Coxiella burnetii pulmonary conduit endocarditis in a child with complex congenital heart disease: a case report
Ana-Maria Hodea, Paolo Ciliberti, Eugen Sandica, Carmen-Cristina OlteanuAbstract
Background
Coxiella burnetii is a well-recognized cause of culture-negative endocarditis in patients with prosthetic cardiac material. In pediatric populations, diagnosis is uncommon and frequently delayed, particularly in the presence of immunological abnormalities that may impair serological responses.
Case presentation
We present a case of Coxiella burnetii endocarditis in an 11-year-old boy with complex congenital heart disease and multiple prior cardiac surgical interventions who developed chronic systemic manifestations associated with prosthetic conduit infection. He was first evaluated at our center at nine years of age, presenting with a two-year history of low-grade fever, hepatomegaly, hypoalbuminemia, hypogammaglobulinemia, peripheral edema, and progressive right-sided heart failure. His medical history was notable for splenectomy performed for severe unexplained splenomegaly with hypersplenism. Extensive investigations failed to identify an infectious etiology. Echocardiography demonstrated severe conduit stenosis without vegetations. Two years later, during hybrid surgical replacement of the stenotic conduit, fluorescence in situ hybridization of the explanted Contegra conduit detected Coxiella burnetii , while blood PCR and serology were initially negative. Following conduit replacement and initiation of doxycycline-hydroxychloroquine therapy, the patient showed rapid clinical improvement, with resolution of systemic manifestations and normalization of protein and immunoglobulin levels. Seroconversion with high phase I and II IgG titers occurred after three months of therapy.
Conclusions
In pediatric patients with congenital heart disease and prosthetic cardiac material, Coxiella burnetii infection may present with prolonged systemic manifestations. Despite negative initial serology, tissue-based detection from explanted material can establish the diagnosis when conventional investigations fail, and may support the initiation of targeted long-term antimicrobial therapy.