EXPLANATION


Kawasaki Disease (KD) is a febrile illness of unknown etiology, with associated vasculitis that primarily affects young children. First described in Japan in 1967, it is now known for its potential for coronary artery (CA) complications and is the most common cause of acquired heart disease in developed countries. It has an incidence in North America of approximately 25 cases per 100,000 children aged less than 5 years per year. The incidence is higher in East Asian countries, with children of this ancestry at higher risk for development of KD.


KD typically presents with high fever for longer than five days in duration, erythema and swelling of the palms and soles followed by desquamation, diffuse maculopapular rash, cervical lymphadenopathy, nonexudative conjunctivitis, and oral cavity erythema (strawberry tongue). The diagnosis is made by clinical criteria. Patients who do not meet full criteria but have a high index of suspicion and symptoms consistent with KD are often diagnosed with incomplete KD and may also warrant therapy.


KD constitutes an immune response of unknown cause characterized by systemic inflammation of medium-sized muscular arteries, the most serious of which are coronary arteries. Coronary dilation may be acute, subacute, or chronic, and dilation may lead to aneurysm, thrombosis, or rupture. Myocardial infarction (MI) can occur from thrombosis or chronic stenosis. For patients with minimal coronary artery dilation and early treatment with a good response to intravenous immunoglobulin (IVIG), coronary artery changes are typically transient with 98.6% having normal echocardiograms one to two weeks after discharge. Left anterior descending or right coronary artery z-score is the strongest predictor of outcomes. Risk factors for the development of coronary artery aneurysm (CAA) include a z-score greater than 2.5 at diagnosis and an age less than six months (Jone et al.). Recent guidelines recommend intensification of therapy for high-risk patients.


The standard treatment for KD is aspirin and IVIG. Fever and symptom improvement are expected shortly after initiation of therapy. Additional anti-inflammatory agents are recommended for patients with IVIG resistance, which is defined as fever persistence for greater than 36 hours after initial completion of IVIG, and patients at high-risk for CAA development. These include corticosteroids, tumor necrosis factor α inhibitors (infliximab and etanercept), an interleukin-1 inhibitor (anakinra), and cyclosporine. Patients may also warrant thrombosis prophylaxis with anti-platelet agents and other anti-coagulants. The risk of MI is highest in the first two to three months after KD onset but may persist in adults with CAA. Acute coronary syndrome (ACS) may present with atypical symptoms in children. ACS in pediatric patients is divided into ST-segment elevation MI and non-ST segment elevation MI. Treatment recommendations are based on adult management, with an emphasis on rapid revascularization.


The correct answer is B. The patient in the question stem is less than six months of age and is at high risk for developing CAA. A fever greater than five days in duration is typical with KD. Treatment within ten days of fever onset is associated with a reduced risk or CA dilation or aneurysm . Left anterior descending artery z-score of 2.5 is associated with increased risk of CAA.


REFERENCES


Jone PN, Tremoulet A, Choueiter N, et al. Update on diagnosis and management of Kawasaki disease: a scientific statement from the American Heart Association. Circulation. 2024;150(23):e481-e500.


McCrindle BW, Rowley AH, Newburger JW, et al. Diagnosis, treatment, and long-term management of Kawasaki disease: a scientific statement for health professionals from the American Heart Association. Circulation. 2017;135(17):e927-e999.


To L, Krazit ST, Kaye AD. Perioperative considerations of Kawasaki disease. Ochsner J. 2013;13(2):208-213.