1 introduction

MID 2163PATHOLOGY

DIVISIONS OF PATHOLOGY

GENERAL PATHOLOGY

SYSTEMICPATHOLOGY

CLINICALPATHOLOGY

ANATOMIC PATHOLOGY

SURGICALPATHOLOGY

PATHOPHYSIOLOGY

General Pathology

Also called investigative pathology experimental pathology theoretical pathology

General Pathology Foundation of pathologyStudy of the mechanisms of disease –

etiology & pathogenesis The common changes in all tissues

1. INTRODUCTION TO PATHOLOGY2. CELL INJURY & ADAPTATIONS3. TISSUE INJURY4. HEALING5. HAEMODYNAMIC DISEASES6. NEOPLASIA7. INFECTIOUS & PARASITIC DISEASES

INTRODUCTION TO

PATHOLOGY

What is??

-PATHOLOGY-

“study of disease by scientific method”

pathos : suffering or disease~logos : study of

Objective of Pathology

To identify and describe the different parts of a

disease process

Disease???Abnormal variation in structure or function of

any part of body

Pathology...

Explain the disease by studying the 4 aspects of the disease:

1. Etiology2. Pathogenesis3. Morphological changes4. Functional derangement &

clinical significance

Etiologyaitia: cause

~logos: study

“study of causation or origin of disease”

EtiologyWhy things occur?Factors that produce/predispose toward a

certain disease or disorderCause of disease

– primary etiology: known– idiopathic: unknown

Help in diagnosis, understanding and treatment of disease

Etiology2 major etiological factors

– Genetic: age, genes– Acquired: infectious, environmental,

nutritional etcEtiology is followed by pathogenesis

Pathogenesispathos: disease

genesis: creation

“mechanism / development of

disease”

PathogenesisProcess of diseaseStarting from the initial stimulus to the

ultimate expression of disease− the origin & development of disease:

acute, chronic, recurrent

Gross & microscopic structure, function, chemistry and molecular mechanism

PathogenesisTypes of pathogenesis include

− Microbial infection, inflammation, malignancy & tissue breakdown

Most disease caused by multiple pathogenetical process together

− Example: cancer – multiple pathogenesisPathogensis leads to morphological changes

Morphological Changes

“structural alterations”

Morphological ChangesStructural alterations in cells or tissue

that occur following the pathologenetic mechanisms

− the characteristic of disease or condition− changes maybe specific to a disease− thus, it help the pathologist to identify &

diagnose the disease

Morphological ChangesThe changes can be seen with

● Naked eye – gross morphologic changes● Under microscope – microscopic changes

Morphological changes will lead to functional alteration and the clinical signs & symptoms of disease

Functional Derangement &

Clinical Significance

Functional Derangements

Disturbance of normal function of the organ due to the morphological changes

Determine the clinical features, course and prognosis of a disease

Clinical SignificanceClinical manifestations

● Signs● Symptoms● Prognosis

SignsObjective indication of some medical fact

or characteristic− the characteristic of disease or condition− changes maybe specific to a disease− thus, it help the pathologist to identify &

diagnose the disease

SymptomsSubjective – e.g: stomachache, lower

back pain, fatigue = can be sensed by the patient

3 main types of symptoms− Chronic : long lasting/recurrent

− Relapsing : affected by symptoms again

− Remitting : symptoms improve & sometimes fade away completely

SymptomsAsymptomatic – NO symptom

– Asymptomatic disease condition• Disease present but there ar no

symptom• e.g: Ca Breast

– Asymptomatic infection• Infected person may transmit the

diasease to others• Cause complication that unrelatede

to the infection• e.g: STD – AIDS, genital warts

PrognosisMedical term to describe the likely

outcome of an illnessComplete prognosis include expected time,

function and description of disease course

– Help to determine to attempt certain treatments or withold

Certain test for prognostic indicatorEstimators to describe prognoses =

progression-free survival, survival rate & survival time

Causes of Disease

Can be caused by environmental factors,

genetic factors or combination of the two

Environmental FactorsPhysical agentsChemicalsNutritional dificiencies & excessesInfections and infestationsImmunological factorsPsycogenic factors

Environmental FactorsPhysical agents

– Apply excess energy in any form to the body

– e.g: trauma, radiation, extreme temperature, electric power

Chemicals– Chemical agents = chemically induced

injury

– Effects = toxic to all cell (cyanide), act locally at site of application (strong acids), toxic to certain organ esp liver & kidney

Environmental FactorsNutritional dificiencies & excesses

– Dificiencies • poor supply, interference of absorption,

inefficient transport within the body or defective utilization – major class of food or essential elements

– Excess - obese

Environmental FactorsInfections and infestations

– Infected by viruses, bacteria, fungi, protozoa, metazoa

– Cell destruction directly when infection happen – virus & protozoa

– Destruction from toxins by the infecting agent – diphteria, tetanus

– General or localize effects

Environmental FactorsImmunological factors

– Abnormal immune system• Hypersensitivity reaction : exaggerated

immune response to an antigen – bronchial asthma

• Immunodificiency : increase susceptibility to different diseases – AIDS

• Autoimmunity : abnormal (exaggerated) immune reaction against self antigens - SLE

Environmental FactorsPsycogenic factors

– Mental stress imposed by condition of life

– Maybe contributory factors in some group of diseases

Genetic FactorsHereditary factors that are inherited

genetically from parentsMutation in chromosomes

Course of Disease

“the series of events in a disease incident in a patient”

The natural history of the disease

(if no intervention from other factors)

EXPOSURE

BIOLOGICALONSET

CLINICALONSET

PERMANENTDAMAGE

DEATH

Exposure – Exposure to various risk

– The causative agents

Latency period– Period between exposure and biological

onset of disease

Biological onset– Marks the initiation of disease process

– NO sign or symptom

– May remain asymptomatic or subclinical (no clinical manifestations) or may lead to overt clinical diasease

Incubation period– Variable period of time without any obvious

signs or symptoms from the time of exposure

Clinical onset of disease– Signs and symptoms become apparent

– Expression of disease may be variable in severity or in range of manifestations

Onset of permanent damageDeath

– Clinical death

– Biological death

Clinical DeathOccurs when heart stop beating – cardiac

arrestReversible transmission between life and

biological deathDefinition: period of respiratory,

circulatory and brain arrest during which initiation of resuscitation can lead to recovery

Clinical DeathSigns

– No pulse or blood pressure = completely unresponsive to the most painful stimulus

– Pupils widely dilated

– Recovery can occur with resuscitation

Biological DeathSure sign of deathSets in after clinical deathIrreversible state of cellular destructionManifest with irreversible cessation of

– circulatory and respiratory functions– all functions of the entire brain

including brainstem