Introduction to Inflammation

1. Inflammation- Acute
Inflammation
Prepared by/ Mohamed Hassany Ali
B.Sc.
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2. Inflammation:
• When living tissue is damaged, a series of local processes are
initiated in order to contain the offensive agent, to neutralize its
effect, to limit spread and hopefully to eradicate.
• So, we can define it as :
The mechanism by which the body deals with an injury. Tissue
injury stimulates inflammation.
Inflammation known by Suffix “itis”.
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3. Signs and Symptoms:
• Rubor: redness
• Calor: heat
• Dolor: pain
• Tumor: Swelling
• Functio Laesae : loss of function
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5. Types of Inflammation:
• Acute inflammation
• Chronic inflammation
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6. Acute inflammation:
• short duration, lasting from a few minutes to a few days and the
cellular exudate is rich in neutrophil polymorphonuclear
leucocytes with some macrophages arriving after the initial insult.
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7. Process of Acute inf.
• Microvasculature (vascular change)
• Cellular mediators (cellular change)
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8. Microvasculature
• Vasodialation: increase the blood flow rate causing redness and
heat.
• Permiability: of vessels causing swelling by outpouring of
extracellular excudate. And the affected part lose the ability of
proper function.
• Chemical mediator: and the stretching of tissue by exudate cause
pain.
• exudate is the fluid within the extravascular spaces which is rich in
protein and hence has a specific gravity of greater than 1.020.
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10. Cellular mediators:
• Leukocytes ingest offending agents, kill bacteria and other
microbes, And get rid of necrotic tissue and foreign
substances.
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11. This animation demonstrates the
actions of neutrophils in the
acute inflammatory process.
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14. As in the preceding diagram,
here PMN's that are marginated
along the dilated venule wall
(arrow) are squeezing through
the basement membrane (the
process of diapedesis) and
spilling out into extravascular
space.
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15. Acute inflammatory cells:
• In most forms of acute inflammation, neutrophils predominate in
the inflammatory infiltrate during the first 6 to 24 hours, then are
replaced by monocytes in 24 to 48 hours.
• In viral infections: lymphocytes
• In hypersensitivity reactions: eosinophils
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17. Neutrophils:
• Most abundant granulocyte and resembles (40-75%) of white
blood cells in all mammals.
• Containing nucleus of 2-5 lobes.
• Named due to H&E staining as it stains by neutral pink.
• Polymorphonuclear cell.
• Bacterial killing and phagocytosis.
• Bone marrow origin.
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21. Eosinophils:
• Common in Allergic and parasites condition.
• Named due to H&E staining as it stains by bright red (acid-
loving).
• Resemble 1-6 % in normal persons.
• Contain large granules.
• Have two lobes.
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23. Basophils:
• Resembles less than 1% of all leukocytes.
• Have large granules contain Histamine that cause vasodialation.
• Named due to H&E staining as it stains by dark blue (Alkali-
loving).
• Bone marrow origin
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25. Lymphocyte:
• Agranulocyte with clear cytoplasm.
• Have three types: (T cells, B cells and NK cells).
• Resembles 25-35%
• T cells: recognition, killing and regulation of immune system.
• Lymphoid tissue and thymus origin.
• B cells: give rise to plasma cells.
• Lymphoid tissue and bone marrow origin
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27. Monocyte:
• Resembles 6-9% of all white blood cells.
• Agranulocyte large cell.
• Unilobar nucleus.
• Migrates to tissues to become macrophage which capable of
phagocytosis.
• Bone marrow origin
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29. Plasma cell:
• Secretes large volumes of antibodies.
• Lymphoid tissue and bone marrow origin.
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31. Pus cell:
a necrotic polymorphonuclear leucocyte, a
major component of pus. Also called pus cor
puscle.
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32. Acute inflammation, cytology:
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33. Types of Acute inflammation:
• Suppurative Acute inflammation “pus formation”.
• Non suppurative Acute inflammation “no pus formation”.
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34. Types of suppurative inf.
• Localized
• Diffuse
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35. Acute suppurative Inflammation:
• Def. : severe acute inf. Characterized by Pus formation.
• Causes: Pyogenic microorganisms like:
» Staphylococcus aureus.
» Streptococcus haemolyticus.
» Pneumococcus.
» Bacillus coli.
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36. Pus:
• Composition of Pus:
– Living and dead bacteria and their toxins.
– Liquefied necrotic tissue.
– Cellular exudate: leucocytes, pus cells, macrophages and RBCs.
– Inflammatory tissue exudate.
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37. Abscess:
• Acute localized suppurative inflammation.
• Site: any tissue.
• Cause: staphylococcus aureus
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38. Abscess
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39. Abscess
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40. Abscess, Brain
• Abscess is an exudative purulent localized inflammation.
• In the white matter, a recent abscess consisting in pus :
neutrophils (normal or in lisis), fibrin, necrotic debris, germs.
Vessels present congestion and important perivascular edema.
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41. Abscess, Brain
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42. Acute pyelonephritis
• is an acute suppurative inflammation of the kidney caused by
bacterial infections (Escherichia coli in 70 - 80 % of cases, Proteus
mirabilis, Klebsiella pneumoniae, Enterococus
fecalis, Staphylococcus).
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43. Microscopic:
• The renal presents abscesses (suppurative necrosis), consisting of
purulent exudate (pus) :
• neutrophils, fibrin, cell debris and central germ colonies
(hematoxylinophils).
• Tubules are damaged by exudate and may contain neutrophil
casts, which can be found in urine. In the early stages, glomeruli
and vessels are spared.
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44. Acute Pyelonephritis
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45. Acute suppurative:
• The general morphology of a suppurative inflammation typically
involves several layers:
A necrotic zone is a central focus of proteolytic liquefaction with lipid- rich
detritus producing yellowish pus.
A pus zone contains large numbers of neutrophils and surrounds the central necrotic
area.
A hyperemic zone with perifocal edema of serous exudate is also present.
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46. Acute suppurative appendicitis:
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48. Acute suppurative tonsillitis
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49. Purulent meningitis
• Purulent leptomeningitis (suppurative leptomeningitis) is a
diffuse purulent inflammation.
• The leptomeninges (arachnoida and piamater) contain purulent
exudate (pus): leukocytes (neutrophils), fibrin, germs, proteins,
necrotic debris. Blood vessels in the subarachnoidian space and
those intracerebral are congested and neutrophil margination is
present.
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50. Purulent meningitis
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51. Acute non-suppurative:
1. Catarrhal Inflammation: mucous membrane.
2. Membranous Inflammation.
3. Sero-fibrinous Inflammation.
4. Fibrinous Inflammation.
5. Serous Inflammation.
6. Haemorrahgic Inflammation.
7. Necrotizing Inflammation.
8. Allergic Inflammation.
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52. Catarrhal Inflammation:
• Def. Acute non-suppurative secreting exudate rich in mucin.
• Site: GIT, Nose.
• Ex: Catarrhal rhinitis
• Causes: Common cold virus.
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53. Catarrhal rhinitis:
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54. Hemorrhagic inflammation:
• Definition: Acute inflammation involving microvascular injury with
massive microvascular bleeding, producing an exudate with a high
erythrocyte content ( A).
• Biologic purpose: Exudative inflammation despite severe vascular
injury.
• Morphology: The inflamed area is usually necrotic and filled with
blood.
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55. Hemorrhagic Inflammation
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56. Fibrinous inflammation:
• Definition: Acute inflammation with exudation of fibrinogen-containing
serum that polymerizes to fibrin outside the blood vessels ( A, B). Here
the exudate takes the form of serum- containing fibrinogen.
• Biologic purpose: Immediate temporary barrier against additional
effects of inflammation.
• Etiologic factors include:
Infectious toxic tissue injury;
Tissue injury from physical trauma;
Chemical and toxic tissue injury;
Excretion of toxic metabolites (uremic toxins);
Ischemic tissue injury.
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57. Fibrinous inflammation
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58. Fibrinous pericarditis
• Fibrinous pericarditis is an exudative inflammation. The visceral
pericardium (epicardium) is infiltrated by the fibrinous exudate.
• This consists in fibrin strands and leukocytes. Fibrin describes an
eosinophilic (pink) network, amorphous.
• Leukocytes (mainly, neutrophils) are found within the fibrin.
• Vascular congestion is also present.
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59. Fibrinous Pericarditis
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60. Fibrinous Pericarditis
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61. Psedomembranous inf:
• Acute non-suppurative inflammation charactrized by exudate rich
in membrane-like material.
• Site: mucous membrane, GIT, upper respiratory tract.
• Cause: Diphtheria bacilli
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63. Pseudomembranous Diphtheria
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64. Pseudomembranous colitis
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65. Necrotizing inflammation:
• Definition: Acute inflammation in which tissue necrosis
predominates.
• Several types are differentiated according to demarcation of the
inflammation or infestation with putrefactive bacteria. These
include:
Ulcerous necrotizing type;
Diffuse necrotizing type;
Nonreactive necrotizing type;
Gangrenous type.
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66. Necrotizing inflammation
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