Question Of The Day #53

This patient endured a high-speed motor vehicle accident, arrives with hypotension and bradycardia, and has a C6 vertebral body fracture on imaging.  These details support a diagnosis of neurogenic shock, a type of distributive shock.

Shock is an emergency medical state characterized by cardiovascular or circulatory failure.  Shock prevents peripheral tissues from receiving adequate perfusion, resulting in organ dysfunction and failure.  Shock can be categorized as hypovolemic, distributive, obstructive, or cardiogenic.  The different categories of shock are defined by their underlying cause (i.e., sepsis, hemorrhage, pulmonary embolism, etc.) and their hemodynamics which sometimes overlap.  The diagnosis of shock is largely clinical and supported by the history, vital signs, and physical exam.  Additional studies, such as laboratory investigations, bedside ultrasound, and imaging tests help narrow down the type of shock, potential triggers, and guide management.  The chart below details the categories of shock, each category’s hemodynamics, potential causes, and treatments.  

Neurogenic shock is caused by spinal cord damage above the T6 level.  Unlike other types of shock, neurogenic shock is characterized by hypotension and bradycardia (not tachycardia).  These vital sign abnormalities are caused by damage to sympathetic nervous system (Choice C).  Neurogenic shock has decreased systemic vascular resistance (warm extremities), not increased systemic vascular resistance (cool extremities) (Choice A).  Occult hemorrhage (Choice B) is always a concern in a trauma patient.  However, this would present with findings of hypovolemic/hemorrhagic shock (tachycardia, hypotension, cool extremities).  Tension pneumothorax (Choice D) is also unlikely as the patient has clear bilateral lung sounds on exam.  The best answer is Choice C.