Download ETIOLOGY: Cause of disease. PATHOGENESIS

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‫(وفى األرض آيات للموقنين‬
‫وفى أنفسكم أفال تبصرون )‬
‫صدق هللا العظيم‬
‫الذاريات آية ‪21‬‬
Introduction to Pathology
Dr. Abdel Monem H. Lubbad ,PhD, MD
Professor of Pathology
Faculty of Medicine
Islamic University Gaza
2016
Definition of pathology
It is the “Scientific
study of disease"
.
"scientific study of the molecular, cellular,
tissue,
or
organ
system
response
to
injurious agents."
Pathology serves as a "bridge" or "link" between the
preclinical sciences (anatomy, physiology, ……etc.) and
the courses in clinical medicine.
What is the Disease?

It is the “State in which an individual
exhibits an anatomical, physiological, or
biochemical deviation from the normal”
•Disease may be defined as :
an abnormal alteration of structure or
function in any part of the body.
Basic Language of Pathology
In order for a subject or course to
be meaningful, one should become
familiar with the basic terminology
applicable to that subject.
Pathology is the study of suffering (Latin
word ) !
– Logos = study
– Pathos= suffering
 • Etiology = Cause
 • Pathogenesis = sequence of events
 • Morphology = structural alterations in
cells and tissues
 – Gross = Changes in the tissue or organ
 – Microscopy = Changes noted under a
light microscope

Classification of Diseases:

Developmental – genetic, congenital.

Acquired:
*Inflammatory – Trauma, infections, immune,
etc.
*Neoplastic – tumors cancers
*Degenerative – ageing.
*Metabolic.
*Iatrogenic: Drug induced.
Branches of Pathology
General Pathology
 Systemic Pathology
 Gross Pathology
 Cellular Pathology
 Surgical Pathology
 Clinical Pathology
 Immunopathology

Learning Pathology:

General Pathology

Common changes in all tissues. e.g.. Inflammation,
cancer, ageing, edema, hemorrhage ….etc.

Systemic Pathology

Discussing the pathologic mechanisms in relation to
various organ systems e.g. CVS, CNS, GIT…..etc.
What should we Know About A Disease
•
•
•
•
•
•
•
•
•
Definition.
Epidemiology – Where & When.
Etiology – What is the cause?
Pathogenesis - Evolution of dis.
Morphology - Structural Changes
Functional consequences
Management
Prognosis
Prevention
Pathology focuses on 4 aspects of disease:

ETIOLOGY: Cause of disease.

PATHOGENESIS:
Mechanisms of development of disease.

MORPHOLOGY:
The structural alterations induced in cell and tissues.

FUNCTIONAL CONSEQUENCES:
Functional results of the morphologic changes, as
observed clinically.
Etiology
“Study of the cause of a disease"
Knowledge of etiology remains the backbone of:

Disease diagnosis

Understanding the nature of diseases

Treatment of diseases.
Etiology ……

An etiologic agent :
is the factor (bacterium, virus, etc.) responsible for lesions or a
disease state.
1- Predisposing Causes of Disease:
Factors which make an individual more susceptible to a disease (damp
weather, poor ventilation, smoking , etc.)
2- Exciting Causes of Disease:
Factors which are directly responsible for a disease (hypoxia, chemical
agents…. etc.).
Etiology
Disease Disease
Disease
Disease
One
etiologic agent
one disease, as
Malaria.
• Several etiologic
agents
one
disease, as diabetes .
Disease
• One etiologic
agent
several diseases,
as smoking.
Etiology:
What is the cause?

Environmental agents:
Physical
• Chemical
• Nutritional
• Infections
• Immunological
• Psychological
•

Genetic Factors:
•
•
Age
Genes
Multifactorial:
As Diabetes,
Hypertension
Cancer
pathogenesis
The sequence events in the response of the cells or
tissues to the etiologic agent, from the initial
stimulus
to
the
ultimate
expression
of
the
disease,”from the time it is initiated to its final
conclusion in recovery or death”
The core of the science of pathology —
the study the
pathogenesis of the disease.
Morphology: Structural
Changes
Structural changes in
disease.
Tumor in a cancer.
Ulcer in an infection.
Atrophy in dementia.
Gross & Microscopic.
Technique of Morphology
Gross appearance:
size, shape
weight
color
consistency
surface
edge, section
Histologic and cytologic
observation:
most common and basic formalin fixed
→ HE (hematoxylin and eosin) stained
Hemangioma of ventrical wall
Histochemistry and cytochemistry
PAS→BM
Immunohistochemistry
1. Ag-Ab specific reaction
2. Applications
(1) Location analysis
cytokeratin→cell membrane
(2) Clinical diagnosis and
distinguishing
diagnosis of tumor histogenesis
Leiomyosarcoma Actin (+)
Ultrastructural observation
TEM (transmitting electron microscope)
Filtering membrane
SEM (scanning electron
microscope)
Podocyt
e
Flow cytometry (FCM)
1. One kind of cells→quantitative
2. DNA ploidy analysis
3. Protein nucleus acid→quantitative
analysis
4. Selection of collection of cells
Molecular biology technique
1. Polymerase chain reaction (PCR)
2. DNA sequencing
3. Biochip technique
(1) Gene chip (DNA chip)
(2) Protein chip (protein
microarray)
(3) Tissue chip (tissue microarray)
Polymerase
chain
reaction
(PCR)
prognosis

Expected outcome of the disease, It is the
clinician's estimate of the severity and possible
result of a disease.
Robbins Basic Pathology . Page 1
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