Still ou Pseudo-Still : difficultés et pièges du diagnostic de maladie de Still de l'adulte

Adult-onset Still's disease (AOSD) is a rare systemic auto-inflammatory disorder whose diagnosis is difficult. In typical cases of AOSD, four cardinal signs are associated in a patient in a patient older then sixteen: high (39-40 °C) hectic fever, skin rash occurring during peaks of temperature, arthralgia or arhtitis, hyperleukocytosis ≥ 10,000 cells/mm3 with neutrophils ≥ 80%. A lot of other of symptoms can be associated to these signs. However, no clinical or biological manifestation is specific of the disease. Before finally diagnosing AOSD, it is thus essential to first rule out neoplastic, infectious or inflammatory conditions that can mimic the disease. Classification criteria can help the clinician to raise the diagnosis. However, AOSD is a heterogeneous disease, and atypical forms are not rare. The disease can be life threatening, because of the predominant involvement of one organ or of systemic complications with multiple organ failure from the outset, while the diagnosis isn't clearly confirmed. The articular signs may often fall by the wayside because of the gravity of the complications of such clinical forms, which can contribute to misdirect the clinicians who are not familiar with AOSD. The objective of this article is to remind briefly the manifestations of the typical clinical forms of the disease, but also to alert the rheumatologist to atypical and misleading situations that should evoke the diagnosis of AOSD. In this complex diagnostic approach, it is advised to contact one of the reference centers for auto-inflammatory disorders.