Burns Flashcards
What are burns?
injuries to tissue caused by heat, chemicals, and/or radiation
What 2 factors influence the severity of a burn?
depth and the surface area involved
What are Lund-Browder charts?
Age-specific charts are used to calculate the surface area covered by a burn.
- Most accurate method for both adults and children
What is the Wallaces rule of 9’s?
A quick but reliable method for estimating the surface area covered by burns in the case of adults
- The rule of nines is unreliable among children
Describe Wallaces rules of nines?
head - 9%
trunk - 36% (4x9%)
arms - 18% (2x9%)
thighs - 18% (2x9%)
lower legs and feet - 18% (2x9%)
genital region - 1%
Etiology of burns?
- Thermal injury - scalding, contact with a hot surface, fires
- Non-thermal injury - radiation, chemical burns, electrical burns
What is Jackson model of the burn wound?
describes local changes at the burn site
1. zone of coagulation
- a central zone of irreversible, coagulative necrosis
2. Zone of stasis
- surrounds the central zone of coagulation and is comprised of damaged but viable tissue with decreased perfusion
3. Zone of hyperemia
- surrounds the zone of stasis and is characterized by inflammation and increased blood flow
What pathogens commonly colonize burns?
- MRSA
- Pseudomonas
- Klebsiella
- Acinetobacter
- Candida
What is an eschar?
dead tissue that eventually sloughs off healthy tissue
What are the constrictive effects of eschars?
- Significant eschar on chest or neck → restriction of chest excursion
→ asphyxia - Circumferential eschars
→ loss of skin elasticity
→ impaired blood flow and/or compartment syndrome (caused by an accumulation of fluids)
→ acute ischemia distal to the eschar
Systemic effects of burns?
- Release of cytokines and other inflammatory mediators
→ systemic inflammatory response syndrome - Evaporative fluid loss
→ hypothermia, dehydration - Hemolysis, muscle damage
→ hemoglobinuria and/or myoglobinuria
→ acute tubular necrosis - Immunosuppression
Describe the systemic inflammatory response syndrome?
Increased vascular permeability
→ extravasation of protein and fluid from the intravascular compartment into interstitial tissue causing:
1. generalized edema
2. acute respiratory distress syndrome
3. hypovolemic shock with paralytic ileus
4. Disseminated intravascular coagulation (DIC)
How are burns classified?
1st-degree burn (superficial burn)
2nd-degree burn
- 2a (superficial partial-thickness burn)
- 2b (deep partial-thickness burn)
3rd-degree burn (full thickness burn)
4th-degree burn (deeper injury burn)
Describe 1st-degree burns? (superficial burn)?
- affected layers
- superficial layers of the epidermis - pain
- yes (localized) - wound blanching on pressure
- yes, rapid refill - appearance
- similar to sunburn
- localized features: erythema, swelling, skin appears dried out, no blister - prognosis
- healing within 3 - 6 days
- no scarring
Describe 2a (superficial partial thickness) burns?
- affected tissue
- epidermis and upper layers of dermis (papillary dermis) - pain
- esp. with movement of air or changes in temp. in the area surrounding the wound - wound blanching on pressure
- yes, slow refill - appearance
- swelling
- local rise of temp.
- vesicles/bullae
- erythema - prognosis
- healing within 1 - 3 weeks with hypo/hyper-pigmentation
- no scarring
Describe 2b (deep partial thickness) burns?
- tissue layers
- deeper layers of the dermis (papillary and reticular dermis) - pain
- yes, minimal but felt when applying pressure - wound blanching on pressure
- no or only sluggish - appearance
- vesicles/bullae fragile (rupture easily)
- mottled skin with red and/or white patches - prognosis
- healing takes 3 weeks or longer
- scar formation
Describe 3rd degree (full thickness) burns?
- tissue layers
- epidermis, dermis and subcutaneous - pain
- no (perception of deep pressure is intact) - wound blanching on pressure
- no - appearance
- tissue necrosis with black, waxy-white or gray lether lie skin (eschar)
- dried out inelastic appearance - prognosis
- the burn does not heal by itself
Describe 4th degree (deeper injury burn) burns?
- affected tissue
- epidermis, dermis and deeper structures (muscles, fat, fascia and bones) - pain
- no (minimal perception of deep pressure) - wound blanching on pressure
- no - appearance
- tissue necorsis with black, waxy white or grey leather skin (eschar)
- dried out ineslastic appearance - prognosis
- the tissue is dead and requires amputation
Clinical features of burns?
Clinical features of shock
e.g., hypotension, poor urine output) and/or ARDS (e.g., dyspnea)
Clinical features in case of circumferential burns around limbs?
- Compartment syndrome
- Clinical features of acute limb ischemia
e.g., weak/absent pulse, paresthesia, pallor in the affected limb
Clinical features in case of circumferential burns around abdomen?
- Abdominal compartment syndrome
→ impaired function of nearly every organ system
e.g., oliguria, acute pulmonary decompensation, hypoperfusion - Signs of increased intraabdominal pressure
e.g., jugular venous distension, hypotension, tachycardia
Shock in burns in adults?
In adults, shock sets in if burns involve > 15% of the body surface
Note: Burns that involve 50–70% of the body surface are usually lethal.
Shock in burns in children?
In children, signs of shock appear if > 10% of the body surface is involved. Note: Burns that involve 60–80% of the body surface are usually lethal
Describe the pathophysiology of chemical burns?
- Acid exposure
→ coagulative necrosis
→ limited depth of tissue damage - Alkali exposure
→ cell membrane fatty acid saponification and protein complex formation
→ liquefactive necrosis
→ deeper penetration of the agent
→ increased risk of systemic poisoning
Describe the pathophysiology of electrical burns?
Electrical current enters the body (entry point) → tissue resistance converts electrical energy to heat → direct heat damage → current exits the body (exit point)
Classification of electrical burns?
- low voltage electricity
- high voltage electricity
Describe low-voltage electricity burns?
Low-voltage electricity (< 1000 V): entry and exit points are typically close together → burns at the site of contact
Describe high voltage electricity burns?
High-voltage electricity (≥ 1000 V)
entry and exit sites are far away from each other
→ extensive deep-tissue and/or organ damage despite little or no apparent skin injury
→ high risk of rhabdomyolysis, compartment syndrome, and vascular thrombosis
Pathophysiology of radiation burns?
- UV waves
- x-ray waves
- gamma waves
- alpha particles
- beta particles → DNA damage (directly or indirectly via free radical formation) → cell apoptosis
