A 75-year-old Jamaican male presented to the hospital with a large pericardial effusion, ejection fraction of 56-60%, and moderate pulmonary hypertension on echocardiogram. His medical history involved renal transplant (from daughter) in 2002 and on tacrolimus, mycophenolate mofetil, and prednisone. The patient was prescribed tacrolimus to take 0.5 mg daily, but took 1.5 mg in morning and 2mg in evening. Patient was COVID negative. He had emergent pericardiocentesis (750 cc of serosanguinous fluid), followed by a pericardial sub-xyphoid window and drain placement, removed a few days later.  Fluid analysis (AFB stain, Gram stain, with fungal, viral, and tissue culture) was negative.  Pericardial biopsy showed benign fibroadipose tissue consistent with pericardium. Cytology showed normal mesothelial cells and no malignant cells.  The consulted nephrologist reduced frequency of the tacrolimus from 0.5 mg twice daily to once daily.  The patient was discharged, but re-admitted about 3 months later with fatigue, anorexia, poor oral intake, abdominal distention, and bilateral peripheral edema.  CT abdomen and pelvis showed anasarca with moderate ascites.  A follow up echo showed normal EF 56-60% and a moderate to large pericardial effusion anterior to heart with concerns for cardiac tamponade.  The tacrolimus was discontinued for a couple days which improved creatinine from 1.55 to 1.32 with baseline 1.3-1.4. However, tacrolimus was restarted, which increased creatinine to 1.59 over couple days. He underwent a right thoracoscopy and Video-Assisted Thoracoscopic Surgery with pericardial window, which recovered serous fluid. Repeat fluid analysis, biopsy, and cytology were unchanged. His post-thoracoscopy chest tube was later removed.  Rheumatology followed. He had negative ANA comprehensive panel (SCL-70, SM Ab, SM/RNP), CRP, ESR, Rheumatoid Factor, anti-CCP Ab IgG, and CK. He subjectively improved and was later discharged.     

The final diagnosis was Tacrolimus-induced pericardial effusion with reduced dose Tacrolimus to 0.5mg and follow up with Nephrology and Cardiology.