Macrophage activation syndrome as the initial manifestation of systemic onset juvenile idiopathic arthritis.

more commonly among men in their 50s. Back pain (19.1%) was the most common rheumatic manifestation. Myalgia (15.5%) was also frequently observed, as was arthra l gia without art h ritis (10%). Pe ri p h e ra l arthritis (13.6%) was also present, but generally as monoarthritis. In contrast, sacroiliitis was only observed in a single patient. This patient was a man in his early twenties, who had positive blood cultures for Entero coccus faecalis, and experienced a progressive improvement of his sacroiliac pain foll owing antibiotic therapy with ampicillin and gentamicin (2). It is worth noting that in our series of patients with IE and rheumatic manifestations m i c ro h e m at u ria was observed in almost 60% of the patients, versus 27% in IE patients without rheumatic manifestations (2). In summary, u n explained peri p h e ral synov i t i s , a rt h ra l gia or low back pain along with unexplained microhematuria may be possible warning signs for the presence of IE. Awareness of these complications may be useful to avoid inappropriate delay in the diagnosis of this severe disease.