Kawasaki Disease Complicated with Macrophage Activation Syndrome: The Importance of Prompt Diagnosis and Treatment–Three Case Reports

Abstract

Kawasaki disease (KD) is an acute vasculitis that mainly affects children under 5 years of age, leading to coronary artery alterations (CAAs) in 25% of untreated patients. Macrophage activation syndrome (MAS) is a secondary hemophagocytic lymphohistiocytosis (HLH) that can complicate the acute, subacute, and chronic phases of KD. We retrospectively reviewed three cases of children affected by KD complicated with MAS hospitalized in two pediatric units in Emilia Romagna, a northern region of Italy. Case 1: a previously healthy 23-month-old female with full clinical criteria of KD and a hemorrhagic rash due to MAS during the acute phase of the illness. This patient responded promptly to a high dose of intravenous immune globulin (IVIG) and three pulses of high doses of methylprednisolone (MPD) with improvement in clinical signs and laboratory tests without the development of CAA at any phase of illness. Case 2: a previously healthy 10-month-old female with incomplete KD with persistent fever and maculopapular rash. This patient did not respond to IVIG and developed MAS during the subacute phase, characterized by persistent fever, hypertransaminasemia, hyperferritinemia, and hypofibrinogenemia after two high doses of IVIG and boluses of MPD. The patient responded to the addition of IL-1 blocker and anakinra and did not present CAA alterations during any phase of the illness. Case 3: a previously healthy 26-month-old male with incomplete KD with fever, maculopapular rash, cheilitis, and hyperemic conjunctivitis. This patient developed gallbladder hydrops and CAA in the acute phase and did not respond to two high doses of IVIG and a high dose of MPD. In the subacute phase, this patient was complicated with MAS and responded to intravenous anakinra. During the subacute phase, the patient developed transient aneurysms that regressed during the chronic phase. These cases reiterate that prompt diagnosis and aggressive immunomodulatory treatment can limit the most severe complications of MAS complicating KD. High doses of IVIG and MPD may result in a favorable outcome or more aggressive adjunctive treatment may be needed. Anakinra, cyclosporine, monoclonal antibodies, and plasmapheresis can be used as adjunctive treatment in the case of unresponsive MAS in KD. Notably, MAS, present during the subacute phase in cases 2 and 3, promptly responded to anakinra, an IL-1 blocker, without the use of cyclosporine. Our experience confirms that the IL-1 blocker can be considered an optimal choice after non-response to IVIG and MPD in KD complicating with MAS, avoiding over-treatment with cytotoxic drugs.