1.intro of pathology

Dr. Bikesh Pandey

Introduction of PathologyIntroduction of Pathology

?Basic medicine

Clinical medicine

Pathology is “What, Why and How” of diseases

Medical Knowledge:Medical Knowledge:

• Epidemiology – Where & When…outbreaks

• Etiology – What is the cause?

• Pathogenesis - Evolution of disease.

• Morphology - Structural Changes

• Clinical Significance – Patient signs and symptoms are related to underlying pathology

• Management - What treatment is suitable for this patient?

• Prognosis - Is he going to recover or die soon?

• Prevention

Pathology

One etiologic One etiologic agent agent several several diseases, as diseases, as smoking.smoking.

Disease

Several etiologic Several etiologic agents one agents one disease, as cancer .disease, as cancer .

Disease Disease

DiseaseDisease

One etiologic One etiologic agent agent - - one disease, as one disease, as Malaria.Malaria.

EtiologyEtiology

PathogenesisPathogenesis

The sequence of events in the response of the cells or tissues to the etiologic agent, from the initial stimulus to the ultimate expression of the disease.

CELLS Response to injurious agentCELLS Response to injurious agent

Either :Either :

ADAPTATIONADAPTATION

SUSTAINS REVERSIBLE INJURYSUSTAINS REVERSIBLE INJURY

SUFFERING IRREVERSIBLE INJURY SUFFERING IRREVERSIBLE INJURY

DEATHDEATH

PathogenesisPathogenesis

MorphologyMorphology

• Many diseases shows structural changes.

• Eg: Tumor,

Neurofibromatosis Leprosy

Elephantitis

Clinical Symptoms & SignsClinical Symptoms & Signs

Clinical signsClinical signs : : can be observed only by can be observed only by

doctors by doing physical examination doctors by doing physical examination

through the help of refined medical through the help of refined medical

knowledge.knowledge.

ClinicalClinical symptoms symptoms : : are are the patient’s the patient’s

complain usually by its own words as pain.complain usually by its own words as pain.

Indrawn chest, sign of pneumonia

Lyme diseaseBull’s eye

Pathology Pathology

Pathos = suffering; logos = studyPathos = suffering; logos = study

Pathology = “The study of suffering”Pathology = “The study of suffering”

"scientific study of the molecular, cellular,

tissue, or organ system response to

injurious agents and its course"

PathologyPathology

“Is the foundation of medical science and practice.

Without pathology, the practice of medicine would be reduced to myths and

folklore”

Cellular Injury Cellular Injury

Genetic

Monocyte

Physic barrier

Homeostasis

Immunoreaction

Inflammation

Coagulation

Detoxification

Radiation

Microbe

StressorPyrogen

Teratologic

Carcinogen

Trauma

Process of damage and anti-damage

Cellular Injury & AdaptationCellular Injury & Adaptation

Normal cell is always in a dynamic state of ------------------------“Homeostasis”

Normal physiologic stress : Normal homeostasis – no issue

Stress - Adaptation, e.g. hypertrophy, atrophy

Stress - Cell Injury

Reversible Irreversible Cell Death

Cellular AdaptationsCellular Adaptations

• It refers to changes made by a cell in response to adverse environmental changes.

•  The adaptation may be:

– Physiological (normal)

– Pathological (abnormal)

Cellular AdaptationsCellular Adaptations• Growth adaptationsGrowth adaptations:

– Hyperplasia / Hypoplasia

– Hypertrophy / Atrophy

– Metaplasia

– Dysplasia

– Neoplasia

• DegenerationsDegenerations: (Accumulations)

– Hydropic change (cell swelling/edema) -- Fatty Change

– Hyaline Change -- Pigment storage – wear & tear..

AtrophyAtrophy• Decrease in cell size and functional ability.

• Etiology :

– Physiologic:Physiologic:

• Developmental – e.g.. thymus

• Uterus following parturition

– PathologicalPathological

• Decreased workload / Disuse (Immobilization)

• Ischemia , eg: atherosclerosis

• Lack of hormonal / neural stimulation

• Malnutrition

• Aging

Normal Brain surfaceNormal Brain surface

Cerebral atrophy - Alzheimer's diseaseCerebral atrophy - Alzheimer's disease

This is cerebral atrophy in a patient with Alzheimer's disease. The gyri are narrowed and the sulci widened toward to frontal pole.

HypertrophyHypertrophy• It is an increase in cell size and functional ability by

gain of intracellular components.

• With the involvement of a sufficient number of cells, an entire organ can become hypertrophic.

• Hypertrophy is caused by:

– Increased functional demand

• Physiological – muscle hypertrophy in weight lifter

• Pathological – cardiac muscle in hypertension

– Endocrine stimulations

• Puberty – GH , androgens / estrogens

• Lactating breast – prolactin and estrogen

Left ventricle hypertrophy - Left ventricle hypertrophy - HypertensionHypertension

This is cardiac hypertrophy involving the left ventricle. The number of myocardial fibers does not increase, but their size can increase in response to an increased workload, leading to the marked thickening of the left ventricle in this patient with systemic hypertension.

HypertrophyHypertrophy

Hypertrophy sometimes can reach a limit beyond which degenerative changes and

organ failure can occur.

HyperplasiaHyperplasia

• It is an increase in the number of cells in a tissue or organ.

• Can occur only with cells capable of synthesizing DNA and dividing (e.g., epithelial, hematopoietic)

• Some cell types are unable to exhibit hyperplasia (eg: nerve, cardiac, skeletal muscle)

HyperplasiaHyperplasia

• Etiology of hyperplasia:

– Physiological causes

• Compensatory – after partial hepatectomy

• Hormonal – breast development during puberty

• Antigenic stimulation – lymphoid hyperplasia

– Pathological hyperplasia

– Endometrial hyperplasia

– Prostatic hyperplasia of aging

BPH - Benign Prostatic HyperplasiaBPH - Benign Prostatic Hyperplasia

This is an example of prostatic hyperplasia. The normal prostate is about 3 to 4 cm in diameter. The number of prostatic glands, as well as the stroma, has increased. The pattern of increase here is not uniform, but nodular. This increase is in response to hormonal manipulation.

Endometrial HyperplasiaEndometrial HyperplasiaThe prominent folds of endometrium in this uterus opened to reveal the endometrial cavity are an example of hyperplasia.

Cells forming both the endometrial glands and the stroma have increased in number. As a result, the size of the endometrium has increased. This increase is physiologic with a normal menstrual cycle.

HyperplasiaHyperplasia

• Hypertrophy and hyperplasia can occur together.

• Hyperplasia is often a predisposing condition to neoplasia.

MetaplasiaMetaplasia• Metaplasia is a “reversible” change in which one adult

cell type is replaced by another adult cell type.

• Metaplasia is a cellular adaptation in which indigenous cells are replaced by cells that are better suited to tolerate a specific abnormal environment.

• Because of metaplasia, normal protective mechanisms, which it was meant for, may be lost.

• Persistence of irritation that result in metaplasia often

lead to neoplasia.

Lung- Metaplasia in smokerLung- Metaplasia in smoker

Metaplasia of laryngeal respiratory epithelium has occurred here in a smoker. The chronic irritation has led to an exchanging of one type of epithelium (the normal pseudostratified cilliated columnar epithelium at the right) for another (the more resilient squamous epithelium at the left).

May lead to neoplasia

SMOKING KILLS

Barretts esophagus - metaplasiaBarretts esophagus - metaplasia

Metaplasia of esophageal squamous mucosa has occurred here, with gastric type columnar mucosa at the left.

DysplasiaDysplasia• An abnormal proliferationof cells characterized by

changes in cellular shape, size, and organization.

• Dysplasia is not a cancer but may progress to cancer

• AKA preneoplastic lesions.

• E.g. Cervical dysplasia

• By some professors, Dysplasia is not considered as a true adaptation; rather, it is thought to be related to hyperplasia and is sometimes called "atypical hyperplasia."

Cervical dysplasiaCervical dysplasia

This is dysplasia. The normal squamous epithelium at the left transforms to a disorderly growth pattern at the right. This is farther down the road toward neoplasia.

“ medical doctor knows everything does nothing”

“surgeon does everything knows nothing”

“Pathologist knows everything and does everything”

But it’s already to let

See you in next class…….