Rebound warfarin toxicity presenting with spontaneous hemopericardium in cardiac tamponade: a case report

The spontaneous hemopericardium due to warfarin toxicity is uncommon but can be fatal if it leads to cardiac tamponade and timely interventions are not administered. An 80-year-old male with a medical history of hypertension, chronic obstructive pulmonary disease (COPD), and atrial fibrillation presented with chest pain and shortness of breath. On examination, he had tachycardia, hypotension, and muffled heart sounds. The 2-D echocardiogram confirmed pericardial effusion with cardiac tamponade. An emergent pericardiocentesis was performed in the emergency department (ED), following which the patient hemodynamically improved. The past medical history was significant for recurrent ED visit with warfarin toxicity in the form of calf hematoma. His most recent ED visit was three days ago, where he received fresh frozen plasma (FFP) for a supra-therapeutic International Normalized Ratio (INR) of 8.66 without bleeding manifestations and was discharged with an INR value of 2.27. During the current ED presentation, the hemopericardium was likely due to rebound warfarin toxicity, as the INR reported was found to be 6.38 despite having previously corrected to 2.27 and discontinuing warfarin after the recent ED discharge. In the current ED presentation, coagulopathy was corrected with FFP and vitamin K. The patient was admitted to the ward for evaluation. The pericardial fluid analysis showed no evidence of tuberculosis or other infections, and his recovery was uneventful. On follow-up after 3 months, he was doing well on dabigatran for stroke prevention. The treatment of warfarin toxicity requires consideration of the half-life of the offending agent, warfarin, as well as the antidotes (FFP and vitamin k) widely practiced in low-middle income countries to prevent rebound warfarin toxicity.