What is the characteristic heart rate response in neurogenic shock?

• A. Increased heart rate
• B. No heart rate compensation
• C. Bradycardia with high blood pressure
• D. Normal heart rate response

Answer: (B)

In neurogenic shock, the characteristic heart rate response is a lack of compensatory tachycardia, which corresponds to the "no heart rate compensation" option. This is a result of the loss of sympathetic tone due to spinal cord injury or disruption of the autonomic nervous system, particularly affecting the sympathetic outflow that normally helps regulate heart rate.

In healthy individuals, when blood pressure drops, the body typically responds with an increase in heart rate to help maintain adequate circulation; however, in neurogenic shock, the autonomic balance is disrupted. The vagus nerve remains active, leading to unopposed parasympathetic activity which can cause bradycardia. This response is atypical and is a defining feature of neurogenic shock compared to other types of shock where an increased heart rate would generally be expected as a compensatory mechanism.

Thus, the absence of the expected heart rate increase despite hypotension is a hallmark of neurogenic shock, distinguishing it from other shock states where tachycardia is the norm.