Introduction to Pathology And its rule in the diagnostic process

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Introduction to Pathology And its rule in the
diagnostic process

• Dr. Atif Ali Bashir, MD Pathology
• Assistant Professor
• College of Medicine
• Majmaah University

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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.
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What is Pathology?

• Greek Pathos suffering, fate, harm logos/logia
  study or discourse
• Pathology The study of suffering.
• Involves
• study of disease processes and
• the structural and functional changes in organs
  and tissues that cause or are caused by disease.
• Explains
• The whys and hows of signs and symptoms
  manifested by patient.

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What is the Disease?

• It is the State in which an individual exhibits
  an anatomical, physiological, or biochemical
  deviation from the normal
• Disease (dis ease not at ease).

• Disease may be defined as
• an abnormal alteration of structure or function
  in any part of the body.

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Classification of Diseases

• Developmental genetic, congenital.
• Acquired
• Inflammatory Trauma, infections, immune, etc.
• Neoplastic tumors cancers
• Degenerative ageing.
• Metabolic.
• Iatrogenic Drug induced.

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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.
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Branches of Pathology

• General Pathology
• Systemic Pathology
• Gross Pathology
• Cellular Pathology
• Surgical Pathology
• Clinical Pathology
• Immunopathology

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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.

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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
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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.

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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.

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Etiology Study of the cause of a disease"

• An etiologic agent
• is the factor (bacterium, virus, etc.)
  responsible for lesions or a disease state.
• Predisposing Causes of Disease
• Factors which make an individual more susceptible
  to a disease (damp weather, poor ventilation,
  etc.)
• Exciting Causes of Disease
• Factors which are directly responsible for a
  disease (hypoxia, chemical agents. etc.). 

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Etiology

• One etiologic agent several diseases,
  as smoking.

• Several etiologic agents one disease,
  as diabetes .

• One etiologic agent
  - one disease, as Malaria.

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Etiology What is the cause?

• Environmental agents
• Physical
• Chemical
• Nutritional
• Infections
• Immunological
• Psychological
• Genetic Factors
• Age
• Genes

Multifactorial As Diabetes, Hypertension
Cancer
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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.
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Morphology Structural Changes

• Structural changes in disease.
• Tumor in a cancer.
• Ulcer in an infection.
• Atrophy in dementia.
• Gross Microscopic.

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Clinical Symptoms Signs

• Clinical symptoms are the patients complain
  usually by its own words.

• Clinical signs are seen only in the living
  individual.
• Functional evidence of disease which can be
  determined objectively or by the observer"
  (fever, tenderness, increased respiratory rate,
  etc.)

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• Necropsy Gross examination of the animal cadaver
  by systematic dissection in order to evaluate any
  abnormal changes (lesions) that may be present.
• Autopsy Synonymous to necropsy in human medicine
• Biopsy Removal and examination of tissue
  obtained from the living body
• Euthanasia Intentional putting to death of an
  individual with an incurable or painful disease
  by employing humane means

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prognosis

• Expected outcome of the disease, It is the
  clinician's estimate of the severity and possible
  result of a disease. 

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I hear, I forget I see, I remember I do, I
understand Chinese Proverb..