PMI03-2013

Question 1

When can chronic inflammation develop?

Answer 1

As progression from acute inflammation

Following repeated episodes of acute inflammation

“de novo” if the causative agent only produces a mild (undetected) acute response

Question 2

What are the two main processes we should consider with chronic inflammation?

Answer 2

Healing/repair

Tissue damage

Question 3

What are the general features of chronic inflammation?

Answer 3

Later onset and longer duration

More tissue destruction and ulceration than acute inflammation

Inflammatory infiltrate contains macroophages, plasma cells and lymphocytes (few PMNs)

Granulation tissue and fibrosis

Question 4

Describe the general mechanism of chronic inflammation?

Answer 4

Continued recruitment of macrophages and lymphocytes to area then activation

Local proliferation

Enhanced survival and immobilisation of cells in inflamed area

Question 5

Give examples of cellular mediators involved in inflammation.

Answer 5

Histamine

Prostaglandins

Leukotrienes

Cytokines

Question 6

Give examples of plasma-derived mediators involved in inflammation.

Answer 6

Clotting factors

Complement

Kinins

Fibrinogen/fibrin

Question 7

What process does hydrocortizone interfere with?

Answer 7

Protein/enzyme synthesis

Question 8

What patterns of chronic inflammation are there?

Answer 8

Serous (watery, around jaws)

Fibrinous (blood clotting)

Suppurative/purulent (pus)

Granulomatous (granuloma)

Question 9

What is a granuloma?

Answer 9

Collection of epithelioid cells (activated macrophages with abundant eosinophilic/pale-staining cytoplasm, spindle nuclei)

Also some Langhans Giant Cells

Question 10

What is a Langhans Giant Cell?

Answer 10

Large multinucleated cell formed by fusion of macrophages

Crescent nucleus at periphery

Question 11

When may solitary granulomas form?

Answer 11

In response to persistent local inflammatory stimuli (eg foreign body)

Question 12

What are chronic granulomatous diseases? Give an example.

Answer 12

Diseases characterised by granuloma formation

Tuberculosis

Sarcoidosis

Crohn’s disease

Oro-facial granulomatosis

Question 13

What causes tuberculosis?

Answer 13

Mycobacterium tuberculosis = intracellular bacteria

Question 14

Describe the progression of tuberculosis.

Answer 14

1. Primary lesions (Ghon Focus) - childhood, mainly lungs and may heal without symptoms
2. Migration to regional lymph nodes (Ghon Complex) - primary lesions with hilar lymphadenopathy; may heal or be controlled
3. Spread to bronchi and blood if immune system cannot control:
   - millary TB = widespread
   - organ TB = single organ

Question 15

Describe how Mycobacterium tuberculosis causes damage.

Answer 15

Mycobacterium ingested into macrophages and excite a T cell response

Intracellular => protected from attack and reside in tissues

Macrophages containing M. tuberculosis continue to proliferate and secrete pro-inflammatory cytokines

Caseating granuloma forms and most damage/fibrosis is a result of host immune response (type IV sensitivity reaction)

Question 16

What is a caseating granuloma?

Answer 16

Dense mass of epithelioid cells walled off with fibrous tissue (may have Langhans Giant Cells)

Caseous necrosis centrally

Question 17

What is rheumatoid arthritis?

Answer 17

Chronic systemic inflammatory disorder

Mainly affects joints symmetrically which become deformed and painful with loss of function

Unknown stimulus

Question 18

How many joints are involved in a “poly-arthritis”?

Answer 18

> 5

Question 19

How is arthritis relevant to dentistry?

Answer 19

TMJ

Hand joints = holding toothbrush/other dental aids

Question 20

Describe how the joints become deformed in rheumatoid arthritis.

Answer 20

Inflammation of synovium and inflammatory cells enter joint space

Synovium expands and fills joint space

Fibrous tissue forms to try and wall off inflammation/tissue damage

Fibrous tissue eventually ossifies causing loss of function, distortion and further tissue damage

Question 21

What can stimulate the formation of foreign body granulomas?

Answer 21

Lip filler

Sutures

Question 22

Why are granulomas harmful?

Answer 22

Continuous production of mediators = ongoing inflammation (usually requires surgery/therapy to remove)