What is Kawasaki disease (Mucocutaneous Lymph Node Syndrome)?

From the Guidelines

Kawasaki disease is an acute, self-limited febrile illness of unknown cause that predominantly affects children <5 years of age, and its diagnosis rests on the identification of principal clinical findings and the exclusion of other clinically similar entities with known causes. The disease is characterized by inflammation in blood vessels throughout the body, and if left untreated, it can lead to serious complications, including coronary artery aneurysms, which develop in 20% to 25% of affected children 1.

Key Characteristics and Treatment

• The disease is the most common cause of acquired heart disease in children in developed countries 1.
• Treatment should begin as soon as possible with intravenous immunoglobulin (IVIG) at 2g/kg as a single infusion over 10-12 hours, along with high-dose aspirin (80-100mg/kg/day divided into four doses) during the acute phase 1.
• After fever resolves, aspirin is reduced to a low dose (3-5mg/kg/day) for 6-8 weeks to prevent coronary thrombosis 1.
• If fever persists 36-48 hours after IVIG, a second dose may be needed, and corticosteroids are sometimes added for refractory cases.

Long-term Management

• Prompt treatment is crucial as it significantly reduces the risk of coronary artery aneurysms, the most serious complication 1.
• Kawasaki disease causes systemic inflammation through an abnormal immune response, possibly triggered by infectious agents in genetically susceptible children.
• Even after treatment, patients with coronary abnormalities need long-term cardiac follow-up with echocardiograms to monitor for complications 1. The long-term prognosis is determined by the initial and current level of coronary artery involvement, and certain subsets of patients are at risk for myocardial ischemia from coronary artery thrombosis and stenoses 1.

From the Research

Definition and Overview of Kawasaki Disease

• Kawasaki disease (KD) is an acute self-limiting systemic vasculitis with a specific predilection for the coronary arteries that affects previously healthy young infants and children 2, 3, 4.
• It is the leading cause of childhood-acquired heart disease in the developed world 2.
• The disease can result in coronary artery aneurysms, myocardial infarction, and sudden death in previously healthy children 3.

Clinical Features and Treatment

• Clinical and epidemiologic features support an infectious cause, but the etiology remains unknown 3.
• Standard initial therapy is intravenous immunoglobulin (IVIG) and aspirin 2, 3, 5.
• IVIG therapy results in rapid resolution of clinical symptoms in 80-90% of patients and has been shown to reduce the risk of coronary disease 2, 5.
• The addition of corticosteroids to IVIG and aspirin may improve outcomes in patients, particularly those at high risk of developing adverse coronary artery outcomes 2, 4.

Prevention of Coronary Artery Aneurysms

• The use of IVIG has been shown to prevent coronary artery aneurysms (CAAs) in children with KD 5.
• A dose of 2 g/kg of IVIG is more effective than lower doses in preventing CAAs 5, 6.
• The KD CAA prevention (KD-CAAP) trial is currently investigating the use of adjunctive corticosteroid treatment to standard IVIG and aspirin therapy to reduce CAA rates in unselected KD patients 4.

Management of Refractory Kawasaki Disease

• Non-responders to initial IVIG therapy remain a challenge, and options for treatment include repeat IVIG, corticosteroids, and other immunosuppressive therapies 2, 3.
• Patients who fail to respond to two doses of IVIG present a unique challenge, and treatment with infliximab, cyclosporine, or methotrexate may be considered 2.