DEFINITIONS OF SHOCKMany different

DEFINITIONS OF SHOCK
Many different categorization schemes have been used to define shock; in some instances
there may be overlap between categories. For the purposes of this discussion shock has been
categorized into four different forms based upon the causative pathophysiologic mechanism.
Ultimately the focus of therapy will be to optimize oxygen delivery. Cardiogenic shock is a
form of shock that results from heart failure but excludes those factors, which are outside the
heart (i.e. cardiac tamponade; caval syndrome). Pump failure may be due to hypertrophic or
dilative cardiomyopathy, valvular insufficiency or stenosis, arrhythmias or fibrosis. Distributive
shock is often used to describe shock states that are associated with flow maldistribution.
Initiating causes for this form of shock include sepsis, anaphylaxis, trauma and neurogenic.
Obstructive shock results from a physical obstruction in the circulatory system. Heartworm
disease, pericardial effusion, pulmonary embolism and gastric torsion can all contribute to
impaired blood flow. Hypovolemic shock is the result of decreased intravascular volume. The
decreased volume may be due to blood loss, third space loss or fluid losses due to excessive
vomiting, diarrhea, and diuresis. Hypovolemic shock is the most common form of shock seen
in small animals.