A halo may lead the way

A 71-year-old man consults for left temporal headache, fatigue, weight loss, jaw claudication and proximal myalgia with subacute onset. Blood analysis shows an increased erythrocyte sedimentation rate (115 mm/h) and elevated C-reactive protein level (154.4 mg/l). Ultrasound examination of the temporal arteries displayed the bilateral presence of a dark halo surrounding the lumen (Figure 1A). Giant cell arteritis was confirmed by histopathology of the temporal artery (Figure 1B). The patient was treated with corticosteroids.

Figure 1.

A. Axial ultrasound image: an ultrasound revealed bilateral circumferential wall thickening (arrow), which is typically observed as a dark halo around the lumen of the temporal artery. The red centre represents the artery lumen. B. A histological section of the temporal artery shows an intimal thickening that reduces the lumenal diameter. In the different layers of the artery there is an infiltration by macrophages, lymphocytes and neutrophils. Giant cells can be observed (inset).

In line with previous reports (1,2), this image illustrates that ultrasound of the temporal arteries might be of value in the diagnosis of giant cell arteritis because the inflammation can be patchy, making it possible to miss the characteristic findings on a randomly selected biopsy specimen of the superficial temporal artery. The ‘halo’ sign, which represents hypoechoic circumferential wall thickening probably caused by oedema, is characteristic and can be a supporting factor in the diagnosis of giant cell arthritis although stenoses and occlusions can also be found (1,2).