Ch 1 Intro to Pathology

Disease

Defined as a pattern of the body's response to some form of injury that causes a deviation from, or variation of, normal conditions

Pathophysiology

Defined as the physiology of altered health

Pathology

study of the structural and functional changes in cells, tissues, and organs of the body that cause or are caused by disease

Physiology

functions of the human body

Health

A state of complete physical, mental, and social well-being and not merely the absence of disease and infirmity

Etiology

Study of the cause of the disease process

Cause of a disease:

• biologic agents (bacteria, viruses)

• physical forces (trauma, burns, radiation)

• chemical agents (poisons, alcohol)

• genetic inheritance

• nutritional excesses or deficits

Majority of diseases are multifactorial:  

• Cancer

• Heart disease

• Diabetes

Idiopathic

Underlying cause is unknown

Signs

Measurable or objective manifestations

Symptoms

Feelings that the patient describes—subjective manifestations

Asymptomatic

Without subjective or objective manifestations

Diagnosis

Identification of disease process

Prognosis

Probable patient outcome

Syndrome

Linked combination of signs and symptoms

Iatrogenic

Disease caused by physician or treatment

Nosocomial infections

Infections contracted in the acute care facility

Community-acquired infections

Infections contracted in a public setting outside of the acute care facility

Congenital Conditions

Defects that are present at birth

Acquired Conditions

Caused by events that occur after birth

Pathogenesis

Explains how the disease process evolves

Morphology

Structure or form of cells or tissues

Histology

The study of the cells and extracellular matrix of body tissues

Complications

possible adverse extensions of a disease or outcomes from treatment

Sequelae

lesions or impairments that follow or are caused by a disease

Acute Disease

A disease that is severe but self-limiting.

Chronic Disease

A continuous, long-term process that may present with exacerbations and remissions.

Cardinal Signs of Inflammation

Redness (rubor), warmth (calor), swelling (tumor), pain (dolor), and loss of function.

Inflammation

Initial response of the tissue to local injury

Granulation tissue

Fibrous scar replaces destroyed tissue

Pyogenic bacteria

Thick, yellow fluid called pus (dead white cells)

Abscess

Localized, usually encapsulated, collection of fluid

Bacteremia

Potential involvement of other organs and tissues in the body by organisms invading the blood vessels

Granuloma

localized area of chronic inflammation with central necrosis, seen in tuberculosis.

Phagocytosis

The process of enzymatic digestion of dead cells and tissue during inflammation.

Subacute disease

intermediate or between acute and chronic; not as severe as an acute disease and not as prolonged as a chronic disease

Acute Inflammation

Begins after a specific injury: short duration, lasting from minutes to days, depending on the extent of injury

Subacute Inflammation

transformational period from acute to chronic which lasts from 2 to 6 weeks

Chronic Inflammation

Prolonged, dysregulated immune response that can lead to tissue damage

Inflammatory response consists of four overlapping events that occur sequentially

1. Alterations in blood flow and vascular permeability

2. Migration of circulating white blood cells (WBC) to the injured tissue

3. Phagocytosis and enzymatic digestion of dead cells and tissue

4. Repair of injury by regeneration of normal parenchymal cells or proliferation of granulation tissue and eventual scar formation

Inflammatory response event 1

Alterations in blood flow and vascular permeability

Inflammatory response event 2

Migration of circulating white blood cells (WBC) to the injured tissue

Inflammatory response event 3

Phagocytosis and enzymatic digestion of dead cells and tissue

Inflammatory response event 4

Repair of injury by regeneration of normal parenchymal cells or proliferation of granulation tissue and eventual scar formation

Causes of inflammation are classified into two main groups:

1. Exogenous inducer

2. Endogenous inducer

Exogenous inducer - Infectious factors:

bacteria, viruses, and microorganisms

Exogenous inducer - Non-infectious factors:

• frostbite

• Burn

• Allergens

• physical injury

• foreign bodies

• trauma

• ionizing radiation

• chemical/toxic compounds

• fatty acids

• toxins

• alcohol

• chemical irritants

Endogenous inducer

Signals released by tissues that are dead, damaged, malfunctioned, or stressed

Bacterial Infection

Bacteria produce toxins that damage the tissue and incite an inflammatory response

Granulomatous Inflammation

Manifests as a distinct pattern

Granulomatous Inflammation is seen in:

tuberculosis, syphilis, and sarcoidosis

Granuloma

localized area of chronic inflammation with central necrosis

Edema

Accumulation of abnormal amounts of fluid in the intercellular tissue spaces or body cavities

Localized Edema

Results from: inflammatory reaction or localized obstruction of lymphatic drainage (elephantiasis)

Generalized Edema

Pronounced swelling of subcutaneous tissues throughout the body (anasarca)

Ischemia

A decrease in blood flow below the level necessary to sustain normal cell structure and function

Ischemia - Caused by:

arterial narrowing or thrombotic/embolic occlusion (most common)

Ischemia - Common finding in:

the feet of diabetic patients leading to gangrene and foot/toe amputation

Infarct

Localized area of ischemic necrosis from occlusion of arterial supply or venous drainage May be myocardial or pulmonary

 Necrosis

Death of cells or tissue

Gangrene

Serious condition characterized by the death of body tissue secondary to infection, ischemia, or both

Dry gangrene

dehydrated ischemic tissue caused by reduction or blockage of arterial flow

Wet gangrene

caused by venous obstruction secondary to infection, has associated edema and erythema but no crepitus (cracking or popping sounds when tissue rubs together); develops sepsis and may cause death within a few days

Gas gangrene

specific type of necrotizing infection with edema, crepitus, and gas seen on radiographs

Hemorrhage

Rupture of a blood vessel caused by injury: trauma, atherosclerosis, inflammatory or neoplastic erosion of vessel wall

Hematoma

collection of blood outside of the blood vessels, usually resulting from internal hemorrhage

Hemothorax

accumulation of blood around the lung

Hemopericardium

accumulation of blood around the heart

Hemoperitoneum

accumulation of blood in the peritoneal cavity (abdomen)

Hemarthrosis

accumulation of blood within a joint

Petechiae

minimal hemorrhage into the skin, mucous membranes, or serosal surface

Purpura

larger hemorrhage into the skin, mucous membranes, or serosal surface

Ecchymosis

large (>1 cm) subcutaneous hematoma (bruise)

Atrophy

Reduction of tissue or organ due to a decrease in size and/or number of cells leading to decreased function

Disuse

decreased functional demand

Denervation

loss of innervation (nerve supply)

Loss of endocrine stimulation

loss of hormonal stimuli Inadequate nutrition

Ischemia

decreased blood flow

Disuse Atrophy

Condition that occurs when muscles are not used for an extended period

Hypoplasia

Underdevelopment or incomplete development of tissue or organ

Aplasia

Congenital failure of a tissue or organ to develop normally

Hypertrophy

An increase in the tissue or organ size due to an increase in cell size, without an increase in cell number

Hyperplasia

An increase in the tissue or organ size due to increased cell number, without an increase in cell size

Dysplasia

Loss of uniformity of individual cells and their architectural orientation

Neoplasia

Abnormal "new growth" of tissue that grows by cellular proliferation more rapidly than normal and continues to grow after the stimuli that initiated the new growth ceases

Oncology

the study of tumors and their treatment

Tumor

Swelling caused by several conditions, including inflammation and trauma; mass of cells due to overgrowth

Well differentiated tumors

grow slowly

Undifferentiated tumors

grow rapidly

Benign Neoplasia

Non-cancerous (non-malignant); lesion or tumor that does not invade or metastasize

Malignant

Neoplastic growth that invades and destroys adjacent structures

Metastasize

Malignant neoplasms that travel to distant sites

Carcinoma

Malignant neoplasm of epithelial cell origin

Anaplastic

Undifferentiated cell growth—without form (bizarre)

Sarcoma

Highly malignant tumor originating from connective tissue

Hematogenous spread

Malignant tumors that have invaded the circulatory system and travel as neoplastic emboli

Benign and malignant neoplasms are both made up of:

1. Parenchyma (organ tissue) made of proliferating neoplastic cells

2. Supporting stroma (supporting tissue) consisting of connective tissue, blood vessels, and lymphatic vessels

Adenoma

benign tumor of glandular epithelial tissue

Osteoma

benign growths of bone that typically occur in the skull or jawbone

Cystadenoma

benign tumors that form large cystic masses