What is Kawasaki's disease?

From the Guidelines

Kawasaki disease is an acute, self-limited febrile illness of unknown cause that predominantly affects children <5 years of age, causing inflammation in blood vessels throughout the body, and is now the most common cause of acquired heart disease in children in developed countries. The disease presents with a persistent high fever lasting at least five days, along with a combination of symptoms including rash, red eyes, swollen hands and feet, red cracked lips, and swollen lymph nodes in the neck.

Key Characteristics

• The standard treatment consists of intravenous immunoglobulin (IVIG) at 2g/kg as a single infusion, given within 10 days of fever onset, plus high-dose aspirin (80-100mg/kg/day divided into four doses) during the acute phase, followed by low-dose aspirin (3-5mg/kg/day) until inflammatory markers normalize, as recommended by the American Heart Association 1.
• Early treatment is crucial as it significantly reduces the risk of coronary artery aneurysms, the most serious complication, from 25% to ≈4% 1.
• The disease is believed to be triggered by an abnormal immune response to an infection in genetically susceptible children, though the exact cause remains unknown.
• Patients require follow-up echocardiograms to monitor for cardiac complications, with the frequency depending on the severity of coronary involvement.

Diagnosis and Treatment

• Diagnosis relies on clinical criteria and supporting ancillary studies, with an algorithm for the evaluation and treatment of patients in whom incomplete or atypical Kawasaki disease is suspected 1.
• The long-term prognosis is determined by the initial and current level of coronary artery involvement, with certain subsets of patients at risk for myocardial ischemia from coronary artery thrombosis and stenoses 1.
• Medical management of such patients hinges on judicious use of thromboprophylaxis and vigilance to identify evolving stenoses, with invasive revascularization procedures might be required for selected patients 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.
• It is the leading cause of childhood-acquired heart disease in the developed world 2.
• KD is characterized by an intense inflammatory process that has a predilection for the coronary arteries, resulting in the development of aneurysmal lesions, arterial thrombotic occlusion, or potentially, sudden death 3.

Clinical Features and Diagnosis

• The criteria for classic Kawasaki disease are clearly defined, but many children present with atypical forms, and clinicians need to consider this possibility 4.
• Diagnostic criteria, including fever and other principal features, have been established 5.
• There is no specific diagnostic test for KD, but treatment with immunoglobulin and aspirin effectively reduces cardiac complications 3.

Treatment and Management

• Standard initial therapy for KD is intravenous immunoglobulin (IVIG) and aspirin 2.
• Non-responders to initial therapy remain a challenge, and therapeutic options for these patients are limited 2.
• Corticosteroids may be considered as an adjunctive treatment to IVIG and aspirin, particularly in high-risk patients 6.
• Other immunosuppressive agents, such as infliximab, cyclosporine, or methotrexate, may be considered in patients who fail multiple doses of IVIG and steroids 2.

Complications and Prognosis

• Coronary artery abnormalities, including aneurysms, are a significant concern in KD, as they can lead to thrombosis, evolve into segmental stenosis, or rarely, rupture 5.
• The principal cause of death from Kawasaki disease is myocardial infarction 5.
• Early recognition and treatment of KD can reduce the development of potentially life-threatening coronary artery abnormalities 5.