Inflammation and Infection Flashcards
Three Lines of Defence in the Body?
1st Line: Skin and mucous membranes (non-specific, innate).
2nd Line: Inflammation (non-specific, innate).
3rd Line: Immunity (specific, adaptive).
What is the definition, purpose and signs of Inflammation?
Definition: Non-specific protective response to tissue damage, disease, or injury.
Purpose: Destroy/dilute injurious agents, prevent infections, and prepare tissues for repair.
Cardinal Signs:
1. Redness (Rubor)
2. Swelling (Tumor)
3. Warmth (Calor)
4. Pain (Dolor)
5. Loss of Function (Function Laesa)
Factors That Cause Inflammation?
Physical/thermal injuries: Trauma, radiation.
Infections: Bacteria, viruses, fungi, parasites.
Infarction: Tissue death due to ischaemia (e.g., heart attack).
Immune Reactions: Autoimmunity, allergies.
Nutrient Deprivation.
Mechanism of Inflammation?
Vascular Response: Vasodilation, increased vascular permeability, protein-rich exudate formation.
Cellular Response: Leucocyte emigration (neutrophils → monocytes → macrophages).
Phagocytosis: Ingestion of foreign materials.
Lymphatic Drainage: Clears excess fluid and antigens.
Consequences of Acute Inflammation
Redness: Due to vasodilation and increased blood flow.
Heat: Increased blood flow to the area.
Pain: Tissue compression and chemical mediators.
Swelling: Accumulation of extracellular fluid.
Loss of Function: Tissue damage, swelling, and pain.
Common Blood Tests for Acute Inflammation?
White Blood Cell (WBC) Count: Elevated levels >10,000/mm³.
Erythrocyte Sedimentation Rate (ESR): Increased due to RBC clumping.
C-Reactive Protein (CRP): >10 mg/L indicates significant inflammation.
Fibrinogen: Elevated during inflammation to promote clotting.
Difference between Acute and Chronic Inflammation
Acute:
Onset: Rapid
Duration: Self-limiting
Main Cells: Neutrophils → macrophages.
Outcome: Full resolution, repair.
Chronic:
Onset: Slow, insidious.
Duration: Persistent and unremitting.
Main Cells: Macrophages, fibroblasts.
Outcome: Scar tissue, deformity, loss of function.
Common Medications for Inflammation?
Aspirin
NSAIDs: Ibuprofen, Diclofenac sodium, Naproxen.
Corticosteroids: Prednisolone.
Immunosuppressants: Methotrexate.
Define the roles of the immune system.
Protects the body from injury, harmful agents, or infectious organisms through:
Physical and chemical barriers
Inflammatory response
Immune response
What are the components of immunity?
Bone Marrow
Thymus Gland
Lymph Nodes
Spleen/Tonsils
What are the two types of immunity?
Cell-mediated immunity
Humoral immunity
What are the functions of CD8 and CD4 T cells in cell-mediated immunity?
CD8 T Cells: Release perforin (causing autolysis) and lymphotoxin (causing apoptosis).
CD4 T Cells: Manage immune response by increasing T and B cells, activating CD8 into killer T cells, and B cells into plasma cells.
What is the role of B cells in humoral immunity?
Mature into plasma cells in bone marrow.
Activated by Helper T cells.
Plasma cells produce immunoglobulin that interacts with specific antigens.
List the actions of antibodies (immunoglobulin).
Agglutination: Clumps pathogens together, making them easier to remove.
Precipitation: Causes soluble toxins or antigens to solidify and fall out of solution.
Neutralisation: Blocks harmful effects of toxins or viruses.
Lysis: Breaks down the cell walls of pathogens, destroying them.
Opsonisation: Marks pathogens so immune cells can identify and attack them.
Activation of the complement cascade: Triggers a chain reaction that helps kill pathogens.
Define infection.
A complication of immune function and an extension of inflammatory and immune processes leading to tissue destruction caused by microorganisms.
What are the phases of acute infection?
Exposure: The pathogen enters the body.
Incubation: The pathogen grows without causing symptoms yet.
Prodrome: Early, mild symptoms appear (e.g., fatigue, fever).
Acute clinical illness: Full-blown symptoms of the infection occur.
Convalescence: The body recovers and symptoms fade.
Name the common types of pathogens.
Bacteria
Viruses
Fungi
Protozoa
Rickettsiae
Helminths
Mycoplasma
What laboratory and diagnostic tests are used to diagnose infections?
White blood cell count
Serum antibody levels
Cultures
Sensitivities
List common clinical manifestations of infection.
Pain, heat, redness, swelling
Lymphadenopathy, loss of function, purulent exudate
Fever, malaise, weakness, anorexia, headache, nausea
