Burns injury

Question 1

What is the aetiology of burns? (x3)

Answer 1

Thermal, electrical and chemical.

Question 2

What is the pathophysiology of burns? (x4)

Answer 2

• LOCAL RESPONSE: coagulation of injured tissue and microvascular reactions in surrounding dermis
• SYSTEMIC RESPONSE: in burns covering over 20% of the body surface, leading to release of vasoactive mediators from injured tissue. The result is interstitial oedema and organ dysfunction
• There is also fluid loss through the burn itself
• In well-resuscitated patients, the body responds to burns with a hypermetabolic response characterised by almost doubling the CO with increased gluconeogenesis and protein catabolism

Question 3

How are burns classified?

Answer 3

Based on size (percentage total body surface area) and depth (first to fourth degree)

Question 4

What defines the degree of a burn?

Answer 4

• FIRST-DEGREE: erythema of epidermis only, usually dry and painful e.g., sunburn
• SECOND-DEGREE: epidermis and upper dermis leading, usually WET and painful e.g., scalding
• THIRD-DEGREE: full thickness of epidermis and dermis, usually dry and insensate (lacking sensation) e.g., flame or contact injury
• FOURTH-DEGREE: involves subcutaneous tissue, tendon or bone e.g., high-voltage electrical injury

Question 5

What are the signs and symptoms of burns? (x4)

Answer 5

• Erythema, dry and painful in first degree
• Wet and painful in second degree
• Dry and insensate in third degree
• Cellulitis (esp. Staph aureus) is common in burns wounds

Question 6

What are the investigations for burns? (x4)

Answer 6

• FBC: in severe burns which may show hypovolaemia, neutropenia or thrombocytopenia (latter two are also indicators of sepsis)
• METABOLIC PANEL: fluid loss may lead to hyponatraemia, hypokalaemia
• CARBOXYHAEMOGLOBIN/ABG: if inhalational mechanism involved, common in thermal burns
• WOUND BIOPSY CULTURE: if wound infection