Acute Inflammation Quiz

Inflammation-2

• Presentation by Dr. Gehan Abdelmenam
• Topics covered include the inflammatory cellular exudate, phagocytosis, acute inflammation, fate of acute inflammation, types of acute inflammation, and abscesses.

Intended Learning Objectives

• Recall the definition and mechanism of formation of inflammatory cellular exudate.
• Define phagocytosis and its steps.
• List systemic effects and local signs of acute inflammation.
• Describe the fate and types of acute inflammation.
• Recall the definition, sites, and complications of an abscess.

Inflammatory Cellular Exudate

• Definition: The passage of leukocytes to the interstitial space of the inflamed area.
• Steps:
  • Margination: Accumulation of leukocytes along the endothelial surface.
  • Rolling: Leukocytes loosely adhere to the endothelium and roll along it.
  • Adhesion: Firm adhesion of leukocytes to the endothelium.
  • Transmigration (Diapedesis): Leukocytes migrate through the endothelial walls.
  • Chemotaxis: Movement of leukocytes toward the irritant.

Phagocytosis

• Definition: The process of engulfing and destroying particulate material, such as tissue debris, bacteria, etc., by phagocytic cells (neutrophils and macrophages).
• Steps:
  • Recognition and Attachment: Receptors on leukocytes recognize the particle to be ingested and attach to it by opsonization (coating of particle with opsonins like IgG and C3b).
  • Engulfment: The phagocytic cell sends out pseudopods to surround and engulf the particle, forming a phagosome.
  • Killing and Degradation: The phagosome fuses with lysosomes to form a phagolysosome and the lysosomal contents kill and degrade the ingested material. Mechanisms include oxygen-dependent (ROS) and oxygen-independent (hydrolytic substances) pathways.

Local Signs of Acute Inflammation

• Hotness: Due to vasodilation and hyperemia.
• Redness: Due to vasodilation and hyperemia.
• Swelling: Due to fluid exudate.
• Pain: Caused by irritation of nerve endings by toxins and pressure of inflammatory exudate on sensory nerves, along with the release of prostaglandin E2 and bradykinin.
• Loss of function: Due to tissue destruction or to avoid pain.

Systemic Effects of Acute Inflammation

• Fever (Pyrexia): Elevated body temperature.
• Anorexia: Loss of appetite.
• Headache: Pain in the head.
• Malaise: Feeling of discomfort or illness.
• Leucocytosis: Increased white blood cell count.

Fate of Acute Inflammation

• Resolution: The usual course of acute inflammation, where no tissue loss occurs, and the inflamed area returns to normal as products of inflammation are rapidly removed and cells return to normal.
• Regression and Healing: The body overcomes the irritant, necrotic tissue is removed by macrophages, and healing occurs through regeneration (replacement by the same cell type) or fibrosis (scarring) depending on the cell type.
• Progression and Spread: Inflammation spreads through blood, lymph, and direct spread of bacteria, causing conditions like septicemia, toxemia.
• Chronicity: The causative irritant is not completely overcome, leading to persistent inflammation.

Acute Inflammatory Reaction

• Consists of:
  • Dilated blood vessels
  • Acute inflammatory cells (neutrophils, macrophages)
  • Exudate

Types of Acute Inflammation

• Suppurative (pus-forming): localized (boil, abscess, carbuncle), and diffuse (cellulitis, appendicitis).
• Non-suppurative (non-pus-forming): catarrhal, pseudomembranous, serous, fibrinous, sero-fibrinous, hemorrhagic, necrotizing, allergic.

Acute Suppurative Inflammation (Pyogenic/Septic)

• Definition: Severe acute inflammation characterized by pus formation.
• Causes: Pyogenic microorganisms (like Staphylococcus aureus, pneumococcus, gonococcus, bacillus coli)

Abscess

• Definition: A localized collection of pus in a tissue space.
• Etiology: Often caused by Staphylococcus aureus, which produces coagulase to localize the infection.
• Sites: Common in subcutaneous tissues, but any organ can be affected (e.g., lungs, brain, liver, breast).
• Complications: Blood spread (septicemia, toxemia), chronicity, lymphangitis, lymphadenitis.

Subcutaneous abscess

• Subtype of abscess.

This is a summary based on the provided images. Please note that some terms may have varying nuances depending on the specific context.