3- Inflammation Flashcards
Characteristics of inflammation
Rapid onset, Short duration
Initial reaction of tissue to injury
If there is a vascular component this causes
dilation of vessels
What is the exudative component
protein rich fluid leaks from vessels
Causes of inflammation
MHPCT
- Microbial infections: e.g. pyogenic bacteria, viruses
- Hypersensitivity reactions e.g. to parasites, allergens
- Physical agents e.g. radiation, heat, trauma
- Chemical agents e.g. corrosives, acids, alkalis, toxins
- Tissue necrosis (death)
Appearance of inflammation
- Redness – Due to increased blood flow
Histamines released by mast cells and cause vasodilation and increase vascular permeability - Heat
- Swelling – oedema due to fluid accumulation
- Pain – Due to release of chemical mediators
Prostaglandins – Lipid molecule, causing vasodilation and vascular permeability - Loss of function
- Exudate from blood vessels (fluid that leaks out of blood vessels into affected tissue
What do dilation and permeability allow for
exudation of plasma and leukocytes from blood to affected tissue
Stages of inflammation
Early
- Vasoconstriction to stop bleeding, Vasodilation following this to increase blood flow and immune cells
- Leukocyte recruitment
Late
- Phagocytosis then tissue repair
Types of inflammation
Osis = Abnormal process or state
Itis = Disease or inflammation
Endo = inside eye
Pan= whole eye affected
Further on types of inflammation
Endophthalmitis (Endo = inside eye) Acute red eye + Hypopyon (Pus in anterior chamber). Affects Intraocular aqueous and vitreous
Panophthalmitis
Pan = all eye
Infectious process caused by a pyogenic organism that encompasses all structures of the globe e.g. lens, sclera, vitreous abscess, retina, choroid, blood, optic nerve
What dominates in chronic inflammation (longterm/ recurrent)
Lymphocytes, plasma cells and macrophages predominate.
Usually primary but may follow acute inflammation.
- Granulomatous inflammation is a specific subtype
Causes of chronic inflammation
- Persistent infectious agent
- Autoimmune diseases and transplant rejection
- Primary granulomatous diseases (e.g. sarcoidosis)
- Foreign body
- Chronic diseases e.g. Crohn’s disease, ulcerative colitis
Appearance of chronic inflammation
- Tissue destruction – Scarring Fibrosis
- Abscess formation
- Fatigue
- Granulomas
What are granulomas
inflammation which consists of…
An immune response forming an organized collection of activated epithelioid macrophages (Type of WBC) (macrophages in tissues larger than normal)
Other cell types and matrix may be present and indicative of cause.
What can granulomas include
Can include giant cells derived from macrophages (multinucleate cells). Examples below:
Specific infections: Myobacteria ( tuberculosis, Leprosy)
Fungal infections: parasites, larva eggs and worms
Foreign bodies: endogenous such as keratin necrotic bone or exogenous such as sutures
Specific chemicals or Drugs e.g. sulphonamides
Unknown causes Crohn’s disease, sarcoidosis
Stages of chronic inflammation
Early
Late
Early chronic inflammation
- Persistent inflammation
- Infiltration of immune cells
- Fibrosis
Late chronic inflammation
- Continued tissue destruction
- Proliferation of immune cells – Form nodules or masses i.e granulomatous inflammation
What can chronic inflammation lead to
Can lead to long term changes to blood vessels structure and function:
Cytokines can be released to stimulate angiogenesis for new blood vessels
Blood vessels can be leaky and…
prone to bleeding – more accumulation of fluid.
Overall leading to fibrosis and increase pressure (Due to accumulation)
What are the outcomes
of inflammation
RSOPN
Resolution
Suppuration (Discharge of pus)
Organisation into healthy new tissue Progression to chronic inflammation
Necrosis
Characteristic of acute inflammation
Rapid onset, Short duration
Initial reaction of tissue to injury
- Vascular component: dilation of vessels
- Exudative component: protein rich fluid leaks from vessels
- Cellular component: characteristic cell is the neutrophil polymorphs (Type of leukocyte)
