Burns

Question 1

What are burns?

Answer 1

injuries to tissue caused by heat, chemicals, and/or radiation

Question 2

What 2 factors influence the severity of a burn?

Answer 2

depth and the surface area involved

Question 3

What are Lund-Browder charts?

Answer 3

Age-specific charts are used to calculate the surface area covered by a burn.
- Most accurate method for both adults and children

Question 4

What is the Wallaces rule of 9’s?

Answer 4

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

Question 5

Describe Wallaces rules of nines?

Answer 5

head - 9%
trunk - 36% (4x9%)
arms - 18% (2x9%)
thighs - 18% (2x9%)
lower legs and feet - 18% (2x9%)
genital region - 1%

Question 6

Etiology of burns?

Answer 6

1. Thermal injury - scalding, contact with a hot surface, fires
2. Non-thermal injury - radiation, chemical burns, electrical burns

Question 7

What is Jackson model of the burn wound?

Answer 7

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

Question 8

What pathogens commonly colonize burns?

Answer 8

1. MRSA
2. Pseudomonas
3. Klebsiella
4. Acinetobacter
5. Candida

Question 9

What is an eschar?

Answer 9

dead tissue that eventually sloughs off healthy tissue

Question 10

What are the constrictive effects of eschars?

Answer 10

1. Significant eschar on chest or neck → restriction of chest excursion
   → asphyxia
2. 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

Question 11

Systemic effects of burns?

Answer 11

1. Release of cytokines and other inflammatory mediators
   → systemic inflammatory response syndrome
2. Evaporative fluid loss
   → hypothermia, dehydration
3. Hemolysis, muscle damage
   → hemoglobinuria and/or myoglobinuria
   → acute tubular necrosis
4. Immunosuppression

Question 12

Describe the systemic inflammatory response syndrome?

Answer 12

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)

Question 13

How are burns classified?

Answer 13

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)

Question 14

Describe 1st-degree burns? (superficial burn)?

Answer 14

1. affected layers
   - superficial layers of the epidermis
2. pain
   - yes (localized)
3. wound blanching on pressure
   - yes, rapid refill
4. appearance
   - similar to sunburn
   - localized features: erythema, swelling, skin appears dried out, no blister
5. prognosis
   - healing within 3 - 6 days
   - no scarring

Question 15

Describe 2a (superficial partial thickness) burns?

Answer 15

1. affected tissue
   - epidermis and upper layers of dermis (papillary dermis)
2. pain
   - esp. with movement of air or changes in temp. in the area surrounding the wound
3. wound blanching on pressure
   - yes, slow refill
4. appearance
   - swelling
   - local rise of temp.
   - vesicles/bullae
   - erythema
5. prognosis
   - healing within 1 - 3 weeks with hypo/hyper-pigmentation
   - no scarring

Question 16

Describe 2b (deep partial thickness) burns?

Answer 16

1. tissue layers
   - deeper layers of the dermis (papillary and reticular dermis)
2. pain
   - yes, minimal but felt when applying pressure
3. wound blanching on pressure
   - no or only sluggish
4. appearance
   - vesicles/bullae fragile (rupture easily)
   - mottled skin with red and/or white patches
5. prognosis
   - healing takes 3 weeks or longer
   - scar formation

Question 17

Describe 3rd degree (full thickness) burns?

Answer 17

1. tissue layers
   - epidermis, dermis and subcutaneous
2. pain
   - no (perception of deep pressure is intact)
3. wound blanching on pressure
   - no
4. appearance
   - tissue necrosis with black, waxy-white or gray lether lie skin (eschar)
   - dried out inelastic appearance
5. prognosis
   - the burn does not heal by itself

Question 18

Describe 4th degree (deeper injury burn) burns?

Answer 18

1. affected tissue
   - epidermis, dermis and deeper structures (muscles, fat, fascia and bones)
2. pain
   - no (minimal perception of deep pressure)
3. wound blanching on pressure
   - no
4. appearance
   - tissue necorsis with black, waxy white or grey leather skin (eschar)
   - dried out ineslastic appearance
5. prognosis
   - the tissue is dead and requires amputation

Question 19

Clinical features of burns?

Answer 19

Clinical features of shock
e.g., hypotension, poor urine output) and/or ARDS (e.g., dyspnea)

Question 20

Clinical features in case of circumferential burns around limbs?

Answer 20

1. Compartment syndrome
2. Clinical features of acute limb ischemia
   e.g., weak/absent pulse, paresthesia, pallor in the affected limb

Question 21

Clinical features in case of circumferential burns around abdomen?

Answer 21

1. Abdominal compartment syndrome
   → impaired function of nearly every organ system
   e.g., oliguria, acute pulmonary decompensation, hypoperfusion
2. Signs of increased intraabdominal pressure
   e.g., jugular venous distension, hypotension, tachycardia

Question 22

Shock in burns in adults?

Answer 22

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.

Question 23

Shock in burns in children?

Answer 23

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

Question 25

Describe the pathophysiology of chemical burns?

Answer 25

1. Acid exposure → coagulative necrosis → limited depth of tissue damage 2. Alkali exposure → cell membrane fatty acid saponification and protein complex formation → liquefactive necrosis → deeper penetration of the agent → increased risk of systemic poisoning

Question 26

Describe the pathophysiology of electrical burns?

Answer 26

Electrical current enters the body (entry point) → tissue resistance converts electrical energy to heat → direct heat damage → current exits the body (exit point)

Question 27

Classification of electrical burns?

Answer 27

1. low voltage electricity 2. high voltage electricity

Question 28

Describe low-voltage electricity burns?

Answer 28

Low-voltage electricity (< 1000 V): entry and exit points are typically close together → burns at the site of contact

Question 29

Describe high voltage electricity burns?

Answer 29

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

Question 30

Pathophysiology of radiation burns?

Answer 30

1. UV waves 2. x-ray waves 3. gamma waves 4. alpha particles 5. beta particles → DNA damage (directly or indirectly via free radical formation) → cell apoptosis