Med Conditions: Phases of Wound Healing

skin

what is the largest organ in the body?

- protective shield/barrier from outside elements

- regulates body temp

- stores water and fat

- sensory functions

- prevents water loss

- prevents entry of invaders (bacteria)

- aids in production of Vitamin D

what are the functions of the skin?

epidermis, dermis, and subcutaneous tissue

what are the three layers of the skin?

subcutaneous tissue

what is deep to the dermis?

melanocytes

what produces pigment, found deepest later of the epidermis and other tissue such as hair, eyes, organ tissue

langerhan cells

what cells are immune system cells (type of WBC) found in the epidermis and is the first line of defense against pathogens?

germinative cells

in the deepest layer of the epidermis, what cells are found and can continually divide? Many of these cells migrate to the surface of the epidermis and are sloughed off

false. it is avascular

true or false. the epidermis is vascular and contains blood.

re-epithealialization

In normal healing, the epidermis regrows from those germinative cells in the basal layer of the epidermis at the edges of the wound. what is this process called?

surface wounds

what type of wounds are confined to the epidermis and are known as epidermal wounds that usually heal quickly with little to no scarring?

dermis

what layer of skin is mainly composed of connective tissue (dense and irregular) and it varies in thickness?

strength

dermis is responsible for the ___ of the skin

true

true or false. the dermis is the stronger than the epidermis

papillary layer and reticular layer

what are the 2 layers of the dermis?

- small blood vessels

- lymphatics, nerves and nerve ending

- hair follicles

- sweat glands

- different cell types: macrophages, fibroblast, mast cells

what does the dermis contain?

the interlacing of the collagen fibers

what is responsible for the strength of the dermis and has elastic fibers?

- areolar loose connective tissue

- highly vascularized

- dermal ridges (which contributes to fingerprints)

- nerve endings & touch receptors (meissner's corpuscles)

what can be found in the papillary layer of the dermis?

20%

what percentage of the dermis does the papillary layer take up?

- dense irregular connective tissue

- collagen fibers = strength

- elastic fibers = stretch and recoil

what is found in the reticular layer of the dermis?

80%

what percentage of the dermis does the reticular layer take up?

tears in the dermis

what do stretch marks indicate?

true breaks in the skin

wounds that penetrate the dermis are ____

false. scars are never as strong as original tissue

true or false. scars are just as strong as original tissue

subcutaneous tissue

what tissue contains fast as well as blood vessels, nerves, and other collagen fibers

they must be cleaned very carefully to remove all the dirt and debris because their is a potential for infection

what must be done if you have a wound that extends into the subcutaneous tissue?

by the type of force that causes them

how are external wounds named?

1. abrasions

2. lacerations

3. contusions or crush wounds

4. punctures

5. avulsions

6. burns

7. ulcers

what are the 7 basic types of wounds?

traumatic wound

what type of wound is often a mixture of the different types of wounds?

abrasions

what type of wound are scrapes; mild forms remove the epidermis, more serious forms remove the dermis and possibly the subcutaneous tissue

abrasions

this type of wound is usually broad, shallow wound with irregular edges; tx - cleaning is critical; amy use moist dressing and topical antibiotics

lacerations

what type of wound is it where cuts are narrow, deep wounds with sharp edges when made with a knifelike object

lacerations

what wound is made with a blunt object, and appears more of a 'rip' with jagged edges; tx - consists of cleaning the wound of blood clots, foreign material, debrided; irrigated using local anesthetic, the wound margins are approximated; sterile dressings and immobilization for the more complex wounds

contusions or crush wounds

what type of wound are compression wounds with bruising and damage to the skin and underlying tissue; may be caused by a forceful blow; heal well with minimal care since skin is not broken; skin may not break (a closed type of injury)

punctures

these wounds are narrow, deep wounds, typicaly small openings with sharp edges; nail punctures; these have a high risk of infection

avulsions

tissue has been torn out; torn tissue may still be partly attached to the surrounding tissues; tx - depends on if tissue is viable and can be reattached

burns

wound made by external destructive energy - such as heat, chemical, electrical burns etc.

ulcers

wounds that result from ischemia (loss of oxygen); tissue destruction is usually in a broad, roughly circular area (elderly, spinal cord pts, etc)

- necrotic

- epithelial

- granulation

- hypergranulation

what are the different types of tissue

necrotic tissue

what form of tissue is dead; slough - yellow, green or grey; eschar - black, brown, dry, may be hard

epithelial tissue

tissue that is deep pink to pearly pink color, light purple edges in full thickness wounds

granulation tissue

tissue the is beefy red, puffy, or mounded bubbly appearance

hypergranulation tissue

tissue that is granulated that forms above the surface of the surrounding epithelial tissue; slows the process of epithelialization

- primary wound healing

- wound is cleaned and irrigated

- dead tissue is debrided

- the wound edges are brought together

- wound closure with sutures, staples or adhesive tape; glue; may include grafts; used within 24 hours of following injury where there is a viable, clean wound

what is done for healing by FIRST intention?

within hours of repair

when does healing begin for "healing by FIRST intention?'

surgical repair of clean lacerations, reduced bone fracture, healing after flap surgery

what are some examples of healing by FIRST intention?

healing by secondary intention

secondary wound healing or spontaneous healing - the wound is left open and allowed to close and heal by the process of epithelialization and contraction

healing by secondary intention

Commonly used in contaminated or infected wounds; may heal slower; daily wound care important; Surgeon may pack the wound with gauze or use a drainage system; wound is allowed to granulate; results in a broader scar

healing by third intention

tertiary wound healing or delayed primary healing - for grossly contaminated wounds; if wound edges cannot be approximated immediately, then there is delayed primary wound healing; in contaminated wounds

Wound is cleaned, debrided and observed, closure usually 4 or 5 days later; wound is purposely left open; if wound appears clean and well-vascularized after this time, then wound edges are approximated

what is the process for healing by third intention?

healing of wounds by use of tissue graft

what is an example of healing by third intention?

angiogenesis

what is the formation of new blood vessels which occurs at the same time as fibroblast proliferation

formation of new blood vessels

what is very important for the survival of the cells that are necessary in wound healing - the fibroblast and epithelial cells need oxygen and nutrients; reason why wound looks red

bleeding

what is the initial response following tissue injury whether a trauma or a surgical procedure ?

vasoconstriction and coagulation

what are the following steps after bleeding that occurs in the events in wound healing; this involves clotted blood leading to homeostasis

chemokines and cytokines

what factors are released to attract the macrophages to begin cleaning the wound; other factors for continued healing

fibrin clot

what is the desired result following vasoconstriction and coagulation to stop the bleeding and to keep the healing factors from the blood within the wound?

inflammatory phase

first phase of healing - the body's natural response to trauma. After the wound has been inflicted, homeostasis begins - the blood vessels constrict and seal themselves off as the platelets create substances that form a clot and halt bleeding. Once homeostasis is achieved the blood vessels dilate, letting nutrients, white blood cells, antibodies, enzymes and other beneficial elements into the affected area to promote good wound healing and stave off infection

platelets

when the inflammatory phase occurs, what are present in high numbers - help release a number of factors that are important in formation the primary plug with clotting

Polymorphonuclear neutrophils

what is a type of white blood cell that begins to phagocytize the debris and bacteria - Important because dirty wounds do not heal

false. inflammatory phase is both vascualar and cellular

true or false. the inflammatory phase is only vascular

large wounds

what kind of wounds caused by deep pressure injury may not go through an inflammatory phase? May have an accumulation of fluid, cells, clotting factors that form a pale yellow looking sticky 'viscous' exudate

macrophages

what cells are derived from monocytes [type of white blood cell] found in high numbers in the spleen?

macrophages

what type of cell come about 2 days later; become the dominant cell type; essential to wound healing to continue the process of phagocytosing the bacteria and damaged tissue; 'debride' damaged tissues (kills microorganisms and removes dead cells); Secrete a number of growth factors important in the next phase of healing

macrophages

what cell help aid in the transition from inflammatory phase to proliferation phase?

when inflammation decreases and you see fewer inflammatory factors like polymorphonuclear leukocytes or macrophages

what represent the beginning of the proliferative phase?

if the inflammatory phase continues past the normal time frame - not good!

what can lead to a chronic wound?

presence of dirt and bacteria

what can extend the inflammatory phase?

fibroblast cells

what marks the beginning of the proliferative phase; wound becomes more cellular in composition

- fibroplasia (increased collagen deposits)

- Granulation tissue (formation with angiogenesis (new blood vessels))

- Epithelialization

- Wound Contraction

what are the several steps in the overlap between inflammatory phase and proliferative phases

fibroplasia

these cells are found in the wound site as early as 2 days post-injury and their numbers peak around 1 to 2 weeks post-injury; ends approx. 2 to 4 weeks post-injury

granulation tissue

what functions as rudimentary tissue that replaces the fibrin clot; continues to grow until the wound bed is covered

collagen deposition

produced by the fibroblasts - its most important function; The presence of collagen is needed for the strength of the wound closure; until this occurs, the wound is only closed by the fibrin-fibronectin clot which is fragile and is vulnerable to further injury

fibroblasts die

what happens at the end of the granulation phase?

characterized by angiogenesis; collagen deposits, formation of granulation tissue; epithelialization and wound contraction [myofibroblast cells]

how is the proliferative phase characterized?

diabetes, venous or arterial disease, age and infection

what factors can lead to failure of healing resulting in chronic non healing wound?

wound contraction

what is a key phase of wound healing; involves the entire wound; if this lasts too long it can lead to disfigurement as well as loss of function

several weeks - even after re-epithelization has concluded

how long can wound contraction last?

maturation phase begins

When the levels of collagen production and degradation equalize, what happens?

- large wounds (where much tissue is loss, heals slowly and produce large scar)

- wounds containing dirt (increased problems)

- wounds with poor blood supply (healing can be slow or even stop healing; concern for elderly)

- infection (most common impediment to wound healing)

What are some common impediments to wound healing?

infection

what is the most common impediment to wound healing?

1. Venous diseases

2. Infection

3. Diabetes

4. Metabolic deficiencies in the elderly

chronic wounds are due to the failure to progress in stages of wound healing to due what factors?

infection

Wounds that have been significantly contaminated by bacteria or other foreign material are at greater risk for ___

pus

With persistent contamination, the neutrophils (WBC, immune function) die and clog up the wound - forming ___

pus

what slows the formation of granulation tissue, thus interfering with the re-epithelization

Fever

Pus

Abscess

Abnormal smell (ex: foul or sweet odor)

Cellulitis

Persistent inflammation with an exudate

Warmth and redness

Delayed healing

Continued or increasing pain

Edema

Weak, crumbly granulation tissue that bleeds easily

what are some signs of infection?

- re-injury

- ischemia

- local skin tenison

- disease

- malnutrition

- age

- smoking

What are some other factors influencing healing?

re-injury

what can can slow down and/or stop wound healing; new scars are weaker than the surrounding tissues; Care must be taken to protect the healing wound - bandages, splints

ischemia/hypoxia

The granulation tissue has a temporary dense capillary bed so that the healing tissues receive adequate blood supply carrying the necessary oxygen & nutrients for the cells; After the inflammatory phase, oxygen is important for the strengthening of the collagen in the new connective tissue

local skin tension

Skin and the deeper tissues are under normal tension; regions where the wound gapes more widely will heal slower and with a larger scar

diseases that might effect healing

Diabetes mellitus - diabetic scars have less collagen and the collagen that is constructed is more brittle than normal; may not have a good blood supply, especially in the distal extremities; peripheral neuropathy

malnutrition

slow healing due to the breakdown of proteins for a source of energy; may have a vitamin deficiency that leads to poor healing

age

higher in age = slower to heal

smoking

leads to poor wounding healing - decreased oxygen content in blood, etc.

scar

what are areas of fibrous tissue [fibrosis] that replaced normal tissue after an injury; are the results of normal biological processes to repair the wound

scar

less resistant to ultraviolet light, sweat glands and hair follicles do not grow back within scar tissue, etc

problem scars

can result from normal scars; If the healing process is interfered with or some other insult occurs, scars are more likely to become a problem; With poor healing, scars may be larger than necessary; weaker than one would expect; too much collagen is produced

hypertrophic scars

what occurs due to over production of collagen; usually elicited by a prolonged proliferation phase during the process of healing

keloid scars

what are essentially hypertrophic but the scars grow beyond the margins of the original wound; are due to excessive deposition of collagen in the healing wound

keloid scars

what scars can be caused by surgery, body piercings, may form spontaneously; there is a heredity component; Are non-cancerous, are inert masses of collagen, can become itchy

contractures

what is the process that all scars go through of shrinking/contracting but some large scars contract excessively; can become disabling and disfiguring; if formed over joints, the scars can reduce ROM