Inflammation Overview

Inflammation-2

• Inflammation is a complex biological response to harmful stimuli, such as pathogens, damaged cells, or irritants.
• Inflammation aims to eliminate the initial cause of cell injury, clear out necrotic cells and tissue debris, and initiate tissue repair.
• Inflammatory cellular exudate is the passage of leukocytes (white blood cells) to the interstitial space of the inflamed area.
• Steps in inflammatory cellular exudate include: Margination, Rolling, Adhesion (or diapedesis), and Chemotaxis.
• Phagocytosis involves the engulfment and destruction of particulate matter like bacteria, foreign particles, and dead cells.
• The steps in phagocytosis include: Recognition and Attachment, Engulfment, and Killing and Degradation.
• Oxygen-dependent killing involves the use of reactive oxygen species (ROS) to destroy the ingested material.
• Oxygen-independent killing uses enzymes and other substances within the granules of leukocytes.
• Local signs of acute inflammation include: Hotness (vasodilation), Redness (vasodilation), Swelling (fluid exudate), Pain (irritation of nerve endings, exudate pressure), and Loss of function (tissue destruction).
• Systemic effects of acute inflammation include: Fever (or Pyrexia), anorexia, headache, malaise, and Leukocytosis (increased white blood cell count).
• Acute inflammation has a range of possible outcomes: resolution, regression and healing, progression and spread, and chronicity.
• Resolution involves restoration of the inflamed tissue to normal.
• Healing occurs by cell replacement (regeneration) or fibrosis.
• Progression and spread can occur if the inflammatory response can't overcome the irritant.
• Chronicity involves a long-term inflammatory response.
• Acute inflammation consists of dilated blood vessels, acute inflammatory cells (macrophages and neutrophils), and exudate.

Types of Acute Inflammation

• Suppurative inflammation produces pus. Localized examples include boils, abscesses, and carbuncles. Diffuse examples include cellulitis, acute appendicitis, and meningitis.
• Non-suppurative inflammation does not produce pus. Examples include catarrhal, pseudomembranous, serous, fibrinous, sero-fibrinous, hemorrhagic, allergic, and necrotizing inflammation.

Acute Suppurative Inflammation (Pyogenic or Septic)

• Definition: Severe acute inflammation characterized by pus formation.
• Causes: Pyogenic microorganisms are the main cause, including staphylococcus aureus (most common cause of abscesses and carbuncles), pneumococcus, gonococcus, and bacillus coli.

Abscess

• Definition: Localized suppurative inflammation forming a cavity filled with pus.
• Etiology: Primarily caused by staphylococcus aureus, which produces coagulase that facilitates fibrin formation and localizes the infection.
• Sites: Common sites include subcutaneous tissue, lungs, brain, liver, and breasts.

Complications of Abscesses

• Blood spread with septicemia (blood poisoning) and toxemia (toxin in the blood).
• Lymphangitis (inflammation of lymphatic vessels) and lymphadenitis (inflammation of lymph nodes).

This quiz dives into the complex biological response known as inflammation. It covers the steps involved in inflammatory cellular exudate, phagocytosis, and the mechanisms of oxygen-dependent and oxygen-independent killing. Test your understanding of local signs and the overall process of inflammation.