inflammation

1. Inflammation and Repair
Lecture 6

2. Outcome of Acute Inflammation &
Morphologic Patterns in Acute Inflammation

3. OBJECTIVES AND KEY PRINCIPLES TO BE
TAUGHT:
Upon completion of this lecture, the student should:
• 1. Enumerate the fate of acute inflammation and the
conditions that leads to resolution or fibrosis
• 2. Discuss abscess formation and its fate
• 3 .Discuss how chronic inflammation follows acute
inflammation
• 4. Enumerate the morphologic patterns of acute
inflammation.
• 5. Define: abscess, furuncle, carbuncle, and cellulitis and
identify their aetiology and morphology

5. Inflammation Outcome
Acute
Inflammation
Resolution
Chronic
Inflammation
Abscess
SinusFistula
Fibrosis/Scar
Ulcer
Injury
Fungus
Virus
Cancers
T.B. etc.

6. Possible outcomes of acute inflammation
• Complete resolution
– Little tissue damage
– Capable of regeneration
• Scarring (fibrosis)
– In tissues unable to regenerate
– Excessive fibrin deposition organized into fibrous tissue
• Abscess formation occurs with some bacterial or
fungal infections
• Progression to chronic inflammation

7. Outcomes
• Resolution
– The complete restoration of the inflamed tissue back to a normal
status. Inflammatory measures such as vasodilation, chemical
production, and leukocyte infiltration cease, and damaged
parenchymal cells regenerate. In situations where limited or short
lived inflammation has occurred this is usually the outcome.
• Fibrosis
– Large amounts of tissue destruction, or damage in tissues unable to
regenerate, can not be regenerated completely by the body. Fibrous
scarring occurs in these areas of damage, forming a scar composed
primarily of collagen. The scar will not contain any specialized
structures, such as parenchymal cells, hence functional impairment
may occur.

8. Outcomes
• Abscess formation
– A cavity is formed containing pus, an opaque liquid containing dead
white blood cells and bacteria with general debris from destroyed
cells.
• Chronic inflammation
– In acute inflammation, if the injurious agent persists then chronic
inflammation will ensue. This process, marked by inflammation lasting
many days, months or even years, may lead to the formation of a
chronic wound. Chronic inflammation is characterized by the
dominating presence of macrophages in the injured tissue. These cells
are powerful defensive agents of the body, but the toxins they release
(including reactive oxygen species) are injurious to the organism's own
tissues as well as invading agents. Consequently, chronic inflammation
is almost always accompanied by tissue destruction.

10. Morphologic patterns of acute
inflammation
• Inflammation is classified into two main
morphologic groups
• A) Non suppurative inflammation
• B) Suppurative inflammation
• A) Non suppurative inflammation
• 1- Serous
– Watery, protein-poor effusion (e.g., blister) and
contain few leukocyte.

11. BLISTER, “Watery”, i.e., SEROUS

12. Serous

13. Organ: Pericardium Diagnosis: Fibrinous Inflammation
2-Fibrinous
Exudation of fluid rich in Fibrin

14. ACUTE FIBRINOUS
PERICARDITIS

15. Patterns (cont’d)
• 3-Catarrhal- involve mucous secreting surfaces, fibrin and
protein exudate mixed with mucus as in common cold
affecting nasal passages .
• 4-Membranous(pseudomembranous): false membrane
formed by exudate adherent to underlying mucous
surface e.g. diphtheria.
• 5-Hemorrhagic: sever inflammatory exudate associated
with damage to capillaries as in hemorrhagic pancreatitis
• 6-Gangrenous : The acute inflammation is complicated by
superadded death and putrefaction of the tissues

16. B) Suppurative inflammation
• Characterized by purulent exudate containing large numbers
of PMN which is localized or diffuse
• 1- Localized
• Abscess: cavity full of pus commonly due to Staph.
Aureus infection
• Special types of abscesses
• 1.Boil(Furuncle):small abscess related to hair follicle or
sebaceous glands
• 2. Stye: Abscess in the eye lid related to eye lashes
• 3. Carbuncle: multilocular abscess in the skin and
subcutaneous tissue discharging pus through
numerous openings

17. PUS
=
PURULENT
ABSCESS
=
POCKET
OF
PUS

18. Abscess

19. • 2-Diffuse suppurative inflammation :
• a. Phlegmonous inflammation of hollow organ:
e.g. acute suppurative appendicitis
• b. Diffuse suppuration in a body cavity : e.g.
• suppurative pleuritis and meningitis
• c. Collection of pus in the lumen of an organ : e.g.
Empyema of the gall bladder
• d. Cellulitis: inflammation of connective tissue,
Panniculitis inflammation of subcutaneous tissue

20. Empyema of the gall bladder

21. Redness of the left foot due to cellulitis

22. Sequence of acute inflammation
• Ulceration(e.g. Peptic
ulcers of the stomach or
duodenum and diabetic
ulcer of the legs )
– Necrotic and eroded
epithelial surface
– Underlying acute and
chronic inflammation
– Trauma, toxins, vascular
insufficiency

23. Peptic ulcer of the stomach

24. • Fistula :communication between two
organs (epithelial surfaces) or organ and
surface.
• Sinus : Blind ended track from a cavity to
the surface e.g. Pilonidal sinus .
• Bacteremia , Toxemia , Septicemia
• Pyemia : Septic emboli in blood stream
arrested in different organs causing
multiple small pyemic abscesses .
Sequence of acute inflammation

25. FOREIGN BODY REACTION
(PILONIDAL SINUS)

26. Small cortical
pyemic abscesses

28. Continuous assessment
• Focal collection of pus is called
• A) Abscess .
• B) Ulcer .
• C) Scar .
• D) Fistula