CHAPTER 4 INFLAMMATION AND INFECTION Defense Mechanisms Three

Defense Mechanisms � Three lines of defense protect the body against foreign invasion: �Physical

Inflammation � Non-specific cellular and vascular reaction to tissue � Repels and destroys invader;

Inflammatory Process � Signs and symptoms: �Redness �Heat �Edema �Pain Copyright © 2006 by

Chronic Inflammation � Last two weeks or longer � Acute inflammation lasts less than

Inflammatory Exudates � Appearance and amount of exudate (blood fluid) reveals acute or chronic

Inflammatory Exudates � Fibrinous exudate �Indicates larger injury with severe inflammation �Commonly called scab

Inflammatory Exudates � Purulent exudate called “pus” � Collection of pus is an abscess

Inflammatory Lesions � Due to physical or pathologic injury � Inflammatory lesions include: �Abscesses

Tissue Repair and Healing � Ongoing process � Tissue repair: �Regeneration �Fibrous connective tissue

Tissue Repair and Healing � Regeneration leads to normal function � Fibrous connective tissue

Tissue Healing � Primary Union (First Intention) �Involves approximating edges of wound �Steps of

Tissue Healing � Primary Union (First Intention) �Steps of primary healing: ○ Fibroblast grows

Tissue Healing � Secondary Union (Secondary Intention) �Larger, deeper wounds with more inflammation than

Tissue Healing � Secondary Union (Secondary Intention) �After a week, new soft red tissue

Delayed Wound Healing � Debridement (washing or cutting away necrotic tissue and foreign material)

Delayed Wound Healing � Factors affecting healing time: �Age �Size of wound �Location �Nutrition

Delayed Wound Healing � Factors affecting healing time: �Circulation �Organism virulence �Steroids Copyright ©

Complications of Wound Healing � Poor or excessive scar formation � Dehiscence - separation

Infection � Invasion of microorganisms causing cell or tissue injury � Pathogenic - microorganisms

Infection � Conditions for flora to become pathogenic �Microorganisms gain access to body through

Frequency and Type of Infection � Infectious diseases leading cause of death in the

Frequency and Type of Infection � CDC - Centers for Disease Control and Prevention

Frequency and Types of Infection � Bacteria �Primary or secondary disease �Staphylococcus is bacterium

Frequency and Types of Infection � Viruses �Smallest infective organism �Must be visualized by

Frequency and Types of Infections � Viruses �Immunizations are effective in preventing many viral

Frequency and Types of Infection � Fungi �Microscopic plant-like organisms larger than bacteria �Only

Frequency and Types of Infections � Fungi �Treated with antibiotics and antifungal medications �Often

Frequency and Types of Infections � Rickettsiae �Microscopic organisms that are intermediate between bacteria

Frequency and Types of Infections � Protozoa �Single-celled microscopic organisms �Found in soil; live

Frequency and Types of Infections � Helminths �Roundworms or flatworms �Pinworms and tapeworms are

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CHAPTER 4 INFLAMMATION AND INFECTION

Defense Mechanisms � Three lines of defense protect the body against foreign invasion: �Physical or surface barriers �Inflammation �Immune response Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 2

Inflammation � Non-specific cellular and vascular reaction to tissue � Repels and destroys invader; cleans up debris to promote healing � Requires blood supply Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 3

Inflammatory Exudates � Appearance and amount of exudate (blood fluid) reveals acute or chronic condition � Serous exudate is clear serum-like fluid �Acute state of inflammation �Skin blisters and cold sores Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 6

Inflammatory Exudates � Fibrinous exudate �Indicates larger injury with severe inflammation �Commonly called scab �Strep throat or bacterial pneumonia forming a mesh-like lesion Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 7

Inflammatory Exudates � Purulent exudate called “pus” � Collection of pus is an abscess � Accumulation of pus in body cavity is empyema Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 8

Tissue Healing � Primary Union (First Intention) �Involves approximating edges of wound �Steps of primary healing: ○ Forms scab ○ 1 to 2 days, new capillaries begin to bridge gap between wound edges Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 12

Tissue Healing � Primary Union (First Intention) �Steps of primary healing: ○ Fibroblast grows across deeper wound layers forming granulation tissue ○ Scar forms ○ Example of primary healing is surgical incision Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 13

Tissue Healing � Secondary Union (Secondary Intention) �Larger, deeper wounds with more inflammation than primary union �Need more capillaries, fibroblasts, and collagen Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 14

Tissue Healing � Secondary Union (Secondary Intention) �After a week, new soft red tissue called granulation tissue is produced �Scar tissue is formed �Healing time is dependent on size of wound Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 15

Complications of Wound Healing � Poor or excessive scar formation � Dehiscence - separation of tissue margins � Keloid - hard, raised scar � Adhesions - fibrous bands of tissue that attach to surfaces of adjacent organs as scar tissue develops Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 19

Infection � Invasion of microorganisms causing cell or tissue injury � Pathogenic - microorganisms causing disease � Opportunistic - normal flora become pathogenic under certain conditions Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 20

Infection � Conditions for flora to become pathogenic �Microorganisms gain access to body through portal of entry �Pathogen is resistant to defenses of host �Number of invading microorganisms �Condition of individual or host Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 21

Frequency and Type of Infection � Infectious diseases leading cause of death in the world � Identifying and tracking infectious diseases is crucial Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 22

Frequency and Types of Infection � Bacteria �Primary or secondary disease �Staphylococcus is bacterium on skin �Streptococcus live on skin and in throat �Escherichia coli, Kelbsiella, Pseudomonas, Shigella, and Salmonella are common enteric bacteria Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 24

Frequency and Types of Infection � Viruses �Smallest infective organism �Must be visualized by electron microscope �Cannot reproduce or live outside cell �Viral infections are not easily treated �Antibiotics do not kill a virus but help prevent secondary infections Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 25

Frequency and Types of Infections � Viruses �Immunizations are effective in preventing many viral diseases such as measles, mumps, rubella, and smallpox �Latent viruses lay dormant in cells and replicate and cause symptoms during times of stress Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 26

Frequency and Types of Infection � Fungi �Microscopic plant-like organisms larger than bacteria �Only few are pathogenic �Types of infections: ○ Tinea - skin ○ Candida - superficial infection of skin and mucous membranes Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 27

Frequency and Types of Infections � Fungi �Treated with antibiotics and antifungal medications �Often difficult to cure �May require long-term therapy Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 28

Frequency and Types of Infections � Rickettsiae �Microscopic organisms that are intermediate between bacteria and viruses �Must live in host cell like a virus �Spread by fleas, ticks, mites, and lice �Most common infection: Rocky Mountain Spotted Fever Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 29

Frequency and Types of Infections � Protozoa �Single-celled microscopic organisms �Found in soil; live on dead or decaying material �Infection through bite of infected insect or ingestion of spores �Malaria is most common disease Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 30

Frequency and Types of Infections � Helminths �Roundworms or flatworms �Pinworms and tapeworms are most common �Pinworms cause anal itching �Tapeworms cause intestinal disease due to inadequately cooked meat Copyright © 2006 by Thomson Delmar Learning. ALL RIGHTS RESERVED. 31