Chronic Inflammation

Question 0

What is chronic inflammation?

Answer 0

Chronic response to injury with associated fibrosis

Question 1

List the cells predominantly involved in chronic inflammations, and the role of each

Answer 1

Macrophages - phagocytosis, antigen presenting, synthesis of cytokines, complement components, blood clotting factors and proteases, control of other cells by cytokine release
Lymphocytes - B differentiate to produce antibodies, T involved in control and cytotoxic functions
Plasma cells - produce antibodies
Eosinophils - allergic reactions, parasite infestation, tumour
Fibroblasts/myofibroblasts - make collagen
Giant cells - Langhans (TB), foreign body type, touton (fat necrosis)

Question 2

List the situations in which chronic inflammation typically arises

Answer 2

1. Take over from acute inflammation if damage is too severe to be resolved in a few days
2. De novo - autoimmune conditions (RA), chronic infections (viral hepatitis), chronic low level irritation
3. Develops alongside acute inflammation in severe persistent or repeated irritation

Question 3

List the effects of chronic inflammation

Answer 3

1. Fibrosis e.g. chronic cholecystitis, chronic peptic ulcers, cirrhosis
2. Impaired function e.g. chronic inflammatory bowel disease
3. Atrophy e.g. gastric mucosa, adrenal glands
4. Stimulation of immune response - macrophage-lymphocyte interactions

Question 4

Describe some major clinical examples of chronic inflammation, how they arise, the complications which ensue and the treatment which is available

Answer 4

Chronic cholecystitis - repeated obstruction by gall stones, fibrosis of gall bladder wall. Treat with surgical removal of gall bladder.
Gastric ulceration - chronic due to Helicobacter pylori, ulceration occurs because of imbalance of acid production and mucosal defence. Treat with PPI inhibitor, two antibiotics.
Inflammatory bowel disease (Ulcerative colitis, Crohn’s) - idiopathic affecting large and small bowel, diarrhoea, rectal bleeding, strictures, fistula. Treat with immunosuppressants, colectomy.
Cirrhosis - alcohol, infection, drugs and toxins, disorganisation of architecture, attempted regeneration. Cannot be reversed so treat with lifestyle changes of liver transplant.
Thyrotoxicosis (Graves’) - antibodies stimulate TSH, overactive, head intolerance, tachycardia. Treat with radioactive iodine, Carbimazole.
Rheumatoid arthritis - autoimmune, synovial inflammation, leads to joint destruction, can cause amyloidoses,

Question 5

Describe and give examples of granulomatous inflammation

Answer 5

Granuloma - accumulation of macrophages with associated lymphocytes
Caused by mildly irritant ‘foreign’ material, infections (TB, leprosy, syphilis, fungus), sarcoid, Crohn’s.
Tuberculosis - caused by mycobacterium, produces no toxins or lytic enzymes, causes disease by persistence and induction of cell-mediated immunity.
Outcomes - arrest, fibrosis, scarring, erosion into bronchus, tuberculous emphysema, erosion into blood stream.