Difference between revisions of "General Pathology"

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#REDIRECT[[:Category:General Pathology]]
+
==An Introduction to General Pathology==
 +
 
 +
* The term '''pathology''' is derived from:
 +
** '''Pathos''', or suffering
 +
** '''Logos''', or reasoning/logic.
 +
* Pathology is defined as the study of disease including:
 +
** '''Aetiology''' - causal factor(s)
 +
** '''Pathogenesis''' - the development of the disease within the body.
 +
** '''Lesions''' - the observable structural changes in the tissues and fluids of the body.
 +
** '''Pathophysiology''' - the functional changes in diseased tissues.
 +
** '''Sequel''' - the consequences of the disease in the body.
 +
** '''Remote effects''' - the effect of disease in one tissue on other tissues in the body.
 +
 
 +
===Lesions===
 +
 
 +
* Lesions are the abnormalities or changes seen in living tissues due to disease.
 +
* Observed in
 +
** The live animal
 +
** Tissues surgically removed from the live animal
 +
*** Biopsy/ excision
 +
** Animals soon after death
 +
*** Necropsy, post-mortem examination.
 +
 
 +
====Decription of Lesions====
 +
 
 +
* Descriptions of lesions is very important
 +
* Whole organs, tissues or individual lesions are described under headings such as
 +
*# Size
 +
*# Shape
 +
*# Colour
 +
*# Weight
 +
*#* Generally in relation to body weight
 +
*# Texture and Consistency
 +
*# Appearance of the cut surface
 +
*# Contents of hollow organs
 +
*# Position, relationships and effects on adjacent tissues
 +
 
 +
*'''See [[General Pathology - Recognition and Description of Lesions|Recognition and Description of Lesions]]'''
 +
 
 +
===Disease===
 +
 
 +
====Definition and Type====
 +
 
 +
* '''Disease''' is  a definite morbid (illness producing) process, having a characteristic train of symptoms or signs.
 +
** May affect the whole body or any of its parts.
 +
** The disease's aetiology, pathology and prognosis may be known or unknown.
 +
* There are two main categories of disease.
 +
*# '''Acute'''
 +
*#* Characterised by sudden onset and short duration.
 +
*#* The outcome of acute disease may be:
 +
*#** Death
 +
*#** Resolution due to host defence response or clinical therapy
 +
*#** Progression to chronic disease
 +
*# '''Chronic'''
 +
*#* Characterised by insidious onset and protracted course.
 +
*#* The outcome of chronic disease may be:
 +
*#** Progressive destruction of tissue
 +
*#*** Compromises funtion and  endangers life,
 +
*#** The halting of the course of disease, with tissue repair by scarring.
 +
 
 +
====Factors Involved in the Development of Disease====
 +
 
 +
* There are three factors which conspire with each other to produce disease.
 +
*# '''The individual animal'''.
 +
*#* In particular, the animal's nutritional and immune status
 +
*#** This is modified by:
 +
*#*** Recent or concurrent disease
 +
*#*** Previous exposure to the agent(s) responsible
 +
*# '''The disease-causing agent(s)'''.
 +
*#* Most do not cause a uniform pattern of disease
 +
*#** Host defences are important in determining the presentation of the disease.
 +
*#* An agent's capacity to produce disease depends upon:
 +
*#** The dose
 +
*#** The virulence of the agent
 +
*#* Several agents may be involved.
 +
*#** Usually one agent debilitates, allowing others to exert a greater effect within the body
 +
*#* The presence of an agent does not necessarily mean it is the cause of the disease!
 +
*#* A pathogenic agent may be absent from the tissues, due to:
 +
*#** Clinical therapy
 +
*#** Host defence systems
 +
*# '''Environment''', for example:
 +
*#* Overcrowding of animals
 +
*#* Mixing animals from differing origins
 +
*#** Carriers are allowed to infect susceptible animals.
 +
*#*** Carriers are animals which harbour the pathogenic agent but do not show signs of disease.
 +
*#* Changes in management routine
 +
 
 +
====Types of Agents Causing Disease====
 +
 
 +
# '''Infectious organisms'''
 +
#* [[Viruses|Viruses]]
 +
#* [[Bacteria|Bacteria]]
 +
#* [[Fungi|Fungi]]
 +
#* [[Parasites|Parasites]]
 +
# '''Physical'''
 +
#* Trauma
 +
#* Pressure
 +
#* Heat
 +
#* Cold
 +
#* Radiation
 +
# '''Chemical'''
 +
#* Toxic organic and inorganic substances
 +
#* Toxins produced by infectious organisms
 +
# '''Nutritional'''
 +
#* Deficiencies of vitamins and trace elements
 +
#* Excess vitamins and trace elements
 +
# '''Genetic defects'''
 +
#* There is a very wide range of potential defects.
 +
#** Some are incompatible with life
 +
#** Others affect specific systems within the body
 +
 
 +
====Aspects of Disease====
 +
 
 +
* There are many aspects of a disease that must be considered in order to understand it in full.
 +
*# '''Incidence'''
 +
*#* How much of the disease is present?
 +
*#* Where is the disease found?
 +
*#* In what species is the disease seen?
 +
*# '''Aetiology'''
 +
*#* Causal agent(s)
 +
*#* Predisposing factors
 +
*# '''Transmission'''
 +
*#* How is the disease spread between individuals?
 +
*#* Is the disease zoonotic?
 +
*# '''Pathogenesis'''
 +
*#* How the causal agent(s) exert their effect within the body.
 +
*# '''Diagnosis'''
 +
*#* History
 +
*#* Clinical findings
 +
*#** Clinical examination
 +
*#** Clinical pathology
 +
*#* Biopsy or post-mortem examination
 +
*# '''Prognosis and Treatment'''
 +
*# '''Control and Prevention'''
 +
*#* The ideal situation
 +
 
 +
====Post-Mortem Examination====
 +
 
 +
* Post-mortem examination (PME) investigates the observable structural changes in the animal.
 +
* Information relating to the disease withing the body or specific tissue is gained from PME.
 +
** This includes information on the disease's
 +
*** Aetiology (cause).
 +
*** Pathogenesis (development).
 +
* Several types of [[General Pathology - Post-Mortem Change|changes]] are encountered at post-mortem examination.
 +
*# Those due to the '''disease'''
 +
*#* Lesions
 +
*# Those occuring '''immediately prior to death'''
 +
*#* [[General Pathology - Post-Mortem Change#Agonal Changes|Agonal]]
 +
*# Those occuring '''after death'''
 +
*#* Post-mortem
 +
 
 +
====Techniques Involved in Pathological Examination====
 +
 
 +
* '''Fluid examination'''
 +
** E.g. blood, urine, discharges from orifices and so on.
 +
* '''Cytology'''
 +
** Examination of cells in smears, aspirates and fluids.
 +
* '''Necropsy'''
 +
** Visual examination of the gross changes in the dead body.
 +
* '''Histopathology'''
 +
** Microscopic examination of:
 +
*** Tissues selected from the dead body after necropsy.
 +
*** Biopsy/excision materials from lesions in the living animal.
 +
* '''Histochemistry'''
 +
** Microscopic visualisation of enzymatic activity in tissues.
 +
* '''Immunological methods'''
 +
** Specific antibody activity can be detected in tissues and fluids.
 +
*** Examination of serum can show prior exposure to a particular infectious agent (i.e. specifice antibodies).
 +
** Specific antigens can be detected in tissues.
 +
*** When linked to a marking agent (e.g. a fluorescent dye), an antibody can localise its antigen in the tissue.
 +
* '''Electronmicroscopy'''
 +
** Electronmicrosopcy shows fine detail of the surfaces or internal structures of cells.
 +
* '''Bacteriology/ Virology/ Parasitology'''
 +
** These techniques allow the isolation and identification of pathogenic bacteria, viruses and parasites.
 +
* '''Toxicology'''
 +
** Analysis of tissues for particular poisons and toxins.
 +
 
 +
==General Pathology - Contents==
 +
 
 +
===[[General Pathology - Recognition and Description of Lesions|Recognition and Description of Lesions]]===
 +
 
 +
===[[General Pathology - Degenerations and Infiltrations|Degenerations and Infiltrations]]===
 +
 
 +
===[[General Pathology - Necrosis|Necrosis]]===
 +
 
 +
===[[General Pathology - Post-Mortem Change|Post-Mortem Change]]===
 +
 
 +
===[[General Pathology - Pigmentation and Calcification|Pigmentation and Calcification]]===
 +
 
 +
 
 +
 
 +
==Circulatory Disorders==
 +
 
 +
===Introduction====
 +
 
 +
====Venous Congestion and Hyperaemia====
 +
 
 +
====Oedema====
 +
 
 +
 
 +
====Dehydration====
 +
 
 +
====Shock====
 +
 
 +
====Haemorrhage====
 +
=====Rhexis=====
 +
=====Diapedesis=====
 +
 
 +
====Haemostasis====
 +
 
 +
====Thrombus====
 +
=====Causes=====
 +
=====Evolution=====
 +
=====Embolism=====
 +
=====Post Mortem Clots=====
 +
 
 +
====Disseminated Intravascular Coagulation====
 +
 
 +
==Inflammation==
 +
 
 +
===Cardinal Signs===
 +
 
 +
===Causes===
 +
 
 +
===Acute===
 +
====Introduction====
 +
====Sequence of Events====
 +
====Fluids====
 +
=====Serous=====
 +
=====Catarrhal=====
 +
=====Fibrinous=====
 +
=====Diptheritic=====
 +
=====Haemorrhagic=====
 +
=====Purulent=====
 +
=====Functions of Exudate=====
 +
=====Sequel to Exudation=====
 +
====Cells====
 +
=====Neutrophils=====
 +
=====Eosinophils=====
 +
=====Mast Cells=====
 +
=====Basophils=====
 +
 
 +
===Chronic===
 +
====Introduction====
 +
====Cells====
 +
=====Macrophages=====
 +
=====Lymphocytes=====
 +
====Types====
 +
=====Granulomatous Inflammation=====
 +
=====Granulation Tissue=====
 +
=====Lymphocytic Inflammation=====
 +
 
 +
===Changes in Inflammatory Cells Circulating in Blood===
 +
====Neutrophilia====
 +
====Neutopenia====
 +
====Eosinophilia====
 +
====Eosinopenia====
 +
====Lymphocytosis====
 +
====Lymphopenia====
 +
====Plasma Cells====
 +
====Monocytosis====
 +
 
 +
===Role of The Lymph Node in Inflammation===
 +
 
 +
===Healing and Repair===
 +
====Introduction====
 +
====Repair====
 +
=====Regeneration=====
 +
=====Replacement=====
 +
====In Particular Tissues====
 +
=====Skin=====
 +
======First Intention======
 +
======Second Intention======
 +
=====Bones=====
 +
=====Respiratory Tract=====
 +
=====Alimentary Tract=====
 +
=====Urinary Tract=====
 +
=====Genital Tract=====
 +
=====Central Nervous System=====
 +
 
 +
==Disorders of Cell Growth==
 +
 
 +
===Atrophy===
 +
===Hypertrophy===
 +
===Hypoplasia===
 +
===Hyperplasia===
 +
===Metaplasia===
 +
===Dysplasia===
 +
===Anaplasia===
 +
===Neoplasia===
 +
====Benign Tumours====
 +
====Malignant Tumours====
 +
====Aetiology of Tumours====
 +
====Phases of Tumour Growth====
 +
====Tumour Classification and Nomenclature====
 +
 
 +
 
 +
==Congenital and neonatal disease==
 +
 
 +
===Congenital===
 +
====Causes====
 +
====Malformations====
 +
=====Cyclops=====
 +
=====Bulldog Calf=====
 +
=====Cleft Palate=====
 +
=====Cystic Kidney=====
 +
=====Spina Bifida=====
 +
=====Hydrocephalus=====
 +
=====Cerebellar Hypoplasia=====
 +
=====Skeletal Malformations=====
 +
=====Skin Defects=====
 +
=====Muscular Defects=====
 +
=====Cardiac Defects=====
 +
=====Sexual Organ Malformation=====
 +
=====Metabolic Diseases=====

Revision as of 12:16, 21 August 2007

An Introduction to General Pathology

  • The term pathology is derived from:
    • Pathos, or suffering
    • Logos, or reasoning/logic.
  • Pathology is defined as the study of disease including:
    • Aetiology - causal factor(s)
    • Pathogenesis - the development of the disease within the body.
    • Lesions - the observable structural changes in the tissues and fluids of the body.
    • Pathophysiology - the functional changes in diseased tissues.
    • Sequel - the consequences of the disease in the body.
    • Remote effects - the effect of disease in one tissue on other tissues in the body.

Lesions

  • Lesions are the abnormalities or changes seen in living tissues due to disease.
  • Observed in
    • The live animal
    • Tissues surgically removed from the live animal
      • Biopsy/ excision
    • Animals soon after death
      • Necropsy, post-mortem examination.

Decription of Lesions

  • Descriptions of lesions is very important
  • Whole organs, tissues or individual lesions are described under headings such as
    1. Size
    2. Shape
    3. Colour
    4. Weight
      • Generally in relation to body weight
    5. Texture and Consistency
    6. Appearance of the cut surface
    7. Contents of hollow organs
    8. Position, relationships and effects on adjacent tissues

Disease

Definition and Type

  • Disease is a definite morbid (illness producing) process, having a characteristic train of symptoms or signs.
    • May affect the whole body or any of its parts.
    • The disease's aetiology, pathology and prognosis may be known or unknown.
  • There are two main categories of disease.
    1. Acute
      • Characterised by sudden onset and short duration.
      • The outcome of acute disease may be:
        • Death
        • Resolution due to host defence response or clinical therapy
        • Progression to chronic disease
    2. Chronic
      • Characterised by insidious onset and protracted course.
      • The outcome of chronic disease may be:
        • Progressive destruction of tissue
          • Compromises funtion and endangers life,
        • The halting of the course of disease, with tissue repair by scarring.

Factors Involved in the Development of Disease

  • There are three factors which conspire with each other to produce disease.
    1. The individual animal.
      • In particular, the animal's nutritional and immune status
        • This is modified by:
          • Recent or concurrent disease
          • Previous exposure to the agent(s) responsible
    2. The disease-causing agent(s).
      • Most do not cause a uniform pattern of disease
        • Host defences are important in determining the presentation of the disease.
      • An agent's capacity to produce disease depends upon:
        • The dose
        • The virulence of the agent
      • Several agents may be involved.
        • Usually one agent debilitates, allowing others to exert a greater effect within the body
      • The presence of an agent does not necessarily mean it is the cause of the disease!
      • A pathogenic agent may be absent from the tissues, due to:
        • Clinical therapy
        • Host defence systems
    3. Environment, for example:
      • Overcrowding of animals
      • Mixing animals from differing origins
        • Carriers are allowed to infect susceptible animals.
          • Carriers are animals which harbour the pathogenic agent but do not show signs of disease.
      • Changes in management routine

Types of Agents Causing Disease

  1. Infectious organisms
  2. Physical
    • Trauma
    • Pressure
    • Heat
    • Cold
    • Radiation
  3. Chemical
    • Toxic organic and inorganic substances
    • Toxins produced by infectious organisms
  4. Nutritional
    • Deficiencies of vitamins and trace elements
    • Excess vitamins and trace elements
  5. Genetic defects
    • There is a very wide range of potential defects.
      • Some are incompatible with life
      • Others affect specific systems within the body

Aspects of Disease

  • There are many aspects of a disease that must be considered in order to understand it in full.
    1. Incidence
      • How much of the disease is present?
      • Where is the disease found?
      • In what species is the disease seen?
    2. Aetiology
      • Causal agent(s)
      • Predisposing factors
    3. Transmission
      • How is the disease spread between individuals?
      • Is the disease zoonotic?
    4. Pathogenesis
      • How the causal agent(s) exert their effect within the body.
    5. Diagnosis
      • History
      • Clinical findings
        • Clinical examination
        • Clinical pathology
      • Biopsy or post-mortem examination
    6. Prognosis and Treatment
    7. Control and Prevention
      • The ideal situation

Post-Mortem Examination

  • Post-mortem examination (PME) investigates the observable structural changes in the animal.
  • Information relating to the disease withing the body or specific tissue is gained from PME.
    • This includes information on the disease's
      • Aetiology (cause).
      • Pathogenesis (development).
  • Several types of changes are encountered at post-mortem examination.
    1. Those due to the disease
      • Lesions
    2. Those occuring immediately prior to death
    3. Those occuring after death
      • Post-mortem

Techniques Involved in Pathological Examination

  • Fluid examination
    • E.g. blood, urine, discharges from orifices and so on.
  • Cytology
    • Examination of cells in smears, aspirates and fluids.
  • Necropsy
    • Visual examination of the gross changes in the dead body.
  • Histopathology
    • Microscopic examination of:
      • Tissues selected from the dead body after necropsy.
      • Biopsy/excision materials from lesions in the living animal.
  • Histochemistry
    • Microscopic visualisation of enzymatic activity in tissues.
  • Immunological methods
    • Specific antibody activity can be detected in tissues and fluids.
      • Examination of serum can show prior exposure to a particular infectious agent (i.e. specifice antibodies).
    • Specific antigens can be detected in tissues.
      • When linked to a marking agent (e.g. a fluorescent dye), an antibody can localise its antigen in the tissue.
  • Electronmicroscopy
    • Electronmicrosopcy shows fine detail of the surfaces or internal structures of cells.
  • Bacteriology/ Virology/ Parasitology
    • These techniques allow the isolation and identification of pathogenic bacteria, viruses and parasites.
  • Toxicology
    • Analysis of tissues for particular poisons and toxins.

General Pathology - Contents

Recognition and Description of Lesions

Degenerations and Infiltrations

Necrosis

Post-Mortem Change

Pigmentation and Calcification

Circulatory Disorders

Introduction=

Venous Congestion and Hyperaemia

Oedema

Dehydration

Shock

Haemorrhage

Rhexis
Diapedesis

Haemostasis

Thrombus

Causes
Evolution
Embolism
Post Mortem Clots

Disseminated Intravascular Coagulation

Inflammation

Cardinal Signs

Causes

Acute

Introduction

Sequence of Events

Fluids

Serous
Catarrhal
Fibrinous
Diptheritic
Haemorrhagic
Purulent
Functions of Exudate
Sequel to Exudation

Cells

Neutrophils
Eosinophils
Mast Cells
Basophils

Chronic

Introduction

Cells

Macrophages
Lymphocytes

Types

Granulomatous Inflammation
Granulation Tissue
Lymphocytic Inflammation

Changes in Inflammatory Cells Circulating in Blood

Neutrophilia

Neutopenia

Eosinophilia

Eosinopenia

Lymphocytosis

Lymphopenia

Plasma Cells

Monocytosis

Role of The Lymph Node in Inflammation

Healing and Repair

Introduction

Repair

Regeneration
Replacement

In Particular Tissues

Skin
First Intention
Second Intention
Bones
Respiratory Tract
Alimentary Tract
Urinary Tract
Genital Tract
Central Nervous System

Disorders of Cell Growth

Atrophy

Hypertrophy

Hypoplasia

Hyperplasia

Metaplasia

Dysplasia

Anaplasia

Neoplasia

Benign Tumours

Malignant Tumours

Aetiology of Tumours

Phases of Tumour Growth

Tumour Classification and Nomenclature

Congenital and neonatal disease

Congenital

Causes

Malformations

Cyclops
Bulldog Calf
Cleft Palate
Cystic Kidney
Spina Bifida
Hydrocephalus
Cerebellar Hypoplasia
Skeletal Malformations
Skin Defects
Muscular Defects
Cardiac Defects
Sexual Organ Malformation
Metabolic Diseases
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