Reactive haemophagocytic syndrome in adult-onset Still's disease: a report of six patients and a review of the literature

Abstract
Objective: To examine the prevalence and characteristics of patients with reactive haemophagocytic syndrome (RHS) complicating adult-onset Still’s disease (AOSD). Methods: Of 50 patients with AOSD fulfilling Yamaguchi and Fautrel criteria followed in our department, clinical and laboratory data, course and treatment of six patients with histologically proven RHS and without any obvious cause other than AOSD were retrospectively recorded. Results: RHS led to AOSD in two cases, whereas it appeared after a mean duration of 3.5 years from onset of AOSD in the other cases. The main symptoms were fever (n = 6), polyarthralgias or myalgias (n = 4), lymphadenopathy or splenomegaly (n = 3), pharyngitis (n = 3), rash (n = 3), pleuritis (n = 3), hepatomegaly (n = 1), normal or low leucocyte count (n = 4), anaemia (n = 6), lymphocytopenia (n = 6), thrombocytopenia (n = 4), hyperbasophilic lymphocytes (n = 2), abnormal liver function tests (n = 6) and increased serum triglyceride level (n = 6). Serum ferritin concentration was constantly increased (>10 000 µg/l in five cases, with Conclusion: RHS is not uncommon in AOSD. It should be evoked in a patient with AOSD in the absence of hyperleucocytosis, thrombocytopenia, lymphopenia and coagulopathy, or in the presence of high serum ferritin and triglyceride levels.