A 62-year-old man presented with a 3-month history of chronic non-productive cough and unexplained fever. Further questioning revealed that he had headaches and myalgia. Bilateral thickened temporal arteries were noted on physical examination. The erythrocyte sedimentation rate was 96 mm in 1 h. A biopsy specimen of the left temporal artery showed inflammatory changes consistent with the diagnosis of giant cell arteritis. Commencement of prednisolone resulted in rapid and dramatic resolution of his symptoms. Physicians should be aware of respiratory symptoms in patients with giant cell arteritis in order to avoid delay in diagnosis and therapy of this condition.
Macrophages are key players in the pathogenesis of large-vessel vasculitis (LVV) and may serve as a target for diagnostic imaging of LVV. The radiotracer, 18F-FDG has proven to be useful in the diagnosis of giant cell arteritis (GCA), a form of LVV. Although uptake of 18F-FDG is high in activated macrophages, it is not a specific radiotracer as its uptake is high in any proliferating cell and other activated immune cells resulting in high non-specific background radioactivity especially in aging and atherosclerotic vessels which dramatically lowers the diagnostic accuracy. Evidence also exists that the sensitivity of 18F-FDG PET drops in patients upon glucocorticoid treatment. Therefore, there is a clinical need for more specific radiotracers in imaging GCA to improve diagnostic accuracy. Numerous clinically established and newly developed macrophage targeted radiotracers for oncological and inflammatory diseases can potentially be utilized for LVV imaging. These tracers are more target specific and therefore may provide lower background radioactivity, higher diagnostic accuracy and the ability to assess treatment effectiveness. However, current knowledge regarding macrophage subsets in LVV lesions is limited. Further understanding regarding macrophage subsets in vasculitis lesion is needed for better selection of tracers and new targets for tracer development. This review summarizes the development of macrophage targeted tracers in the last decade and the potential application of macrophage targeted tracers currently used in other inflammatory diseases in imaging LVV.
A case of giant cell arteritis with systemic and panocular involvement is reported here. This elderly Indian male presented with symptoms of unilateral temporal headache and intermittent jaw claudication for a month followed by diplopia and blurring of vision and later loss of vision in the right eye. The right eye showed some limitation of ocular movements, presence of relative afferent pupil defect, anterior segment ischaemic changes and anterior ischaemic optic neuropathy. Visual evoked potential showed an absent P1 wave while the left eye with normal 6/6 vision sowed a prolonged P1 wave. Fundus fluoresceine angiography showed delay in choroidal perfusion. His erythrocyte sedimentation rate (ESR) was 120 mm/hr and he was started on oral prednisolone. Superficial temporal artery biopsy obtained one week after starting steroids was positive for giant cell arteritis. Steroids led to the resolution of optic disc swelling, disappearance of anterior segment signs, full recovery of right ocular movements and no further deterioration of the fellow eye. On steroids, he developed insomnia and progressive myopathy which resolved and is now symptom free at lower doses of steroids.