Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
July 2016
Next case coming August 2 …
Giant Cell Arteritis Involving the Extradural Vertebral Arteries
- Clinical Case:
- A 72-year-old caucasian woman with new-onset daily headache 3 months prior presents to the emergency department with a subacute onset of nausea, vomiting, and progressive gait incapacity. Neurologic examination was notable for time and space disorientation, dysarthria, axial and appendicular ataxia. Temporal arteries were both palpable and non-tender, and there were no trophic changes of skin. Erythrocyte sedimentation rate (ESR) was 57 mm/h, and C-reactive protein was 22,2 mg/L.
- Both CT and MRI were compatible with ischemia in vertebrobasilar territory. Color Doppler sonography was suggestive of an inflammatory process involving vertebral and superficial temporal arteries bilaterally. Vasculitis was suspected and intravenous high-dose steroids were started.
- CT angiogram showed narrowing and beading of both vertebral arteries, and gadolinium-enhanced MRI revealed thickening and contrast enhancement of vertebral artery wall.
- After a negative investigation — including infectious (HIV, HBV, HCV, and neurosyphilis) and autoimmune systemic disorders (SLE, RA, pauci-immune vasculitis) — and positive clinical, laboratory (ESR), and ultrasonographic responses to immunosuppression, the diagnosis of giant cell arteritis (GCA) was assumed.
- Discussion:
- Bilateral occlusion of vertebral arteries (BVAO) is a rare cause of stroke, with an estimated incidence of 1û2 per 1000 patients with cerebrovascular disease. There are 3 main etiologies of BVAO, namely trauma, atherosclerosis, and GCA. Traumatic etiology can be revealed in a straightforward fashion, but the difference between atherosclerosis and vasculitis is more challenging. One of the main distinguishing characteristics of GCA-BVAO is its involvement of extradural segments of the intracranial vertebral arteries (distal V2 to proximal V4), while BVAO of atherosclerotic origin affects distal V4 and proximal V1 segments. Vessel wall is also differently affected in both atherosclerotic and vasculitic processes, as a located versus diffuse process, respectively. Imaging methods can be quite helpful in this distinction because they display anatomic and pathophysiologic information.1
- GCA is a chronic idiopathic vasculitis affecting large- and medium-sized arteries containing elastic lamina. It commonly affects temporal superficial arteries along with ophthalmic, posterior ciliary, and vertebral arteries, sparing intracranial vessels. It is the most common type of vasculitis affecting people over the age of 50 years and rarely causes stroke (occurs only in 2–4% of patients with GCA).2
- Diagnostic consensus criteria of the American College of Rheumatology must include 3 out of 5 between: 1) > 50 years, 2) new onset headache, 3) temporal artery tenderness to palpation or decreased pulsation, 4) ESR > 50 mm/h, and 5) biopsy proven vasculitis.2 Imaging techniques are progressively replacing biopsy, which is not a procedure free of complications. Ultrasonographic “halo sign” (hypoechoic ribbon around the lumen) of the superficial temporal artery has a reported specificity of 91% when found unilaterally and 100% when bilaterally present.3 High-resolution contrast-enhanced MRI imaging of the vessel wall in patients suspected GCA has a sensitivity that is superior to temporal artery biopsy (80.6%) and high specificity (97%).4
- We used multimodal imaging technics to increase accuracy of diagnosis, avoiding an invasive diagnostic method (temporal artery biopsy), and we used Doppler ultrasound to monitor response to corticosteroids.
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