point of entry for the bacteria, or obvious wound; but does often have a rash
Streptococcal commonly has a visible skin/soft tissue infection and severe pain at skin; but doesn’t often have a rash
Note: Staphylococcal TSS has 3-5% mortality
Streptococcal TSS has 5-10%
What are superantigens?
Cause of Toxic Shock Syndrome - they activate high percentages of immune cells by binding directly to MHC II molecules and the Vß subunit of the TCR
- bypass antigen-processing
- bind outside MHC peptide groove
–> Activation of up to 20% of all CD4+ Tcells leading to diffuse inflammation
What is the treatment of TSS?
1. IV fluids
- *2. Thorough search for site of infection**
- -> removal of tampon
- -> debridement of infected wounds
- -> drainage of abscesses
3. Antibiotics (vancomycin for Staph if MRSA, nafcililn if MSSA, IV PCN if GAS) + clindamycin (blocks toxin production)
+/- IVIG therapy
What is endotoxemia?
Endotoxins in the blood –> can lead to shock
(Endotoxins are poisonous substances that come from within pathogenic organisms - i.e.LPS)
How is LPS recognized?
It is a PAMP recognized by TLR4 (a Pattern Recognition Receptor (PRR))
How does LPS cause the symptoms of endotoxemia (septic shock due to gram negative bacteria)?
Ligation of TLR4 by LPS results in a cascade of inflammation:
TNF and cytokines (By macrophages)
NO, PAF, O2, LT, Kinins, Coagulation (by other cells)
What is the treatment of septic shock due to Gram - bacteria?
- IV fluids
- Eradication of infxn (broad spect. abx +/- surgery)
- Vasopressors and inotropes if needed
Why does meningococcus make clinicians nervous?
Fever and infection can quickly spread to Waterhouse-Freidrichson Syndrome and death within hours
