Path - Inflammation (Ischemia, Infarcts, Shock, & Atrophy) Flashcards
Pg. 221-22 in First Aid 2014 Sections include: -Ischemia: susceptible areas -Infarcts: red vs. pale -Shock -Atrophy
What areas in the brain are susceptible to hypoxia/ischemia and infarction?
ACA/MCA/PCA boundary areas;
Explain the general blood supply of watershed areas. What are these areas protected from versus susceptible to in terms of hypoxia/ischemia and infarction? Give 2 organs and specific areas within them to which the concept of watershed areas applies.
Watershed areas (border zones) receive dual blood supply from most distal branches of 2 arteries, which protects these areas from single-vessel focal blockage. However, these areas are susceptible to ishcemia from systemic hypoperfusion; (1) Brain - ACA/MCA/PCA boundary areas (2) Colon - Splenic flexure, rectum
What is HIE, and what cells/regions does it affect?
Hypoxic ischemic encephalopathy (HIE) affects pyramidal cells of hippocampus and Purkinje cells of cerebellum
What area in the heart is susceptible to hypoxia/ischemia and infarction?
Subendocardium (LV)
What 2 areas in the Kidney are susceptible to hypoxia/ischemia and infarction?
(1) Straight segment of proximal tubule (medulla) (2) Thick ascending limb (medulla)
What area in the liver is susceptible to hypoxia/ischemia and infarction? Both describe/define and name this area.
Area around central vein (zone III)
What 2 areas in the Colon are susceptible to hypoxia/ischemia and infarction?
(1) Splenic flexure (2) Rectum
What causes reperfusion injury?
Reperfusion injury is due to damage by free radicals
What is another name for red infarcts? In what setting/context do they occur? Give 3 examples of such organs.
Red (hemorrhagic) infarcts occur in loose tissues with multiple blood supplies, such as liver, lungs, and intestine; Think: “REd = REperfusion”
In what setting/context do pale infarcts occur? Give 3 examples of such organs.
Pale infarcts occur in solid tissues with a single blood supply, such as heart, kidney, and spleen
What is the first sign of shock?
First sign of shock is tachycardia
What kind of presentation involving shock would suggest an etiology of sepsis?
Shock in the setting of DIC secondary to trauma is likely due to sepsis
What are 3 types of distributive shock?
Distributive shock includes septic, neurogenic, and anaphylactic shock
Compare/contract the output failure in Distributive versus Hypovolemic/Cardiogenic shock. Give the change in relevant variables in each case.
DISTRIBUTIVE: High-output failure (low TPR, high CO, high venous return); HYPOVOLEMIC/CARDIOGENIC: Low-output failure (high TPR, low CO, low venous return)
Compare/contract the PCWP in Distributive versus Hypovolemic/Cardiogenic shock.
DISTRIBUTIVE: Low PCWP; HYPOVOLEMIC/CARDIOGENIC: PCWP high in cardiogenic & low in hypovolemic
Compare/contract the vascular change in Distributive versus Hypovolemic/Cardiogenic shock. Give the relevant clinical presentation/findings in each case.
DISTRIBUTIVE: Vasodilation (warm, dry skin); HYPOVOLEMIC/CARDIOGENIC: Vasoconstriction (cold, clammy patient)
Compare/contract the use of IV fluids in Distributive versus Hypovolemic/Cardiogenic shock.
DISTRIBUTIVE: Failure to increase blood pressure with IV fluids; HYPOVOLEMIC/CARDIOGENIC: Blood pressure restored with IV fluids
What is atrophy?
Reduction in the size and/or number of cells
What are 7 causes of atrophy?
Causes include: (1) low endogenous hormones (e.g., post-menopausal ovaries) (2) high exogenous hormones (e.g., factitious thyrotoxicosis, steroid use) (3) low innervation (e.g., motor neuron damage) (4) low blood flow/nutrients (5) low metabolic demand (e.g., prolonged hospitalization, paralysis) (6) high pressure (e.g., nephrolithiasis) (7) Occlusion of secretory ducts (e.g., cystic fibrosis)
What hormonal changes cause atrophy? Give at least one example of each change.
(1) low endogenous hormones (e.g., post-menopausal ovaries) (2) high exogenous hormones (e.g., factitious thyrotoxicosis, steroid use)
What change in innervation causes atrophy? Give an example of this.
low innervation (e.g., motor neuron damage)
What change in blood flow/nutrients causes atrophy?
low blood flow/nutrients
What change in metabolic demand causes atrophy? Give 2 examples of this.
low metabolic demand (e.g., prolonged hospitalization, paralysis)
What change in pressure causes atrophy? Give an example of this.
high pressure (e.g., nephrolithiasis)
What kind of occlusion causes atrophy? Give an example of this.
Occlusion of secretory ducts (e.g., cystic fibrosis)
