[Eperythrozoonosis complicated with hemophagocytic syndrome: report of four cases and review of literature].

To analyze the clinical characteristics of eperythrozoonosis complicated with hemophagocytic syndrome (HPS) in 4 children. Four patients diagnosed with eperythrozoonosis complicated with HPS in the Children's Hospital Affiliated Capital Institute of Pediatrics during the period from June 2014 to July 2016 were enrolled. The clinical manifestations, laboratory examination data and therapeutic strategies were analyzed. A literature search (search terms included 'eperythrozoonosis' and 'hemophagocytic syndrome') was conducted using CNKI, Wanfang database, Chinese biomedical literature database and PubMed to include recently published studies (searched from the database establishment to January 2017). Four patients were included in the study. One was boy and the other three were girls. The age range of the 4 patients was between 9 months and 17 years (9 months, 2 years and 17 years, 11 months respectively). All the patients presented with recurrent high fever. During the course of fever, 3 patients presented with rash, and 2 patients presented with joint pain and swelling, which mimicked systemic juvenile idiopathic arthritis. Only 1 patient had the contact history of infectious disease. All patients had normal or decreased white blood cell count ((0.80-13.12)×10/L), suffered from varied degrees of anemia and showed the increased C reactive protein (13.0-84.7 mg/L) anderythrocyte sedimentation rate (13-72 mm/1 h). Examination of peripheral blood smears confirmed eperythrozoonosis. After fever continued about 1 month, all the 4 patients rapidly progressed. Among the 4 patients, 1 patient died for giving up further therapy, and the other 3 patients completely recovered after treatment, including azithromycin for the treatment of eperythrozoonosis, and high-dose intravenous methylprednisolone pulse therapy and human immunoglobulin for the treatment of HPS. For the disease not satisfactory, the hemophagocytic lymphohistiocytosis-2004 (HLH-2004) protocol is given. After the hospitalization of 1 to 2 months, the conditions improved and the children were discharged from hospital. Three patients were followed up for 8 months to 2 years, and their conditions were stable. In the PubMed database, no report was found. Nine cases of children with eperythrozoonosis were found in CNKI, Wanfang database and Chinese biomedical literature database, and 1 case was complicated with HPS. These findings, taken together our report, provided the data of 5 children with eperythrozoonosis complicated with HPS (4 cases were younger than 2 years old). A patient had contact history of infectious disease. Five patientss showed fever of unknown origin. All the patients had severe eperythrozoonosis, and 2 cases at younger age died. Children with eperythrozoonosis often present with the protracted fever of unknown origin, and clinical manifestations mimic those of juvenile idiopathic arthritis (systemic type). The patients with eperythrozoonosis of mild-to-moderate disease severity may have a good prognosis. Children with severe eperythrozoonosis, especially those HPS cases with early onset before 2 years old, may have high risk of mortality. Once the patient's condition aggravates in the course of fever, HPS should be highly suspected. For the patients with eperythrozoonosis complicated with HPS, early diagnosis and the combination of anti-infection with the treatment of HPS are crucial for a good prognosis. For the treatment of HPS, HLH-2004 protocol is recommended.