Cardiac Tamponade in Late Pregnancy Caused by Corynebacterium amycolatum Pericarditis and Managed by a Surgical Pleuro-Pericardial Window

Cardiac tamponade in pregnancy is an exceptional maternal–fetal emergency in which physiological tachycardia, hypervolaemia and dependent oedema mask the classical signs of tamponade. Corynebacterium amycolatum is a non-diphtherial, Gram-positive coryneform commensal of human skin and mucosa that is increasingly recognised as a true invasive pathogen, although pericardial infection has rarely, if ever, been reported. We aimed to describe the diagnostic and decompression strategy in such a case. We report a 29-year-old woman at 30 + 4 weeks of gestation with class III obesity (pre-pregnancy body mass index 36 kg/m2), pregnancy-induced hypertension and diet-controlled type 2 diabetes referred after a routine echocardiogram suggested tamponade despite preserved haemodynamic compensation. Transthoracic echocardiography demonstrated a large circumferential pericardial effusion with diastolic right-atrial and right-ventricular collapse, a plethoric inferior vena cava and respiratory mitral-inflow variation. Severe maternal obesity superimposed on advanced gestation degraded the acoustic windows, elevated the diaphragm, displaced the heart anteriorly and brought the gravid uterus into the subxiphoid corridor, rendering percutaneous pericardiocentesis prohibitively hazardous. After multidisciplinary heart-team review, a left anterior mini-thoracotomy with pleuro-pericardial window evacuated approximately 1000 mL of fluid. Aerobic culture yielded C. amycolatum (MALDI-TOF), with histological pericarditis and a consistent antibiogram; autoimmune, viral and neoplastic causes were excluded, although blood cultures and extended viral testing were not performed. Targeted intravenous cefazolin was given, and the patient delivered a healthy term neonate at 39 weeks, with a normal 7-month echocardiogram. To the best of our knowledge, this is among the first reported cases of C. amycolatum pericardial tamponade in pregnancy. Because blood cultures and molecular confirmation of pericardial involvement were not obtained, a contaminant or incidental role for the organism cannot be entirely excluded, and the causal attribution should be regarded as probable rather than definitive. The case highlights heart-team-based individualised decompression and the cautious microbiological interpretation of organisms traditionally regarded as commensals.