Diagnosis and Assessment of Disease Activity in Takayasu Arteritis: A Childhood Case Illustrating the Challenge

Takayasu Arteritis (TA) is a rare, debilitating large vessel vasculitis occurring in patients of all ages, including infants, but the disease most commonly presents in the third decade. Diagnosis is often delayed and consequently TA is associated with significant morbidity and mortality. Accurate methods of monitoring disease activity or damage are lacking and currently rely on a combination of clinical features, blood inflammatory markers, and imaging modalities. In this report we describe a case of a 14-year-old boy with childhood-onset TA who, despite extensive negative investigations, did indeed have on-going active large vessel vasculitis with fatal outcome. Postmortem analysis demonstrated more extensive and active disease than originally identified. This report illustrates and discusses the limitations of current modalities for the detection and monitoring of disease activity and damage in large vessel vasculitis. Clinicians must be aware of these limitations and challenges if we are to strive for better outcomes in TA. 1. Introduction Takayasu Arteritis (TA) is a large vessel vasculitis of unknown aetiology that affects the aorta and its branches. The cause is unknown, but genetic contribution to disease susceptibility is increasingly recognised [1], whilst suggested links with tuberculosis infection remain unproven [2]. Diagnosis is often considerably delayed: in a recent paediatric classification criteria exercise, the mean time from symptom onset to diagnosis was 1.3 years (SD ± 1.6 years) [3]. Even when the diagnosis is secured, challenges occur in distinguishing between the acute or “active” phase of the illness and the chronic, stenotic phase when symptoms or signs are the result of tissue ischaemia from progressive arterial narrowing [4]. It is important to identify active disease since this requires immunosuppressive treatment, but it is unclear whether immunosuppression is effective in the late stage of the disease when a risk-benefit balance must be made [5]. Revascularisation procedures, such as angioplasty and/or stenting, or more invasive surgical interventions such as aortic bypass grafting are commonly required to provide relief from symptomatic ischaemia but are associated with significant life threatening risks and morbidity and are not completely effective in all cases [6, 7]. Moreover the risk of restenosis is high, particularly if the disease is active at the time of surgery [8–11]. We present a case that highlights the difficulties clinicians face in relation to the diagnosis and monitoring of large vessel vasculitis. 2.