A 19-year-old man is brought to the emergency department after a major motor vehicle accident. He was an unrestrained driver and confesses to consuming a moderate amount of alcohol several hours earlier. He did not lose consciousness. The patient's blood pressure is 150/95 mm Hg and heart rate is 110/min. His respirations are shallow and rapid. He is able to move his extremities and obey commands. His pupils are equal and reactive to light. Inspection shows anterior chest bruises and peripheral cyanosis. Neck veins are flat and the trachea is midline. Breath sounds are heard symmetrically over both lung fields. Which of the following is the most likely diagnosis in this patient?

Question

A 19-year-old man is brought to the emergency department after a major motor vehicle accident.  He was an unrestrained driver and confesses to consuming a moderate amount of alcohol several hours earlier.  He did not lose consciousness.  The patient's blood pressure is 150/95 mm Hg and heart rate is 110/min.  His respirations are shallow and rapid.  He is able to move his extremities and obey commands.  His pupils are equal and reactive to light.  Inspection shows anterior chest bruises and peripheral cyanosis.  Neck veins are flat and the trachea is midline.  Breath sounds are heard symmetrically over both lung fields.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c1d6_2558_8f63_518f0ce2a72c_MD0005_00 This patient has tachypnea and tachycardia, with shallow breathing, anterior chest bruises, and signs of inadequate ventilation (cyanosis); together these suggest possible occult flail chest. Flail chest is usually the result of double rib fractures in more than one site, with paradoxical motion of the free segment of the chest wall during inspiration. It is often accompanied by muscular spasm and pain as well as pulmonary contusions, which lead to hypoxemia and increased work of breathing. The paradoxical or segmental chest wall movement will typically make the diagnosis of flail chest obvious. However, in many cases, gross findings may be absent due to muscle splinting, shallow breathing, or mechanical ventilation. Uncomplicated cases of flail chest may be managed nonoperatively with supplemental oxygen, noninvasive positive-pressure ventilation, and medications for pain control. However, mechanical ventilation and surgical stabilization may be necessary in more severe cases. (Choice A) Cardiac contusion, especially if massive, may lead to hemodynamic instability; however, disordered breathing (rapid, shallow breathing) with stable vital signs would not be typical. (Choice B) Cardiac tamponade is characterized by hypotension and neck vein distension. (Choices D and E) Pneumothorax and massive hemothorax are typically associated with hypotension, tracheal deviation, and a unilateral decrease in breath sounds. Educational objective: Flail chest is the result of double rib fractures in more than one site, resulting in paradoxical movement of the flail segment during inspiration. The diagnosis may be obvious on examination, but many cases are occult. Management includes supplemental oxygen, pain control (invasive or noninvasive), positive-pressure ventilation, and surgical stabilization. References: The management of flail chest. (http://www.ncbi.nlm.nih.gov/pubmed/17650694)

A 19-Year-Old Man Is Brought to the Emergency Department After