Haemorrhagic Mycobacterium avium complex pericarditis presenting with cardiac tamponade in an immunocompetent woman

A young woman in her mid-40s was referred by her primary care physician for fever, worsening shortness of breath, pleuritic chest pain and tachycardia. CT angiogram of the chest revealed a large pericardial effusion. Echocardiogram confirmed tamponade physiology despite her being haemodynamically stable. She had an emergency pericardiocentesis which revealed evidence of a haemorrhagic pericardial effusion. However, the patient was still symptomatic after treatment and had to undergo video-assisted thoracoscopic surgery with a pericardial window and chest tube. Postoperatively, her fevers resolved. Pan-culture was initially negative, and all antibiotics were discontinued. Acid-fast bacilli cultures later grew Mycobacterium avium complex. She continued to have chest discomfort postoperatively, but follow-up CT of the chest 3 months postoperatively showed continued resolution of her pericardial effusion. The patient's symptoms improved, and she has had no recurrence of effusion without the need for anti-tuberculosis drugs.