01 introduction to pathology
TRANSCRIPT
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Introduction to
PathologyLourdes T. M. Dominguez, MD, DPSPFaculty of PharmacyUniversity of Santo Tomas
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Definition of Terms
Pathology
Greekpathos = pain and logos = study
Also calledpathobiology
It is a form of science and a branch of medicine
that involves testing samples and diagnosing
physical health problems from their evidence.
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Definition of Terms
Pathology
Study of the nature, causes, processes,
development, consequences of disease and the
modifications in cellular function and changes incellular structure produced in any cell, organ, or
part of the body by disease.
Pathology addresses 4 components of disease:
1. Cause/etiology2. Mechanisms of development (pathogenesis)
3. Structural alterations of cells (morphologic changes)
4. Consequences of changes (clinical manifestations)
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Definition of Terms
**The microscope is an
important factor in detecting
tissue changes, especially in
the examination of small
sections of tissue removed for
diagnosis; for this reason real
progress in pathology was not
made until the 19th century.
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Pathogenesis The development of a diseased or morbid
condition.
Pathologist A physician who interprets and diagnoses the
changes cause by disease in the body.
A physician who interprets and diagnoses thechanges cause by disease in the body.
Definition of Terms
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Pathologist A specialist physician expert in the origin and
development of disease and the microscopicanalysis of body tissues.
A doctor who studies all aspects of disease withan emphasis on the nature, causes, anddevelopment of abnormal conditions, as well asthe structural and functional changes that result
from disease processes. The laboratory expert behind the front-line clinical
team.
Definition of Terms
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Medical Technologist
An Allied Health Professional who performs
diagnostic analysis on human blood, urine, and
body fluids such as cerebral spinal fluid,peritoneal, pericardial, and synovial, as well as
other specimens such as stool and sputum.
Definition of Terms
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Autopsy
In Greek, a seeing for oneself: auto-, auto- +
opsis, sight
Also called necropsy,postmortem examination. Systematic examination of a cadaver for study or
for determining the cause of death.
Uses many methodical procedures to determine
the etiology and pathogenesis of diseases, forepidemiologic purposes, for establishment of
genetic causes, for family counsel, and for
improvement of safety standards for the living.
Definition of Terms
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Biopsy
Examination of cells or tissues from a living organism.
Excised material may be studied in order to
diagnose disease or to confirm findings ofnormality.
Incisions may be made and total or partial lesions
removed in the form of wedges or cylindrical
pieces, or scrapings of the surface membranes of
internal organs may be collected.
Tumors are routinely biopsied in order to
determine whether they are benign or malignant.
Definition of Terms
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I. Gross Pathology & Microscopic
Pathology
II. Anatomic Pathology
III. Clinical Pathology
Divisions of Pathology
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I. Gross Pathology & MicroscopicPathology
Gross Pathology
The recognition of disease based on macroscopic
examination of surgical specimens generated at
the time of surgery or at autopsy.
Microscopic Pathology
The recognition of disease based on microscopicexamination of surgical specimens generated at
the time of surgery or at autopsy.
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Anatomic Pathology
The study of changes in the function, structure, or
appearance of organs or tissues, including
postmortem examinations and the study of biopsy
specimens.
Sections:
A. Surgical Pathology
B.A
utopsy PathologyC. Exfoliative Cytology
II. Anatomic Pathology
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A. Surgical Pathology
The pathology of disease processes that are
surgically accessible for diagnosis or treatment.
The study of gross appearance and histology oftissues removed during surgery.
II. Anatomic Pathology
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B.Autopsy Pathology
It involves the external and internal examination
of a human body after death.
The study of gross appearance and histology oftissues removedfollowing death.
The most important task is to identify the cause of
death.
II. Anatomic Pathology
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C. Exfoliative Cytology
Also known as cytopathology
The study of desquamated cells from a body
surface or lesion to detect malignancy. Cells are collected from lesions, sputum, urine,
secretions or any body fluid accumulation.
The cells may be collected through aspiration,
brushing, washing, smear and scraping.
II. Anatomic Pathology
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Clinical Pathology
The branch of general pathology directed to the
diagnosis and monitoring of diseases through the
examination of blood, body fluids, secretions, and
tissue biopsy specimens for chemical,
morphological, microbiological, and
immunological abnormalities.
III. Clinical Pathology
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Identifies and interprets changes that characterizedifferent diseases or disease states in cells,
tissues, and fluids of the body
Monitor the metabolic status of patients under
medical therapy
Decipher specific markers that characterize
individual patients for purposes such as
transfusion or transplantation
III. Clinical Pathology
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A. Clinical Chemistry (incl. Toxicology)B. Hematology
C. Clinical Microscopy
D. Blood Banking (incl. Transfusion Medicine)
E. MicrobiologyF. Clinical Immunology & Serology
III. Clinical Pathology
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A.ClinicalChemistry (incl. Toxicology)
Division of clinical pathology involving
biochemical analysis performed on human
samples (blood, fluids, tissues) outside the body
(in vitro).
Substances which could be assayed include sugars,
lipids, proteins, antibodies, enzymes, hormones,
vitamins, metals, electrolytes.
III. Clinical Pathology
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A.ClinicalChemistry (incl. Toxicology)
Methods employed are spectrophotometry,
fluorometry, enzyme kinetics, enzyme
immunoassay (EIA), electrophoresis, flame
photometry, ion selective electrodes, HPLC, gaschromatography, mass spectrometry, and atomic
absorption spectrometry.
Most instruments are however almost completely
automated.
III. Clinical Pathology
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A.ClinicalChemistry (incl. Toxicology)
In the toxicology subsection, the blood, urine, and
other body fluids are analyzed for the presence of
drugs and substances of abuse.
An equally important application of toxicology
testing is to measure the blood levels of
therapeutic drugs to assure that concentrations
are adequate to treat the disease but not so high
as to cause toxic side effects.
III. Clinical Pathology
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B. Hematology
Involves assessment of the cellular elements (red
blood cells, white blood cells, and platelets) in
blood samples.
The blood cells may be enumerated, either by
manual cell-counting techniques or by automated
particle-sensing and particle-sizing instruments.
III. Clinical Pathology
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B. Hematology
Microscopic observation of stained peripheral
blood smear is limited to assessing the
morphology of atypical cells as they may appear in
cases of dysplastic syndromes and overt
leukemias.
III. Clinical Pathology
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B. Hematology
Pathologists specialized in this field i.e.
hematopathologists also examine bone marrow
and lymph node biopsies. They are expert in the
field of anemia, leukemia and lymphomas.
In complicated cases where the diagnosis of a
hematological disorder cannot be made by study
of the peripheral blood smear, a bone marrow
examination may be necessary.
III. Clinical Pathology
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C.ClinicalMicroscopy Deals with the processing and analysis of body
fluids such as urine, stool, CSF etc.
The laboratory identification of parasitesinvolves detecting microscopically the typicalforms in body fluids and secretions
III. Clinical Pathology
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D.BloodBanking (incl. TransfusionMedicine)
Also called Immunohematology
Deals with collection, storage, compatibility andsafety of blood and its various components for thepurpose of human transfusion.
III. Clinical Pathology
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D.BloodBanking (incl. TransfusionMedicine)
Specific tasks include:
1. Blood collection after donor screening
2. Chemical and serologic tests to excludetransmission of infective diseases
3. Component preparation and proper storage
4. Blood typing, screening for antibodies againstred cells and compatibility testing
5. Immunophenotyping of blood cells
6. Investigation into transfusion reactions
III. Clinical Pathology
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D.BloodBanking (incl. TransfusionMedicine)
Specific tasks include:
7. Apheresis & Plasmapheresis
A procedure where plasma or platelets can beseparated from the withdrawn blood and theformed elements (red cells and platelets).
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E.Microbiology A division of clinical pathology involved in
isolation, culture, and identification, of micro-organisms (parasites, fungi, bacteria & viruses) in
biological samples.
In addition to conventional microscopic andbiochemical methods for identification, DNA/RNA
based assays (including PCR) and immunoassaysare increasingly being used.
III. Clinical Pathology
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E.Microbiology
Subdivisions include bacteriology, parasitology,
mycology (fungi) and virology.
Presumptive identification of microbes can be
made by microscopically examining direct mounts
of an appropriate portion of the specimen or thin
smears that have been stained with one of a
variety of dyes.
Rapid presumptive diagnoses can also be made by
directly testing specimens with a variety of
immunological reagents.
III. Clinical Pathology
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E.Microbiology
Specimens are applied to the surface of a variety
of agar culture media for the purpose of
recovering in pure culture any bacterial speciesthat may be clinically significant.
Gram stains may determine the cellular
morphology and staining characteristics of the
bacteria, and a variety of rapid, direct tests can beperformed to provide an early identification.
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E.Microbiology
Bacterial identifications and antibiotic
susceptibility tests may be performed in a variety
of packaged systems.
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E.Microbiology
The laboratory identification of fungi and the
diagnosis of fungal infections is similar to that
described for the bacteria.
Specimens are inoculated on special fungal media,
the plates are incubated for periods as long as 4
weeks, and the growth of any mold or yeast is
identified morphologically and biochemically.
Nucleic acid probes are available to quickly
confirm any fungus colony suspected of being one
of the dangerous pathogens
III. Clinical Pathology
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E.Microbiology
Viruses can live only in viable cells and, for the
most part, can survive briefly outside human or
animal hosts.
Culture techniques must use embryonated eggs,
cell culture suspensions, thin cell sheets called
monolayers, or laboratory animals.
Species of viruses are identified by observing their
ability to produce certain cytopathic effects in the
cells where they are growing or to cause
recognizable diseases in laboratory animals.
III. Clinical Pathology
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F.ClinicalImmunology and Serology
The discipline in which infectious diseases are
diagnosed by detecting antibodies in serum and
other body fluids.
In practice, immunologic and serologic techniques
are used to diagnose an infectious disease when
the agent may be too difficult to recover in
culture.
III. Clinical Pathology
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The Medical Technologist's Role inthe Healthcare Process
A Medical Technologist's role in the healthcare
process is to provide accurate results in a timely
manner.
These results will ultimately be used to help makea diagnosis or monitor treatment.
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The Medical Technologist's Role inthe Healthcare Process
Observe details of cells, ova and cysts of parasiticinfections.
Test whether the blood of the donor is
compatible with the blood of patient-recipient.
Utilize special stains to identify microorganisms.
Measure substances in blood and other bodysubstance
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The Medical Technologist's Role inthe Healthcare Process
Reagent preparation
Collect specimen for study
Preparation of specimen
Quality control
Water testing
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End of Presentation