Consultation with the Specialist
Shock
Jon Tingelstad MD
A 7-year-old boy complains of left upper quadrant pain following a fall from a tree 4 hours earlier. A 3-year-old girl has a spreading hemorrhagic rash and a temperature of 40.6°C (105.2°F). An 18-month-old boy returned to the pediatric intensive care unit 3 hours ago following prolonged open heart surgery for repair of a complex congenital heart defect. What do these three pediatric patients have in common? Each is a potential candidate for the development of shock.
Discussion
Shock is a complex pathophysiologic state that results from circulatory dysfunction and leads to failure to provide adequate quantities of oxygen and other nutrients to meet the metabolic requirements of the body's tissues. The etiologies of shock are numerous. Hypovolemic shock results from the loss of effective blood volume. For example, it may follow trauma to the spleen with unrecognized massive hemorrhage or it may be the result of severe dehydration caused by acute, explosive gastroenteritis. Septic shock, often the combination of multiple factors, follows the release of a series of mediators that cause peripheral vasodilation, myocardial depression, hypotension, ventilatory insufficiency, and anemia. Cardiogenic shock may occur after surgical repair of congenital heart defects, especially if the procedure is prolonged and difficult, or it may be associated with severe myocarditis, cardiomyopathy, or prolonged tachyarrhythmias. Decreased myocardial contractility leads to low cardiac output and hypotension.
