Mechanisms of Disease

By: Mary Beth Vogel, BSN, RN-C

Not So Useless Facts!

• 50 million in US have HTN; @ 50% don’t know it bc it’s asymptomatic

• Cardiovascular disease is the #1 killer in the US

• CVA is the #1 cause of adult disability

• MVA is the #1 cause of death for teens

• In 2009, 104 million MVA were caused by drivers using cell phones; 200,000 of these were caused by drivers texting

Studying Disease

• Disease terminology• Health—physical, mental, and social well-

being—not merely the absence of disease

• Disease—an abnormality in body function that threatens health

• Etiology—the study of the factors that cause a disease

Studying Disease

• Disease terminology• Idiopathic—refers to a disease with an

unknown cause

• Signs and symptoms—the objective and subjective abnormalities associated with a disease

• Pathogenesis—the pattern of a disease’s development

Studying Disease

• Patterns of disease• Epidemiology is the study of occurrence,

distribution, and transmission of diseases in human populations

• Endemic diseases are native to a local region

• Epidemics occur when a disease affects many people at the same time

Studying Disease

• Patterns of disease• Pandemics are widespread, perhaps global,

epidemics

• Discovering the cause of a disease is difficult because many factors affect disease transmission

• Disease can be fought through prevention and therapy (treatment)

Pathophysiology

• Mechanisms of disease

• Pathophysiology—the study of underlying physiological aspects of disease

• 7 Categories of Mechanisms of Disease:1. Genetic mechanisms

2. Pathogenic organisms and particles

3. Tumors and cancer Neoplasms

Pathophysiology

• Categories of Mechanisms of disease (Cont.)4. Traumatic mechanism - Physical and chemical agents

5. Metabolic mechanism

6. Inflammationa. Autoimmune b. Inflammation

7. Degeneration

Categories of Disease Mechanisms

1.Genetic Mutations

• Direct cause or an associated risk factor

• Ex: Hemophelia, Down syndrome, oncogene

2. Infectious Mechanism

• Pathogenic organisms or particles

• Disease causing microorganisms

• Bacteria, fungus, virus, parasite, etc

• Spread of Pathogens:

• Person to person

• Environmental

• Opportunistic invasion

• Transmission by vector

3. Neoplastic Mechanism

• Cancers or neoplasms

• Abnormal cell growth/division

• Neoplasm

• Hyperplasia

• Anaplasia

4. Traumatic Mechanism

• Physical or chemical causative factors

• Ex: lacerations, burn, contusion, fx, poisoning

5. Metabolic Mechanisms

• Malnutrition

• Endocrine imbalance

• Ex: night blindness, ricketts, anemia, impaired post op wound healing, DM, hypothyroid

6. Inflammatory Mechanisms

• A. Autoimmune

• B. Inflammation

• Ex: Lupus, asthma, crohn’s disease, RA

• Inappropriate or abnormally prolonged inflammation

7. Degeneration

• Usually d/t aging

• Ex: DJD, osteoporosis,

Dementia

Risk Factors

• Predisposing conditions

• Contribute to likelihood of dev illness

• May be minimized, controlled, eliminated

• Common risk factors and associated diseases?

Risk Factors

• Genetics• Age• Lifestyle• Sleep• Stress• Environment• Preexisting

conditions• Abuse: substance,

physical, emotional

• Race• Gender• Socioeconomics• Medical hx• Nutrition• Travel• Trauma• Obesity• Immunocompromise

Prevention/Control

• Prevent spread of pathogens/control transmission

• Manage risk factors

• Aseptic techniques: sterilization, disinfection, antisepsis, isolation

• Vaccination: attenuated/weakened or inactive/killed

• Antibiotics

• Antivirals

Types of Pathogenic Organisms

1. Viruses

2. Prions

3. Bacteria

4. Fungi

5. Protozoa

6. Pathogenic Animals

Cancer

• Neoplasm – “new matter” – aka “tumors”

• Malignant or benign

• Metastasis

• Can be distinct lump or diffusely spread

• Most common: skin, prostate

• Most # CA related deaths are d/t lung CA

• Least common: pancreatic

• http://www.cancer.gov/cancertopics/types/commoncancers

• http://apps.nccd.cdc.gov/uscs/toptencancers.aspx

1. Benign:

• Localized

• Encapsulated

• Grows slowly

• No metastasis

• Usually not life threatening

• Differentiated cells• A.Benign Epithelial Tumors:

Papilloma, Adenoma, Nevus

• B. Benign Conn Tiss Tumors:

Lipoma, Osteoma, Chondroma

2. Malignant:

•Not encapsulated

•Can metastasize by blood or lymph

•Rapid growth

•Undifferentiated cells

•Life threatening

• A. Malignant Epithelial Tumors (carcinomas):

Melanoma, Adenocarcinoma

• B. Malignant Conn Tiss Tumors (sarcomas):

Lymphoma, Osteosarcoma, Myeloma, Fibrosarcoma

Other Cancers:

• Neuroblastoma

• Cancers labeled acc to general organ location

What causes CA?•Genetics•Env•Virus•Lifestyle •Aging cells

•Hyperplasia•Anaplasia

•Diagnosing CA:• Self exam•Imaging•Biopsy•Blood testing

Major Forms of Cancer…

• Lung CA

• Colorectal CA

• Breast CA

• Prostate CA

• Uterine (including cervical) CA

• Urinary CA (bladder and kidney)

• Oral CA (lip, mouth, throat)

• Pancreatic CA

• Leukemia (cancer of blood tissue)

• Lymphoma (cancer of lymphoid tissue)

• Ovarian CA

• Skin CA

CA Warning Signs:

•Unusual bleeding/bruising

•Sore that doesn’t heal

•Change in wart/mole

•Lump/thickening

•Cough/hoarseness

•Chronic indigestion

•Change in bowel/bladder habits

•Bone pain

•Extreme fatigue

•Unexplained wt loss

• CA Prognosis:

• Staging: (I-IV) size/extent of spread

• Grading: (A-D) degree of cell abnormality

• Also extent of lymph node and other organs involved

CA Imaging & Diagnosis

•Xray, CT, MRI, US, PET

•Biopsy & Blood tests

CA Tx:

•Surgery

•Radiation

•Chemotherapy

•Laser therapy

•Immunotherapy

CA Tx complications:

• Cachexia

•Death: tx complication or secondary infection

Inflammation

Inflammatory response

Protective response, combo of body processes with goal of minimizing tissue injury and maintaining homeostasis

Regeneration & replacement of tissues

Signs of Inflammation:

•Redness

•Swelling/Edema

•Heat

•Pain

• Types of Inflammation:

• Acute

• Chronic

• Localized

• Systemic

Inflammatory response

Inflammation Mediators:

• Kinins, prostaglandins, histamines

• Cause a series of events…

Irritant: Cell damage (intro of bac) causing the rel of inflamm med

Inc bld vess permeability ChemotaxisBld vess Dilation

Inc bld vol and WBCs to area

Inc WBCs, inc H2O to dilute and bld prot that encapsulate irritant

WBC attraction and phagocytosis

Redness

HeatEdema

Pain

Irritant = cell damage/release of inflamm med; causes 3 events:

•1. Bld vessel dilation= redness/heat

•2. Increase Bld vessel permeability: = edema/pain

•3. Chemotaxis: WBC to site

•Inflammatory exudate =

Pus (tiss fl w/ WBCs,

pathogens, debris)

Irritant: Cell damage (intro of bac) causing the rel of inflamm med. Names of these?

Redness

HeatEdema

Pain

• Fever – purpose??

• Pyrexia/febrile

• Systemic inflammatory response

• Pediatrics/geriatrics: altered fever response

• Increased temp kills/inhibits pathogens

• TX: ASA, Acetominophen, Ibuprofen, etc.

• Meds to tx inflamm:

• Acetaminophen

• Antihistamines

• NSAIDs

• Steroids

• Is acetominophen an NSAID?

• Inflammatory Diseases:

• RA, Allergies, Lupus, Crohns

• Eczema, Chronic bronchitis, Asthma

Tissue Repair• Regeneration

• Replacement = scar

• Keloid – abnormal scarring beyond original inj site

• Adhesion - internal

Review!

• The pt states they feel nauseous. Is this a sign or symptom?

• Name the 5 vital signs. Why are they signs?

• What is an ex of an acute illness?

• What is an ex of a chronic illness?

• What is an illness endemic to the northeast US?

• Name 2 current pandemics.

Disease Terminology

• 1.Health

• 2. Pathology

• 3. Pathophysiology

• 4. Disease

• 5. Sign

• 6. Symptom

• 7. Syndrome

• 8. Acute

• 9. Chronic

• 10. Etiology

• 11. Idiopathic

• 12. Pathogenesis

• 13. Communicable/infectious

• 14. Epidemiology

• 15. Morbidity

• 16. Mortality

• 17. Remission

• 18. Incubation

• 19. Convalescence

• 20. Endemic

• 21. Epidemic

• 22. Pandemic