Acute phase reactants in the initial phase of giant cell arteritis

Glucocorticoids and cardiovascular risk factors

Glucocorticoids remain a valuable and necessary component of therapy for many diseases. Nonetheless, sustained glucocorticoid treatment increases potential for future cardiovascular disease through multiple pathways, resulting in a tradeoff between benefit and harm. This article explores the potential mechanisms of glucocorticoid-induced hyperglycemia and dyslipidemia. Interactions between glucocorticoids and other potential cardiovascular risk factors are also reviewed. Safe, alternate strategies for minimizing the need for glucocorticoids are urgently needed.

A genetic association study of serum acute-phase C-reactive protein levels in rheumatoid arthritis: implications for clinical interpretation

BACKGROUND

The acute-phase increase in serum C-reactive protein (CRP) is used to diagnose and monitor infectious and inflammatory diseases. Little is known about the influence of genetics on acute-phase CRP, particularly in patients with chronic inflammation.

METHODS AND FINDINGS

We studied two independent sets of patients with chronic inflammation due to rheumatoid arthritis (total 695 patients). A tagSNP approach captured common variation at the CRP locus and the relationship between genotype and serum CRP was explored by linear modelling. Erythrocyte sedimentation rate (ESR) was incorporated as an independent marker of inflammation to adjust for the varying levels of inflammatory disease activity between patients. Common genetic variants at the CRP locus were associated with acute-phase serum CRP (for the most associated haplotype: p = 0.002, p<0.0005, p<0.0005 in patient sets 1, 2, and the combined sets, respectively), translating into an approximately 3.5-fold change in expected serum CRP concentrations between carriers of two common CRP haplotypes. For example, when ESR = 50 mm/h the expected geometric mean CRP (95% confidence interval) concentration was 43.1 mg/l (32.1-50.0) for haplotype 1 and 14.2 mg/l (9.5-23.2) for haplotype 4.

CONCLUSIONS

Our findings raise questions about the interpretation of acute-phase serum CRP. In particular, failure to take into account the potential for genetic effects may result in the inappropriate reassurance or suboptimal treatment of patients simply because they carry low-CRP-associated genetic variants. CRP is increasingly being incorporated into clinical algorithms to compare disease activity between patients and to predict future clinical events: our findings impact on the use of these algorithms. For example, where access to effective, but expensive, biological therapies in rheumatoid arthritis is rationed on the basis of a DAS28-CRP clinical activity score, then two patients with identical underlying disease severity could be given, or denied, treatment on the basis of CRP genotype alone. The accuracy and utility of these algorithms might be improved by using a genetically adjusted CRP measurement.

Giant cell arteritis

Giant cell, or temporal, arteritis is a vasculitis of the medium and large arteries that preferentially involves vessels originating from the arch of the aorta. Classically, this disease manifests in an older individual with new-onset persistent headache, an abnormal temporal artery on examination, and increased serum inflammatory markers. The level of clinical suspicion for giant cell arteritis should be based upon patient age, clinical symptoms, and laboratory evaluation. However, the diagnostic gold standard is achieved by histologic confirmation by temporal artery biopsy. Prompt treatment with corticosteroids is essential in order to minimize the frequency of permanent sequelae such as visual loss and stroke.

Are steroids alone sufficient for the treatment of giant cell arteritis?

Glucocorticosteroids are the cornerstone of treatment of giant cell arteritis. An initial dose of prednisone or its equivalent of at least 40-60mg per day as single or divided dose is usually adequate. Glucocorticosteroids may prevent, but usually do not reverse, visual loss. A treatment course of 1-2 years is often required. Some patients, however, have a more chronic-relapsing course and may require low doses of glucocorticosteroids for several years. Glucocorticosteroid-related adverse events are common. In studies on immunosuppressant agents, methotrexate has been used as a glucocorticosteroid-sparing drug with conflicting results. This drug may, however, be given to patients who need high doses of glucocorticosteroids to control active disease and who have serious side effects. A recent pilot study found that infliximab was efficacious in patients with glucocorticosteroid-resistant giant cell arteritis. However, randomized controlled trials are required to define the role of anti-tumor necrosis factor-alpha agents in the treatment of giant cell arteritis. Finally, low-dose aspirin has been shown in a recent retrospective study to decrease the rate of cranial ischemic complications secondary to giant cell arteritis. It is conceivable that the definition of different patterns of inflammation in giant cell arteritis in the future might facilitate the design of differentiated therapeutic approaches.

Ocular manifestations and concepts of systemic vasculitides

Vasculitic disorders are relatively rare. Their etiology and pathophysiology remain enigmatic, leading to confusing nomenclature and multiple classification schemes. Untreated vasculitis can be fatal. Early diagnosis is the key to successful treatment and better prognosis. However, early diagnosis can be difficult; vasculitic conditions usually present with non-specific symptoms for a long period before clinically overt manifestations occur. Ophthalmologists should be familiar with the ocular manifestations of the vasculitic disorders because they may not only be sight-threatening, but more importantly could be the presenting manifestations of active, potentially lethal systemic disease. This review summarizes clinical and ocular manifestations of systemic vasculitic disorders. Furthermore, it discusses general concepts in diagnosis and treatment of these diseases in an effort to provide a practical framework for the ophthalmologist evaluating patients with vasculitis.

Update on giant cell arteritis

PURPOSE OF REVIEW

Giant cell arteritis (GCA) is the most common form of systemic vasculitis that causes visual loss in the elderly. This review highlights current concepts dealing with the diagnosis, treatment, and visual prognosis of patients with GCA.

RECENT FINDINGS

Recent evidence suggests that recovery of visual function in patients with visual loss from GCA is poor. An algorithm has been constructed to assist clinicians in the evaluation and management of patients suspected of having GCA.

SUMMARY

Despite a number of new adjunctive agents, corticosteroids remain the standard treatment in patients with GCA.

Late ipsilateral recurrence of ischemic optic neuropathy in giant cell arteritis

A patient with arteriosclerosis, diabetes mellitus, and giant cell arteritis (GCA) treated continuously with low-dose prednisone developed anterior ischemic optic neuropathy (AION) at 5 and 13 months after clinical diagnosis of GCA. At the time of late recurrent AION, there were no systemic symptoms or elevations in acute phase reactants to signal active arteritis, yet temporal artery biopsy disclosed dramatic inflammation, forcing the presumption that the infarct was arteritic. Recurrent systemic symptoms and elevation of acute phase reactants are not reliable warning signs of reactivated GCA. In patients at high risk for corticosteroid complications, late biopsy may be a reasonable guide to corticosteroid weaning.

Current concepts in giant cell (temporal) arteritis

Giant cell (temporal) arteritis continues to be a sight-threatening, systemic vasculitis with a poorly understood pathogenesis. The characteristic granulomatous inflammation of the vessel wall commonly leads to local ischemia. Recent advances in immunological investigations have characterized the cellular components of the disease process, but the etiology has so far remained unresolved. A reappraisal of the clinical features of giant cell (temporal) arteritis demonstrates the heterogeneity of the manifestations of the disease, including ischemic optic neuropathy. A range of new laboratory investigations and blood flow studies with color Doppler imaging have demonstrated promising roles, with respect to diagnosis and long-term follow-up. Prompt diagnosis and expeditious treatment require a high index of clinical suspicion, particularly for atypical cases. Corticosteroids remain the treatment of choice, other immuno-suppressive agents being used as second line steroid-sparing agents. Giant cell (temporal) arteritis leads to increased vascular and visual morbidity and, if untreated, may prove fatal. To maintain high standards of management of this enigmatic disorder, ophthalmologists need to be aware of the clinical spectrum of giant cell (temporal) arteritis and currently available diagnostic tests and treatment strategies.

Plasma viscosity in giant cell arteritis as a predictor of disease activity

Thirty one patients with giant cell arteritis (GCA) receiving standardised prednisolone treatment were followed up for one year with analyses of plasma viscosity, erythrocyte sedimentation rate (ESR), C reactive protein (CRP), and fibrinogen concentration. On the day of diagnosis all patients had an increased plasma viscosity and ESR, whereas the concentration of CRP was normal in three patients and fibrinogen concentration and haptoglobin values were normal in one patient. IgG levels were increased in two patients. Plasma viscosity correlated significantly with the ESR, IgG level, and fibrinogen concentration. Laboratory variables in subgroups of patients with GCA proved by biopsy were not different from the whole group of patients with GCA. The follow up showed that CRP normalised faster than the ESR, plasma viscosity, and fibrinogen concentration. Plasma viscosity and the ESR paralleled clinical findings more closely and predicted flare ups better than the other variables. Plasma viscosity had advantages over the ESR for predicting flare ups and in the clinical monitoring of treatment with glucocorticoids.

Laboratory investigations including liver in polymyalgia rheumatica/giant cell arteritis

The most useful investigation in supporting the clinical diagnosis of PMR/GCA is elevation of the ESR or viscosity. Acute phase proteins, particularly C-reactive protein, are also elevated but in most cases are not more helpful than the ESR in either diagnosis or follow-up. The definitive investigation is the demonstration of giant cell arteritis histologically, usually from temporal artery biopsy. The classical changes are internal elastic lamina fragmentation and destruction, with marked intimal thickening and an inflammatory infiltrate in the vessel wall with giant cells. Changes of healed arteritis can be distinguished from ageing changes and can therefore confirm the diagnosis. Positive biopsies are found in about 70% of patients with clinical GCA but are unlikely to be helpful in pure PMR. Elevation of alkaline phosphatase of liver origin is seen in one-third to half of patients with both PMR and GCA. Abnormal tracer uptake has been reported in radionuclide scans with a variety of non-specific abnormalities on liver biopsy. Promising developments include measurement of CD8+ lymphocytes and interleukins.

The American College of Rheumatology 1990 criteria for the classification of giant cell arteritis

Criteria for the classification of giant cell (temporal) arteritis were developed by comparing 214 patients who had this disease with 593 patients with other forms of vasculitis. For the traditional format classification, 5 criteria were selected: age greater than or equal to 50 years at disease onset, new onset of localized headache, temporal artery tenderness or decreased temporal artery pulse, elevated erythrocyte sedimentation rate (Westergren) greater than or equal to 50 mm/hour, and biopsy sample including an artery, showing necrotizing arteritis, characterized by a predominance of mononuclear cell infiltrates or a granulomatous process with multinucleated giant cells. The presence of 3 or more of these 5 criteria was associated with a sensitivity of 93.5% and a specificity of 91.2%. A classification tree was also constructed using 6 criteria. These criteria were the same as for the traditional format, except that elevated erythrocyte sedimentation rate was excluded, and 2 other variables were included: scalp tenderness and claudication of the jaw or tongue or on deglutition. The classification tree was associated with a sensitivity of 95.3% and specificity of 90.7%.

Vascular protein deposits in temporal arteritis with special reference to failure of histological findings

The object of an immunohistochemical search for vascular protein deposits in temporal arteritis is to assess the diagnostic possibilities in cases which are clinically typical but unconfirmed by biopsy results. In a group of older patients with arteritis, however, vascular aging may give rise to intimal thickening and a broad-spectrum deposition of protein. In an inter- and intra-individual comparison of vascular segments with and without arteritis we, however, found a few protein markers in arteritis which are essentially different from those in vascular aging. The intimal thickening and immune reaction in 9 selected marker proteins were graded 0-2, using the tunica media as reference for both properties. Of the nine proteins studied, alpha-2-macroglobulin was significantly increased, not only in segments affected with arteritis, but also in unaffected segments from the same biopsy as compared with biopsies from patients not suffering from this disease. 79% of patients with biopsy-confirmed arteritis also showed a significantly elevated serum alpha-2-macroglobulin as compared to 27% of those having only changes attributed to aging. In conclusion, immunohistochemical demonstration of deposits in the arterial wall and elevated serum levels of alpha-2-macroglobulin substantiate the clinical suspicion of arteritis in the absence of histological and inflammatory changes.

Behavior of prealbumin in the acute phase of polymyalgia rheumatica treated with 6-methylprednisolone

Serum levels of prealbumin, fibronectin, fibrinogen, alpha 1-acid glycoprotein, C-reactive protein, immunoglobulins, and white blood cell count were prospectively studied in 33 patients affected by polymyalgia rheumatica during the first 45 days of treatment with 6-methylprednisolone. Almost all parameters considered, except for fibronectin and IgM, settled within the normal range fairly quickly, while prealbumin showed a specular course compared with the other reactants. This behavior reflected the improvement of clinical symptoms registered in all patients after steroid treatment. Finally, the genesis of the low baseline prealbumin levels found in polymyalgia rheumatica/giant cell arteritis and their behavior during treatment are discussed.