0- Intro to Patho and Infectious Diseases

PPT Wk 1

Health

Complete physical, mental, and social well-being, and not only the lack of disease or infirmity. (World Health Organization)​

Pathophysiology

Branch of science that studies structural and functional changes in tissues and organs that lead to disease.

Pathology

Study of changes to cells and tissues associated with disease.​

Disease

• Deviation from the normal state of health or wellness leading to a disruption of homeostasis

• biologic or psychologic alteration that results in a malfunction of a body organ or system

Homeostasis

The regulation and stabilization of a normal internal body environment.​

Disability

any physical, mental, cognitive, or developmental condition that impairs, interferes with, or limits an individual's ability to engage in specific tasks or actions, or to participate in common daily activities and interactions.​

What does ICF stand for?

International Classification of Functioning, Disability, and Health

Physiological functional capacity

• describes a person's level of performance and assesses their ability to perform daily physical tasks, and how easily these can be performed.

• Declines with aging

Illness

sickness or deviation from a healthy state

Acute Illness

Illness or disease that has a relatively rapid onset and short duration.

Subacute Illness

how long a disease has been present between acute and chronic, but no set time

Chronic Illness

includes one or more of the following characteristics: permanent impairment or disability, residual physical or cognitive disability, and the need for special rehab and/or long-term medical management

ICF qualifiers

• 0 – no problem (0-4%)​

• 1 – mild problem (5-25%)​

• 2 – moderate problem (25-49%)​

• 3 – severe problem (50-95%)​

• 4 – complete problem (96-100%)​

Why is it important to study pathophysiology as a PTA?

• To understand the complexity of diseases

• The study of disease raises ethical, legal, and social issues

• A good way to know how to treat the whole person

Congenital and hereditary (disease classification)

Caused by developmental disturbances such as chromosomal and genetic abnormalities, intrauterine injury, or a combo of environmental and genetic factors. (Ex: hemophilia, congenital heart disease caused by Rubella)​

Chronic (disease classification)

Cause degeneration of various body parts, often as a result of aging. (Ex: types of arthritis and arteriosclerosis)​

Disabling (disease classification)

Can result in inability to work. (Ex: arthritis, back pain, cancer, depression, diabetes, heart disease)​

Inflammatory (disease classification)

Body reacts to injury or harmful agents with inflammation. Causes include various microorganisms, allergic reactions, hypersensitivity states, and autoimmune states. (Ex: pneumonia, sore throat, hay fever)​

Metabolic (disease classification)

Cause disturbances in normal metabolic processes. (Ex: diabetes, thyroid conditions, endocrine gland disturbances, fluid and electrolyte imbalances)​

Neoplastic (disease classification)

Characterized by abnormal cell growth and lead to various benign and malignant tumors.​

What are some risk factors for disease?

• Age

• Gender

• Environment

• Heredity

• Lifestyle

• Physical activity level

• Socioeconomic status

Psychological factors (of health and illness)

PTAs can assist with stress and must look for indicators such as:

• Appearance

• Behavior

• Communication

• Judgment

• Mood

• Thought Process

How can a PTA help a patient with stress?

• Allowing for self-regulation and self-efficacy

• Assessing a pt’s readiness to change (before changing lifestyle or exercise)

• Promoting wellness and strategies to improve self-efficacy

• Educating on stress-relieving strategies such as diaphragmatic breathing

• Provide feedback to exercise attempts

• Develop coping mechanisms

Psychological aspects of health and illness: functional symptoms

• Occur without significant physical dysfunction of brain cells

• Ex. Depression, considered to be psychologic consequence of a general medical condition such as MI

Psychological aspects of health and illness: organic symptoms

• Can be caused by abnormal physiologic changes in brain tissue

• Occur as a direct physiological consequence of medication or medical condition

• Ex: end-stage liver disease, develops hepatic encephalopathy when toxic substances in the blood such as ammonia reach the brain

Mitochondria

Powerhouse of the cell (produces energy - ATP)

Endoplasmic reticulum

Transport system within the cell

Ribosomes

Protein synthesis (turns info from RNA to energy)

Golgi apparatus

• Carbohydrate synthesis (changes proteins from carbs)

• Produces lysosomes

Cytoplasm

• Contains hyaloplasm

• Composed mainly of water

Plasma membrane

• Surrounds the cytoplasm of each cell

• Protects the cell

Nucleus

• Brain of the cell

• Stores DNA

• Coordinates the cell’s activities including growth, intermediary, metabolism, protein synthesis, and reproduction

Nucleolus

House of RNA synthesis

Lysosomes

Digestion of wastes in the cell

What is cellular adaptation?

• Used by cells to protect themselves

• Not the same as a normal cell yet is not an injured cell either

• Types: atrophy, dysplasia, hypertrophy, hyperplasia, metaplasia, neoplasia

Atrophy

• A decrease or shrinkage in cellular size resulting reduced tissue mass (organ size)

• If enough cells shrink, an organ can become atrophic

• Classified as pathologic or physiologic

• Most common in skeletal muscle, heart, brain, and secondary sex organs

What are some causes of atrophy?

• Insufficient nutrition

• Reduced tissue use

• Aging

• Decreased hormonal or neurologic stimulation

Dysplasia

• Abnormal development and maturation of body cells that may exhibit abnormal size, shape, and relationship to other cells; including loss of cell organization

• Often have large nuclei and inc mitosis

• May result in the formation of a tumor (cancerous cells)

• A common site is the epithelium covering the cervix

• Range from mild to severe or low to high grade

• May be reversible

What causes dysplasia?

• Chronic infection

• Irritation

• Precancerous cells

*Common test to detect it is a Pap smear

Hypertrophy

• An increase in cell and organ size

• Protein accumulated in the cellular components

• Can be pathologic or physiologic

• Mostly affects the kidneys and heart

What causes hypertrophy?

• Consistent exercise (inc skeletal muscle mass)

Hyperplasia

• Inc in the # of cells due to an increased rate of cellular division (and tissue mass)

• Occurs to nerve, skeletal muscle myocardial, and lens of the eye cells

• Commonly occurs alongside hypertrophy and can potentially inc risk of cancer

• Ex. callus

Metaplasia

• Reversible replacement of a single mature cell type by another cell type - change in a cell’s morphology (makeup) and function

What causes metaplasia?

• Stem cell “reprogramming” in epithelial and connective tissue

• Lack of vitamin A

• Smoking

How does cell injury occur?

• Happens when a cell cannot maintain homeostasis because of harmful stimuli

• Can be reversible or irreversible

What are ways a cell can be injured (or killed)?

• Environmental irritants or hormonal irritants

• Changes in metabolic processes

• Altered cell pH

• Cell membrane damage

• Reduced levels of ATP

• Intracellular calcium and loss of calcium

• Oxygen and oxygen-derived free radicals (lack of O2)

*Cells usually recover when stimulus is removed that caused injury

What are common forms of cell injury?

• Chemical agents

• Hypoxia

• Free radicals

• Infectious agents

• Immunologic reactions

• Physical an mechanical factors

• Genetics

• Nutrition

What is the PTAs role in cell injury?

• Aerobic exercise to increase the circulation and delivery of oxygen to all cells

• Low intensity exercises with a heart rate above 50%

How do you calculate target heart rate (for aerobic exercise)?

• 1.) 220 - patient age = predicted max HR

• 2.) Max HR - resting HR = HR reserve (HRR)

• 3.) HRR x 50% + RHR = aerobic target HR

• Ex. 220 - 50 (years old) = 170 (max HR) , 170 - 80 (resting HR) = 90 (HR reserve), 90 × 50% = 45 + 80 (resting HR) = 125 (target HR)

Eukaryotes

Organisms containing a membrane-bound nucleus​

Prokaryotes

nucleus is not separated​

Viruses

Smallest pathogens, no organized cellular structure

Parasites (protozoa, helminths, arthropods)

Cause infections and disease in other animals which then transmit them to humans.​

Resident flora

• Indigenous or "normal" flora – consists of microorganisms (primarily bacteria) that live on the skin and inside most areas of the body.​

• Ex. in the body are streptococci, hemophilus, staphylococc

What are areas in the body that are sterile (free from microorganisms or resident flora)?

• Blood

• CSF

• Lungs

• Stomach

• Uterus

• Fallopian tubes

• Ovaries

• Bladder

• Kidneys

What is the chain of infection?

1.) Infectious agent

2.) Reservoir of source

3.) Portal of exit from the reservoir of source

4.) Modes of transmission

5.) Portal of entry to host

6.) Susceptible host

Direct transmission

• Touching of an infectious lesion, sexual intercourse, contact with bodily fluids, crossing of the placental barrier to the fetus

• Ex. treponema pallidum (causes syphilis and fetal defects or death)

Indirect transmission

• Via contaminated body part, contaminated food, or a fomite (inanimate object such as bed linens)

Droplet transmission

• Oral or respiratory; pathogens are expelled from the body and inhaled into or contacted by others

• Ex. Legionnaire’s disease, various skin infections, tuberculosis

Vector-borne transmission

• When an insect or animal transmits an infection

• Ex. Malaria, Lyme’s disease, encephalitis, West Nile virus

Nosocomial infections

• Infections that occur in healthcare facilities

• Ex. UTI, diarrhea, pneumonia, surgical wound infections, C-diff

What are ways that the host resists disease?

• Skin

• Mucous membranes

• Body secretions (tears, stomach acid)

• Inflammatory responses

• Interferon production

What are factors that decrease host resistance?

• Age (very young or old)

• Genetic predispositions

• Immunodeficiencies

• Poor nutrition

• Inadequate hygiene

• Drug or alcohol abuse

What is considered standard precaution?

• The assumption that all blood, bodily fluids, and wastes are infected (or could be)

• Includes:

  • Hand hygiene

  • Standards for handling sharps, spills, disinfections, soiled linens, cleaning up facilities

Cells parts

Necrosis

• AKA cellular dissolution (cell and tissue death)

• A result of cellular death and autolysis (cellular self-digestion)

• Stages include pyknosis and karyolysis

Coagulative necrosis

Caused by severe ischemia or hypoxia due to chemical injury

Liquefactive necrosis

Usually results from ischemic injury to neurons and glial cells in the brain, sometimes caused by bacterial infection

Causeos necrosis

Usually results from tuberculous pulmonary infection, with tissues resembling soft, clumped cheese

Fat necrosis

Usually results from powerful lipase enzymes that break down triglycerides to release free fatty acids; the tissue appears opaque and chalk white

Gangrenous necrosis (gangrene)

Usually results from severe hypoxic injury due to arteriosclerosis of major arteries; may lead to wet or dry gangrene

Ischemia

• Lack of blood flow (and therefore oxygen) to tissue due constricted blood vessels or other blockages

• The most common cause of cell damage and tissue necrosis

Exogenous

Occurring from a source outside the body

Endogenous

Occurring from within the body