Adult-onset Still’s disease revealed by a complete atrioventricular block, totally regressive under corticosteroid therapy

We report the case of a 40-year-old veterinary surgeon who was admitted for spiking fevers, arthralgia, and a complete atrioventricular block. Tests revealed an inflammatory syndrome, hepatic cytolysis, neutrophilic leukocytosis, and increased troponin levels. Cardiac magnetic resonance imaging showed a small myocarditis but no tissue abnormality on the conduction pathways. In the absence of evidence-based infection and favorable evolution under broad spectrum antibiotherapy, an adult-onset Still’s disease was suspected and corticosteroid therapy administered. Evolution was then impressively favorable, with a persistent sinus heart rhythm 3 days later.