DOI: https://doi.org/10.36347/sjmcr.2026.v14i11.026

Pages: 2516-2519

Background: Pericardial effusion is recognized in cardiac amyloidosis, although a large collection raises questions about its cause and clinical significance. Case presentation: A 69-year-old man with transthyretin cardiac amyloidosis investigated by bone-avid tracer scintigraphy showing grade 3 myocardial uptake and a reportedly negative AL amyloidosis work-up, atrial fibrillation treated with rivaroxaban, and a history of surgically managed traumatic subdural hematoma presented after six weeks of worsening exertional dyspnea, fatigue, and weight loss. He was clinically stable (blood pressure 100/67 mmHg; heart rate 70 beats/min), despite jugular venous distension. Echocardiography showed increased left ventricular wall thickness, an ejection fraction of 30–35%, grade III diastolic dysfunction, right-sided chamber enlargement, and a predominantly posterior pericardial effusion measuring 30 mm with right atrial indentation. Approximately 300 mL of straw-colored fluid was drained, and a pericardial biopsy was obtained. Histology revealed chronic changes without malignancy; fluid cytology was reactive and GeneXpert was negative. A small residual effusion and persistent dyspnea were noted after the procedure. Discussion: Neither the size of the effusion nor right atrial indentation alone establishes tamponade. Although the effusion occurred in the setting of ATTR cardiomyopathy, direct pericardial amyloid involvement was not demonstrated. Conclusion: Large pericardial effusion in ATTR cardiomyopathy warrants careful hemodynamic assessment and an independent search for treatable causes.