What are the four types of shock?

• A. Hypovolemic, Cardiogenic, Distributive, Obstructive
• B. Hypovolemic, Cardiogenic, Anaphylactic, Septic
• C. Hypoxic, Cardiogenic, Distributive, Obstructive
• D. Hypovolemic, Neurogenic, Distributive, Obstructive

Answer: (A)

Shock is categorized by the underlying problem with circulating blood. The four broad types are hypovolemic, cardiogenic, distributive, and obstructive. Hypovolemic shock arises from loss of intravascular volume (bleeding, dehydration). Cardiogenic shock results from pump failure of the heart (myocardial infarction, significant arrhythmias). Distributive shock involves widespread vasodilation and maldistribution of blood flow (seen in sepsis, anaphylaxis, and neurogenic causes). Obstructive shock is due to a physical barrier to blood flow (cardiac tamponade, tension pneumothorax, massive pulmonary embolism).

Other options mix conditions that aren’t separate categories of shock or represent just causes within distributive shock (like anaphylaxis or septic shock) or label a non-shock issue (hypoxic). The four primary categories above best capture the major mechanisms of shock.