Which type of shock may occur due to a massive pulmonary embolism?

A massive pulmonary embolism (PE) leads primarily to obstructive shock. In this type of shock, there is a physical obstruction in the cardiovascular system that impairs the heart's ability to pump blood effectively. When a large embolus occludes a significant portion of the pulmonary vasculature, it greatly increases the pressure in the pulmonary arteries, leading to reduced blood flow to the left side of the heart and subsequently to systemic circulation.

This results in a decreased cardiac output, which is the hallmark of obstructive shock. Patients may present with signs such as sudden onset dyspnea, hypotension, tachycardia, and potentially altered mental status due to inadequate perfusion. This scenario starkly contrasts with other forms of shock, such as hypovolemic shock, which involves a significant loss of blood volume, or cardiogenic shock, which results from the heart's failure to pump effectively due to conditions like myocardial infarction. Distributive shock, characterized by systemic vasodilation and impaired vascular tone, is often associated with sepsis or anaphylaxis, rather than a mechanical obstruction caused by a PE.

Therefore, in the context of a massive pulmonary embolism, the classification as obstructive shock is well-supported by the underlying