Pathology 5 - Chronic Inflammation

Question 1

What is chronic inflammation?

Answer 1

Chronic response to injury with associated fibrosis

Question 2

How may chronic inflammation arise?

Answer 2

• may take over from acute inflammation (if damage is too severe to be resolved quickly)
• can arise de novo (in some autoimmune conditions, some chronic infections)
• may develop alongside acute inflammation (in severe persistent/repeated irritation)

Question 3

Why is the appearance of chronic inflammation much more variable than that of acute inflammation?

Answer 3

It is characterised more by the type of cell present, which can vary

Question 4

What are macrophages derived from?

Answer 4

Blood monocytes

Question 5

What are the functions of macrophages?

Answer 5

• PHAGOCYTOSIS (+ destruction of debris and bacteria)
• processing and PRESENTATION OF ANTIGEN to immune system
• SYNTHESIS of cytokines, complement components, blood clotting factors and proteases
• CONTROL of other cells via cytokine release

Question 6

What are the functions of lymphocytes?

Answer 6

• complex and usually immunological
• B-lymphocytes differentiate to produce antibodies
• T-lymphocytes involved in control and cytotoxic functions

Question 7

What are plasma cells?

Answer 7

Differentiated antibody-producing B lymphocytes. These usually imply that the condition is chronic

Question 8

In what situations would lots of eosinophils be found in the body?

Answer 8

Allergic reactions, parasite infestations, some tumours

Question 9

What is the function of fibroblasts/myofibroblasts?

Answer 9

They are recruited by macrophages and make collagen

Question 10

What are ‘giant’ cells?

Answer 10

Multinucleate cells made by fusion of macrophages due to ‘frustrated phagocytosis’

Question 11

What are the three types of giant cell?

Answer 11

• Langhans (tuberculosis)
• Foreign Body Type
• Touton (fat necrosis)

Question 12

What are the effects of chronic inflammation?

Answer 12

• fibrosis
• impaired function
• atrophy
• stimulation of immune response

Question 13

What is chronic cholecystitis?

Answer 13

Repeated obstruction of the gall bladder by gall stones. Repeated acute inflammation leads to chronic inflammation and therefore fibrosis of the gall bladder wall.

Question 14

What is inflammatory bowel disease?

Answer 14

An idiopathic inflammatory disease affecting the large and small bowel. Patients have diarrhoea, rectal bleeding and other symptoms. May be caused by ulcerative colitis (which causes diarrhoea and bleeding) or Crohn’s disease (which causes strictures and fistulae)

Question 15

Give some common causes of cirrhosis

Answer 15

• alcohol
• infection with HBV or HCV
• immunological
• fatty liver disease
• drugs and toxins
• obesity

Question 16

Give an example of a condition causing increased function as a result of chronic inflammation

Answer 16

Graves disease causes hyperthyroidism

Question 17

True or false - chronic inflammation and immune responses are very separate?

Answer 17

False - they often overlap

Question 18

What is a granuloma?

Answer 18

A small, nodular aggregation of inflammatory cells that stick together

Question 19

What is granulomatous inflammation?

Answer 19

Chronic inflammation with granuloma formation

Question 20

Give some causes of granulomatous inflammation

Answer 20

• irritant ‘foreign’ material
• infections by mycobacteria, such as tuberculosis or leprosy
• unknown causes such as sarcoid, Wegener’s granulomatosis, Crohn’s disease

Question 21

True or false - Tuberculosis produces no toxins or lytic enzymes?

Answer 21

True

Question 22

What is the rough structure of a tuberculous granuloma?

Answer 22

A circle of epithelioid histiocytes surrounded by lymphocytes, with a patch of caseous necrosis in the centre. There may be giant Langhans cells present