Flashcards in Toxic Shock, Endotoxemia, and Meningococcus Deck (18):
What are superantigens?
Antigens that activate high percentages of immune cells by bypassing usual steps in antigen mediated response
Bind to MHCII molecules and variable B subunit of TCR
Activate up to 20% of all T cells
What is secreted in response to superantigens?
Extremely high levels of TNF-a, IL-1, and IL-6 causing the symptoms of TSST
What is toxic shock syndrome?
Acute, systemic illness with fever and hypotension due to a bacterial superantigen; causes capillary leak, tissue damage, multiorgan failure, and death
What two bacteria most commonly cause TSS?
S. Aureus and S. Pyogenes
What are signs and symptoms of TSS?
(Think Sepsis) Fever, confusion, headache, diarrhea, vomiting, photophobia, myalgias, sunburn like rash, pelvic pain, sore throat, and hypotension
What is the CDC definition of Staph Toxic Shock?
What is the CDC definiton of Strep Toxic Shock?
Isolation of strep from sterile site
How do you treat TSS?
Identification of the site of infection and removal/debridement
Penicillin G (or Nafcillin or Vanc) + Clindamycin to block toxin production
(Can give IVIG to neutralize superantigen)
What is the role of TLRs in the host immune system?
TLRs are Patter Recognition Receptors (PRRs) that recognize Pathogen Associated Molecular Patterns (PAMPs)
How many different TLRs are there in humans and what happens when they are ligated?
There are 10 different TLRs
When ligated they release inflammatory cytokines (TNF-a, IL-1, and IL-6) and upregulate costimulatory and adhesion molecules
What is Endotoxin and how does it activate the immune system?
Endotoxins (LPS for our purposes) are poisonous substances that come from pathogenic organisms that activate the immune response by binding to TLRs. (TLR4 in the case of LPS)
What are the common early symptoms of infection with N. Meningitidis?
When does infection with N. Meningitidis usually occur?
People in their late teens to early twenties during the winter months
What are the classic late symptoms of N. Meningitis?
Hemorrhagic petechial rash near pressure areas
Meningismus (Neck stiffness, pain on flexion, photophobia)
How rapidly can symptoms progress?
Often less than 24 hrs, progression to Waterhouse-Friedrichson syndrome is associated with increased release of inflammatory cytokines.
How is N. Meningitis diagnosed?
Culture from blood or CSF is the gold standard, the gram stain will show gram negative diplococci within 45 minutes
Bx of skin lesion is more sensitive than CSF
What is the treatment for N. Miningitis?
Abx for 10-14 days
Penicillin, Ceftriaxone, Chloramphenicol
Steroids are often needed to help clear infection