BURNS Flashcards
WHAT IS A BURN?
Injury to tissues caused by contact with Flames, Friction, Radiation, Electrical, Chemical and Heat. Heat is temp and
time dependent to cause burns, e.g., 4°C temp takes 6 hours to cause deep burns. 65°C takes 45–60 seconds to cause deep full thickness burn
HOW ARE BURNS CLASSIFIED?
- Classification based on Skin thickness involved
(i) Superficial burn-First degree burn
(ii) Partial thickness burn-Second Degree
a. Superficial partial thickness
b. Deep partial thickness
(iii) Full thickness burns-Third Degree
(iv) Fourth degree - Depending on the Percentage of Burns
a. Mild (Minor)
b. Moderate
c. Major (severe)
DESCRIBE SUPERFICIAL (1ST DEGREE) BURNS
Involves epidermis only
No blisters
Reddish(Erythema)
Capillary return is clearly visible when blanched
Painful - Pin prick test is positive- (severe pain to pin prick)
Heals rapidly by re-epithelialization with no scars / without residual scarring in 2 weeks.
DESCRIBE SUPERFICIAL PARTIAL THICKNESS BURNS
Involves epidermis and the papillary dermis
burns goes no deeper than the papillary dermis
Red/erythematous
Blistering, moist
Painful
Heal by epithelialization, complete by 14 days
Minimal or no permanent scars but can leave discoloration
DESCRIBE DEEP PARTIAL THICKNESS BURNS
Involves epidermis, upper dermis and varying degrees of lower dermis
Involve damage to the deeper parts of the reticular dermis
Pale, mottled appearance
Fixed staining (no blanching)- Colour does not blanch with pressure under the examiner’s finger
May be painful or insensate (depending on depth) - Reduced sensation & pt. is unable to distinguish sharp from blunt pressure with a needle exam.
Heal by combination of epithelialization and wound contracture
May take weeks can leave significant scars and contractures over joints depending on time taken to heal
DESCRIBE FULL THICKNESS (3RD DEGREE) BURNS
Both dermis and epidermis burnt.
No blisters
Skin appendages damaged- whole of the dermis is destroyed
Have a hard, leathery feel
Look dull or dark with no capillary return ( no blanching)
Pin prick sensation test - negative (Insensitive) Extensive third degree burns with Escher.
Burns are completely anaesthetised: a needle can be stuck deep into dermis without any pain or bleeding.
Escher to the limb extremities may be present- affected area is charred, parchment like, painless and insensitive, with thrombosis of superficial vessels.
- Charred, denatured, insensitive contracted full thickness burn is called as Escher.
It requires grafting
DIFFEREENTIATE BETWEEN PARTIAL THICKNESS AND FULL THICKNESS BURNS
a. Partial thickness burns: Either 1st or 2nd degree burn which is red and painful, often with blisters.
b. Full thickness burns: 3
rd degree burns which is charred, insensitive, deep involving all layers of the skin.
DESCRIBE MILD BURNS ON THE BASIS OF %
Partial thickness burns <15% in adult or <10% in children.
Full thickness burns less than 2%.
Can be treated on outpatient basis
DESCRIBE MODERATE BURNS ON THE BASIS OF %
Second degree of 15–25% burns (10–20% in children).
Third degree between 2–10% burns.
Burns which are not involving eyes, ears, face, hand, feet, perineum
DESCRIBE MAJOR BURNS ON THE BASIS OF %
Second degree burns more than 25% in adults, in children more than 20%.
All third degree burns of 10% or more.
Burns involving eyes, ears, feet, hands, perineum.
All inhalation and electrical burns.
Burns with fractures or major mechanical trauma
WHAT ARE THE 3 MAIN CONCERNS UPON PRESENTATION OF A PT WITH BURNS AND WHY?
When you are on call, the pt. comes with burns. What 3 things would you tell the consultant on phone about pt.?
a. The % ESTIMATE of burns: as this will help in Mx of pt., whether to admit or not and expected complications
b. What CAUSED the burns - this will help tell the depth of the burns
Domestic burns are usually superficial
Industrial burns are usually deep
c. What TIME did the pt. get burnt - this will help in fluid replacement therapy
HOW DO YOU ESTIMATE THE % OF BURNS?
Wallace’s rule
Lund & Browder chart
Rule of palms
OUTLINE WALLACE RULE IN ESTIMATING BURN %
A) Wallace’s rule - used for early assessment. This rule can either be;
(i) Rule of 9 in adults
Head – 9%
Arm- 9%
Trunk- 18x2= 36%
Leg – 18%
Perineum- 1%
(ii) Rule of 7 in children
Head – 28%
Arm- 7%
Trunk – 28%
Perineum- 2%
Leg- 14%
WHAT IS THE LUND & BOWDER CHART?
b) Lund & Browder chart- most accurate
Better method for assessing the burn wounds.
Here each part of the body is individually assessed for involvement of burns.
OUTLINE THE RULE OF PALMS IN ESTIMATING BURN %
c) Rule of palms
Patient’s entire hand area is 1%. Clean piece of paper
is cut to size of hand and through that percentage of
burns is assessed
EXPLAIN THE PATHOPHYSIOLOGY OF BURNS
Burns cause damage to the skin (most common), airway and lungs, with life-threatening consequences.
Changes occur because burned skin activates a web of inflammatory
cascades →release of neuropeptides →increase capillary permeability → decreased plasma oncotic pressure caused by loss/extravasation of protein and fluid → intravascular fluid compartment depletion → Hypovolaemia→Shock
Increase capillary permeability and reduced oncotic pressure cause fluids, solutes & proteins to move from intra- to extravascular space
Volume of fluid lost is directly proportional to area of burns
Above 15% of TBSA, the loss of fluid can produce shock.
Catecholamine levels are raised leading to lipolysis, proteolysis, increased release of glutamine & alanine from skeletal muscles.
Urea production is increased due to more proteolysis.
Physical burn injury by dry hot air to airway below the larynx is rare as heat exchange mechanisms in supraglottic airway are usually able to absorb the heat from hot air. That mechanism will cause the epithelium to be damaged and supraglottic oedema ensues blocking the airway
But steam has large latent heat of evaporation & cause thermal damage to lower airway epith leading to rapid swelling & may detach from bronchial tree, creating casts, both of which compromise the patency of airway.
Inhalational injury: caused by minute particles within thick smoke, which are not filtered by the upper airway, but are carried down to lung parenchyma.
These stick to moist lining, cause an intense reaction in alveoli (chemical pneumonitis) leading to edema within alveolar sacs & decrease gaseous exchange, & may gives rise to a bacterial
pneumonia
OUTLINE THE ZONES OF BURNT INJURY AS DESCRIBED BY JACKSON
- Zone of coagulation- this occurs at the point of maximum damage. In this zone there is irreversible tissue loss due to coagulation of the constituent proteins.
- Zone of stasis- surrounds zone of coagulation & is characterized by reduced tissue perfusion. The tissues of this zone are potentially salvageable. The main aim of burn resuscitation is to increase tissue perfusion here and prevent any tissue damage becoming irreversible. Additional insults, such as prolonged hypotension, infection or eodema – can convert this zone into an area of complete tissue loss
- Zone of hyperemia – in this outermost zone, tissue perfusion is increased. Tissues here will invariably recover unless there is sepsis or prolonged hypotension
WHAT ARE THE CLINICAL FEATURE OF BURNS?
History of burn
Pain, burning, anxious status, tachycardia, tachypnoea, fluid loss
In severe degrees features of shock
WHAT IS INDICATIVE OF A POTENTIALLY BURNED AIRWAY?
- A H/O being trapped in the presence of smoke or hot gases
- Burns on palate or nasal mucosa, or loss of all hairs in the nose
- Deep burns around the mouth and neck
SYSTEMATICALLY OUTLINE THE EARLY COMPLICATIONS OF BURNS
(i) Respiratory System- Altered ventilation-perfusion ratio.
a. Airway obstruction - due to inhalation burns (causes pulmonary edema, ARDS, respiratory arrest)
b. Breathing difficulties as a result of respiratory distress due to eschar around the chest. -Mechanical block on rib movement- Burned skin is very thick and stiff, and can physically stop the ribs movt if there is a large full-thickness burn across the chest
c. Pulmonary oedema due to burn injury, fluid overload, inhalation injury causing ARDS
(ii) CVS- Cardiac dysfunction is due to: Hypovolaemia, release of cardiac depressants and Hormonal causes like catecholamines, vasopressin, and angiotensins
a. Edema due to release of inflammatory mediator to produce vasodilatation leading to increased capillary permeability. It’s due to altered pressure gradient because of injury to basement membrane.
b. Hypovolaemia due to fluid loss as a result of increased capillary permeability due to SIRS, and this may lead to renal failure.
c. Hypoxia due to destruction of red blood cells because thermal injury causes coagulative necrosis to the epidermis and underlying tissue. And also its due pulmonary eodema, and breathing difficulties
d. Shock - due to hypovolaemia & systemic inflammatory response syndrome (SIRS) or due to an inflammatory response causing release of inflammatory mediators like cytokines which leads to vasodilatation in burnt areas
e. Toxic shock can occur if there is 20 bacterial infection causing bacteremia. It is a life-threatening exotoxin mediated disease caused by Staphylococcus aureus, common in children,
(iii)MSS
a. Hypothermia as a result of loss of thermoregulatory function of the skin due to damage
(iv) GUS
a. Fluid and electrolyte imbalance due to dehydration, hypernatraemia, hypokalaemia and hypocalcaemia
b. Renal changes are due to:
Release of ADH from posterior pituitary to cause maximum water reabsorption.
Release of aldosterone from adrenals to cause maximum sodium reabsorption.
(v) Metabolic.
Hyperglycemia due to hypercatabolism and mobilization of glucose as a result of release of stress hormones
Many poisonous gases are given off in a fire e.g. CO, (a product of incomplete combustion), which binds to Hb with an affinity 240 times > that of O2 and so blocks O2 transport.
Another metabolic toxin produced in house fires is hydrogen cyanide, which causes a metabolic acidosis by interfering with mitochondrial respiration
Hypermetabolic rate – lead to deficiency of vitamins and essential elements→ malnutrition
Negative Nitrogen balance
Metabolic acidosis due to hypoxia and lactic acid
OUTLINE THE INTERMEDIATE COMPLICATIONS OF BURNS
(i) Wound infection- by staphylococcus aureus, beta haemolytic streptococcus, Pseudomonas, Klebsiella leads to bacteraemia, septicaemia. Occasionally it can also be Fungal & viral. Can be local or systemic infection.
Low immunity, loss of proteins and Igs, loss of barrier causes sepsis. Opportunistic infection is also common
(ii) Septicemia- Burns itself creates immunosuppression (cell-mediated immunity). Sepsis is identified by fever, lethargy, leucocytosis, and thrombocytopenia. Hypothermia is an omnious sign of infection
(iii) Anemia- due to haemocoagulation
(iv) Stress ulcers (curling ulcers) - due to decreased mucosal defence; not due to increased HCl. Hypovolaemia→ischaemia of GIT mucosa, erosive gastritis - Curling’s ulcer (seen in burns >35%)
(v) Paralytic ileus due to electrolyte imbalance
(vi) Compartment syndrome due to eschar (slough produced) - A circumferential full thickness burn to a limb acts as a tourniquet as the limb swells. If untreated, this will progress to limb-threatening ischaemia
(vii) Bowel mucosal ischaemia causes poor motility, reduced food digestion and absorption with increased translocation of bacteria causing peritoneal oedema, septicaemia and abdominal compartment syndrome
(vii) Poor healing, ankylosing (joint stuffiness)
(viii) Renal failure- Toxins released from the wound along with sepsis causes acute tubular necrosis, e.g. Myoglobin released from muscles (in case of electric injury or from eschar) is most injurious to kidney
(ix) Septic arthritis
(x) Hypoproteinemia leading to malnutrition
(xi) Ectropion- retraction of eyelid
(xii) Amputation
OUTLINE THE LATE COMPLICATIONS OF BURNS
Late Complications
(i) Contractures
(ii) Hypertrophic scar or keloids
(iii) Marjolins ulcers (malignant)
(iv) Nerve compression
(v) Psychological effects- cosmetic effect
(vi) Chemical injury causes severe GIT disturbances like erosions, perforation, stricture oesophagus (alkali), pyloric stenosis (acid), and mediastinal injury.
(vii) Other problems commonly seen are DVT, pulmonary embolism, urinary infection, bed-sores, severe
malnutrition due to hypercatabolic status, respiratory infection
