Chronic intestinal inflammation and granuloma formation

Question 1

What are the signs of inflammation?

Answer 1

Redness (rubor)
Heat (calor)
Swelling (tumor)
Pain (dolor)
Lack of function

Question 2

What causes redness and heat in inflammation?

Answer 2

dilation of BVs => increased blood flow

Question 3

what causes swelling, pain and lack of function in inflammation?

Answer 3

Increased vessel permeability => leaky to fluids and immune cells

Question 4

Describe chronic inflammation

Answer 4

Can occur if no return to normal conditions after acute infection
Infectious cause or immune mediated => constant immune output
Granuloma may form (example of Type IV hypersensitivity)

Question 5

what are the causes and disorders leading to chronic inflammation?

Answer 5

Autoimmune disorders
Toxins
chronic exposure to Irritant or foreign material
Auto-inflammatory syndromes
Infection
Trauma

Question 6

give examples of disorders associated with chronic inflammation with no granuloma formation

Answer 6

Question 7

Give examples of disorders leading to chronic inflamation with granuloma formation

Answer 7

Question 8

What cells and cytokines are involved in granuloma formation?

Answer 8

Macrophages
T cells

Question 9

Describe the role of macrophages in granuloma formation

Answer 9

Histiocytes (macrophages in tissues) fail to clear foreign agent and become chronically infected
Activated macrophages secrete TNF-a which promote influx of T-cell and other cells
Stimulated macrophages further mature into epithelioid cells that secrete proinflammatory cytokines
Prolonged stimulation causes epithelioid cells to fuse together => multinucleated Giant/Langerhans cells
Giant cells can phagocytosise and secrete cytokines

Question 10

What is the role of T-cells in granuloma formation?

Answer 10

TNF-a from macrophages inhibits regulatory T cells and T-cell apoptosis
T cells around periphery secrete IFN-y => contribute to chronic reactivity of macrophages

Question 11

What are the pros and cons of granuloma formation?

Answer 11

Pros:
- forms a focal killing point
- prevent dissemination of micro-organisms
Cons:
- break-down of granuloma can cause bacteria to disseminate
- can cause severe tissue necrosis affecting organ function
- can cause fibrosis and tissue thickening => impaired organ function

Question 12

What are the forms of chronic enterocolitis in dogs and cats?

Answer 12

Lymphocyte plasmocytic enteritis
Eosinophilic (gastro)enteritis
Neutrophilic colitis
Granulomatous colitis (histiocytic ulcerative colitis)

Question 13

Describe lymphocytic plasmolytic enteritis

Answer 13

Increased lymphocyte and plasma cells infiltration into lamina propria intestines

Question 14

Describe eosinophilic (gastro)enteritis

Answer 14

Infiltration of eosinophils into lamina propria of intestines

Question 15

What is Hypereosinophilic syndrome in cats

Answer 15

overproduction of eosinophils in bone marrow => eosinophilic infiltration of multiple organs

Question 16

Describe neutrophilic colitis

Answer 16

Infiltration of neutrophils into lamina propria of intestines

Question 17

Describe granulomatous colitis (histiocytic ulcerative colitis)

Answer 17

Pro-inflammatory macrophages in colonic mucosa
Thickened, partially obstructed segment of bowel

Question 18

What is the treatment for chronic gastroenteritis?

Answer 18

Infectious cause treated first
Diet change
Antibiotics and anti-inflammatory drugs