Fundamentals of Pathophysiology

The Basis of Disease in the Human Being

Pathology 101 Under normal conditions, the body tries to

maintain internal stability Homeostasis

When homeostasis is not maintained, disease ensues

Pathologists study these diseases There are two specializations within the field

Anatomic Pathology: performs autopsies to determine cause of death

Clinical Pathology: review lab specimens to determine evidence of abnormal tissue or the presence of chemicals

Pathogenesis The sequence of events that leads from

Cause of disease to structural and functional abnormalities How the disease manifests itself Resolution or recovery of the disease

Ex.: Common Cold Cause: exposure and inoculation of the cold virus Incubation time: virus multiplies Manifestation: host begins to have signs and symptoms Recovery: return to the previous state of health

Usually explained in terms of time Acute disease: disease of sudden onset which runs a

severe but short course Chronic: long-term illness, possibly reoccurring

Risk Factors: Age

Newborns Elderly Immature immune

system Liver enzymes

lacking Fewer nutritional

reserves Less body fat to

insulate against cold

Decrease in immune function

Decline in homeostasis mechanisms

Depression, isolation and malnutrition

Risk Factors: Sex Some diseases are

more prone to strike one gender than the other Men or more prone to

develop gout Women are more

likely to develop osteoporosis

Risk Factors: Misc. Genetic Makeup

Diabetes, asthma, migraines Stress

Increases production of corticosteroids, which decrease immune system function

Lifestyle Personal habits: alcohol consumption, sexual

practice, smoking Occupation

Exposure to loud noises, pollutants, repetitive movements

Risk Factors: Misc., cont. Preexisting illnesses

Illnesses can lower the body’s resistance and make individuals more susceptible to other diseases

Chronic illness interferes with the proper function of some body systems; therefore complicating disease

Environmental exposure Prolonged exposure to cold or heat can lower the

body’s resistance Exposure to allergens Long-term exposure to sunlight Long-term exposure to occupational chemicals

Disease Categories: Structural Disease Involves physical and

biochemical changes within the cells

Structural changes in cells are initiated by two types of agents Exogenous – those that are

external Ex.: trauma, chemical injury,

and microbial infections Endogenous – those that are

internal and diseases that are a result of abnormal metabolism

Ex.: vascular insufficiency, immunological/autoimmune reactions

Disease Categories: Structural Disease The hallmark

characteristic of structural disease is the lesion. A widely used term to

describe many types of cellular changes that result in tissue abnormalities (cuts, fractures, masses, etc.).

Primarily detected by observation with the naked eye or with a microscope.

Disease Categories: Functional Diseases Diseases in which the

onset begins without the presence of any lesion

The basic change is physiological Referred to as a

pathophysiological change.

Examples Tension headaches and

functional bowel syndrome

Effects of Structural and Functional DiseasesDisease Type of Disease Nature of

Manifestation

Common cold Structural: viral infection

Structural: runny nose and sneezing

Tension Headaches Functional: muscle spasms

Functional: pain

Benign tumor that produces mass

Structural: tumor Structural: mass

Exogenous obesity caused by craving food

Functional: hunger Structural: obesity

Cancer of the esophagus

Structural: cancer Functional: inability to eat

Causes of Disease: Infectious Agents Caused by invasion

and colonization of pathogenic microorganisms

Examples of pathogenic infection Fungal infection Bacterial infection Viral infection

Causes of Disease: Immunologic Hypersensitivity

Overreaction by the immune system

Immune Deficiency Underreaction by the

immune system AIDS

Autoimmune Destruction of one’s

own tissues by antibodies produced by one’s own immune system

Causes of Disease: Nutritional Diseases created by

insufficient resources for the body

Protein deficiency Difficulty in healing or

formation of new body tissue; decrease in antibody production

Vitamin or mineral deficiencies May lead to interference

in biochemical reactions of metabolism

Obesity

Causes of Disease: Metabolic An upset in the

biochemical reactions that govern body processes or metabolism

Sub-classified as nutritional Upset is often

connected to carbohydrate, fat, or protein metabolism

Causes of Disease: Genetic Inherited or

hereditary diseases Due to transmission

of defective gene(s) or chromosome(s) from one or both parents

Ex.: diabetes, Down Syndrome, hemophilia, cleft lip

Causes of Disease: Congenital A defect in fetal

development that may create a functional (physiologic) or structural (physical) abnormality which presents itself at birth

May be Genetic Exposure to chemicals,

drugs, or viruses during the pregnancy

Spontaneous event

Causes of Disease: Trauma A physical force that

mechanically disrupts the structure of the body (and therefore, disrupts body function)

Generally referred to as injuries

Ex.: bruises, abrasions, cuts, fractures, burns, etc.

Disease Process: Manifestation How a disease “presents or shows itself.” Also called clinical presentation Includes both signs and symptoms. Signs

Objective physical observations as noted by the person who examines the patient

Referred to as physical or physical examination Ex.: temperature, blood pressure, respiratory rate,

abnormal heart sounds, mass, enlarged organs, edema Symptoms

Patient’s awareness of abnormalities or discomfort Not measurable and are based on the patient’s subjective

perceptions Ex.: pain, nausea, weakness, fatigue, and dizziness

Disease Process: Manifestation During the physical, the health professional

may use techniques such as Inspection (looking at or observing areas of the

body) Auscultation (use of a stethoscope to listen to

body cavities) Palpation (feeling lightly or pressing firmly on

internal organs or structures) Percussion (tapping various body areas to

produce a vibrating sound indicative of air, fluid, size of organ, etc.)

Olfaction (using smell to note abnormalities)

Disease Process: Care of the Patient Involves three major steps Obtaining a history

Determines patient’s symptoms Review any past or present medical problems that

might relate Performing a physical examination of the

patient Laboratory tests, and radiologic and clinical

procedures Detects chemical and physiologic abnormalities to

aid in establishing the diagnosis

Disease Process: Etiology Study of causes of a disease Idiopathic

Cause of the disease has never been discovered One may also refer to an idiopathic disease as having

“unknown etiology.” Latrogenic disease (-iatro = medicine, physician)

Disease arose as a result of a prescribed treatment Ex.: Immunosuppression and/or anemia as a result of

chemotherapy Healthcare Acquired

Disease acquired from a clinical setting Ex.: A child develops a cold after being exposed to

other sick children at the pediatrician’s office

Disease Process: Diagnosis The process of

assigning a name to a patient’s condition Needed to determine

the treatment and potential outcome of a disease

Syndromes Clusters of findings

with more than one disease

Disease Process: Treatment Should be as precise as possible in order to

attempt a cure. Treatment interventions may include exercise,

nutritional modifications, physical therapy, medications, surgery, and education.

There are three types of treatment Supportive Therapy

Includes rest, optimal nutrition, fluids, and possibly antibiotics to prevent a secondary infection while the immune system is recovering

Disease Process: Treatment Palliative Therapy

Not a healing therapy Provides relief from signs and symptoms of a

disease Ex.: steroids, pain relievers, possible surgery Used for terminal illness and other serious chromic

conditions for which there is no cure Preventive Therapy

Care given to prevent disease Ex.: mammograms, BP screenings, routine dental

care

Disease Process: Prognosis Predicted or

expected outcome of the disease

Often listed as Good: full recovery Guarded: full recovery

may or may not occur Poor: not expected to

recover

Misc. Terminology Communicable Disease

Disease transmitted from one person to another Epidemic

Disease that affects many people in a given region at the same time

Endemic Disease that appears to be native to a specific area or region

Localized Disease Disease confined to one area of the body

Systemic Disease Disease that spreads throughout the body or to many system

Asymptomatic No noticeable symptoms

Self-Limiting Disease Disease that does not require treatment to be cured