Session 2 ILO's Acute inflammation Flashcards
Describe the common causes (aetiology) of acute inflammation
- Microbial infections
- Hypersensitivity reactions
- Physical and chemical agents
- Tissue necrosis
Explain the tissue changes that occur in acute inflammation
Changes to vascular flow:
- Initial vasoconstriction at initial injury site (seconds)
- Then vasodilation occurs, allowing more blood (fluid and leukocytes) to flow to the affected area
CAUSES heat and redness
Fluid exudate is formed:
- Permeability increases as well to allow: fluid, cells and proteins to escape
- Exudate is a protein rich fluid, containing red and white cells
Neutrophil emigration:
- Neutrophils Rapidly migrate to site of infection for phagocytosis / to cause the immune response
Evaluate how these tissue changes (including vascular flow, formation of a fluid exudate, neutrophil emigration) constitute an effective response to injury
Increase delivery of:
- Nutrients
- Oxygen
- Antibodies
- Inflammatory cells
Cause:
- Dilution of toxins
- Stimulation of immune response
- Destruction and removal of dead or foreign material
All of which constitute an effective response to injury
Recognise what a neutrophil is and describe its actions in mediating acute inflammation.
Describe: multi-lobed nucleus - they form pus
Actions in mediating acute inflammation:
- Phagocytose - the phagosome fuses with the lysosome and also release inflammatory mediators
- Directed to the correct substance via opsonisation
- Kill the pathogens, either through oxygen dependant (respiratory burst) or oxygen independant (lysozyme, hydrolytic enzymes, defensins) mechanisms
Recognise and explain the action of some of the key chemical mediators involved in acute inflammation
Vasoactive amines, e.g. histamine
- Increase vasodilation
- Increase vascular permeability
Vasoactive peptides, e.g. bradykinin
- Increase vascular permeability
- Increase pain response
Mediators derived from phospholipids, e.g. prostaglandin
- Increase vasodilation
- Increase temperature
- Increase pain response
Complement components, e.g. C3a
- Increase vascular permeability
- Help with chemotaxis
Cytokines and chemokines, e.g. tumour necrosis factor (TNF)
- Help with chemotaxis
- Increase temperature
Exogenous mediators, e.g. endotoxin
- Help with chemotaxis
Define inflammation
Response of living tissue to injury controlled by chemical mediators
Consists of vascular phase(changes in blood flow&accumulation of exudate) and cellular phase(delivery of neutrophils)
Recognise and interpret the clinical signs of acute inflammation and how these relate to tissue changes.
rubor - redness - increased blood flow due to vascular phase
tumour - swelling- increased capillary permeability and hydrostatic pressure increase
calor - heat - vasodilation from vascular phase
dolor - pain
loss of function - this enforces rest and reduces the chance of further damage
Understand the local and systemic short and long term consequences of acute inflammation and interpret how these might affect organs.
Local acute inflammation:
- Local swelling, could lead to obstruction and compression of tubes
- Exudate can cause compression of organs
- Loss of fluid (e.g. burns)
- Pain (muscle atrophy)
Systemic acute inflammation:
- Fever
- Leucocytosis (increased production of WBC)
- Acute phase response (feeling generally unwell e.g. reduced appetite, altered sleep etc.) it induces rest
- Acute phase proteins (e.g. CRP, fibrinogen, alpha-1 antitrypsin)
- SEPTIC SHOCK risk factor
Long term consequences:
- Could be completely resolved
- Repair with connective tissue (fibrosis) if there has been substantial destruction
- Progression to chronic inflammation (prolonged inflammation with repair)
Describe the features seen in some common clinical examples of acute inflammation: COVID-19 infection, lobar pneumonia, acute appendicitis
COVID-19 infection: Acute injury to the alveoli (4)
- Thrombus production
- Fever or chills
- Cough
- Shortness of breath or difficulty breathing
Lobar pneumonia: inflammatory exudate within the intra-alveolar space resulting in consolidation that affects a large and continuous area of the lobe of a lung (4)
- Productive cough
- Dyspnoea
- Pleuritic pain
- Sputum
Acute appendicitis: sudden inflammation of the appendix (4)
- Initial pain starts in the middle of your tummy before moving towards the right iliac fossa region
- Low-grade fever that may worsen as the illness progresses
- loss of appetite
- vomitting
Understand a few clinical examples of inherited disorders of the acute inflammatory process: Hereditary angio-oedema, Alpha-1 antitrypsin deficiency, Chronic granulomatous disease.
Hereditary angio-oedema:
- Deficiency in the C1 esterase inhibitor of the complement pathway
- Leads to reduced C2 and C4
- Rapid swelling and oedema of the skin randomly, with no clear trigger
Chronic granulomatous disease:
- Deficiency in NADPH oxidase
- No respiratory burst defence so can engulf pathogens, but cannot kill them
- Granulomas form (accumulations of neutrophils/macrophages with trapped bacteria)
Alpha-1 antitrypsin deficiency:
- Deficiency in alpha-1-anti-trypsin which is a protease inhibitor that breaks down bacteria that is released from neutrophils
Describe the features seen in some common clinical examples of acute inflammation: bacterial meningitis, ascending cholangitis and liver abscess.
Bacterial meningitis: entry of bacteria into the CSF leading to inflammation of the adjacent brain tissue (5)
- Fever of 38C or above
- Rash that does not fade when a glass is rolled over it (but a rash will not always develop)
- Dislike of bright lights
- Intense headache
- Stiff neck
Ascending cholangitis: is an infection of the biliary tree, most commonly caused by obstruction with inflammation and bacterial seeding and growth (less severe form.) (3)
- Right upper quadrant pain
- Fever
- Jaundice
Liver abscess
- collections of thick fluid or pus containing blood, dead cells and germs that develop after infections affecting the liver, bile ducts or other sites in the body (8)
- There is necrosis from infection
- Chest &upper abdomen pain
- Dark urine
- Fevers
- night sweats
- nausea
- vomiting
- weight loss
