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
What bacteria causes meningococcemia?
Neisseria meningitides
Gram -, aerobic, diplococci
At least 13 serogroups
Capsules protect against:
Dessication
Phagocytosis
Complement-mediated lysis
Have the ability to undergo capsule switching
What are the symptoms of meningococcus infection?
Initial symptoms are non-specific
Common:
Fever
N/V
Headache
Decreased Concentration
Muscle Pains
Uncommon:
Sore throat
(runny nose, cough)
**Occurs in winter months, often confused for influenza or, lest often, strep pharyngitis
Classic symptoms (occur late in disease course):
Hemorrhagic Rash
Meningismus
Impaired consciousness
What is meningismus?
Stiff neck
pain on flexion of neck or when moving knee to cheset
photophobia
–> Signs of mengitis
What are the clinical syndromes of meningococcal infection?
Meningitis
Meningitis with meningococcemia
Meningococcemia without meningitis
How is the hemorrhagic rash of menincococcal infection described?
Petechial (non-blanching discrete round red lesions)
- can coalesce into larger purpuric lesions
Usually on trunk and lower portions of body
Often first occurs in areas where pressure is applied to skin by belts and elastic straps
What is the natural reservoir for Neisseria meningitides?
Humans
Carriage can last for months
Invasive disease usually occurs wihtin days after new acquisition of N. meningitids in nasopharynx
Increased populations in confined quarters leads to increased rates of meningococcal infection
What are risk factors for N. meningitides infection?
- Terminal complement component deficicency (C5-9)
- Variants in mannose-binding lectin
- Asplenia
- Cigarette smoking
- Preceding URI
How is mengicoccal infection diagnosed?
Gold standard = Culture from blood or CSF
- Gram stain of blood or CSF for gram (-) diploccoci
Latex agglutination on CSF or urine
PCR (still investigational)
What is the treatment for meningococcal infection?
Antibiotics for 10-14 days
- Penicillin (some resistance)
- Third gen cephalosporin (i.e. ceftriaxone)
- cloramphenicol
Treatment of shock (fluids, vasopressors, ICU care)
Steroids sometimes used
