Morphology of Inflammation Flashcards
Classification of Inflammation
Duration
Distribution
Severity
Morphology
Response of the tissue
All of these can be included as components of a morphologic diagnosis
Duration of Inflammation:
Peracute
Begins minutes to hours after insult
Can last for several hours
Prominent vascular changes
Duration of Inflammation:
Acute
Begins 4-6 hours insult
Can last for several days
Vascular and early cellular changes
Duration of Inflammation:
subacute
Begins several days after insult
Can last for several weeks
Mixed cellular response with decreasing vascular response
Duration of Inflammation:
Chronic
Begins several days to weeks after insult
Can last for weeks, months or years
Mononuclear cells and fibrosis with minimal vascular response
Distribution of the lesion:
Focal
Single delineated lesion
Distribution of the lesion:
Multifocal
Multiple, randomly scattered focal lesions
Distribution of the lesion
Locally extensive
A single lesion involving a large area of tissue
Distribution of the lesion:
Diffuse
Lesion involving the entire tissue in which it is found
Severity of the lesion:
Mild
Vascular change, mild cellular change, no tissue destruction
Severity of the lesion:
Moderate
Prominent vascular and cellular change with some tissue destruction
Severity of the lesion:
Severe
Extension of vascular and cellular changes with extensive tissue destruction
Exudate or Cell type
- Common classification include:
- serous
- Catarrhal
- Fibrinous
- Purulent
- Hemorrhagic
- Eosinophilic
- Lymphocytic
- Granulomatous
Serous Inflammation
- Accumulation of serum-fluid
- Causes include:
- Joint trauma
- Early response to bacterial and viral infection
- mild chemical irritant
- certain insect bites
- Effects include
- dilution of the offending agent
- Excessive fluid can interfere with tissue function
Serous Inflammation:
Morphology:
Gross Appearance
- Watery fluid within body cavities or tissues
Serous Inflammation:
Morphology:
Histological
Homogenous pink fluid
Catarrhal inflammation:
- Presence of large amounts of mucus
- Causes include:
- mild upper respiratory viral infections
- mild irritants
- Effects include:
- Protection of mucosal surfaces
- Dilution of the offending agent
Catarrhal Inflammation:
Morphology:
Gross
- Clear, slimy film that covers a mucosal surface
- this can appear as shreds and clumps when it is partially dehydrated
Catarrhal Inflammation:
Morphology:
Histological
- Pale, blue material that covers mucosal epithelium
- mucus producing cells are increased in size and number
Fibrinous Inflammation
- Presence of a large amount of fibrin
- Casuses include:
- bacterial infections
- Certain viral infections
- Burns
- Effects include
- protection of underlying tissues
- Prevention of blood loss
- A scaffold for subsequent formation of fibrous tissue
Fibrinous Inflammation:
Morphology:
Gross
Yellowish adhesive material that can occur as a granular covering over a tissue, to thick sheets clumps or fine
Fibrinous Inflammation:
Morphology:
Histological
Fibrillar, web-like eosinophilic material
Purulent Inflammation
- Presence of large numbers of neutrophils
- Causes include:
- Certain types of bacteria
- Certain chemiccal irritants
- Effects include
- Defense against infectious agents
- Production of pro-inflammatory agents/toxins
- Sometimes, interference with tissue functions
Purulent Inflammation:
Morphology:
Gross
Viscous to watery, cream-colored materail on mucosal surfaces or within tissues
Purulent Inflammation:
Morphology
Histological
Large numbers of neutrophils are present, often accompanied by fibrin and inflammatory debris
Purulent Inflamamtion:
Abscess
- An abscess is a localized and confined accumulation of neutrophils and liquefied debris
- represents a failure of acute inflammation to remove the inflammatory stimulus
- Chronic lesions
- mature abscesses can take several weeks to form
- It has a fibrous capsule
- initially the capsule is very thin, but can thicken over time
- Walled off from normal adjacent tissue
- Can act as a space occupying mass and interfere with tissue/organ function
Hemorrhagic Inflammation
- Presence of large amounts of hemorrhage at an inflammatory site
- Causes include:
- Agents that cause vascular injury
- highly virulent infections agents
- Certain chemicals
- Agents that cause vascular injury
- Effects include:
- typically arises quickly
- Often associated with more severe inflammation
Hemorrhagic Inflammation:
Morphology:
Gross
The inflamed mucosa or tissue is deep red and associated exudate is red-tinged
Hemorrhagic Inflammation:
Morphology:
Histological
Large numbers of erythrocytes are present in the inflammatory region
Eosinophilic Inflammation
- Presence of Large numbers of eosinophils
- Causes include:
- Hypersensitivity reactions
- Parasitic Infections
- Effects Include:
- Mediates local or systemic hypersensitivity reactions
Eosinofilic Inflammation:
Morphology:
Gross
Affected tissue may have a gray to greenish gray appearance
Eosinophilic Inflammation:
Morphology:
Histological
Affected tissue contains large numbers of eosinophils
Lymphocytic Inflammation:
- Presence of large numbers of lymphocytes
- Causes include:
- certain viral infections
- Chronic bacterial and fungal infections
- Immunological reactions
- Effects include:
- Immunological response to antigens
- Important component of chronic inflammation
Lymphocytic Inflammation:
Morphology:
Gross
Not often evident grossly, but may give affected tissue a whitish-appearance
Lymphocytic Inflammation:
Morphology:
Histological
Numerous lymphocytes are present either indivdually or in nodular aggregates
Granulomatous Inflammation
- Presence of large numbers of macrophages
- Causes include
- persistent bacterial infections
- most fungi
- certain parasites
- foreign bodies
- Effects include:
- associated with chornic, difficult to manage inflammatory agents
- Can form solid masses and interfere with tissue function
Granulomatous Inflammation:
Morphology:
Gross
This can occur as diffuse thickening of an affected tissue, or the formation of firm nodules or masses
Granulomatous inflammation:
Morphology:
Histological
Numerous macrophages are present along with cells derived from macrophages, and lymphocytes and plasma cells
Granuloma Morphology
- Typical granulomas consist of:
- a central zone of caseous necrosis
- A zone of epithelioid macrophages and giant cells
- Zone of lymphocytes
- Outer zone of fibroblasts and collagen
- There are many variation depending on the age of the granuloma and the inciting stimulus
- some lack a central necrotic core
- Some have minimal fibrosis around their border
Response of the Tissue:
Alterative chages
necrotizing
ulcerative
atrophic
fibrosing
Response of the Tissue
Proliferative changes
hyperplastic
hypertrophic
