Physiopathologie de l’artérite à cellules géantes

Giant cell arteritis is a large-vessel vasculitis affecting all three layers of the arterial wall. Histopathology of this vasculitis consists of an inflammatory infiltrate with CD4⁺ T cells, macrophages, multinucleated giant cells, forming granulomas in the media. This infiltrate is associated with a destruction of the arterial wall, a fragmentation of the internal elastic lamina and a vascular remodeling leading to intimal hyperplasia. Recent studies have clarified the role of Th17 cells in the initial phase of the disease, pro-inflammatory cytokines and vascular smooth muscle cells in vascular remodeling. This review aims to update data on giant cell arteritis pathogenesis and to propose clues of investigation for a better understanding of this condition.     

Caractéristiques cliniques,paracliniques et profil évolutif de l’atteinte aortique de la maladie de Horton : à propos de 26 cas d’aortite parmi 63 cas de maladie de Horton

Purpose

Aortic involvement that occurs in temporal arteritis is probably underestimated because it is usually asymptomatic. The characteristics of giant cell arteritis with aortic involvement are still poorly described and the relationship between aortitis and vascular outcome of the disease has not been clearly delineated. The objective of this retrospective study of 63 patients with giant cell arteritis, including 26 with aortic involvement, was to compare the features of patients with and without aortitis, and to assess the contribution of CT-scan and FDG-PET-scan in screening for vascular disease, monitoring, and therapeutic management of patients.

Methods

This retrospective study was conducted in the internal medicine department of the university hospital in Marseille, France, from January 1, 2005 to September 30, 2011. Patients had at least three out of the five American College of Rheumatology criteria for temporal arteritis and aortic involvement was investigated in all patients using CT-scan. Aortic wall thickness greater or equal to 3 mm was considered to be abnormal.

Results

Of 63 patients diagnosed with giant cell arteritis, 26 (41.3%) had aortic involvement diagnosed by aortic CT-scan. Age at diagnosis was significantly younger (66.8 vs 73.8 years; P = 0.002) in the group with aortitis. Inflammatory dorsal and low back pain, signs of vascular disease of the upper limbs (P = 0.009), and higher level of acute phase reactants were associated with aortitis. Aneurysmal lesions of the aorta were significantly more frequent in the group with aortitis. Twenty patients had both aortic CT-scan and FDG-PET-scan. For patients in whom aortic involvement was not demonstrated with CT-scan, FDG-PET-scan was always non-contributive. With corticosteroids, aortitis resolved within 6 months in all patients as evaluated by aortic CT-scan. However, aortitis persisted in 80% of cases at 6 months when evaluated with FDG-PET-scan, and in 66% of cases at 12 months, without influencing the treatment.

Conclusion

This case series shows no specific features of aorta and its main roots involvement in giant cell arteritis, justifying a systematic screening by CT-scan. The high frequency of this arterial involvement could help physicians in the diagnosis of giant cell arteritis. Aortitis seems to be associated with vascular complications as highlighted by the frequency of aortic aneurysm and a case of early aortic dissection. Finally, the role of PET-CT-scan for screening vascular disease and therapeutic monitoring remains to be clarified.     

Complications de la corticothérapie chez les patients souffrant de maladie de Horton ou de pseudopolyarthrite rhizomélique

Giant cell arteritis and polymyalgia rheumatica are common reasons for prescribing long-term glucocorticoid therapy. Glucocorticoids efficacy in these patients is rapid and undeniable, but it is often overshadowed by adverse events, appearing more or less early during treatment course. These adverse events are usually minor but some of them may be life threatening. Because of the absence of randomized, controlled trials comparing glucocorticoids to placebo in this indication and in this aged population, it is difficult to precise the role of corticosteroids in the occurrence of some complications that can also be precipitated by the disease itself (e.g., vascular complications) or related to aging. In this context, analysis of the crude morbidity and mortality can help in anticipating the potential problems that these patients will encounter. In addition, the long duration of glucocorticoid exposure should prompt physicians to be particularly vigilant regarding some adverse events that are minimally symptomatic on the short term but have a major long-term impact.     

Manifestations ophtalmologiques de la maladie de Horton

Permanent visual loss (PVL) is the most dreaded complication of giant cell arteritis (GCA). It results from anterior ischemic optic neuropathy or, less commonly, retinal artery occlusion. This complication still occurs in 14 to 20% of patients and is typically devastating and permanent, although it is highly preventable by an early diagnosis of giant cell arteritis and appropriate glucocorticoid treatment. Transient ischemic symptoms such as amaurosis fugax, episodes of blurred vision or diplopia may occur, either heralding visual loss or remaining isolated. In studies, the main predictors of PVL are jaw claudication, amaurosis fugax, lack of systemic “B” symptoms, a modestly increased ESR and a higher haemoglobin level. The evaluation of a GCA patient with PVL includes emergency fundoscopy completed by fluorescein angiography, immediate erythrocyte sedimentation rate, C-reactive protein, and complete blood count. Treatment is extremely urgent mainly because, if left untreated, GCA is associated with visual loss in the fellow eye within days in up to 50% of individuals. Treatment may begin with high-dose intravenous methylprednisolone, followed by oral prednisone administered at 1 mg/kg per day. Daily adjunctive aspirin orally may be added since it has been shown, in retrospective studies, to protect against stroke and visual loss. Although treatment duration of complicated GCA is not codified, an initial PVL deserves close monitoring of patient's systemic symptoms, ESR and CRP to avoid relapses due to a significant risk of late recurrence of visual loss during steroid tapering.     

Caractéristiques des patients de moins et de plus de 75 ans atteints d’artérite à cellules géantes : étude comparative de 164 patients

Purpose

Giant cell arteritis (GCA) is the most common vasculitis of the elderly. In order to assess the impact of age at diagnosis, we compared the characteristics of patients of less than 75 years (< 75 years), to those of the 75 years and over (≥ 75 years).

Efficacité clinique et biologique du tocilizumab au cours de la maladie de Horton : à propos de trois observations et revue de la littérature

Introduction

Treatment of giant cell arteritis is based on prolonged corticosteroid therapy but adverse side effects are common especially in the elderly.

Case reports

We report three patients with giant cell vasculitis treated by tocilizumab, an interleukin-6 receptor antibody, owing to resistance or intolerance to corticosteroid therapy. A favorable outcome was rapidly observed both on clinical and biological data allowing a corticoid therapy sparing.

Conclusion

Tocilizumab is a promising treatment of giant cell arteritis but controlled trials are needed to confirm its efficacy.     

Peripheral arterial involvement in giant cell arteritis: how to differentiate between atheroma and inflammation?

Giant cell arteritis (Horton's disease) is an inflammatory arteritis involving medium and large diameter arteries. The disease typically occurs in patients aged 50 years or more who may otherwise have atherothrombotic lesions. It is sometimes difficult to determine whether an arterial stenosis arises from an inflammatory or an atherothrombotic mechanism in a patient with giant cell arteritis. Therefore we describe, through a case report, the clinical features and complementary investigation data helpful for distinguishing between these two entities.