أسئلة السابعة باثو PPPM (قبل التعديل)

Types of Acute Inflammation

• Acute inflammation is either suppurative or non-suppurative.
• Suppurative inflammation involves pus.
• Non-suppurative inflammation lacks pus.

Acute Suppurative Inflammation

• May be localized or diffuse
• Localized cases typically arise from Staphylococcus aureus.
  • Staphylococcus aureus produces coagulase, leading to fibrin coagulation and deposition, which aids localization.
  • Examples: abscesses, furuncles (boils), and carbuncles
• Diffuse cases typically linked to streptococci.
  • Streptococci produce hyaluronidase and streptokinase (fibrinolysin) that dissolve fibrin, which allows spread.
  • Examples: cellulitis and suppurative appendicitis

Mechanism of Suppuration (Pus Formation)

• Most severe form is caused by strong pyogenic bacteria, such as Staphylococcus aureus and Streptococcus hemolyticus
• Pyogenic bacteria causes necrosis.
• Attracts neutrophils that die due to bacteria virulence.
• Presence of proteolytic enzymes.
• Pus is mainly a mix of dead neutrophils (pus cells) and necrotic tissue, liquified by proteolytic enzymes.
• Liquefied material combined with pus cells and fluid exudate to create pus.

Abscess

• Localized suppurative inflammation leads to an irregular pus-filled cavity.
• Commonly subcutaneous but found in deep organs.
• Early abscesses have a center necrotic zone surrounded by a zone of acute inflammation and neutrophils.
• Abscesses then show zones of central necrotic core, mid zone with pus (formed in about 48 hours), and a peripheral zone of inflamed tissue (pyogenic membrane).
• Abscesses grow through further necrosis and liquefaction; staphylococci produce coagulase enzyme, which helps fibrin formation to localize the inflammation.
• Subcutaneous abscesses appear as tender, red, edematous skin swellings with an opaque yellow center.
• Covering epidermis may necrose, leading to slough (separated necrotic tissue), pus evacuation, and ulcer formation.
• Internal abscesses in organs like the lung, liver, or kidney may open into bronchi, ureter, or intestines

Abscess Fate and Complications

• Fate depends on size
• Small abscesses: Pus may be absorbed, followed by healing
• Large abscesses: Pus slowly absorbed; osmotic pressure absorbs water, increasing size and causing throbbing pain.
  • If not surgically evacuated, pointing and rupture can occur spontaneously on the skin or in hollow organs, followed by secondary intention healing.
• Complications of spontaneous evacuation and non-healing: ulcer, sinus, fistula, and hemorrhage.
• Complication of healing: keloid formation (excessive projecting scar).
• If not evacuated (chronic abscess): surrounded by fibrosis and addition of cholesterol crystals & dystrophic calcification, leading to a chronic breast abscess
• Spread of infection can occur directly by enlargement of the abscess.
• Lymphatic spread causes lymphangitis and lymphadenitis.
• Blood spread causes:
  • Toxemia: Bacterial toxins circulate in the blood.
  • Septicemia: Virulent bacteria and toxins circulate in the blood.
  • Pyemia: Septic emboli from septic thrombi cause multiple small abscesses.

Furuncle (Boil)

• Small abscess related to a hair follicle, sebaceous gland, or sweat gland.
• Caused by Staphylococci
• Commonly found in hairy areas (face, axilla).
• Neighboring boils is called furunculosis.

Carbuncle

• Acute localized suppurative inflammation forming multiple communicating suppurative foci in skin and subcutaneous (S.C.) fat, discharging pus through openings.
• Caused by Staphylococci and occurs in individuals with diabetes
• Areas: back of the neck, scalp, and buttocks.
• Bacteria invade S.C. fat, forming multiple communicating suppurative foci, like an abscess.
• Foci open on the surface at multiple points, especially at the base of hair follicles.

Cellulitis

• Acute diffuse suppurative inflammation.
• Streptococcus hemolyticus produces fibrinolysin (streptokinase) to dissolve fibrin and hyaluronidase to dissolve hyaluronic acid to spread bacteria.
• In loose connective tissue, such as areolar tissue of the orbit, scrotum, and wall of the appendix.
• Lymphatic spread causes lymphangitis and lymphadenitis
• Blood spread causes septicemia and pyemia.
• Pus is thin, bloody, and contains sloughs (necrotic debris) from necrosis.

Non-Suppurative Inflammation

• Serous Inflammation:
  • Excess watery fluid exudate, poor in fibrin.
  • Examples: skin blister after burn, skin vesicles from viral infection
• Serofibrinous Inflammation:
  • Excess fluid exudate rich in fibrin.
  • Examples: serous membranes (pleura, peritoneum, pericardium)
• Allergic Inflammation:
  • Fluid exudate rich in eosinophils.
  • Examples: hypersensitivity reactions (urticaria, bronchial asthma, allergic rhinitis, and contact dermatitis)
• Catarrhal Inflammation:
  • Excess mucous secretion.
  • Example: catarrhal rhinitis.
• Pseudomembranous Inflammation:
  • Pseudomembrane contains fibrin, desquamated epithelium, and inflammatory cells.
  • Examples: Diphtheria and Bacillary dysentery caused by Shigella bacilli
  • Complications:
    • Toxemia (most common).
    • Suffocation from detached membranes, as in diphtheria
• Hemorrhagic Inflammation:
  • Vascular damage and hemorrhage in exudate
  • Example: Meningococci
• Necrotizing Inflammation:
  • Extensive tissue necrosis
  • Example: oral mucosa in debilitated malnourished children