Sepsis and Bacteremia Flashcards
Why have incidences of sepsis and septic shock continued to increase
Increased use of invasive devices, cytotxic and immunosuppressive drugs for cancer and transplants, increased lifespan of cancer and diabetes patients, and increased infections with antibiotic resistant bacteria
Systemic Inflammatory Response Syndrome or SIRS
Temperature above 38 or below 36, HR above 90bpm, respiratory rate above 20, WBC count above 12000 or below 4000 OR 10% immature forms, requires 2 or more of those symptoms
Sepsis
SIRS plus blood infection with any microorganism, it is often assumed and treated as such if patient shows symptoms with no other clear or likely diagnosis
Septic shock
Sepsis plus organ dysfuntion, hypotension, or hypoperfusion
What is the mortality rate once septic shock progresses to multiple organ dysfunction syndrome (MODS)
90%
Is microbial blood stream invasion required to produce sepsis
No, microbe invasion is usually involved but systemic spread of signal molecules and toxins can elicit the same response
What are the most common microbes involved in sepsis and septic shock
Fungi and bacteria, mostly gram negatives
What factors predispose people to bacteremia, especially with gram negative rods
Diabetes, lymphoproliferative diseases, cirrosis, burns, invasive procedures or devices, renal insufficiency, alcoholism, and drugs that cause neutropenia
What types of infections are more likely to lead to sepsis
Any infection can progress to sepsis BUT pylelonephritis, pneumonia, peritonitis, cholangitis, cellulitis, meningitis, or abscesses are more likely causes (many nosocomial)
Are you more likely to find the original site of infection in an immunocometant or immunocomprmised patient
Competent, immunocompromised patients, esp neutropenic, often have clinically unapparent infections in skin or bowel
What is the most potent gram negative bacterial antigen
Lipopolysaccharide
What is correlated with detectable plasma levels of bacterial endotoxin
Positive blood cultures, decreased systemic resistance, depressed ventricular ejection fraction, and lactic academia
What do endotoxins activate/release
They activate complement and release anaphylotoxins C5a and C3a that cause vasodilation/platelet aggregation and they activate factor XII which releases bradykinin that causes vasodilation and coagulation and can lead to consumption of coagulation factors and DIC
Examples of bacterial antigens that illicit inflammatory response
Polysaccharides, extracellular enzymes, peptidoglycan, lipoteichoic acid, and other toxins
Components of the innate immune system
Neutrophils, macrophages, complement, and cytokines
Anti-inflammatory cytokines to modulate inflammatory response
IL-4, IL-10, IL-11, and transforming growth factor
What can cause imbalance in inflammatory response
Overproduction of pro-inflammatory mediators, underproduction of anti-inflammaroty mediators, or genetic absence of any component, resulting aberrant response leads to diverse clinical signs of sepsis
Describe cardiac function in sepsis
Low vascular resistance, high CO, decreased ventricular ejection fraction and a dilated ventricle
Describe cardiac function in sepsis
Low vascular resistance, high CO, decreased ventricular ejection fraction and a dilated ventricle
Progressive hypotension or complete failure od one or more organ systems (ARDS, DIC, renal failure, or hepatic failure)
What infections are not cleared from the blood by the reticuloendothelial system
What infections are not cleared from the blood by the reticuloendothelial system
Endocarditis and severe intravascular infections
3 categories of sepsis/septic shock clinical manifestations
- signs related to the primary focus of infection found through history, labs, imaging and exam 2. Signs of systemic infection such as fever, hyperventilation, and disorientaiton 3 rapid end organ responses showing cytokine effects
What causes tachycardia and hyperventilation in septic shock
Initial increase in sympathetic tone
What causes edema in septic shock
Low vasomotor tone causing leaky capillaries
What causes mental status changes like agitation in septic shock
Increased catecholamines
What cause is stupor or coma in septic shock
CNS hypoperfusion
What causes lactic acidosis in septic shock
Hypoperfusion of the liver and periphery
What happens to liver metabolism in septic shock
A switch from anabolism to catabolism which causes the release of acute phase proteins
Lab abnormalities seen in sepsis
Leukocytosis from bone marrow stimulation or lekopenia from consumtion, thrombocytosis or thrombocytopenia (DIC), RBC production decrease to sequester iron stores, and other abnormal chemistries related to affected organ
Antibiotic treatment of sepsis
Take sterile fluid samples for culture before regimen and determine the most likely pathogen based on history and treat with emperic broad spectrum drugs
Antibiotic treatment of sepsis
Take sterile fluid samples for culture before regimen and determine the most likely pathogen based on history and treat with emperic broad spectrum drugs
What have studies shown about broad spectrum antibiotics used alone and in combination for sepsis
A single broad spectrum is as efficacious as a combination, combining penicillins and aminoglycosides show synergistic killing, refinement to the most specific drug lowers antibiotic pressure toward resistance
Non-antibiotic treatment for sepsis
Evaluation and possible resection and drainage of primary site of infection, removal of indwelling devices, and support of failing organ systems
Treatment for septic shock
Initially predetermined and titrated blous fluids to treat hypotension and hyperperfusion and vasopressors (dopamine, norepinephrine, epinephrine, phenylephrine, and dobutamine) if that fails
What does dopamine do at low, medium, and high doses
Low doses stimulate dopaminergic receptors that dilate renal mesenteric and coronary capillaries, medium stimulates beta-1 receptors to increase HR and contractility and high stimulates alpha receptors that constrict arteries
What do norepinephrine and epinephrine do
Increase MAP
