Question

A young boy, age 2 years, pulled a pot of boiling water over his head, arms, and chest, resulting in a mixed burn to the anterior surface of his head and arms, chest, and feet.

Discuss the pathophysiology to the manifestations listed above.

Answer 1

The pathophysiology of the burn

Is characterized by an inflammatory reaction that leads to a rapid oedema formation, due to increased microvascular permeability, vasodilation and increased extravascular osmotic activity. Due to the direct heat effect on the microvasculature and due to chemical mediators of inflammation these reactions occur. Due to the histamine, release the earliest stage of vasodilatation and increased venous permeability is commonly seen. Damage to the cell membranes caused by oxygen-free radicals that are released from polymorphonuclear leucocytes which would activate the enzymes catalyzing the hydrolysis of prostaglandin precursor (arachidonic acid) with rapid formation of prostaglandin as the result. Prostaglandins inhibit the release of norepinephrine and may thus be of importance in modulating the adrenergic nervous system; activated in response to thermal injury. The morphological interpretations of the changes in the functional ultrastructure of the blood lymph barrier following thermal injury are an increase in the numbers of vacuoles and many open endothelial intercellular junctions. Furthermore changes of the interstitial tissue after burn trauma are of great importance. The continuous loss of fluid from the blood circulation within the thermally damaged tissue leads to an increased haematocrit level and a rapid fall in plasma volume, with decreased cardiac output and hypoperfusion on the cellular level. If the fluids are not adequately restored burn shock develops. Furthermore, the burn wound provides a vast area of entry of surface infection with a high risk of septic shock(Aurturson, 1980)