Pathology 5 - Chronic Inflammation Flashcards
What is chronic inflammation?
Chronic response to injury with associated fibrosis
How may chronic inflammation arise?
- 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)
Why is the appearance of chronic inflammation much more variable than that of acute inflammation?
It is characterised more by the type of cell present, which can vary
What are macrophages derived from?
Blood monocytes
What are the functions of macrophages?
- 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
What are the functions of lymphocytes?
- complex and usually immunological
- B-lymphocytes differentiate to produce antibodies
- T-lymphocytes involved in control and cytotoxic functions
What are plasma cells?
Differentiated antibody-producing B lymphocytes. These usually imply that the condition is chronic
In what situations would lots of eosinophils be found in the body?
Allergic reactions, parasite infestations, some tumours
What is the function of fibroblasts/myofibroblasts?
They are recruited by macrophages and make collagen
What are ‘giant’ cells?
Multinucleate cells made by fusion of macrophages due to ‘frustrated phagocytosis’
What are the three types of giant cell?
- Langhans (tuberculosis)
- Foreign Body Type
- Touton (fat necrosis)
What are the effects of chronic inflammation?
- fibrosis
- impaired function
- atrophy
- stimulation of immune response
What is chronic cholecystitis?
Repeated obstruction of the gall bladder by gall stones. Repeated acute inflammation leads to chronic inflammation and therefore fibrosis of the gall bladder wall.
What is inflammatory bowel disease?
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)
Give some common causes of cirrhosis
- alcohol
- infection with HBV or HCV
- immunological
- fatty liver disease
- drugs and toxins
- obesity
Give an example of a condition causing increased function as a result of chronic inflammation
Graves disease causes hyperthyroidism
True or false - chronic inflammation and immune responses are very separate?
False - they often overlap
What is a granuloma?
A small, nodular aggregation of inflammatory cells that stick together
What is granulomatous inflammation?
Chronic inflammation with granuloma formation
Give some causes of granulomatous inflammation
- irritant ‘foreign’ material
- infections by mycobacteria, such as tuberculosis or leprosy
- unknown causes such as sarcoid, Wegener’s granulomatosis, Crohn’s disease
True or false - Tuberculosis produces no toxins or lytic enzymes?
True
What is the rough structure of a tuberculous granuloma?
A circle of epithelioid histiocytes surrounded by lymphocytes, with a patch of caseous necrosis in the centre. There may be giant Langhans cells present
