Topic: Chronic Inflammation, Wound Healing, Fracture Healing Faculty: Pathology Course: Nursing 2nd year

1. Chronic inflammation,
Wound healing
Dr. Salman Ansari(MBBS)
Tutor, Dept. of Pathology
Kanachur Institute of Medical Sciences

2. ● Chronic inflammation
● Wound healing

3. CHRONIC INFLAMMATION

4. Chronic inflammation
Definition: Inflammation of prolonged duration(weeks or months) in
which inflammation, tissue damage and healing occurs at same
time
It may occur: after an acute inflammation which did not resolve.
E.g: acute osteomyelitis → chronic osteomyelitis
It may begin as an insidious, low-grade chronic response without
any inflammatory reaction

5. Causes
- Persistent infections - by microbes which are hard to
eradicate. E.g: Mycobacterium tuberculosis
- Immune-mediated diseases: E.g: autoimmune diseases,
allergic reactions
- Prolonged exposure to toxic agents. E.g: silicosis due to
silica particles

6. Morphology
Chronic inflammation is characterised by:
- Infiltration by mononuclear cells: macrophages,
lymphocytes and plasma cells
- Tissue destruction
- Healing by fibrosis

7. Chronic granulomatous inflammation
- Special pattern of of chronic inflammation
- Can be due to infectious and non-infectious causes
- Seen in: tuberculosis, fungal infections
- involves immune reactions
- Microscopic feature: presence of granuloma
- Granuloma is formed from macrophages and T-cells
- Macrophages transform into epithelium-like cells, called
epithelioid cells
- Epithelioid cells may fuse with each other to form Langhan’s
giant cell
SN

8. Granuloma
Definition: defined as a type of chronic inflammation
characterised by microscopic aggregation of macrophages
which are transformed into into epithelium-like(epithelioid) cells
and surrounded by a rim of lymphocytes
- Old granulomas also have a layer of fibroblasts as the
outermost layer
SN

9. Components of granuloma
Epithelioid cells:
- They are modified macrophages which look like epithelial cells
- Elongated nucleus
Giant cells:
- Epithelioid cells fuse to form giant cells
- The nuclei are shaped like a horse-shoe
Epithelioid cells
Giant cells

11. Types of granuloma
Foreign body granuloma. E.g: around sutures, talc
Immune granuloma. E.g: tuberculosis

12. HEALING AND REPAIR

13. Healing
Definition: Healing is the process of replacement of
dead tissue by living tissue
Divided into Regeneration
Repair

14. Regeneration
“Process by which lost/damaged tissue is completely replaced by
tissue of similar type.”
Occurs in tissues which have regenerative cells. E.g: skin
epithelium, hematopoietic cells

15. Repair
“Process in which lost/damaged tissue is replaced by
fibrous tissue(scar).”
E.g: healed myocardial infarction

16. Granulation tissue
- First 24-72 hours: Fibroblasts and vascular endothelial cells
multiply and form a special type of tissue called “granulation
tissue”
- Granulation tissue:
Gross: pink, soft, granular on the surface of the healing wound
Micro: - formation of new blood vessels, called angiogenesis
- proliferation of fibroblasts
SN

17. - Granulation tissue grows into the incision/wound
- If it is healing by secondary intention, the amount of
granulation tissue will be more
- By 5-7 days: the wound is filled by granulation tissue

21. Types of healing
Cutaneous healing
Healing of fracture
Healing by primary union
Healing by secondary union
LE

22. Cutaneous wound healing
1) Healing by primary union or healing by first intention:
Definition: Healing of sterile, surgical wounds
- Simplest type of cutaneous wound healing
- Minimal disruption of epithelial basement membrane
- Edges of wound are approximated by surgical sutures
- Minimal scarring
LE

23. Stages of healing by first intention
LE
First 24 hours - Blood clots in the space between the suture wound margins
- Neutrophils at the margins
- Epithelial cells at the edges multiply and migrate across the wound
Day 2 - Macrophages begin to appear
- Surface epithelial continuity is established and is thin
Day 3-7 - Granulation tissue begins to form
- Surface epithelium is of normal thickness
- Collagen deposited
Day 10-14 - Wound gains 10% strength of normal skin
- Fibroblasts multiply with collagen deposition
Weeks to months - Collagens deposition and wound achieves maximal 80% of tensile strength of
normal skin

27. Healing by secondary union or second intention
Definition: “Healing of large wounds and infected wounds”
- Healing in such wounds is more complicated
- There is more tissue loss in these wounds
LE

28. Features of healing by secondary intention:
- severe inflammatory reaction
- formation of abundant granulation tissue
- more deposition of collagen
- large scar formation
- wound contraction occurs
-
- Wound contraction occurs due to myofibroblasts which
contract and decrease the dermal edges of the wound and
reduce the surface area of the wound

31. Large scar
formation

32. Factors that affect wound healing
Local factors
Systemic factors

33. Local factors
- infection: causes delay in wound healing
- mechanical factors: movement of wounded area results in
delayed healing
- foreign bodies: sutures or pieces of steel, glass, bone etc
delay healing
- Location: delayed if wound is over a bone with little tissue in
between. E.g: skin over anterior tibia
- Blood supply: good blood supply results in faster healing.
E.g: face

34. Systemic factors:
- Nutrition: protein deficiency, vitamin C deficiency inhibits
collagen synthesis and slows healing
- Age: faster in young
- Metabolic status: delayed in Diabetes mellitus
- Circulatory status: poor blood supply(arteriosclerosis) or
venous abnormalities(e.g: varicose veins) results in poor
healing
- Hormones: steroids inhibit collagen synthesis & delay wound
healing

35. Complications of wound healing:
1) Inadequate granulation tissue formation: poor scar formation
can lead to
- dehiscence: rupture of wound - due to increased abdominal
pressure or stress from vomiting, coughing
- ulceration: due to poor new blood vessel formation and can
lead to non-healing ulcer. E.g: wounds in varicose veins
- incisional hernia: due to weak scar

36. Wound dehiscence

37. Incisional hernia

38. 2) Excessive scar formation: can result in:
- hypertrophic scar: excessive collagen deposition
leads to a raised scar at the site of the wound, called a
hypertrophic scar - develops after thermal injury or
traumatic injury
- keloid: if the scar grows beyond the boundaries of the
original wound
- exuberant granulation: pyogenic granuloma(proud

39. Hypertrophic scar

40. Keloid

42. Exuberant granulation tissue or “Proud flesh”

43. Exuberant
granulation
tissue or “Proud
flesh”

44. 3) “contracture”: decrease in the size of a wound is
called contraction. Excessive contraction is called
"contracture" and results in deformity and reduced
mobility

46. 4) wound infection
5) pigmentation of wound area

47. Healing of fracture
● Takes about 6-8 weeks in total
● 3 phases
LE
1) Inflammatory phase
↓
2) Repair phase
↓
3) Remodelling phase

48. 1) Inflammatory phase
- Rupture of blood vessels leads to hemorrhage and hematoma
formation at site of fracture
- Inflammatory cells(neutrophils, macrophages) arrive at fracture site
- Blood clots and forms fibrin mesh work
- New blood vessels form(“neovascularistion”) occurs and
fibroblasts multiply
- formation of granulation tissue between the fracture fragments
- Osteoblasts enter granulation tissue and deposit woven bone(weak)
- Formation of soft tissue callus or pro-callus
- Pro-callus is granulation tissue which contains bone or cartilage,

49. 1) Inflammatory phase

50. 2) Reparative phase
- Formation of lamellar bone
- Woven bone is replaced by lamellar bone
- Lamellar bone is stronger than woven bone and is made of
parallel collagen fibres
- Ossification occurs(cartilage is replaced by woven bone)
- Calcification of callus occurs, which is now called “bony
callus”
- Stiffness and strength of callus increases
- By 2-3 weeks, controlled weight-bearing can be tolerated

51. Woven bone Lamellar bone

53. 3) Remodelling phase
- Starts a few weeks after callus has sealed the bone ends
- Compact bone formation occurs
- Remodelling occurs till original bone shape and strength is
reached

55. & soft callus formation

56. Bony callus formation

58. Causes of delayed fracture healing
Local factors General factors
- Excessive movement of
bone during healing
- Infection at fracture side
- Severe local soft tissue injury
- Wide separation of fracture
ends
- Extensive necrosis of
fracture bone
- Poor blood supply
- Old age
- Poor general health
- Use of steroids

59. Complications of fracture healing
● Delayed union of fracture
● Non-union of fracture
● False joint(“pseudo-arthrosis”): false joint associated
with abnormal movements at site
● Malunion: when fracture heals with a deformity

61. Pseudo-arthrosis(false joint)

63. Malunion

64. For notes,
scan:
References:
● Dr. Purnima S. Rao - Textbook of Pathology and
Genetics for Nursing
● Dr. Ramadas Nayak - Textbook of Pathology for Allied
Health Sciences
Questions:
salman.s.ansari92@gmail.com
For PPT, scan: