Kawasaki disease: Nursing

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Kawasaki disease is a condition associated with acute inflammation of medium-sized arteries; and it’s typically seen in children between the ages of 6 months and 5 years.

First, let’s cover some basic physiology of arteries. There are three main types of arteries: large arteries, like the aorta; medium arteries, like the coronary arteries that supply the heart; and finally, small arteries.

Now, each artery consists of three layers: from outside in, there’s the tunica adventitia, which has loose connective tissue; then the tunica media, which mainly contains smooth muscle cells but also some elastic tissue; and finally the tunica intima, or endothelium, which consists of a single layer of endothelial cells on top of a layer of connective tissue, called lamina propria.

The exact cause of Kawasaki disease remains unknown, but some sources suggest that it might be triggered by an infection or autoimmune process. The most important risk factors associated with Kawasaki disease include being below 5 years of age, being assigned male at birth, and having Asian or Pacific Islander ancestry.

Now let’s look at the pathology of Kawasaki disease. Typically the client’s immune system is activated to fight off an infection. Then, for reasons we still don’t understand, the immune cells like neutrophils, macrophages and even B cells and T cells start attacking the endothelial lining of medium sized blood vessels, most commonly the coronary arteries of the heart. Now, these cells cause inflammation within the artery which damages the endothelial lining. They can even invade into the tunica media where they destroy the elastin and collagen fibers that make up the arterial wall.

Now, Kawasaki disease can cause serious life-threatening cardiovascular complications. First, damage to the endothelium exposes collagen and tissue factors in the tunica media, which can trigger coagulation. Clots forming on the arterial wall reduce blood flow to heart tissue, causing ischemia. Next, inflammation leads to fibrosis within the arterial wall, which makes the walls thicker and the arterial lumen narrower, reducing blood flow even more. Finally, damage to the arterial wall weakens it, so it can balloon out forming an aneurysm. If the aneurysm ruptures, blood flow will be further reduced. So all three processes reduce blood flow to the heart; this causes ischemia, and potentially myocardial infarction or even death.