Clinical Significance of Vascular Ultrasonography in the Diagnosis of Early Childhood Takayasu Arteritis Presenting as Fever of Unknown Origin.

Takayasu arteritis (TA) is a large-vessel vasculitis with unknown aetiology that primarily affects the aorta and its primary branches. Delay in proper diagnosis and intervention may result in vascular stenosis and obstruction, and early diagnosis of TA is important. However, it is challenging for paediatricians to make an early diagnosis of childhood TA (cTA), because early cTA often presents as a fever of unknown origin (FUO) lacking the typical clinical manifestations related to vascular stenosis such as pulseless extremities or bruits, which only appear after wall thickening progresses.1 Here, we report a child with early cTA presenting as FUO in whom vascular ultrasonography was useful for the diagnosis. For 2 weeks, an 8-year-old girl suffered from prolonged fever, and was referred to us as a case of fever of unknown origin. On admission, physical examination revealed enlarged cervical lymph nodes and erythema nodosum-like rash on the lower legs. Blood pressure was normal for age (102/70 mmHg). Laboratory findings were as follows: white blood cells 7900/mm3, platelets 420 000/mm3, CRP 11.9 mg/dL, Ferritin 174 ng/mL and D-dimer 1.6 μg/mL. Autoantibodies were negative. Urinalysis was normal. Cultures of blood, urine, and stool were negative. Vascular ultrasonography revealed 1.3 mm (normal <1.0 mm) of intima-media thickenings in the origin of the right subclavian and internal carotid arteries (Figure 1). No coronary artery lesions were observed. Subsequent contrast enhancement computed tomography (CT) confirmed arterial wall thickening in the aortic arch branches (Figure S1), leading to the diagnosis of TA. Treatment with one course of methylprednisolone pulse followed by oral prednisolone (1 mg/kg/day) and azathioprine (1 mg/kg/day) was started, and her symptoms improved. TA is a rare disease with an estimated annual incidence in the paediatric population of approximately 2/1 000 000 and it constitutes <5% of FUO in children. However, 80% of patients with early cTA present with FUO. The diagnosis of early cTA is usually made by a combination of imaging modalities including US,2 contrast enhancement CT,3 18F-fluorodeoxyglucose positron emission tomography4 and magnetic resonance imaging.3 Among these modalities, vascular US is a non-invasive and low-cost imaging, able to provide higher resolution and sensitivity detecting vascular lesions. US is helpful to detect submillimetre thickness changes in the wall of the carotid arteries. Furthermore, US is free from radiation exposure and the need for sedation in most of the cases. Thus, paediatricians should consider TA in children presenting with FUO, in whom vascular ultrasonography can be used as a first line screening modality. Figure S1 Contrast enhancement computed tomography of aortic arch branches. Arterial wall thickenings were observed in the origin parts of aortic arch branches (yellow triangles). Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.