A 53-year-old woman is evaluated for fatigue, malaise, and exertional shortness of breath. She describes a dry cough that has been present over the last year and frequent joint pain and swelling in her hands and wrists. She has no other medical problems and is a lifetime non-smoker. The patient emigrated from Ecuador 3 months ago. Tuberculosis and HIV testing done for immigration screening 6 months ago were normal.
Vital signs are within normal limits. Her body mass index is 20 kg/m². There is a 2/6 mid-systolic murmur at the right upper sternal border. Breath sounds are decreased at the right lung base. There are no skin rashes or peripheral edema. The patient has mild synovitis involving bilateral metacarpophalangeal joints.
Her hemoglobin is 10.2 g/dL and mean corpuscular volume is 85 fL. Chest x-ray shows a moderate right-sided pleural effusion. Thoracentesis shows yellow-greenish fluid with the following results:

Which of the following is the most likely cause of this patient's pleural effusion?

Question

A 53-year-old woman is evaluated for fatigue, malaise, and exertional shortness of breath. She describes a dry cough that has been present over the last year and frequent joint pain and swelling in her hands and wrists. She has no other medical problems and is a lifetime non-smoker. The patient emigrated from Ecuador 3 months ago. Tuberculosis and HIV testing done for immigration screening 6 months ago were normal.
Vital signs are within normal limits. Her body mass index is 20 kg/m². There is a 2/6 mid-systolic murmur at the right upper sternal border. Breath sounds are decreased at the right lung base. There are no skin rashes or peripheral edema. The patient has mild synovitis involving bilateral metacarpophalangeal joints.
Her hemoglobin is 10.2 g/dL and mean corpuscular volume is 85 fL. Chest x-ray shows a moderate right-sided pleural effusion. Thoracentesis shows yellow-greenish fluid with the following results:

Which of the following is the most likely cause of this patient's pleural effusion?

Quizplus · Accepted Answer

11ec193a_98e5_3b89_853d_e76a72b253fb_MD0002_00 Using Light's criteria, an exudate is defined by the presence of one or more of the following: pleural fluid protein/serum protein ratio >0.5, pleural fluid lactate dehydrogenase (LDH)/serum LDH ratio >0.6, or pleural fluid LDH >2/3 the upper limit of normal for serum LDH. Careful observation of the pleural fluid itself may be helpful in determining the cause (eg, straw-colored [transudate], milky-white [chylothorax], or purulent [empyema]). Pleural fluid with low pH, very low glucose levels (< 30 mg/dL), and extremely high LDH levels (>1000 U/L) are typically found in empyema or rheumatoid pleurisy. Rheumatoid effusions are often yellow-greenish in appearance and have cell counts <5000/µL with predominantly lymphocytes. In contrast, fluid in empyema appears purulent with a high cell count (>50,000/µL) and neutrophilic predominance (Choice A). This patient has symptoms of joint pain and swelling which along with exudative rheumatoid effusion, is suggestive of rheumatoid arthritis (RA). Rheumatoid effusions are typically found in 5% of patients with RA. (Choice B) Hypothyroidism is a relatively rare cause of pleural effusion, which may be transudative or exudative. However, the majority of effusions in patients with hypothyroidism are due to other causes. (Choice C) Pulmonary hypertension (PH) typically presents with fatigue and progressive dyspnea. Severe PH can occasionally cause pleural effusions, but these effusions are typically transudative. (Choice E) Pleural effusions are uncommon in patients with sarcoidosis. They are usually associated with active parenchymal disease and are typically lymphocytic exudates. Chest imaging often shows hilar and mediastinal lymphadenopathy, ground-glass opacification, cysts, and fibrosis. Educational objective: Pleural effusion is a common manifestation of rheumatoid arthritis. The effusion is typically an exudate with a low pH, very low glucose level, and very high LDH level. __________ References: Rheumatoid pleural effusion. (http://www.ncbi.nlm.nih.gov/pubmed/16765714) Pleural effusions in a series of 181 outpatients with sarcoidosis. (http://www.ncbi.nlm.nih.gov/pubmed/16778281)

A 53-Year-Old Woman Is Evaluated for Fatigue, Malaise, and Exertional