Thermal and Radiation Injury Flashcards
What are the three types of thermal burns?
- Superficial burns - limited to epidermis (i.e. sunburn)
- Partial thickness burns - extend into the dermis
- Full thickness burns - destruction through dermis, can involve subcutaneous tissue, tends, skeletal muscle, and bone
How does the skin regenerate in a partial thickness burn? What structure will exist on an acute lesion?
Via the remaining stem cells in the adnexal structures (i.e. matrix cells of the epidermis)
Lesion typically features a prominent blister
How does pathology of superficial / partial thickness burns differ from full thickness burns with respect to inflammaton / appearance?
Superficial / partial thickness -> acute inflammation with coagulative necrosis. Pain will be present.
Fullthickness -> extensive damage to blood vessels, nerve endings, and adnexal structures (i.e. sweat glands)
-> no pain at site of lesion, which will be black and leathery. Periphery may have pain due to partial thickness components.
What type of shock do burns cause initially and why?
Hypovolemic
- > increased vascular permeability due to inflammation and vessel damage (subsequent hypercoagulability)
- > evaporation of interstitial fluid due to loss of skin
What electrolyte imbalance happens in burns and why?
Hyperkalemia, due to cellular lysis from heat (high K+ in cells is released into interstitium)
Also hyponatremia due to loss of plasma into the interstitium and evaporation
What other type of shock can burns cause and how? What will this result in?
Septic shock, due to bacteremia which results from loss of skin barrier.
Septic shock can lead to multisystem organ failure and diffuse alveolar damage -> adult respiratory distress syndrome (ARDS) = respiratory failure
What GI side effect is a result of the acute, extreme physiological distress of burns?
Curling ulcers (think “Curling irons can burn”) -> gastric ulcers in the setting of a burn
What are the chronic results of burns in some people, and especially in children?
Children - contractures
Adults - Hypertrophic scars and keloids (extensive form of scar overgrowth)
What are the three responses to hyperthermia, from mildest to most severe?
- Heat cramps
- Heat exhaustion
- Heat stroke
What are the signs and symptoms of heat cramps, and what causes them?
Involuntary, painful muscle spasms during or after strenuous exercise
Caused by electrolyte abnormalities like hyponatremia (due to only replenishing water but not electrolytes)
What are the signs and symptoms of heat exhaustion? How will the skin feel?
Sudden dizziness, nausea, headache, profuse sweating, fatigue associated with hypotension, tachycardia, and a low-grade fever
Skin feels pale, cool, and moist -> vasoconstriction due to hypovolemia with sweating
What is the pathogenesis of heat exhaustion?
Extreme sweating leads to inadequately compensated hypovolemia, with slightly elevated body temperature and peripheral vasoconstriction to maintain blood pressure
What is the pathogenesis of heat stroke?
Inability to dissipate heat quickly enough and dehydration leads to loss of sweat.
- > highly elevated body temperature
- > denaturation of proteins / cell membranes with expression of heat shock proteins and amplified acute phase response
- > hsp’s will create septic shock-like response
What are the signs and symptoms of heat stroke?
High core body temp (>104F/40C)
Hot, dry, flushed skin (peripheral vasodilation for convection)
Tachycardia, neurologic symptoms, difficulty breathing
What are the most severe manifestations of heat stroke?
Multiorgan failure and rhabdomyolysis (skeletal muscle lysis)
