Shock is defined as hypotension that is severe and results in end-organ hypoperfusion. It is a life threatening condition and appropriate therapy is crucial in a timely fashion.

Cardiogenic shock: This occurs when the primary problem is low cardiac output from heart failure. Causes include acute myocardial infarction, acute valvular regurgitation (aortic or mitral), and dilated cardiomyopathies. Treatment includes correcting the primary cause and intravenous inotropic therapy. Intraaortic balloon counterpulsation is frequently beneficial. Refractory cases may require emergent left ventricular assist device placement.

Hypovolemic shock: This occurs from severe intravascular volume depletion as occurs in dehydration or acute hemorrhage. The treatment is aggressive IV fluid hydration, blood transfusion and correction primary cause.

Distributive shock: This occurs with something causes intense systemic vasodilation (septic shock or neurogenic shock). Treatment is directed at the source. Pressors such as norepinephrine are frequently used to maintain blood pressure until the primary problem resolves.