Chronic Inflammation

Question 1

Define chronic inflammation

Answer 1

Chronic inflammation is chronic response to injury with associated fibrosis

Question 2

State the cells primarily found in chronic inflammation

Answer 2

Macrophages, lymphocytes, plasma cells, eosinophils, fibroblasts/myofibroblasts

Question 3

Describe the role of macrophages in chronic inflammation

Answer 3

Derived from blood monocytes
Various levels of activation
Functions - phagocytosis
Presentation of antigen to immune system
Synthesis of cytokines, complement components, blood clotting factors, proteases
Control of other cells by cytokine release

Question 4

Describe the appearance and role of lymphocytes in chronic inflammation

Answer 4

Small blue dots - large nucleus and small cytoplasm
Mainly immunological function
B lymphocytes differentiate to produce antibodies
T lymphocytes involved in control and some cytotoxic functions

Question 5

Describe the appearance and role of plasma cells in chronic inflammation

Answer 5

Open nucleus (clot face), lumps of chromatin around nucleus
Can see cytoplasm and Golgi (pale area)
Differentiated antibody-producing B lymphocytes

Question 6

Describe the appearance and role of eosinophils in chronic inflammation

Answer 6

Stains bright pink
Bi-lobe nucleus
Allergic reactions, parasite infestations, some tumours

Question 7

Describe the role of fibroblasts in chronic inflammation

Answer 7

Recruited by macrophages, make collagen - cause scarring

Question 8

Describe the different types of giant cells and where they are classically seen

Answer 8

Langhan’s type giant cells - horseshoe of nuclei around periphery
Associated with tuberculosis
Foreign body type giant cells - disorganised irregular aggregated nucleus with foreign material in the middle
Cement and metal in replacement, sand in injury, stitches, fracture where bone moves to new place
Touton giant cell - fat necrosis (high lipid content)

Question 9

What are giant cells

Answer 9

Giant cells - frustrated phagocytosis - macrophages can’t phagocytose
Multinucleate cells made by fusion of macrophages

Question 10

Describe the situations where chronic inflammation arises

Answer 10

Acute inflammation that does not get better
If acute inflammation damage is too severe to be resolved within a few days
De novo - autoimmune conditions, chronic infections (viral hepatitis), ‘chronic low level irritation’
Develop alongside acute inflammation in severe, persistent or repeated irritation
Prolonged exposure to toxic agents

Question 11

Describe the possible complications of chronic inflammation

Answer 11

Abnormal fibrosis - replace normal tissue and impair function of liver
Eg. Gall bladder (chronic cholecystitis), chronic peptic ulcers, cirrhosis
Impaired function - immune system attacks own cells
Eg. Chronic inflammatory bowel disease
Rarely increased function - eg. Mucus secretion, thyrotoxicosis
Atrophy - eg. Gastric mucosa, adrenal glands
Stimulation of immune response - eg. Macrophages - lymphocyte interactions

Question 12

Chronic cholecystisis description

Answer 12

Abnormal fibrosis
Gall bladder with thickened fibrotic wall
Yellow pigment stones
Repeated attacks of acute inflammation
Repeated obstruction by gall stones - tries to move obstruction leading to inflammation

Question 13

Define granulomas

Answer 13

Groups of epitheloid macrophages and lymphocytes that stick together
Histiocytes = macrophages
Epitheloid - looks like epithelium where cells stuck together

Question 14

Describe the causes of granulomas

Answer 14

Irritant foreign material (cement and metal in replacement, sand in injury, stitches, fracture where bone moves to new place)
Infections
Idiopathic granuloma diseases (unknown causes)
Sarcoid, Wegener’s granulomatosis, Crohn’s disease

Question 15

Rheumatoid arthritis presentation, microscopic features, rheumatoid nodule description

Answer 15

Presentation - swelling, stiffness
Microscopic - finger like projections of inflamed epithelial cells, macrophages, lymphocytes, plasma cells
Nodules - swelling with inflammatory cells and necrosis inside

Question 16

Ulcerative colitis presentation, differential diagnosis, microscopic and macroscopic appearance, complications

Answer 16

Presentation - bloody diarrhea, abdominal pain, constipation
Differential diagnosis - Crohns, GI infection
Microscopic/Macroscopic - crypt abscess, distorted crypt architecture, inflammation superficial (mucosa and submucosa)
Complications - severe bleeding, increased risk of colon cancer, liver disease, joint pain, skin ulcers

Question 17

Crohn’s disease presentation, differential diagnosis, microscopic and macroscopic appearance, complications

Answer 17

Presentation - abdominal pain, diarrhea
Microscopic/macroscopic - ‘cobblestone’ appearance to bowel mucosa, granuloma present, anal lesions, bowel fistulae
Complications - obstruction and perforation of small intestine, risk of colon cancer, skin ulcers, liver disease, joint pain

Question 18

Distinguish between Crohn’s disease and ulcerative colitis

Answer 18

Ulcerative colitis limited to colon, Crohn’s affects any part of GI system
Ulcerative colitis limited to mucosa and submucosa, Crohn’s transmural (entire wall) inflammation
Crohn’s has ‘cobblestone’ appearance, discontinuous distribution, granulomas present, anal lesions, bowel fistulae
Ulcerative colitis has distorted crypts, crypt abscesses

Question 19

Helicobacter pylori associated chronic gastritis role of bacteria, microscopic appearance, complications

Answer 19

Bacteria stimulates production of pro-inflammatory cytokines and by directly injuring epithelial cells and increasing acid secretion
Microscopic - chronic inflammation in epithelial and lamina propria layer, lamina propria fibrosis, mucosal atrophy, intestinal metaplasia
Complications - gastric adenocarcinoma, MALT (mucosal associated lymphoid tissue) lymphoma

Question 20

Cirrhosis description, microscopic and macroscopic appearance, causes, complications

Answer 20

Fibrosis (scarring) and impaired function of liver
Microscopic - regenerative nodules of hepatocytes surrounded by fibrous tissue that bridges between portal tracts, lymphocytes
Bands of fibrosis tissue
Causes include alcohol, obesity, hepatitis, drugs, toxins, fatty liver disease
Complications - portal hypertension, oedema in legs, splenomegaly, bleeding, infections, malnutrition, jaundice

Question 21

Tuberculosis pathophysiology, microscopic appearance, differentiation from sarcoidosis

Answer 21

Mycobacterium tuberculosis bacteria (MTB) enters macrophages by endocytosis, replicates within phagosome and proliferates
After 3 weeks, T-helper cells response which activates macrophages
Activated macrophages produce TNF, recruits monocytes which differentiate into granulomas
Results in tissue damage and infection
Microscopic - langhans giant cells, caseous necrosis
Differentiation - sarcoidosis have discrete separate granulomas, no caseous necrosis, microRNA produced in inflammatory response detected in blood test

Question 22

Sarcoidosis presentation, microscopic appearance

Answer 22

Presentation - fever, fatigue, airflow obstruction in lungs

Microscopic - granuloma with no caseous necrosis