A 43-year-old woman on the surgical floor is being evaluated for increasing shortness of breath. She was brought to the emergency department 8 hours ago following a high-speed motor vehicle collision. The patient had been drinking alcohol prior to driving. She was restrained and air bags were deployed, but her right knee smashed against the front console. Trauma workup revealed a right femur fracture as well as bruising of the face and chest without underlying fractures. The patient received 3 L of isotonic fluids and was admitted for observation and pain management prior to anticipated fracture fixation. She now has increased work of breathing. Blood pressure is 138/82 mm Hg, pulse is 102/min, and respirations are 24/min. Pulse oximetry shows an oxygen saturation of 90% on 4 L of oxygen. The patient is alert with no focal neurological deficits. Diffuse rales are heard in the anterior lung fields bilaterally. Heart sounds are normal. There are no other changes to the clinical examination. CT scan of the chest reveals peripheral, anterior ground-glass opacities in both lungs. Which of the following is the most likely diagnosis in this patient?

Question

A 43-year-old woman on the surgical floor is being evaluated for increasing shortness of breath.  She was brought to the emergency department 8 hours ago following a high-speed motor vehicle collision.  The patient had been drinking alcohol prior to driving.  She was restrained and air bags were deployed, but her right knee smashed against the front console.  Trauma workup revealed a right femur fracture as well as bruising of the face and chest without underlying fractures.  The patient received 3 L of isotonic fluids and was admitted for observation and pain management prior to anticipated fracture fixation.  She now has increased work of breathing.  Blood pressure is 138/82 mm Hg, pulse is 102/min, and respirations are 24/min.  Pulse oximetry shows an oxygen saturation of 90% on 4 L of oxygen.  The patient is alert with no focal neurological deficits.  Diffuse rales are heard in the anterior lung fields bilaterally.  Heart sounds are normal.  There are no other changes to the clinical examination.  CT scan of the chest reveals peripheral, anterior ground-glass opacities in both lungs.  Which of the following is the most likely diagnosis in this patient?

Quizplus · Accepted Answer

11ec25c8_d94f_9174_bc81_a533e69056f3_MD0003_00 Despite being restrained during the high-speed motor vehicle collision, this patient sustained blunt thoracic trauma with chest wall (and facial) bruising, likely from airbag impact. Blunt force to the chest wall can injure the underlying lung, resulting in alveolar hemorrhage and edema. Subsequent resuscitative fluid administration can exacerbate the alveolar edema, leading to progressive dyspnea, tachypnea, and hypoxemia. On CT scan, the alveolar edema can appear as ground-glass opacities in the lung adjacent to the affected chest wall (eg, anterior, peripheral lung in this patient); this pattern and distribution is classic for pulmonary contusion. Pulmonary contusion is common (25%-35% of cases) following blunt thoracic trauma. Because clinically significant alveolar edema may take up to 24 hours to accumulate, pulmonary contusion may not be apparent immediately following an injury, and initial chest x-ray is often negative. CT scan of the chest is more sensitive and can identify the classic irregular, nonlobular (ie, not restricted by anatomic landmarks) infiltrates. Management involves pain control, pulmonary hygiene, and respiratory support. CT scan (Choice A) The patient's alcohol use prior to driving increases her risk of aspiration. Although aspiration pneumonia can cause tachypnea and hypoxemia with pulmonary infiltrates, it typically has accompanying fever, cough, and purulent sputum production. The infiltrate distribution depends on the patient's position during the aspiration event; however, peripheral, nonlobular infiltrates are unlikely. (Choice B) Although bronchial rupture can cause progressive shortness of breath and hypoxemia, evidence of air leakage from the tracheobronchial tree (eg, pneumothorax, pneumomediastinum) is typically present on CT scan. (Choice C) Tachypnea and hypoxemia in the setting of femur fracture are concerning for fat embolism. However, patients with fat embolism classically have accompanying neurological abnormalities and petechial rash, as well as a latency period of 12-72 hours after the initial injury. (Choice D) Hemothorax (eg, from injured lung parenchymal vessels) can cause tachypnea and hypoxemia but typically appears as a pleural effusion on CT scan. (Choice E) Myocardial contusion can cause contractile dysfunction (eg, left ventricle) and cardiogenic shock with tachycardia and hypoxemia. However, these symptoms would be accompanied by hypotension. In addition, associated pulmonary edema would be diffuse, rather than anterior and peripheral. Educational objective: Blunt thoracic trauma can injure the underlying lung. The resulting alveolar hemorrhage and edema-often worsened by fluid resuscitation-can cause dyspnea, tachypnea, and hypoxemia. Irregular, nonlobular infiltrates on chest x-ray or CT scan are classic for pulmonary contusion. References: Pulmonary contusion. (http://www.ncbi.nlm.nih.gov/pubmed/30906578) Lung contusion: a clinico-pathological entity with unpredictable clinical course. (http://www.ncbi.nlm.nih.gov/pubmed/27162815)

A 43-Year-Old Woman on the Surgical Floor Is Being Evaluated