Persistent Chest Pain After Cardiac Surgery
A 50 year-old male with history of recently diagnosed Graves' disease, multiple sclerosis and benign prostatic hyperplasia presented to the hospital with chest pain concerning for unstable angina. Initial work-up for his cardiac chest pain, including a coronary angiogram and an echocardiogram showed non-obstructive coronary artery disease, and a severely stenotic bicuspid aortic valve. He subsequently underwent aortic root enlargement with a bovine pericardial patch and bioprosthetic aortic valve replacement without complication. Twenty-three days later, however, he presented to the emergency department endorsing right-sided pleuritic-type chest pain and low-grade fevers.
His medications on presentation included: methimazole, metoprolol tartrate, furosemide, aspirin, atorvastatin, warfarin, dimethyl fumarate and tamsulosin. His vitals signs on presentation were significant for tachycardia (120 bpm) and low-grade fever (100.9 F / 38.2 C) with a low normal resting blood pressure of 98/63 mmHg.
His initial ECG showed sinus tachycardia with incomplete right bundle branch block and possible left atrial enlargement:
Initial laboratory work-up showed normal troponin (<0.01ng/mL), slightly elevated B-natriuretic peptide of 122pg/mL (0-100pg/mL), normal white blood cell count 7.56k/uL (3.73-10.1k/uL), slight anemia with a hemoglobin of 10.1g/dL (13.4 16.8 g/dL), normal platelet count of 337k/uL (146 337k/uL), low thyroid stimulating hormone < 0.008uIU/mL (0.55 4.78uIU/mL), and normal Free T4 1.06ng/dL (0.89 1.76ng/dL).
Initial concern in the post-operative setting was pulmonary embolism, for which a computed tomography (CT) chest was ordered. This showed no signs of pulmonary embolism, but revealed bilateral pleural effusions with atelectasis (Figure 1). Transthoracic echocardiogram (TTE) revealed a normal left ventricle ejection fraction (LVEF) of 60% with trivial pericardial effusion and no valve vegetations.
With overall reassuring tests and labs, he was discharged home, yet presented again 14 days later complaining of persistent symptoms. A repeat CT chest was performed and showed interval worsening moderate-sized right and small left pleural effusions, which were now partially loculated. A therapeutic thoracentesis was performed and yielded 165mL of pleural fluid. Pleural fluid analysis showed:
LDH 737U/L (serum 183U/L), glucose 110mg/dL (serum 127mg/dL), triglycerides 51, protein 4.1g/dL (serum 7.1g/dL), suggesting an exudative effusion based on Light's criteria, with fluid protein more than 0.5 of serum protein and lactate dehydrogenase (LDH) more than 0.6 or more than two-thirds of serum levels. Bacterial and fungal cultures were also negative.
Due to concerns for pericarditis, he was discharged on ASA 325mg daily, colchicine 0.6mg once daily, and 400mg ibuprofen as needed. He returns to the hospital 25 days later with diffuse body aches, dyspnea, fevers, chills and now left sided pleuritic chest pain. Repeat chest imaging shows again worsening bilateral effusions. A repeat TTE was ordered to assess for pericarditis with possibly worsening pericardial effusion. The echocardiogram showed stable systolic LV function (LVEF of 65%) and normal appearing pericardium without signs of underlying constrictive pericarditis. Of note, the inflammatory markers were elevated despite the anti-inflammatory regimen prescribed (ESR 62mm/h, CRP 5.2mg/dL).
Due to his persistent symptoms, now more than 60 days after surgery, with elevated inflammatory markers and no major changes on transthoracic echo, a cardiac magnetic resonance imaging (MRI) is ordered for further clarification.
What is the most likely cause of his clinical picture?