Analysis of the clinical characteristics of five patients with Kawasaki disease complicated with macrophage activation syndrome in Baoding Hospital of Beijing Children's Hospital, Capital Medical University.

Objective: To investigate clinical characteristics of Kawasaki disease (KD) complicated with macrophage activation syndrome (MAS) and to identify possible indicators for early diagnosis.

Method: Clinical data, laboratory indexes, treatment, and prognosis of five patients with KD complicated with MAS admitted to Department of Cardiology, Baoding Children's Hospital from April 2020 to April 2022 were retrospectively analyzed.

Results: Five pediatric patients aged between three months and five years were included in the study. The enrolled patients were non-reactive to intravenous immunoglobulin (IVIG) and presented with mental impairment, abdominal distension, skin rash, and scleroderma of the hands and feet. Four patients had hepatomegaly and two patients had splenomegaly. There were four patients with coronary artery diseases. Triglyceride (TG) levels were increased or showed an upward trend in four patients. Two patients had positive bone marrow hemophagocytosis. All patients had decreased fibrinogen, increased ferritin levels, a decrease or a downward trend in the natural killer (NK) lymphocytes counts, and significantly increased sCD25. Four patients presented with decreased activity of NK cells. All pediatric patients enrolled were treated with two doses of high-dose IVIG +methylprednisolone. One patient died as a result of stopping the treatment, while four remaining patients had a good prognosis.

Conclusions: MAS complication should be suspected in pediatric patients with KD who are non-responsive to IVIG and show signs of mental impairment, abdominal distension, scleroderma of hands and feet, or hepatosplenomegaly. We should monitor trends in blood routine, ferritin, triglyceride, fibrinogen and NK lymphocytes counts.