Session 3 - Chronic inflammation Flashcards
Define chronic inflammation
Characteristics of chronic inflammation
How does chronic inflammation arise?
Chronic inflammation = Prolonged inflammation with associated repair
Characteristics:
Delayed onset, variable duration (days -> years), variable appearance, limits damage, initiates repair, can cause deliberating symptoms
How does chronic inflammation arise?
- Takes over from acute inflammation (if resolution is not possible with acute inflammation)
- Develops alongside acute inflammation (severe/persistent irritation)
- Arises ‘de novo’ (without preceding acute inflammation e.g. autoimmune conditions like rheumatoid arthiritis, inflammatory bowel disease)
Varietry of cells involved in chronic inflammatory process
Macrophage
- name when in circulation
- Appearance
- Function
- In circulation = monocyte
Once enters tissue spaces = macrophages (aka histiocyte)
- Large cytoplasm - has a foamy/bubbly apparance related to its function
- Bubbly appearance - abundance of phagocytosomes repsonsible for this destruction
- Scattering of small dark ‘blobs’ - debris, products of phagocytosis
- Antigen-presentation - Another role of macrophage, presents it on its surface so other immune cells can recognise the antigens
Appearance:
Large Cells Abundant, foamy cytoplasm, Phagolysosomes
Function:
Phagocytosis: Removal of pathogen/necrosis/debris; Antigen presentation to immune system
Inflammatory Mediators: Synthesis and release of many mediators; Controls and regulates inflammatory response
Lymphocyte
- Appearance
- Function
- T cell and B cell
Appearance: Small cells (slightly larger than RBC), spherical nucleus (very thin rim of cytoplasm)
Function: T cell (variety of types, TH cells, assist other inflammatory cells AND TC cells (destroys pathogens directly)
B cell (mature into plasma cells, plasma cells produce antibodies, antigebodies have many function including neutralises pathogens)
Plasma cell
- Appearance
- Function
Appearance:
- Nuclei pushed off to one side (e-centric nuclei)
- Chromatin forms spheres sometimes, arranging around the outside of the nucleus (clock-face chromatin)
- Perinucelar clearing - area of cytoplasm next to the nucleus is slightly paler in colour than the rest of the cytoplasm, related to golgi apparatus
Function:
Produces antibodies
Eosinophil
- Appearance
- Function
- Bi-lobed nucleus
- Granular cytoplasm stains red
Function:
Release of a variety of mediators, particularly in: Hypersenstivitiy reactions, parasitic infections
Giant cells
- what are they?
- types of giant cells (3 types)
Multinucelated cells - fusion of multiple macrophages, “frustrated phagocytosis”
3 types of giant cells:
- Foreign body giant cells (rnadon scattering of nuclei)
- Langhan giant cell (nuclei arranged around the outside of the cell, many produce horseshow appearance)
- Touton giant cell (nuclei lined in a circle in the middle)
Foreign body giant cell
Langhans giant cell
Touton giant cell
When foreign bodies or infection with certain bacteria are present, macrophages can fuse with each other to form single cells called giant cells. FUSE.
These cells can be very large – giant cells can often be seen in granulomatous inflammation.
Three types of giant cells:
- *·** Langhans giant cells – the nuclei are arranged around the periphery of the giant cell, they are often (but not exclusively) seen in tuberculosis
- *· Foreign body giant cells** – the nuclei are arranged randomly in the cell. They are often (but not exclusively) seen when a hard to digest foreign body is present. If the foreign body is small it is phagocytised by the giant cell and can be seen within it. If it is large the foreign body giant cell sticks to its surface
- *· Touton giant cells** – the nuclei are arranged in a ring towards the centre of the cell. They form in lesions where there is a high lipid content such as fat necrosis and xanthomas (xanthomas are discussed in the session on atherosclerosis). Such lesions will also contain cells called foam cells which are simply macrophages whose cytoplasm appears foamy as they have phagocytised a lot of lipid
Cell types in chronic inflammation
Effects of chronic inflammation
Cell types in chronic inflammation:
- Generally non-specific
- Proportion of cell types can indicate a diagnosis e.g. rheumatoid arthiritis = mainly plasma cells, chronic gastritis = mainly lymphoctyes
Effects of Chronic inflammation:
- Fibrosis (THIS IS A REPAIR): Deposition of collagen within the tissue e.g. liver cirrhosis
- Impaired function e.g. inflammatory bowel disease, rarely increased function (e.g. thyrotoxicosis in Graves Diease)
- Atrophy
- Stimulation of immune reponse (antigen presentation)
Effects of chronic inflammation:
- Fibrosis
example
- Impaired function
example and symptoms
Fibrosis:
Repeated obstruction of bile duct by gall stones
Repeated bouts of acute inflammation -> chronic inflammation
Fibrosis of gall bladder wall (thickened and pale)
Liver cirrhosis
Impaired function:
Idiopathic inflammatory bowel disease, divided into: Crohn’s Disease, Ulcerative Colitis
Symptoms - abnormal pain, alteration bowel motion, weight loss, rectal bleeding
Inflammatory bowel disease and Ulcerative colitis - compare these
Liver cirrhosis
End stage damage to the liver
Causes include: Alcohol, Hepatitis, Drugs and toxins, fatty liver disease
Fibrosis and attempted regeneration
What is a granulomatous inflammation?
What is a granuloma?
Granulomatous inflammation:
A specific type of chronic inflammation
Chronic inflammation + Granuloma
Granuloma:
A collection of epithelioid histiocytes, with surrounding lymphocytes
Types of granuloma
Types of granuloma - pic below
Causes of granulomatous inflammation
- Foreign bodies
- Immune mediated - Infections e.g. Mycobacterium… Mycobacterium tuberculosis (tuberculosis), Mycobacterium leprae (Leprosy). Mycobacterium is difficult to destroy due to thick cell wall and mycolic acids. (caseating granulomata) PIC BELOW OF CASEATING GRANULOMATA
- Idiopathic cause - Crohn’s Disease (non-caseating granulomata in GI tract)
- Sarcoidosis (non-caseating granulomata)
