A Tiny Heart, a Massive Challenge: Case Presentation of Pericardial Effusion and Cardiac Tamponade in an Extremely Preterm Neonate and Corresponding Literature Review.

Massive pericardial effusion requiring pericardiocentesis in an extremely preterm, extremely low birth weight (ELBW) neonate is exceedingly rare and infrequently described in neonatal literature. We report the successful management and favorable neurodevelopmental outcome of a 24-week gestation male baby (birth weight 640 g) who developed hemodynamically significant, massive pericardial effusion during a neonatal intensive care unit course. The infant's clinical course was complicated by severe respiratory distress syndrome, persistent pulmonary hypertension of the newborn (PPHN), prolonged ventilator dependence, feed intolerance, and the requirement of a peripherally inserted central catheter (PICC) for total parenteral nutrition (TPN) administration. On day 21 of life, the infant had clinical deterioration with features of circulatory shock and worsening respiratory status. Serial chest radiographs demonstrated progressive cardiomegaly with a characteristic "water-bottle" cardiac silhouette, suggestive of significant pericardial effusion. Echocardiographic evaluation confirmed massive pericardial effusion with cardiorespiratory compromise. The PICC line was immediately removed, and emergency pericardiocentesis was performed. Performing an invasive pericardial drainage procedure in a neonate at the threshold of viability posed considerable technical and hemodynamic challenges. Following the intervention, the infant required respiratory support, antimicrobial therapy, nutritional rehabilitation, and multidisciplinary care in a tertiary neonatal intensive care unit. Gradual cardiopulmonary stabilization was achieved, leading to successful discharge. At follow-up, infant demonstrated satisfactory linear growth with no evidence of cognitive, auditory, or visual impairment. This case highlights the rarity, diagnostic complexity, and therapeutic challenges of massive pericardial effusion in ELBW neonates, and emphasizes the importance of early radiological recognition, prompt echocardiographic evaluation, timely intervention, and multidisciplinary management to improve survival and long-term outcomes in this highly vulnerable population.