KD is an autoimmune vasculitis of unidentified factors. It mainly affects young children aged between 3 months and 10 years. Kawasaki disease was first reported in 1961 . The incidence of KD in Northeast Asian countries including Japan, South Korea, China, and Taiwan is 10–30 times higher than in the USA and Europe . The male-to-female ratio is approximately 1.5:1. Peak incidence is noted between January and March, suggesting an environmental contribution . Our child was a 9-month-old male.
There are no specific diagnostic investigations to differentiate typical and atypical Kawasaki disease. Typical KD should have essential criteria: evidence of prolonged fever (≥ 5 days) associated with the presence of at least four out of five principal clinical features (change in extremities, polymorphous exanthema, bilateral bulbar conjunctival injection without exudate, changes in the lips and oral cavity, cervical lymphadenopathy of more than 1.5 cm) . All the clinical criteria may not be present initially, but evolve subsequently in the second week. An incomplete presentation might have an unexplained fever for ≥ 5 days associated with two or three of the principal clinical features described above . Our patient had fever for more than 5 days, with maculopapular rash and cervical lymphadenopathy. Although not diagnostic, there are some less common features, including gastrointestinal (diarrhoea, emesis, and abdominal pain), respiratory (cough and rhinorrhea), rheumatologic (joint pain and swelling) symptoms , and genitourinary symptoms such as urethritis associated with sterile hematuria and pyuria. Diarrhoea and genitourinary symptoms were the presenting features of the reported child. The laboratory investigations (for example, elevated erythrocyte sedimentation rate and C-reactive protein level, hyponatremia, hypoalbuminemia) and echocardiographic findings might support the diagnosis . About 15–25% of untreated patients might develop coronary artery aneurysms or ectasia and also end up in myocardial infarction, sudden death, or ischemic heart disease. When the initial echocardiography showed no coronary artery alterations, repeat ECHO is mandatory in all patients to confirm coronary abnormalities after 10 days of febrile illness. The reported child had coronary artery dilatation on day 12 of febrile illness.
Diagnosis of incomplete KD depends on incomplete criteria with echocardiographic (ECHO) features with or without elevated inflammatory markers, and exclusion of other similar diseases such as drug hypersensitivity, juvenile idiopathic arthritis, staphylococcal scaled skin syndrome, Stevens–Johnson syndrome, streptococcal scarlet skin syndrome, toxic shock syndrome, and viral infection . Our child had high CRP, ESR, and liver function, high white blood count (WBC) with neutrophil predominant, low hemoglobin, high platelets, and macroscopic hematuria.
According to the American Heart Association (AHA) guidelines, intravenous immunoglobulin (IVIG) and high-dose aspirin have been the main mode of treatment in Kawasaki management [7, 10, 11]. Although the action of IVIG is not known, it is said that it has some immunomodulatory effects such as cytokine production, influence on T-cell activity, and suppression of antibody synthesis . A single dose of 2 g per kg is administered within 10 days of illness, or later if the patient has persistent fever or aneurysms, or persistent inflammation supported by markers. It is estimated that the development of coronary artery abnormalities has been reduced from 25% to 5% and the formation of giant aneurysms to 1%. Besides, the acute disease benefits from high-dose aspirin initially (80–100 mg/kg) to reduce inflammation. Once inflammatory markers return to normal, low-dose aspirin (3–5 mg/kg) as a single dose is suggested to reduce platelet activation and prevent thrombosis for 6–8 weeks. Aspirin should be continued indefinitely if coronary abnormalities persist on follow-up ECHO [10, 11]. It is recommended to give steroids in refractory cases; however, this practice is controversial. Although the described case responded symptomatically to aspirin and IVIG, follow-up ECHO showed persistence of coronary abnormalities. He was scheduled for long-term follow-up with the continuation of aspirin. He was reviewed regularly at pediatric and cardiology clinics. The 2D echocardiogram repeated at 1 year showed normal findings. After 2 years of follow-up in a tertiary care hospital, he was referred to the local hospital for routine follow-up and immunization. As the patient had a risk of Reye syndrome with influenza and varicella, his parents were informed regarding the need for vaccination against those infections [4, 7].