Macrophage activation syndrome in a patient with systemic juvenile idiopathic arthritis and down syndrome

Abstract

Down syndrome is a genetic mutation characterized by a trisomy of chromosome 21. In most cases, the syndrome is combined with other congenital defects of organs and systems, in this category of patients there is an increased risk of developing autoimmune disorders. Macrophage activation syndrome (MАS) is a potentially fatal disease caused by overactivation of macrophages and T- lymphocytes, leading to a systemic inflammatory response. A trigger for the development of MАS can be any infection, prescription of medication or drug replacement. The main clinical symptoms of this syndrome are fever, hepatosplenomegaly, lymphadenopathy, marked cytopenia, and coagulopathy. Clinical manifestations can be signs of the main disease and the onset of MАS. Diagnosis of MАS is difficult due to the lack of clear classical diagnostic criteria, especially in patients with systemic diseases. Additional laboratory findings in MАS include elevated serum triglycerides, lactate dehydrogenase, and ferritin. Timely diagnosis and early therapeutic intervention are the key to preventing the activation of the syndrome.

Aim - to present a clinical case of a patient with Down syndrome in whom the treatment of systemic idiopathic arthritis was the development of MАS, which caused difficulties in diagnosis in the early stages of the syndrome's manifestation and its atypical course.

Clinical case. An 8-year-old girl with Down syndrome and systemic idiopathic arthritis periodically fevered to febrile numbers, had a rash on the body and limbs, blood tests showed thrombocytopenia, increased levels of ferritin and aspartate aminotransferase, which indicated the development of MАS against the background of immunosuppressive therapy.

Conclusions. The article describes a case of a child with Down syndrome and systemic idiopathic arthritis, the treatment of the latter was complicated by the development of MАS, which had atypical clinical manifestations and laboratory parameters. The clinical case described above is an example of a long-term diagnostic search that delayed the appointment of treatment.

The research was carried out in accordance with the principles of the Helsinki Declaration. The informed consent of the patient was obtained for conducting the studies.

No conflict of interest was declared by the authors.