Organ Failure Flashcards
define lymphatics
blind ended capillaries that dump into venous system
low pressure, muscle contractions maintain flow
here for Liz Brain
list the main controls of fluid movement
hormones - RAAS, ANP (cardiomyocytes)
receptors - osmoreceptors, baroreceptors
osmotic/hydrostatic forces
integrity of vascular system
define shock
cardiovascular collapse - systemic hypoperfusion dur to macro/micro-circulatory failures
describe the outcome of shock
hypotension > impaired tissue perfusion > cellular hypoxia > anaerobic metabolism > cellular degeneration > cell death
describe the progression of shock to an irreversible state
hypovolemic shock > initial compensation > progression, metabolism shift to glycolysis > progressive morphological deterioration of cells
list the types of shock via macrocirculatory failure
- cardiogenic - failure of heart to properly pump blood
- hypovolemic - reduced circulation of blood volume by massive blood/fluid loss
list examples of cardiogenic macrocirculatory failure
myocardial infarction
ventricular tachycardia
dilated CM
pericardial tamponade
ID pathology
cardiogenic shock - macrocirculatory failure in horse
expanded pericardial sac, cardiac tamponade
define cardiac tamponade
compression of heart caused by fluid collecting in sac surrounding the heart
*example of macrocirculatory failure
ID pathology
aortic rupture and cardiac tamponade
ID pathology
hemangiosarcoma at R auricle and cardiac tamponade
list the types of shock due to microcirculatory failure
blood maldistribution
1. anaphylactic shock
2. septic shock
3. neurogenic shock
anaphylactic shock is generalized ___
type I (IgE) hypersensitivity
what mainly causes septic shock?
endotoxemia
what causes neurogenic shock?
trauma, electrocution, fear, emotional stress
anaphylactic shock pathogenesis
exposure of insect/plant/drug/vaccine > IgE mediated mast cell degranulation > histamine/mediators > systemic vasodilate and increased vascular permeability > blood hypotension > tissue hypoperfusion
septic shock (most common) pathogenesis
toxin (LPS from gram neg cell wall) > LPS forms complex with blood proteins > LPS binds to TLR-4 > downregulation of anticoags (endothelium) and increased production of IL-1, IL-6, TNF (monocytes and macrophage)
list the major antithrombotic systems
- protein c - protein s thrombomodulin system
- antithrombin III
- tissue factor pathway inhibitor
LPS intoxication is ___ dependant
dose
LPS effect on endothelium triggers coag cascade and damages capillaries, which can lead to what two things?
DIC aka disseminated intravascular coagulopathy
ARDS aka acute respiratory distress syndrome
what can be a result from pathological activation of coagulation due to disseminated intravascular coagulopathy (DIC)?
- small blood clot form inside blood vessels throughout body
- consumption of coag proteins and platelets > disruption of normal coag causing abnormal bleeding
- clots plug normal blood flow to organs > ischemic injury
list what could trigger disseminated intravascular coagulopathy (DIC)
bacterial endotoxins, sepsis
parasites
viruses
carcinoma, hemangiosarcoma, leukemia
heat stroke, antigen-Ab complexes
*diffuse endothelial damage and/or generalized platelet activation initiates
define acute respiratory distress syndrome (ARDS)
multifactorial source of injury to respiratory capillary endothelium (primary)
epithelium (secondary)
list the main causes of acute respiratory distress syndrome (ARDS)
endotoxemia, sepsis, extensive trauma (hit by car), DIC, pancreatitis
ID pathology
ARDS
blue - inflammatory cells
dilated blood vessels
*Liz Brain
neurogenic shock pathogenesis
trauma, spinal cord injury, fear, electricity > triggers generalized ANS > sympathetic tone lost, parasympathetics dominate > massive peripheral dilation and bradycardia > pooling of blood > hypoperfusion
describe what occurs at each stage in the development of shock
compensation - increased HR, vasoconstriction, ADH and AII released, increased BP and blood diversion to vital tissue
progression - anaerobic metabolism, acidosis, peripheral vasoconstrict cannot be maintained so dilation occurs
irreversible - cell and tissue necrosis
