Inflammation-Manifestations of Acute Inflammation

Question 1

What are the systemic manisfestations of acute inflammation?

Answer 1

Leukocytosis
Pyrexia
Acute Phase Response
Anemia
Septic Shock

Question 2

What causes neutrophil leukocytosis?

Answer 2

local bacterial infections
viral infections
trauma

Question 3

What happens when pyogenic bacteria or fungi infect a tissue?

Answer 3

1. Rapid emigration of neutrophils to the site, depleting the levels in the blood (temporary neutropenia)
2. After a few hours, large number of mature cells released from bone marrow (neutrophilia) induced by IL-1, TNF-alpha, and IL-8 synth’d by macrophages and lymphocytes
3. If prolonged, immature neutrophils are released (‘shift to the left’) that will mature when they reach the tissue and come into contact with colony stim factors (CSF).

Question 4

What is the main leukocyte in parasite infections?

Answer 4

Eosinophils

*same thing happens as in neutrophil leukocytosis, except called eosinophil leukocytosis or eosinophilia

Question 5

How is fever (pyrexia) induced?

Answer 5

1. stim of macrophages by infection>synth and secretion of IL-1 and TNF-alpha>induce PGE2>increase in hypothalamic thermostat>fever
2. interaction of microbial products with TLR on brain endothelial cells>PGE2 induced>fever

Question 6

Why is fever beneficial?

Answer 6

decreased microbial rep efficiency, increased leukocyte function

Question 7

What happens during the acute phase response?

Answer 7

Induction of increased synth of host proteins that attract leukocytes into tissues, clear microorganisms, clot blood, and control proteases that are released during inflammation

Question 8

What mediates the acute phase response?

Answer 8

IL-6 released by activated macrophages (autocrine mechanism keeps the whole thing going)

Question 9

What mediates anemia?

Answer 9

action of inflammatory mediators on the liver>liver synths and secretes hepcidin>binds membrane bound iron transporter protein (ferroportin)>complex is taken up by gut epithelial cells, macrophages, and hepatocytes and destroyed

*without ferroportin, iron is not released into plasma and RBC production is stopped

Question 10

What mechanisms are involved in septic shock?

Answer 10

• -Release of cytokines
• -Activation of neutrophils, monocytes, and microvascular endothelial cells
• -Acitvation of neuroendocrine reflexes
• -plasma protein cascade systems (complement, intrinsic and extrinsic pathways of coagulation, fibrinolytic system)

Question 11

What happens in dissiminated intravascular coagulation?

Answer 11

sepsis disturbs the normal homestatic balance between pro- and anticoagulant pathways causing widespread thrombosis and impaired tissue perfusion

Question 12

What mediates the septic reaction?

Answer 12

pro-inflammatory cytokines
lipid mediators
other factors released by macrophages

*activate neutrophils, platelets, and endothelial cells

Question 13

What happens when TNF-alpha acts on endothelial cells?

Answer 13

Production of nitric oxide
vascular smooth muscle relaxation
hypotensive shock