Rosh Emergency Medicine Practice Test 2025 - Free Emergency Medicine Practice Questions and Study Guide

Neurogenic shock is characterized by bradycardia (slow heart rate) and hypotension (low blood pressure) due to the loss of sympathetic tone. This type of shock typically occurs after a spinal cord injury, which disrupts the sympathetic nervous system's ability to regulate vascular tone. Inadequate sympathetic stimulation leads to vasodilation and decreased systemic vascular resistance, causing hypotension. The resulting bradycardia occurs because the heart is not sufficiently stimulated by the autonomic nervous system, which normally helps maintain heart rate in response to lower blood pressure.

In contrast, other types of shock present differently. Cardiogenic shock usually involves tachycardia (rapid heart rate) due to the heart's inability to pump effectively, leading to hypoperfusion. Anaphylactic shock, caused by a severe allergic reaction, typically features hypotension accompanied by tachycardia as the body attempts to compensate for low blood volume after widespread vasodilation and increased permeability. Hypovolemic shock, resulting from significant fluid loss, also presents with tachycardia as a compensatory mechanism to maintain adequate perfusion. Thus, the specific combination of bradycardia and hypotension is a hallmark of neurogenic shock.