PP 3 Chronic Inflamamtion Flashcards
Define chronic inflammation
Prolonged inflammation with associated repair
Features of chronic inflammation
- delayed onset
- variable duration
- variable appearances
- limits damage + initiates repair
- can cause debilitating symptoms
Ways chronic inflammation can arise
- takes over from acute inflammation
- develops alongside acute inflammation
- arrives de novo: without preceding acute inflammation
Examples of chronic conditions which arise de novo
Rheumatoid arthritis
Inflammatory bowel disease
Macrophage naming
In circulation- monocyte
After entering tissue- macrophage/histiocyte
Describe macrophage
Large cell
Abundant foamy cytoplasm
Macrophage functions
- phagocytosis: -removal of pathogens and debris
-antigen presentation - synthesis of cytokines + clotting factors
- control other cells by cytokine release
Describe a lymphocyte
Small cell
Large spherical nucleus
Thin rim of cytoplasm
Two types of lymphocytes
T cells
B cells
T cell functions
- helper T cell: assist other inflammatory cells
- cytotoxic T cell: destroys pathogen
B cell function
Neutralises pathogens
Mature into plasma cells > produce antibodies
Describe a plasma cell
- Eccentric nucleus
- ‘Clock face’ chromatin
- Peri-nuclear clearing (Golgi)- pale space around nucleus
Plasma cell function
Produce antibodies
Describe an eosinophil
Bi-lobed nucleus
Granular cytoplasm - stains red
Eosinophil function
Release variety of mediators
In parasitic infections
In hypersensitivity reactions - allergic reactions
Fibroblast/myofibroblast function
Regeneration and repair
Lay down collagen»_space; scar production
Myofibroblasts - contract and close wound
Describe giant cells
Multinucleated cell
Fusion of multiple macrophages due to ‘frustrated phagocytosis’
Types of giant cells
Foreign body
Langhans
Touton
Describe foreign body giant cell
Nuclei randomly assorted
Describe Langhans giant cell
Nuclei in rim round edge
Full or partial
Describe a Touton giant cell
Nuclei in ring in middle
What cells are mainly in RA?
Plasma cells
What cells are mainly in chronic gastritis?
Lymphocytes
What cells are mainly in Whipple’s disease?
Macrophages
Effects of chronic inflammation
- fibrosis
- impaired function
- increased function (rare)
- atrophy
- stimulation of immune system
Examples of conditions which show the fibrotic effect of chronic inflammation and info
Acute cholecystitis
- repeated obstruction of bile duct by gall stone
- repeated bouts of acute inflammation > chronic inflammation
- fibrosis of gall bladder wall
Liver cirrhosis
- chronic damage > fibrosis > scarring > contraction > portal blood flow impaired > portal hypertension > ascites
Examples of conditions which show loss of function due to chronic inflammation and info
Idiopathic inflammatory bowel disease: Crohn’s disease and Ulcerative colitis
- abnormal pain
- altered bowl motion
- weight loss
- rectal bleeding
What effects of chronic inflammation does cirrhosis show?
Fibrosis
Impaired function
Causes of cirrhosis
Alcohol
Hepatitis
Drugs and toxins
Fatty liver disease
What is a granuloma?
Epithelial histiocyte with surrounding lymphocytes
What is an epithelioid histiocyte?
Macrophage that look like epithelial cells
Types of granuloma
-
foreign body: - destruction + removal of foreign
material (not antigenic)
- few lymphocytes -
immune mediated: - destruction + removal of
pathogens in response to
bacteria/fungi (antigenic)
- can be idiopathic
- can undergo central necrosis
- many lymphocytes
Why is mycobacterium difficult to destroy?
Mycolic acids
Thick cell wall - macrophage resistant
What can mycobacterium cause?
TB - mycobacterium tuberculosis
Leprosy - mycobacterium leprae
What do granulomas look like on H+E stain and why?
Pink
Many macrophages which have an abundant cytoplasm - stains pink
What are granulomas with central necrosis characteristic of?
Rheumatoid arthritis
Colour of granuloma with central necrosis
Central necrosis is pink
What is sarcoidosis?
A disease characterised by the growth of granulomas
Where is sarcoidosis often found?
Lungs
Lymph nodes
Is sarcoidosis necrotising or not?
No necrosis
Colour of healthy lymph nodes on H+E stain
Purple
Many lymphocytes which have a large nucleus (haematoxylin stains nucleus purple) + thin cytoplasm
What condition are Langhans giant cells often seen in?
Tuberculosis
What condition are Touton giant cells often seen in?
Fat necrosis
Xanthomas
What condition are Foreign body giant cells often seen in?
When macrophage is unable to phagocytose foreign body
When are granulomas formed?
When there are particles which are difficult to break down but need to be isolated and contained
e..g splinters, mycobacterium tuberculosis
What are epithelioid cells?
Macrophages which have been modified due to increased activity so look like epithelium
What are the most common cell types in chronic inflammation?
Macrophages
Lymphocytes
What is chronic gastritis?
Inflammation of stomach lining most often due to Helicobacter pylori
What is an ulcer?
A breach in the mucosa to the level of submucosal layer
What is a Mantoux test?
A screening test for TB
Describe what happens when a person inhales mycobacterium tuberculosis
- MTB endocytosed by macrophages
- MTB replicates within phagosome
- MTB proliferates in alveolar macrophages + air spaces
- bacteraemia develops
- T helper cell response activates macrophages»_space; produce TNF
- monocytes differentiate into epithelioid histiocyte»_space; granulomas
- illness contained
