bacteremia & sepsis
Terms
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- _______ is the presence of microorganisms in a normally sterile host tissue.
- Infection
- ________ is defined as the presence of viable bacteria in the blood.
- Bacteremia
- _____ is the systemic response to infection. Clinical signs of systemic inflammation are present together with definitive evidence of infection.
- Sepsis
- Sepsis is a clinical syndrome that complicates severe infection and is characterized by systemic ________ and widespread tissue injury.
- inflammation
- In sepsis , tissues remote from the original insult display the cardinal signs of inflammation, including _______ , increased microvascular _______, and ________accumulation.
-
vasodilatation
permeability
leukocyte - Sepsis is considered ________ when it is associated with organ dysfunction, hypoperfusion, or hypotension
- severe
- ______ is sepsis with hypotension despite adequate fluid resuscitation combined with perfusion abnormalities.
- Septic shock
- Septic shock is in part caused by cytokines produced mainly by activated macrophages. ___ and ____ are principle mediators of septic shock.
-
TNF
IL-1 - Toll Like Receptors on macrophages constitute a molecular “alarm system†to alert the body of intruders (microorganisms). Overactivation of this system can result in ______
- septic shock.
- Blood is normally _____.
- sterile
- ________ are common and can occur after dental procedures, obstetrical procedures or even brushing teeth. They are rapidly cleared by the host immune system.
- Transient bacteremias
- For nontransient bacteremia such as continuous or intermittent, it is usually possible to find a _____ of the infection (where it seeded from).
- focus
- The principal injurious consequences of host responses to extracellular bacteria are inflammation and ______, which are caused by cytokines produced mainly by activated ________.
-
septic shock
macrophages - Septic shock is the most severe cytokine-induced pathologic consequence of infection by gram ______ and some gram ________ bacteria.
-
negative
positive - septic shock is a syndrome characterized by circulatory collapse and ________-
- disseminated intravascular coagulation
- TNF and IL-1 are the principal mediators of septic shock. _____ serum levels are in fact predictive of outcome of severe gram negative infections
- TNF
- Gram negative bacteria have ________ , which stimulates the innate immune system.
- LPS (lipopolysaccharide)
- If an individual is infected with a gram negative bacterium and fails to control its replication, LPS levels can rise to such a level as to cause _______.
- septic shock
- LPS (lipopolysaccharide) or endotoxin binds to a ______ receptor and stimulates secretion of cytokines. This is part of the ____ immune system.
- macrophage innate
- Critical amount of ____ stimulates septic shock.
- LPS
- The polysaccharide moieties on LPS can be highly variable and are recognized by the _____ immune system
- adaptive
- The lipid moiety is highly conserved and is recognized by the ______ immune system.
- innate
- Circulating LPS is bound to a plasma _________
- LPS binding protein (LBP)
- The complex docks with ___ and the LBP is released.
- CD14
- LPS induces __________
- cell signaling
- The macrophage is activated via this receptor and ____
- TLR4
- Macrophages are stimulated to produce ______ and ____, and ______
-
TNF-a
IL-1
IL-6 - Macrophage activation leads to _______
- tissue damage
- TNF-a in combination with IFN-g and IL-1 can induce nitric oxide synthase which produces nitric oxide, which not only has potent micobicidal activities, but is a vasodilator. NO appears to be responsible for _______.
- hypotension
- _______ may become evident in several ways. Systemic activation of coagulation generates the deposition of ______in small blood vessels and microvascular thrombosis in critical target organs leading to organ failure.
-
Disseminated intravascular coagulation (DIC)
fibrin - As components of coagulation are consumed, paradoxically the patient may ______from other sites within the body. So clotting and bleeding may occur simultaneously in the same patient.
- bleed
- Septic shock arises when cardiac output is unable to compensate for falling blood pressure secondary to vasodilatation. At first it is _____ shock due to increased blood flow to the periphery, then ____ shock.
-
warm
cold - Finally in septic shock, Multiple organs show inflammation and intravascular thrombosis, which can produce organ ______
- failure
- Tissue injury in response to LPS can result from the activation of ______ before they exit the vasculature, thus causing damage to endothelial cells and reduced blood flow.
- neutrophils
- The ____ and _____ are particularly susceptible to injury by neutrophils.
-
lungs
liver - Lung damage is commonly called ___________ and results when neutrophil-mediated endothelial injury allows fluid to escape from blood into airspace.
- acute respiratory distress syndrome (ARDS)
- Liver injury and impaired liver function result in failure to maintain normal blood _____ levels because of a lack of gluconeogenesis from stored glycogen.
- glucose
- Toxic Shock occurs when some bacterial toxins stimulate all the ______ in an individual that express a particular set or family of T cell receptor genes. Such toxins are called _______. They activate many T cells with subsequent production of large amoun
-
T cells
super antigens - __________ can produce TSST-1 (toxic shock syndrome toxin).
- Staphylococcus arueus
- ____________ is an enterotoxin that is secreted and can bind nonspecifically to the T-cell receptor to stimulate T-cells. This antigen is capable of stimulating ALL T-cells in a given class.
- toxic shock syndrome toxin )TSST-1
- some strains of streptococci produce _________ that can act as a super antigen. The antigen interacts with T-cells and macrophages stimulating the release of IL-1, IL-2, IL-6, TNF-a, TNF-b, and INF-g
- Streptococcal pyrogenic exotoxins-