Critical Care Medicine Flashcards
List the steps leading from disease to multi-organ failure.
Disease -> Sepsis -> Endotoxemia -> Systemic Inflammatory Response Syndrome -> Compensatory Autoimmune Response Syndrome -> Multi-organ Disfunction Syndrome -> Multi-organ failure
What is the most common cause of death for patients that are admitted to the ICU?
Multi-organ failure/dysfunction
Name two types of MODS/MOF.
- ) Acute respiratory distress syndrome (ARDS)
2. ) Disseminated intravascular coagulation (DIC)
List the criteria (2 minimum) required to diagnose SIRS (systemic inflammatory response syndrome)
Leukopenia, leukocytosis, hyper/hypothermia, tachycardia, tachypnea, sepsis
T/F: Gram negative bacteria are more commonly represented in endotoxemia.
True.
Describe the pathophysiology of endotoxemia.
Bacteria are killed during rapid prolifersation -> lysis. LPS activates cells (Lipid A is the responsible for toxic effect)
Name the 3 structural domains of LPS.
Polysaccharide O region (outer), Core acid polysaccharide (connecter), Lipid A region (inner)
How does the body defend against LPS and bacterial virulence factors?
Mucosal layer, physical barrier, lysozyme & enzyme secretions, circulating anti-endotoxin antibodies, macrophages
What are the five stages of endotoxemia?
- ) Endotoxins breach the physical barrier
- ) Endotoxins stimulate macrophages (chemical)
- ) Cytokine production. Leukocyte activity, procoagulation activity
- ) Compromised organ perfusion
- ) Recovery(?)
What is a sign you will see with initial endotoxemia?
Colic. (abdominal pain)
What are some things that can predispose the horse to endotoxemia?
Enteritis, colitis (potomac horse fever), sand colic, grain overload, drugs, pleuropneumonia, thoracotomy, choke, clostridium (skin), retained placenta (>2 hours), Equine Metabolic syndrome
How does equine metabolic syndrome lead to endotoxemia?
EMS horses have more cytokine factors, leads to increased and prolonged inflammation from exposure to LPS
Describe how LPS interacts with the host immune system.
The host cell PRR’s interact with LPS (PAMP) and produce pro/anti-inflammatory factors. LPS leads to MyD88 -> pro-inflammatory
At what stage of endotoxemia does endothelial damage and hypercoagulation occur?
Stage 3. (of 5)
Describe how Stage 4 endotoxemia leads to multi-organ failure.
Loss of perfusion, vasodilation and vascular leakage, coagulation, and overall hypotension to the organs leads to dysfunction -> failure
How does the Recovery stage (5) work?
LPS induces IL10 which inhibits pro-inflammatory cytokines.
Concerning experimental endotoxemia, what clinical signs will you see early on (90 minutes)?
Tachypnea, pale MM, fever, restlessness
Concerning experimental endotoxemia, what clinical signs will you see at 2 hours?
Peak tachypnea, congested MM, increased CRT, decreased GIT sounds
Concerning experimental endotoxemia, what clinical signs will you see at 4-6 hours? (secondary phase)
Tachycardia, fever, circulatory failure, coagulopathy, dehydration! (sunken eye, skin tenting)
Why would a dehydrated horse still produce urine?
Strong regulatory renal function causes the renal artery to vasodilate and work.
Concerning experimental endotoxemia, what clinical signs will you see in its later stages?
Decreased rectal temperature, oli/anuria, rapid weak pulses, muscle tremors, hemodysfunction
Concerning experimental endotoxemia, what clinical signs will you see after 24 hours?
ventral edema, laminitis
those that do not show signs of laminitis are more worrisome
T/F: Horses have less sensitivity to LPS compared to other species
False. Higher sensitivities!
Flagellin typically activates monocytes in animals, but for horses its NEUTROPHILS
List some symptoms seen with the hyperdynamic state of clinical endotoxemia.
white mucous membranes, normal CRT, strong pulses, tachypnea, fever/hyperthermia
List some symptoms seen with the hypodynamic state of clinical endotoxemia.
dark mucous membranes, prolonged CRT, weak pulses, tachypnea, cold extremeties, normal/hypothermic
What is a ‘toxic line’?
area on the mucous membranes (oral) that signifies endotoxemia. better to look for petechia
What CBC results will you see on a horse with endotoxemia?
leukopenia, neutropenia with a left shift
List some diagnostic factors you can measure through blood work.
Glucose, lactate (measures severity), platelets, fibrinogen
What is the limulus ameobocyte lysate assay?
It is the direct measurement of circulating endotoxins. Typically more for research purposes.
List the three types of limulus ameobocyte lysate assays.
- ) Gel Clot Assay (clots with presence of endotoxins)
- ) Turbidi-metric testing (use of measuring light beams)
- ) Chromogenic limulus amebocyte lysate
Why is it important to recognize endotoxemia early on? (think common sense)
early treatment to prevent multiorgan dysfunction and laminitis
Why is preventing laminitis so important when working with potential endotoxemia?
Studies show preventing laminitis provides a better prognosis.
What are the goals of treating endotoxemia?
Support circulatory system, removal the causes, neutralize the endotoxin and inhibit its inflammation, prevent laminitis
What are some treatment methods for endotoxemia?
IV fluids (preferable polyionic solution - LRS or normosol), treating the cause, certain medications
How do PAMP antibodies fight against endotoxemia?
the antibodies bind and neutralize LPS. shown to decrease mortality rate