A 37-year-old woman comes to the emergency department due to shortness of breath and left-sided chest pain that have been progressively worsening since beginning suddenly 2 days ago. The patient was diagnosed with multiple sclerosis 5 years ago. She uses a wheelchair due to spastic paraparesis and has scanning speech. Temperature is 36.7 C (98.1 F), blood pressure is 120/70 mm Hg, pulse is 110/min, and respirations are 20/min. Pulse oximetry is 94% on room air. Pulmonary examination is normal except for reduced breath sounds and dullness to percussion at the left lung base. The abdomen is soft and nontender. There is no peripheral edema. Laboratory results are as follows: Chest x-ray reveals a small left-sided pleural effusion. No infiltrates are seen. Which of the following is the most likely cause of this patient's pleural effusion?

Question

A 37-year-old woman comes to the emergency department due to shortness of breath and left-sided chest pain that have been progressively worsening since beginning suddenly 2 days ago.  The patient was diagnosed with multiple sclerosis 5 years ago.  She uses a wheelchair due to spastic paraparesis and has scanning speech.  Temperature is 36.7 C (98.1 F), blood pressure is 120/70 mm Hg, pulse is 110/min, and respirations are 20/min.  Pulse oximetry is 94% on room air.  Pulmonary examination is normal except for reduced breath sounds and dullness to percussion at the left lung base.  The abdomen is soft and nontender.  There is no peripheral edema.  Laboratory results are as follows:  Chest x-ray reveals a small left-sided pleural effusion.  No infiltrates are seen.  Which of the following is the most likely cause of this patient's pleural effusion?

Quizplus · Accepted Answer

This young patient with prolonged immobilization has sudden-onset chest pain, dyspnea, tachycardia, and hypoxia, suggesting a pulmonary embolism (PE). Patients with PE commonly develop small pleural effusions due to hemorrhage or inflammation. The effusions tend to be exudative and grossly bloody, and they can be associated with pain due to pleural irritation. Leukocytosis and/or peripheral neutrophilia may be seen, as with any acute inflammatory process. Patients with suspected PE should get confirmatory testing (eg, CT pulmonary angiography). (Choice A) Aspiration pneumonia is common in patients with multiple sclerosis who have bulbar symptoms (eg, scanning speech), which can cause difficulty in swallowing. It may cause pleuritic pain, dyspnea, leukocytosis, and an exudative (parapneumonic) pleural effusion. However, lobar infiltrate on chest x-ray would be expected; parapneumonic effusion within 2 days of symptom onset is extremely unlikely in the absence of an infiltrate. In addition, the onset of aspiration pneumonia is typically insidious (often progressing over several weeks), not sudden as with this patient's presentation; a productive, often foul-smelling cough is common. (Choice B) Congestive heart failure (CHF) can cause transudative pleural effusions due to increased hydrostatic pressure. These effusions are often bilateral (or right-sided) and would be less likely to cause reduced breath sounds at the left lung base only. In addition, this patient has no risk factors for CHF and no signs of volume overload (eg, lower extremity edema, jugular venous distension). (Choice C) Hypoalbuminemia can cause transudative pleural effusions due to decreased oncotic pressure. These effusions are also usually bilateral and are less likely to cause symptoms acutely or to be associated with chest pain. Other manifestations of decreased oncotic pressure (eg, ascites, edema) can be seen. In addition, hypoalbuminemia is uncommon in a young patient in the absence of a comorbidity such as malnutrition. (Choice D) Patients on immunosuppressive medication are at increased risk for malignancy. Malignant effusions tend to be large, presenting with progressive shortness of breath over several days or weeks (subacute) rather than with sudden-onset chest pain. This patient has acute chest pain with a small, painful effusion, making PE more likely. Educational objective: Sudden-onset dyspnea, chest pain, and tachycardia with no consolidation on chest imaging suggests a pulmonary embolism (PE). PE can cause pleural effusions (typically small, exudative, and bloody). References: Pleural effusion in pulmonary embolism. (http://www.ncbi.nlm.nih.gov/pubmed/22498732)

A 37-Year-Old Woman Comes to the Emergency Department Due to Shortness