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Pathology An Introduction‌.

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Man is the Architect of his life‌

Epidemiology Etiology - Causes Pathogenesis - Evolution Morphology - Structural Changes Clinical Significance – Functional Changes Management Complications Prevention


Study of Disease:

Pathology Study of what is abnormal or wrong or disease…! “Scientific Study of Disease” Normal  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

History of Pathology “animism” – Philosophies of Plato – God/devil Magic – Primitive thoughts Humors – Phlegm – excess/deficiency – c300 Abiogenesis – Spontaneous – upto c1800 Environmental – Modern – 1850 to present Genetic – Molecular pathology – 20th century

Past and Present….! In the past, .. people mistook magic for medicine…! Now people mistake medicine for magic….!

Scope of Pathology Experimental Pathology Clinical Pathology

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

Etiology: Environmental agents: – Physical – Chemical – Nutritional – Infections – Immunological – Psychological

Genetic Factors: – Age – Genes


Multifactorial Etiology: Diseases are “caused” due to internal or external factors. Multifactorial: No more “one cause to one disease”

Genetic factors affect acquired diseases and environment has profound effect on genetic diseases.

Classification of Diseases: Developmental – genetic, congenital. Inflammatory – Trauma, infections, immune, etc. Neoplastic – tumors cancers Degenerative – ageing.

Pathogenesis: “Sequence of events in the response of cells & tissues to a stimulus/pathogen” starting from the initial stimulus to the ultimate expression of disease.” Gross and microscopic Structure, Function, Chemistry & molecular mechanisms.

Morphology: Structural and associated functional changes in cells, tissues and organs that are characteristic of the disease or condition.

Clinical Significance: Functional derangements and its clinical manifestations resulting from the morphologic changes. Signs and symptoms, course and prognosis of disease depend on the morphology.

Techniques in Pathology: Gross Pathology: Light Microscopy Histochemistry, Biochemical Immunohistochemistry Electron Microscopy Cell Cultures, Medical Microbiology Molecular Pathology

Sample Case:

Clinical Details: 34 year Fijian male Neck swelling, 2-3 months, Fever, weight loss, no other lymphadenopathy Lymphnode biopsy done

Right neck mass

Lymphnode Biopsy •Diffuse tumour •Capsule

Lymphnode Biopsy •Large cells •Mitotic figures

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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