УДК 616.13-002-036-053.2-07:616.155.02

Kawasaki disease (KD) is an acute systemic vasculitis that is the most common cause of acquired heart disease in children under 5 years of age with hyperthermia. Diagnosis of KD is a clinical challenge, given the wide range of clinical manifestations and similarities with many viral and bacterial diseases. Purpose - to describe a clinical case of refractory КD in a three-month-old girl with an emphasis on the importance of echocardiography and coronary angiography for the final verification of the disease, urgent initiation of treatment with minimal suspicion of КD. Clinical case. The article reports on a three-month-old patient with a difficult diagnosis of refractory form of КD. The disease debuted with hyperthermia, enterocolitis, obstructive bronchitis, and hepatoliver syndrome. The manifestations of skin exanthema were initially considered as an allergic dermatitis to the use of a cephalosporin antibiotic. Multisystemic inflammatory syndrome associated with SARS-CoV-2 infection was suspected. After the use of immunosuppressive therapy with mega-doses of dexamethasone and intravenous human immunoglobulin 2 g/kg/day for 3 days, clinical improvement was achieved. Subsequently, the haemogram showed an increase in neutrophilic hyperleukocytosis to the appearance of blast cells, hyperthrombocytosis and severe anaemia. A differentiation was made between a leukemic reaction, the debut of myeloproliferative disease, juvenile myelomonocytic leukaemia. Against the background of a rapid decrease in the number of leukocytes, the girl developed hyperthermia, migratory intermittent maculopapular rash, and foots edema. Laboratory findings included thrombocytosis and an increase in acute-phase parameters. Echocardiography revealed left ventricular dilation, a small amount of excess fluid in the pericardium, dilatation of the left coronary artery evenly to the bifurcation. Computed tomography revealed giant coronary artery aneurysms, which gave grounds to diagnose KD