Kawasaki at the Extremes of Age: Thinking Outside the Box

An Update on Reports of Atypical Presentations of Kawasaki Disease and the Recognition of IVIG Non-Responder Children

Kawasaki disease (KD) is an acute vasculitis with an intrinsic risk of severe involvement of coronary arteries. The worldwide spread of KD and the importance of early diagnosis for preventing cardiovascular complications have ascertained the need for updating guidelines for prompt disease recognition and treatment efficacy assessment. All KD patients who comply with the definition of classic or atypical disease should be treated with intravenous immunoglobulin (IVIG) soon after diagnosis. The objective of our narrative review was to analyze the medical literature about case reports with atypical KD in relation to diagnosis and potential identification of predictors of non-responsiveness to IVIG. Our analysis has shown that the seminal challenge in KD management is the timeliness of diagnosis, although both extreme variability and transience of clinical manifestations make this goal difficult. A non-negligible percentage of patients, especially in the first 6 months of life, might have atypical manifestations of KD, whose painstaking differential diagnosis may be tricky. Many attempts to develop universal scoring systems and detect children at higher risk of IVIG resistance have been rather unsuccessful. Additionally, KD may show different evolutions according to unraveled demographic, genetic, or epigenetic factors. Further research is needed to elucidate all open questions about KD and clarify the long-term outcome of its potential complications.

Characteristics and trends in diagnosis of Kawasaki disease outside the usual age range

OBJECTIVE

To explore the trends in diagnosis of Kawasaki disease (KD) and determine the characteristics for patients outside the usual age range of 6 months to 4 years.

METHOD

A retrospective review of patients with KD identified in four epidemiological surveys spanning 20 years (1998-2017) in Shanghai was performed.

RESULTS

A total of 8416 patients were included. All in all, 223 (2.6%) were aged 0 to 2 months, 639 (7.6%) were 3 to 5 months, 6556 (77.9%) were 6 months to 4 years, 915 (10.9%) were 5 to 9 years, and 83 (1.0%) were ≥ 10 years. The use of intravenous immunoglobulin increased in all extreme age groups, and delayed treatment rates decreased in all patients except in those aged 0 to 2 months and ≥ 10 years. The number of patients outside the usual age increased over time, but the proportion of these patients did not change significantly. They had more incomplete KD and coronary artery aneurysms (CAA), while those aged 0 to 2 months and ≥ 10 years had more delayed diagnoses in their respective age groups. The incidence of CAA was similar in younger and older children, but the former group had more cases of incomplete KD and abnormal laboratory parameters, while the latter group had longer duration of fever and was more difficult to diagnose promptly.

CONCLUSIONS

The proportion of KD outside the usual age range did not increase over time. Older and younger children have different clinical and laboratory characteristics. Key Points • The number of patients outside the usual age increased over time, but the proportion of these patients did not increase. • Patients aged 0 to 2 months and ≥ 10 years had more delayed diagnoses in their respective age groups. • Younger children had more cases of incomplete KD and abnormal laboratory parameters, while older children had longer duration of fever and were more difficult to diagnose promptly.