Unit 1: Introduction to Pathophysiology
PN 1080
Pathophysiology

Pathophysiology
 Patho = disease of cell and tissue
 Physiology = function of the body
Pathophysiology=
 The study of functional or physiologic
changes in the body that happen as a
result of disease processes

What you need to know for each
disease studied……
The normal A&P
for the system the
disease affects
Classification of
disease
Etiology (Causes)
and Risk Factors
Signs and
symptoms
Diagnostic tests Pathophysiology
Complications Treatment

Homeostasis
• Homeostasis—the maintenance of a
relatively stable internal environment
regardless of external changes
• When homeostasis is maintained,
good health is generally maintained.
• When homeostasis is not maintained,
disease may develop.
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Prevention of
Disease
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Has become a primary focus in health care
• Maintaining routine vaccination
programs (primary prevention)
• Participation in screening
programs (secondary prevention)
• Community health programs
• Regular routine doctor visits
• Chronic pain management or
patient support groups (tertiary
prevention)
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How do we
arrive at
evidence-
based
treatment and
knowledge for
each disease?
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Stage
3
Stage 3
• Clinical trials
• Involving a large number of patients with the
disease or risk of the disease
• “double blind studies"
Stage
2
Stage 2
• Small number of human subjects
Stage
1
Stage 1
• “basic science”
• Identification of technology to be used
• Work done in the laboratory
• Might require animal or cell/tissue cultures

Medical
History
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Current and prior illnesses
Allergies
Hospitalizations
Treatment
Specific difficulties
• Prescription
• Nonprescription
• Herbal items, including food supplements
Any type of therapy or drugs

New
Developments
and Trends
• Constant updating of information and knowledge
• Improved diagnostic tests
• Development of more effective drugs
• New technologies
• Extensive research in efforts to prevent, control, or
cure many disorders
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Basic
Terminology
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Gross level
• Organ or system level
Microscopic level
• Cellular level
Biopsy
• Excision of small amounts of living
tissue
Autopsy
• Examination of the body and organs
after death

Disease
Process
• Diagnosis
• Identification of a basic disease
• Evaluation of signs and symptoms
• Laboratory tests
• Etiology
• Causative factors in a particular disease
• Congenital defects
• Inherited or genetic disorders
• Microorganisms
• Immunologic dysfunctions
• Degenerative changes
• Malignancy
• Metabolic, nutritional problems
• Trauma, burns, environmental factors
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Causes of Disease
•Cause of disease is unknown.
Idiopathic
•Error/treatment/procedure may cause the disease.
Iatrogenic
•Age, gender, inherited factors, environment etc.
Predisposing factors
•Preserve health; prevent spread of disease
Prophylaxis
•Vaccinations; dietary/lifestyle modifications; prevention
of potentially harmful activities etc.
Prevention
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Characteristics of Disease
• Pathogenesis
• Development of the disease
• Onset of disease
• Sudden/acute
• Insidious: gradual, vague or mild signs
• Acute disease
• Short-term, develops quickly
• High fever, severe pain etc.
• Chronic disease
• Develops gradually
• Milder symptoms, often intermitted with acute episodes
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Characteristics of Disease
• Subclinical state
• Pathologic changes, no obvious manifestations
• Latent state
• No symptoms or clinical signs evident
• In infectious diseases: incubation period
• Prodromal period
• Early development of the disease
• Signs are nonspecific or absent
• Manifestations
• Clinical evidence with signs and symptoms
• Local: at site of the problem
• Systemic: general indicators of illness, i.e. fever
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Characteristics of Disease
Signs
Objective
indicators of
disease
Symptoms
Subjective
feelings
Lesions
Specific local
change in the
tissue
Syndrome
Collection of
signs and
symptoms
Diagnostic
tests
Various
laboratory
tests
Appropriate to
manifestations
and medical
history
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Characteristics of Disease
• Remissions and exacerbations
• Mark the course or progress of a disease
Remission: period which manifestations subside
Exacerbation: a worsening of severity
• Precipitating factor
• Condition that triggers an acute episode
• Complications
• New secondary or additional problems
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Characteristics of Disease
• Therapy
• Measures to promote recovery/slow progress
• Sequelae
• Potential unwanted outcomes
• Convalescence or rehabilitation
• Period of recovery and return to healthy state
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Disease Prognosis
Morbidity
• Disease rates within a group
Mortality
• Relative number of deaths resulting from the disease
Autopsy
• Postmortem examination
• Tracking the pattern or occurrence of disease
• Major data collection centers: WHO and CDC
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CDC Epidemiology Game

Disease
Prognosis
•Occurrence of disease
•Incidence
•Number of new cases in a given
population within a given time
period
•Prevalence
•Number of new, old, or existing
cases within a given population
and time period
•Epidemics
•A higher number of expected cases
of an infectious disease occur
within an area
•Pandemic
•Involve a higher number of
infectious diseases in many regions
of the globe
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Disease Prognosis
Communicable diseases
Infectious disease that can spread from one
person to another
Notifiable or reportable diseases
Must be reported by the physician to
designated authorities
Authority varies with local jurisdiction.
Required diseases to be reported may
change over time
Reporting is intended to prevent further
spread of the disease.
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Medical
Interventions
• Interventions that a
physician may do, or
order that will help to
diagnose and treat
the condition
• Medical interventions
NEED a doctor's order
• Ex: Blood tests,
medications,
diagnostic imaging,
and physiotherapy.
• (Gould & Dyer, 2011)
Nursing
Interventions
• Nursing interventions do
not need a physician's
order
• These interventions meet
the unmet needs of the
patient
• Nursing interventions are
patient focused
• Use the nursing process
to guide interventions
• Holistic and comfort
needs

Cellular
Adaptations
• Atrophy
• Decrease in the size of
cells
• Results in reduced
tissue mass.
• Hypertrophy
• Increase in cell size
• Results in
enlarged tissue
mass.
• Hyperplasia
• Increased number of
cells
• Results in
enlarged tissue
mass.
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Cellular
Adaptations
•Metaplasia
• Mature cell type is replaced by a
different mature cell type.
•Dysplasia
• Cells vary in size and shape within a
tissue.
•Anaplasia
• Undifferentiated cells, with variable
nuclear and cell structures
•Neoplasia
• “New growth”―commonly called tumor
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Abnormal Cell Growth Patterns
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Cell
Damage
Cells can be damaged through:
◦ Ischemia (*most common
cause)
◦ Physical agents
◦ Mechanical damage
◦ Chemicals
◦ Microorganisms: bacteria /
viruses / parasites
◦ Abnormal metabolites
◦ Nutritional deficits
◦ Imbalance of fluids and
electrolytes

Cell
Damage
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• Refers to programmed cell death
• Normal occurrence in the body
Apoptosis
• Deficit of oxygen in the cells
Ischemia
• Reduced oxygen in tissues
• Nutritional deficits
Hypoxia
• Results in lysis causing nearby
inflammation.
Pyroptosis

Cell Damage
•Physical damage
• Excessive heat or cold
• Radiation exposure
•Mechanical damage
• Pressure or tearing of tissue
•Chemical toxins
• Exogenous: from environment
• Endogenous: from inside the body
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Cell Damage
Microorganisms
Bacteria and viruses, for
example
Abnormal metabolites
Genetic disorders
Inborn errors of metabolism
Altered metabolism
Imbalance of fluids or electrolytes
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Ischemia
●Decreased blood supply
to an organ or tissue
causes insufficient
oxygen to the cells which
interferes with cellular
metabolism.
●What cells have higher
demands for oxygen?

Hypoxia
 Reduced oxygen
in the tissue
 Interferes with
energy (ATP)
production in the
cell
 Loss of cell
functions
 Anaerobic
metabolism
 Deficit of other
essential
nutrients

Necrosis
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Necrosis: Dying cells cause further cell damage
due to cellular disintegration
Liquefaction necrosis
•Dead cells liquefy because of release of cell enzymes
Coagulative necrosis
•Cell proteins are altered or denatured―coagulation
Fat necrosis
•Fatty tissue broken down into fatty acids
Caseous necrosis
•Form of coagulation necrosis
•Thick, yellowish, “cheesy” substance forms

Necrosis
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• Area of dead cells as a
result of oxygen
deprivation
Infarction
• Area of necrotic tissue
that has been invaded by
bacteria
Gangrene

Liquefaction Necrosis in the Brain
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Coagulative Necrosis of the Kidney
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Fat Necrosis in the Mesentery
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Dry Gangrene of the Toe
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