Which of the following is the most likely cause of this patient’s condition?
This trauma patient arrives with hypotension, tachycardia, absent unilateral lung sounds, and distended neck veins. This should raise high concern for tension pneumothorax, which is a type of obstructive shock (Choice C). This diagnosis should be made clinically without X-ray imaging. Bedside ultrasound can assist in making the diagnosis by looking for bilateral lung sliding, if available. Treatment of tension pneumothorax should be prompt and includes needle decompression followed by tube thoracostomy. Other types of shock outlined in Choices A, B, and D do not fit the clinical scenario with information that is given.
Recall that 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.
- Morgenstern J. (2015). An approach to undifferentiated hypotension. First10EM. Retrieved from https://first10em.com/undifferentiated-hypotension/
- Pickens, A. (2018). EM in 5: Shock. EMDocs. Retrieved from http://www.emdocs.net/em-in-5-shock/
- Richards JB & Wilcox SR. (2014). Diagnosis and management of shock in the emergency department. EB Medicine, 16(3), 1-24. Retrieved from https://www.cmua.nl/Cmua/Inwerken_files/0314%20Shock.pdf