RHPT476

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This lecture deals about the burns in the following sub-categories;
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1. Introduction, definition & causes of burns.
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2. Classification of burns, Skin anatomy & functions of it.
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3. Pathophysiology of burns.
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At the end of this unit - 1, the students will acquire a comprehensive & well found knowledge & develop the process of critical thinking, clinical reasoning & exercise sound clinical judgment in the following;
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1. Definition of burns
2. Major causes of burns
3. Anatomy, structure & functions of the skin
4. Classification of Burns
5. Differentiate between superficial, superficial partial thickness, deep partial thickness, full thickness & sub-dermal burns.
6. Pathophysiology of burns
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Burns are one of the major Health problem of
Industrial world
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U.S Annually records incidence of 2 million burns patient
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Most burn injuries occur in kitchen while cooking, in bathroom, improper use of electrical appliances
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Young children and elderly people are at particularly high risk for burn injury
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An external burn injury comprises damage to the skin , and there can be loss of skin and underlying tissues with impairment of skin functions .
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The effects of a burn depend on its cause and extent and the site of damage .
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The serious burn injury is thought to be the most severe trauma that is survivable
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Loss of the continuity of the skin caused by thermal, mechanical, electrical, atomic agents.
 or
“To damage or injure by fire, heat, radiation, electricity, or a caustic agent“
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Or
Coagulative destruction of the skin and subcutaneous tissue.
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Or
Reaction of the body to some noxious agents which may be thermal, electrical, chemical, irradiant or atomic which results in tissue damage or death.
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THERMAL (WET HEAT & DRY HEAT): Hot water / Direct fire.
CHEMICAL BURNS: Such as acids and alkalis cause the majority of chemical burn. The depth of burn is related to the nature of compound and length of time it remains on the skin.
ELECTRICAL BURNS. Burns will appear on the skin where there has been contact with a live wire. There will be a burn at the entry and exit site of the electric current.
INHALATION BURNS. Direct thermal injury can be sustained by inhalation of flames, hot gases or steam.
RADIATION: Sun light – UVR / IRR
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9 heat
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10 electricity
Chemical materials
Radioactive materials
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Direct contact with electrical current
 entry & exit wounds
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Typical burns from hot water in a child
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It is essential to ensure that kettles and hot pans are out of the reach of children.
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Electrical sockets have shutters , and electrical cables are secure with the insulation intact
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Circuit breakers are in use with external appliances
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Matches and cigarette lighters are stored safely
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Smoke alarms should be fitted
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The Health and Safety at Work Act 1974
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The skin, the largest organ of the body, consists of two layers-the epidermis and dermis .
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The epidermis is the outer layer that forms the protective covering . It is Avascular .
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The thicker or inner layer is the dermis which contains blood vessels, hair follicles, nerve endings, sweat and sebaceous glands . Dermis is divided in to Superficial
Papillary Dermis and deep Reticular Dermis.
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When the dermis is destroyed, so are the nerve endings that allow a person to feel pain, temperature, and tactile sensation
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The most important function of the skin is to act as a barrier against infection .
The skin prevents loss of body fluids , thus preventing dehydration.
The skin also regulates the body temperature by controlling the amount of evaporation of fluids from the sweat glands.
Skin helps in Vitamin D synthesis
The skin serves a sensory reception .
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P hysical barrier
V itamin D production
I mmunity
S ensation
I dentity
T emperature control
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Traditional Classification Alternative Classification

1st degree
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2nd degree
 3rd degree
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Superficial
 Partial Thickness
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Superficial
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Deep
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Full thickness
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Involves epidermis only:
• Painful
• Red
• No blistering
• Heals rapidly (reversible injury)
• No permanent scars
Note that erythema is NOT included when assessing TBSA
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Typical hot water scald
Involves epidermis and upper dermis:
• Red
• Blistering, moist
• Painful
•
Heals by epithelialization
•
Healing complete within 14 days
• Minimal or no permanent scars but can leave discolouration
Patches of skin that would come off on cleaning
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Glistening moist red/pink appearance typical of superficial injury

Pin-point bleeding
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Blister
Pink surface;
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Involves epidermis, upper dermis and varying degrees of lower dermis:
• Pale, mottled appearance
• Fixed staining (no blanching)
• May be painful or insensate
(depending on depth)
•
Heals by combination of epithilialization and wound contracture
• May take weeks to heal
•
Can leave significant scars and contractures over joints depending on time taken to heal
Deep dermal area, reddish with fixed staining
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• Involves all of epidermis and all of dermis
• Dry, leathery (white, dark brown or charred)
• Insensate
• Heals by contraction
• Delayed healing
• Hypertrophic or keloid scars
• Leads to contractures Dry, leathery, charred appearance of a full thickness burn
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Black, charred skin
Typical position of hand in full thickness burns with metacarpophalangeal joints extended and interphalangeal joints flexed
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(A)
(B)
( C )
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Assess the depth of the burn in areas
A, B and C

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Full thickness, dry white leathery appearance
Superficial partial thickness showing pink blanching
Deep dermal with pale pink and white patches, non blanching
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Type [10]
Layers involved
Appearance Texture Sensation Healing Time Prognosis
Superficial
(Firstdegree)
Epidermis [5]
Red without blisters [10]
Dry Painful [10]
5–
10 days [10][11]
Heals well; [10] Repeated sunbur ns increase the risk of skin cancer later in life [12]
Superficial partial thickness
(Seconddegree)
Extends into superficial
(papillary) der mis [10]
Redness with clear blister .
Blanches with pressure.
[10]
Moist [10]
Deep partial thickness
(Seconddegree)
Extends into deep
(reticular) dermis [10]
Yellow or white. Less blanching.
May be blistering.
[10]
Fairly dry [6]
Very painful [10] less than 2–3 weeks [6][10]
Local infection/ cellulitis but no scarring typically [6]
Pressure and
] discomfort [6
3–8 weeks [10]
Scarring, contractures
(may require excision and skin grafting ) [6]
Full thickness
(Thirddegree)
Extends through entire dermis [10]
Stiff and white/brown [10
] No blanching [6]
Leathery [1
0]
Painless [10]
Prolonged
(months) and incomplete [10]
Scarring, contractures, amputation (early excision recommended) [6]
Extends
IV-degree
(SUBDERMAL through entire skin, and into underlying fat, muscle and bone [10]
Black; charred with eschar
Dry Painless
Requires excision [10]
Amputation, significant functional impairment and, in some cases, death.
[10]
Example

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TEST FOR STUDENTS TO MENTION THE CLASSIFICATION TYPE OF BURNS
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Pathophysiology refers to the complex chain of mechanisms that occur in the skin (local effects) and in other organ systems (systemic effects) when a burn injury occurs, as well as what happens as the skin regenerates and heals
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Local Effects
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Systematic Effects
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Skin Regeneration and Scarring
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Electrical Burns
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Zone of Coagulation
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Inner Zone
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Area of cellular death (necrosis)
Zone of Stasis
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Area surrounding zone of coagulation
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Cellular injury: decreased blood flow & inflammation
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Potentially salvable; susceptible to additional injury
Zone of Hyperemia
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Peripheral area of burn
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Area of least cellular injury & increased blood flow
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Complete recovery of this tissue likely. 15-Apr-20

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Summary of local effects:
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Cell death/disturbed function
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Release of inflammatory mediators
Increased capillary permeability
Microvascular thrombosis
1. Cell death/disturbed function
Cellular function is disturbed when the temperature rises above 43 o C. The higher the temperature and more prolonged the contact, the more cells die. An instantaneous full thickness burn occurs at a temperature of 70 0 C or greater.
Due to differences in skin thickness with age, at 55

C, severe damage occurs after 10 seconds in a child and 30 seconds in an adult. Skin thickness is also reduced in older people and in certain conditions (e.g. steroid therapy).
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3. Increased capillary permeability
When capillaries are damaged, they leak protein-rich fluid which results in oedema.
Normal skin; normal capillary permeability
Burn wound oedema with increased capillary permeability and protein leakage
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4. Microvascular Thrombosis
Release of thrombogenic factors such as thromboxane, together with a hypovolaemic state cause sludging in the smallest blood vessels.
This in turn leads to further tissue ischaemia, increased cell death and can cause extension of the depth and surface area of the burn.
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Area of burn increases due to sludging in blood vessels and ischaemia