Pathologic Patterns of Inflammation

Local excavation of the surface of an organ/tissue

Pathogenesis

Produced by sloughing of encrotic surface or tissue

Occurs only if inflammatory necrotic area exist on/near the surface

Morphology

Ulcerated surface covered in a layer of necrotic debris

Necrotic Slough

Acute inflammatory exudate of fibrin and neutrophils

Zone of granulation tissue beneath the slough

Localised collection of purulent inflammatory tissue

form of suppurative inflammation

Lung Abcess

Cerebral Abcess

Etiology

Deep seeding of pyogenic bactieria into tissue

Pathogenesis

Inflammation fails to destroy or remove pyogenic bacteria

Area of infection contained by fibrin deposition and processes of organization

Can become Chronic

Abscess encapsulated by granulation and fibrous tissue

Neutrophils replaced by mononuclear leukocytes as chronic inflammation starts

Morphology

Central region of necrotic leukocytes and cell debris

Liquifactive Necrosis

Surrounded by zone of

Fibrin

inflammatory infiltrate

Vascular dilation

Serous Inflammation

Accumulation of fluid with low plasma protein and cell content

Commonly seen in burns and some viral infections (herpes)

Skin Blister

Suppurative Inflammation

Etiology

Pyogenic Bacteria

E.g. Acute appendicitis

Bacterial meningitis

Morphology

Densely cellular exudates of neutrophils, cellular debris and edema

Fibrinous Inflammation

Etiology

Occurs when exudate has a high plasma protein concentration

Associated with injury to membrane lined cavities

Pericarditis

Peritonitis

Moephology

Eosiniphilic meshwork of threads or amorphous coagulum

Few neutrophils present

Distinct pattern of specific Chronic inflammation

Predominant cell type is an activated macrophage with epithelial-like appearance

Etiology

Specific Bacterial infxn

TB

Leprousy

Brucellosis

Autoimmune Dz

Crohn Dz

Sarcoidosis

Foreign Body Rxn

Beryliosis

Pathogenesis

Immune Granuloma

Caused by insoluble particles that induce cell mediated immune response

Macrophages engulf particles and present to T lymphocytes

Activation of T lymphocytes release cytokines

IL-2 activates more T cells and perpetuates response

IFNy transforms macrophages into epithelioid and giant cells

Foreign Body Granuloma

Forms when material too large to be phagocytosed by a single macrophage

Eiptheloid and giant cells encompass the FB

Morphology

Granuloma

Aggregation epithelioid macrophages

Surrounded by collar of mononuclear leukocytes

Caseating Granuloma

Develop necrosis in central area

Amorphous eosinophilic central zone

TB nodule

Syphilitic Gumma