Childhood-onset Takayasu arteritis: Unique characteristics and outcomes from a Singapore cohort.

Introduction: Takayasu arteritis is the most common large-vessel vasculitis in childhood, but there is a lack of literature regarding childhood-onset Takayasu arteritis (c-TAK) in Southeast Asia. We aim to describe a c-TAK cohort in Singapore and highlight a unique subset that first presents with Kawasaki-like disease (KD).

Method: A single-centre cohort study in Singapore of consecutive children diagnosed with c-TAK between 2002 and 2023 was performed. Demographic and clinical features, laboratory and angiographic findings, treatment, and outcomes were summarised. Disease activity was evaluated using the Paediatric Vasculitis Disease Activity Score and inflammatory markers.

Results: Twenty-three patients, fulfilling both the EULAR/ PRINTO/PReS and ACR/EULAR 2022 criteria, were recruited. The most common clinical features at diagnosis were fever (15, 65%) and neurological symptoms (11, 48%, half of which presented with stroke), while the most prevalent angiographic pattern by Hata's classification was Type V (21, 91%). Eight children (35%) initially presented with refractory KD, and these patients were significantly younger, more male-predominant, and had higher inflammatory markers at diagnosis; all of them had coronary artery involvement, but none had intracranial vascular findings. Of the entire cohort, 16 (70%) achieved inactive disease on medications with a median duration of 6 months (interquartile range [IQR]: 4-11), and 8 (35%) achieved remission off medications with a median duration of 43 months (IQR 35-60).

Conclusion: Our c-TAK cohort has high proportions of neurological involvement and stroke. This is also the first cohort study to describe a distinct group of patients who first presented with refractory KD.