[A] 1.55 Fibrinous inflammation

Question 1

Fibrinous inflammation: Overview

Answer 1

Exudate is rich in fibrinogen (sero-fibrinous)

Question 2

Fibrinous inflammation: Special staining technique

Answer 2

Weigert

Question 3

Fibrinous inflammation: Appearance

Answer 3

• Fine strands
• Gel-like (Exudate + fibrin)
• Thick casts
  
  • Pseudomembranes

Question 4

Fibrinous inflammation: Localisation

Answer 4

• Serosa
• Mucosa
• Inside the lung

Question 5

Fibrinous inflammation: Appearance on serous surfaces

Answer 5

“Cloudy” - precipitation

• Microscopic fibrin threads
• Larger flakes
• Fibrin strands & layers

Types:

• Sero-fibrinous or dry fibrinous

Question 6

Fibrinous inflammation: Outcome on serous membranes

Answer 6

• Absorption → Regeneration (Fibrinolysis)

or

• Organisation (5-6 days)
  
  • Granulation tissue from the subserosa → Villous growth
  • Adhesion
    
    • Extensive thickening
    • Connective tissue ligaments

Question 7

Fibrinous inflammation: On mucosal membranes

Answer 7

• Croupous
• Diphtheroid
• Deep regressive changes

Question 8

Fibrinous inflammation on mucosal membranes: Croupous

Answer 8

• Wide fibrin formation
• Easily removable pseudomembrane
• Limited to the mucosa → Organs
• No deep pathological changes
• Neutrophils loosen the adhesion & quick removal

Question 9

Fibrinous inflammation on mucosal membranes: Diphtheroid

Answer 9

• Diffuse or circumscribed

Question 10

Fibrinous inflammation on mucosal membranes: Deep regressive changes

Answer 10

• Coagulative necrosis
• Superficial: Healing
• Profound: Organisation

Question 11

Fibrinous inflammation on mucosal membranes: Types

Answer 11

• Diffuse - Uneven, dull, friable
• Circumscribed - “Diphtheritic crust”
  
  • Lymph follicles

Question 12

Croupous pneumonia

Answer 12

• Inside the lung
• Fibrinogen-rich exudate precipitates
  
  • In alveolar acini & ducts
  • Fibrin accumulation
• Oedema in the surrounding interstitium
• No ventilation

Question 13

Croupous pneumonia: Stages

Answer 13

1. Congestion (Hyperaemia, fibrinogen)
2. Hepatisation (Neutrophil granulocytes)
3. Lysis (Healing)

Question 14

Croupous inflammation: Outcomes

Answer 14

• Restitutio ad integrum
• Restitutio cum defectu

Question 15

Restitutio ad integrum

Answer 15

• ​Neutrophils are able to lyse the fibrin
• Removal
• Expectoration
• Absorption through the lymph circulation
• Regeneration of the epithelial layer in the acini

Question 16

Restitutio cum defectu

Answer 16

• Organisation from the wall of the alveoli
• Permanent atelectasis - “Carnificatio pulmonum” (lung collapse)

Question 17

Fibrinous inflammation: Appearance in the lung

Answer 17

• Keeps its shape
• Mottled colour
• Liver-like firm

Question 18

Fibrinous inflammation: Lung cut surface

Answer 18

• No crepitation heard
• Unhomogenous colour
• Granular, dry surface