Transcript Document

Introduction to Pathology
By
Dr. Gehan Mohamed
Dr. Abdelaty Shawky
* Pathology: is the science which studies the
nature of the disease.
Pathology Classification
1. General pathology:
– The study of general reactions of cells and
tissues to insults and injuries that are basic to all
disease processes.
2. Systemic pathology:
– The study of specific disease processes or
reactions as they affect particular organs or
organ systems e.g. CVS, CNS, GIT…..etc.
Applied pathology
1. Anatomic pathology:
a. Necropsy pathology
b. Surgical pathology
c. Cytopathology
2. Clinical pathology.
3. Forensic pathology.
1. Anatomic Pathology:
– Making diagnosis by examining tissues.
1. Necropsy pathology:
– Examination of tissues excised from cadavers in an
effort to establish the cause of death.
– This is called “autopsy”.
2. Surgical pathology:
– Examination of tissues excised from living patients in
an effort to establish a specific diagnosis.
– This is called “biopsy”.
3. Cytopathology:
– The microscpocic study of exfoliated cells within body
fluids.
2. Clinical pathology:
– Analysis of various specimens (whole blood, serum,
plasma, urine, stool, CSF, sputum, etc.) from patients
to facilitate diagnosis, direct therapeutic approach
and monitor therapy.
3. Forensic pathology:
– Subspecialty dealing with medicolegal investigation
of death.
Biopsy
- Examination of tissues from the living body to
determine the cause of a disease.
a. Closed biopsy (needle or core biopsy):
– The pathologist or clinician put a needle into the
mass to obtain a bit of tissue.
– Usually won’t give you enough material.
b. Open biopsy (incisional biopsy):
- An incision was made to obtain a larger mass of
tissue.
c. Excisional biopsy:
- Excision of the whole mass for diagnosis.
Needle or core biopsy
Excisional biopsy
FNAC = Fine Needle Aspiration Cytology
• A thin core needle is used to obtain a few cells
from a mass lesion.
• Used for:
– Superficial mass
– Deep mass lesions (with help of CT/USG)
FNAC
The Disease:
The structural and functional changes in organs
and tissues due to exposure to an irritant
(causative agent of the disease).
* Classification of Diseases:
A. Developmental: genetic, congenital.
B. Acquired:
1. Inflammatory .
2. Neoplastic e.g. Tumors
3. Degenerative e.g. Ageing.
4. Metabolic .
What should we know about the disease?
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Definition.
Epidemiology: Where & When.
Etiology: What is the cause?
Pathogenesis: Evolution of dis.
Morphology: Structural Changes
Complications.
Management
Prognosis
Prevention
Etiology
“Study of the cause of a disease"
a. Predisposing Causes of Disease:
Factors which make an individual more susceptible to a
disease (damp weather, poor ventilation, etc.)
b. Exciting Causes of Disease (An etiologic agent ):
Factors which are directly responsible for a disease (hypoxia,
chemical agents , virus, bacteria …. etc.).
Pathogenesis
The sequence of events in the response of
the cells or tissues to the etiologic agent,
from the initial stimulus to the ultimate
expression of the disease or simply the
mechanism of disease occurrence.
MORPHOLOGY OF THE DISEASE
1. Gross (macroscopic) changes: By naked eye
examination.
2. Histologic (microscopic) changes: By light microscope
examination.
3. Ultrastructural changes: By an electron microscope
examination.
(1). Gross appearance:
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Size.
Shape.
Weight.
Color.
Consistency.
Surface.
Edge, section.
(2). Microscopic examination:
for tissue sections fixed in formalin then stained by H&E
(hematoxylin and eosin) to be examined by light
microscope.
Fatty liver
Normal liver
Fatty liver
Hemangioma
Prognosis
• Expected outcome (fate) of the disease.
– Good prognosis: suggests recovery is likely.
– Poor prognosis: suggests permanent disability or
death.
Welcome to Pathology