Fulminant Lyme Carditis With Rapid Hemodynamic Deterioration in an Adolescent: A Case Report.

Lyme carditis is a rare but potentially severe complication of Lyme disease caused by Borrelia burgdorferi. We report the case of a 16-year-old adolescent with no significant past medical history, admitted for hemodynamic instability in a febrile context associated with respiratory and gastrointestinal symptoms evolving over several days. Transthoracic echocardiography showed marked biventricular dilation with global hypokinesia and a left ventricular ejection fraction estimated at 20-25%, associated with a small pericardial effusion. Laboratory investigations revealed a significant inflammatory syndrome and progressively rising troponin levels. Appropriate antibiotic therapy combined with inotropic and vasopressor support was initiated after serological confirmation of Lyme disease. Despite initial hemodynamic improvement, secondary deterioration occurred with the development of refractory cardiogenic shock. The clinical course was rapidly unfavorable within less than 12 hours, ultimately leading to death. This case illustrates the potential severity and fulminant evolution of Lyme carditis, highlighting the importance of early diagnosis, close cardiac monitoring, and timely access to appropriate supportive therapies.