Acute Inflammation Flashcards
What generic name do we give chemical messengers that can trigger an inflammatory reaction?
Inflammation mediators
Cell types in chronic inflammation?
Plasma cells, Lymphocytes, Macrophages, Eosinophils, Fibroblasts/myofibroblasts, Giant cells
Cell types in acute inflammation?
Neutrophil polymorphs
Give an example of when the body’s acquired immune response is triggered without the innate response being triggered first
Viral infection
What are the major causes of acute inflam?
Microbial infections, acute phase hypersensitivity reactions, physical agents, chemicals, tissue necrosis
What is the biological purpose of acute inflam?
Eliminate initial cause of cell injury,
clear out necrotic cells and tissues damaged from original insult and inflam process,
initiate tissue repair.
What are the characteristic signs of acute inflam?
Rubor, calor, tumour, dolor, loss of function
How are the tissue changes brought about?
Vascular flow (vasoconstriction then dilation, increases viscosity = stasis), formation of fluid exudate, neutrophil emigration
What is fluid exudate and how is it formed?
Protein rich fluid from blood vessels and into nearby tissues with an increase in vascular permeability,
composed of serum, fibrin, and white blood cells = oedema = increases lymph drainage
How do neutrophils emigrate?
Margination: stasis = line up at vessel edge.
Rolling: roll and stick intermittently.
Adhesion: stick more avidly.
Emigration: through inter-endothelial cell junctions / digestion of basement membrane
Why do the tissue changes in inflam constitute an effective response to injury?
Delivery of nutrients = oxygen, cells, plasma proteins such as antibodies, inflammatory mediators, fibrinogen,
Dilution of toxins,
Maintenance of temperature,
Stimulation of immune response,
Destruction and removal of dead or foreign material,
Pain and loss of function enforcing rest
How do neutrophils kill microorganisms?
Contact, recognition via opsonins, phagocytosis
1) O2 dependent = superoxide/hydrogen peroxide.
2) O2 independent = lysosomes
How do neutrophils move?
Chemotaxis: movement along conc gradient of chemoattractant
Name the important mediators in acute inflam
Histamine, bradykinin, prostaglandin, complement system, cytokines
What is the function of histamine?
One of the first chemical mediators, in response to damage C3a C5a IL-1, from mast cells, basophils, platelets
vascular dilation, increased vascular permeability, pain
What does bradykinin do?
Vasodilation
What are the local complications of acute inflam?
Damage to normal tissue, Obstruction of tubes, compression of vital structures, Loss of fluid, Pain and loss of function
What are the systemic consequences of acute inflam?
Fever,
leucocytosis,
acute phase response (decreases appetite, raise pulse, changes CRP),
shock (sepsis, damage in response to infection = dangerously low BP and abnormalities in cellular metabolism)
How is acute inflam resolved?
Vascular changes stop,
exudate drains to lymph,
fibrin degraded,
neutrophils die,
damaged tissue might be able to regenerate,
all mediators have short half-lives, can be deactivated
Outline the sequelae of acute inflam?
Abscess, chronic inflam, fibrous repair, death
What are some clinical examples of acute inflam and causative organism?
Lobar pneumonia = acute pneumonia involving one or more lobes of the lung (Strep pneumoniae),
Acute appendicitis = acute inflammation of the appendix (c.diff, e.coli),
Bacterial meningitis = inflam of meninges around brain and spinal cord (Strep pneumoniae, Neisseria meningitides)
Give examples of inherited disorders of acute inflam
Hereditary angio-oedema,
Alpha-1 antitrypsin deficiency,
Chronic granulomatous disease
What does pyogenic mean?
Pus forming
What is the difference between an exudate and a transudate?
Transudate = fluid pushed through capillary due to high hydrostatic pressure, low protein content.
Exudate = fluid that leaks around the cells of the capillaries caused by inflam, high protein content.
