5 - Chronic Inflammation Flashcards
What is chronic inflammation?
Chronic response to injury with associated fibrosis. Destruction and repair occuring at same time
- De novo e.g autoimmune and TB
- Take over from acute inflammation if damage too severe
- Alongside acute in repeated irritation
What are the main cells involved in chronic inflammation?
- Macrophages: phagocytosis, presentation of antigens, synthesis of proteins and enzymes and cytokines and free radicals, control other cells
- Lymphocytes: B make antibodies, T in control and cytotoxic
- Eosinophils: allergies and parasites
- Fibroblasts/Myofibroblasts: make collagen
How do monocytes get from blood to tissue?
Same process as with neutrophils. Once in tissue they differentiate into macrophage and they can live for weeks/months
How do you spot a macrophage histologically?
Foamy cytoplasm with slipper nuclei
Why are lymphocytes involved in chronic inflammation and what do they look like?
- Macrophages release cytokines, e.g TNF, IL-1 to recruit lymphocytes
- They can secrete cytokines for more recruitment of inflammatory cells
- Hyperchromatic, larger nucleus than cytoplasm, 1-2 times the size of RBC
What do plasma cells look like histologically?
- Usually nucleus with tail of cytoplasm
- Clock face nucleus as chromatin around the outside
- From B-cells and produce antibodies against persistent antigens
What do eosinophils look like histologically and when are they seen?
- Tomato with sunglasses
- Recruited by eotoxin as they contain proteins that are toxic to parasites but toxins damage human
- Seen in parasitic infections and allergies with mast cells
What makes the macrophage different to neutrophils
- They are involved in chronic inflammation
- They can live for months and replicate
- Can stimulate fibrosis, angiogenesis, fever, acute phase reaction
Why are fibroblasts involved in chronic inflammation?
- They respond to chemokines and move to where they are needed where they secrete GAG’s, collagen and elastin
- They can differentiate into myofibroblasts for wound healing
What are giant cells?
- Fused macrophages with lots of nuclei
- Occur when certain foreign bodies and bacteria are present
- Involved in granulomatous inflammation
What are Langhans giant cells?
Nuclei arrange around periphery of cell in horse-shoe shape.
Seen mainly in TB
What are foreign body type giant cells?
- Nuclei arranged randomly
- Seen with foreign bodies
- If small body then giant cell will have phagocytosed it, if large the body will stick to it’s surface
What are touton giant cells?
- Nuclei in ring towards centre of the circle
- Form in lesions where there is high lipid content, e.g xanthomas
- Foam cells
- Occurs in breast tissue and associated with fat necrosis
What are some situations where chronic inflammation occurs?
- Autoimmune
- Chronic persistent infections
- After or alongside acute inflammations
- Prolonged exposure to toxic tissues
What sre some of the possible complications of chronic inflammation?
- Atropy e.g gastric mucosa
- Impaired function e.g chronic IBS
- Excessive fibrosis e.g chronic cholecystitis, chronic peptide ulcers
- Tissue destruction
- Stimulation of immune response
What is chronic cholecystitis?
- Repeated obstruction by gall stones in gall bladder
- Repeated bouts of acute cholecystitis leads to chronic inflammation
- Fibrosis of gall bladder wall
What is chronic gastritis?
Acute: alcohol, taking NSAID’s like aspirin, stressful event,
Chronic: Helicobacter Pylori (spirilli bacilli) so use urea breath test
Signs: vomiting blood due to erosion of blood vessels at base, indigestion, pains, fullness, stomach ulcer
What is the difference between ulcerative collitis and Crohn’s disease?
- Ulcerative will have crypt abscess but Crohn’s wont. Crohns will have granulomas but ulcerative won’t
- Ulcerative is continuous from rectum but Crohn’s can come at random intervals from mouth to anus
- Will present with diarrhoea, rectal bleeding, especially with ulcerative as this is superficial
What is a crypt abscess?
What does cirrhosis look like histologically?
- Nodules surrounded by circles of fibrosis (collagen)
- Only cirrhosis if in whole liver
- Chronic inflammation with fibrosis leading to disorganisation of architecture attempted regeneration
What is a granuloma?
- Form in chronic inflammation when body needs to deal with particles that are poorly soluble or difficult to erradicate e.g TB, splinter
- Mass of granulation tissue
What are the two types of granulomas?
Foreign body:
- Contain macrophages, foreign body giant cells, epithelioid cells, few fibroblasts and few lymphocytes.
- Aroun non-antigenic material e.g thread, no immune reaction
Hypersensitivity/Immune Type:
- Macrophages, giant cells, more epithelioid cells, some fibroblasts and lymphocytes
- Central necrosis (mainly TB)
- Around insoluble but antigenic material that cause cell-mediated immunity e.g leprosy, fungi
- Sarcoidosis, Wegener’s granulomatosis and Crohn’s
- Can be harmful as occupy parenchymal space in organ
What does a granuloma look like in TB?
- Central necrosis
What does granuloma look like in sarcoidosis?
- Uknown reason for abnormal clumps of inflammatory cells forming granulomas, mainly in skin, lungs, lymph nodes
What does a foreign body granuloma look like?
What is Wegener’s granulomatosis? (Granulomatosis with polyangitis) ?
Autoimmune disease with necrosis in blood vessels and granulomotous inflammation
