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Introduction to Pathology

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Outline of Lecture:

Definition of pathology

It is the Scientific study of disease” .

“scientific study of the molecular, cellular, tissue, or organ system response to injurious agents.”

What is the Disease?

It is the State in which an individual exhibits an anatomical, physiological, or biochemical deviation from the normal”

Classification of Diseases:

Developmental – genetic, congenital.

Acquired:

*Inflammatory – Trauma, infections, immune, etc.

*Neoplastic – tumors cancers

*Degenerative – ageing.

*Metabolic.

*Iatrogenic: Drug induced.

Basic Language of Pathology

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:

Knowledge of etiology remains the backbone of:

Disease diagnosis

Understanding the nature of diseases

Treatment of diseases.

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.).

Etiology

Etiology:
What is the cause?

Environmental agents:

Physical

Chemical

Nutritional

Infections

Immunological

Psychological

Genetic Factors:

Age

Genes

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” 

Clinical Symptoms & Signs

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.)”

Prognosis

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

Pathology

Study of what is abnormal or wrong or disease…!

“Scientific Study of Disease”

Normal à Abnormal  Treat

Pathology

“Is the foundation of medical science and practice. Without pathology, the practice of medicine would be reduced to myths and folklore”

Diagnosis

What is “Diagnosis”?

The formal name(s) used to describe a patient’s disease

The process of identifying a disease based on the patient’s symptoms, the doctor’s findings, and the results of investigations and laboratory tests

What do you need to make a diagnosis?

A system of classification that supplies the necessary names, definitions, and criteria

The means to ascertain the defining characteristics of a disease in the individual patient

Past and Present….!

In the past, .. people mistook magic for medicine…!

Now people mistake medicine for magic….!

Subdivisions of clinical Pathology:

Histopathology

Cytopathology

Haematology

Microbiology

Immunology

Chemical Pathology

Genetics

Toxicology

Forensic Pathology

Histopathologist

Cytologist

Haematologist

Microbiologist

Biochemist

Geneticist

Toxicologist

Forensic Pathologist

Molecular Biologist

Learning Pathology:

General Pathology

Common changes in all tissues.

E.g.. Inflammation, cancer, ageing.

Systemic Pathology

Specific changes in organs.

E.g.. Goiter, pneumonia, breast cancer.

Study of Disease: (Pathology)

Epidemiology

Etiology – Causes

Pathogenesis – Evolution

Morphology – Structural Changes

Clinical Significance – Functional Changes

Management

Complications

Prevention

Techniques in Pathology:

Gross Pathology:

Light Microscopy

Histochemistry, Biochemical

Immunohistochemistry

Electron Microscopy

Cell Cultures, Medical Microbiology

Molecular Pathology

Sample Case:

Right neck mass

Lymphnode Biopsy

Lymphnode Biopsy

Histiocytic/Tcell NHL

Diffuse pattern – no follicles.

Large cells with moderate cytoplasm

Plenty of mitotic figures, Nuclei are vesicular prominent nucleoli

Features suggest T-cell NHL – malignant lymphoma.

Needs further marker studies for typing & management.

cancer Chemotherapy.

Pathology Summary:

Etiology:

Carcinogenesis. DNA Damage, Mutation.

Pathogenesis:

Uncontrolled cell division, tumor.

Morphology:

Enlarged lymphnodes, liver, spleen, microscopically – lymphoma cells.

Clinical Features:

Fever, Wt loss, tumor-Ln, Liver, Spleen.

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One comment

  1. hey loved the way u broke down pathology

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