Thrombokinetics in giant cell arteritis, with special reference to corticosteroid therapy

Characterization of serological markers of healed/healing arteritis and giant cell arteritis

OBJECTIVE

Temporal artery biopsy (TAB) is the gold standard for confirming the diagnosis of giant cell arteritis (GCA) when positive. However, the clinical significance of healed/healing (HH) arterial injury on TAB is not well understood. The purpose of this study was to evaluate the clinical significance of this finding on TAB by determining its association with seromarkers typically predictive of GCA.

DESIGN

Single-centre, retrospective, investigational cohort study.

PARTICIPANTS

A total of 385 consecutive TABs for clinical suspicion of GCA between January 2009 and January 2016.

METHODS

Elevations in erythrocyte sedimentation rate, C-reactive protein, and platelet count were compared between patients with negative TAB, GCA-positive TAB, and HH arterial injury using statistical trend testing. Odds ratios of seromarker elevations for HH arterial injury versus GCA were calculated.

RESULTS

Seventy-six GCA-positive, 69 HH, and 240 negative TABs were identified. Mantel-Haenszel tests of trend indicated that platelets >400 000/µL (p < 0.01), erythrocyte sedimentation rate ≥50 mm/hr (p < 0.01), and C-reactive protein ≥24.5 mg/L (p < 0.01) occurred with intermediate frequency in the HH TAB group. The odds of HH TAB were 3.6 times greater (95% CI 1.5-8.5) with platelets >400 000/µL.

CONCLUSION

HH arterial injury is a heterogenous group that requires treatment in the appropriate clinical setting. From our study, we found that the HH group is intermediate between GCA-positive and GCA-negative biopsy with respect to serology markers only. Thrombocytosis is an independent predictor of HH TAB. With further studies, this marker may be considered when making treatment decisions. Further studies are required to better understand this entity.

Role of Thrombocytosis in Diagnosis of Giant Cell Arteritis and Differentiation of arteritic from Non-Arteritic Anterior Ischemic Optic Neuropathy

Purpose

To investigate the role of thrombocytosis in the diagnosis of giant cell arteritis (GCA), and differentiation of arteritic (A-AION) from non-arteritic (NA-AION) anterior ischemic optic neuropathy; and comparison of the sensitivity and specificity of platelet count to that of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and some other hematologic variables in the diagnosis of GCA.

METHODS

This retrospective study is based on 121 temporal artery biopsy confirmed GCA patients and 287 patients with NA-AION seen in our clinic. For inclusion in this study, all GCA patients, at their initial visit, prior to the initiation of corticosteroid therapy, must have had ESR (Westergren), platelet count and complete blood count, and temporal artery biopsy. From 1985 onwards CRP estimation was done. For inclusion in this study, all NA-AION patients at the initial visit must have undergone evaluation similar to that described above for GCA, except for temporal artery biopsy. Wilcoxon rank-sum test and the two-sample t-test were used to compare hematologic variables between GCA patients with and without visual loss, between those with and without systemic symptoms, and also between GCA and NA-AION patients. Pearson correlation coefficient was computed to measure the association of platelet counts and the other hematologic variables with ESR. Receiver operating characteristic (ROC) curves were constructed for ESR, CRP, platelet count, combinations of ESR and platelet count, and CRP and platelet count, hemoglobin, hematocrit, and white blood cell (WBC) count and the area under the curve (AUC) were compared.

Results

Comparison of ESR, CRP, and hematologic variables of GCA patients and of A-AION with the NA-AION group, showed significantly (p <0.0001) higher median levels of ESR, CRP, platelet count, and WBC count and lower levels of hemoglobin and hematocrit in the GCA patients and A-AION than in NA-AION. Comparing AUC of the ROC curve between ESR and platelet count, ESR was a better predictor of GCA compared to platelet count (AUC of 0.946 vs. 0.834). There was a slight improvement in prediction of GCA using the combination of ESR and platelet count (AUC=0.953). The other hematologic variables had an AUC that was smaller than platelet count (0.854 for hemoglobin; 0.841 for hematocrit), with WBC being the least predictive of GCA (AUC=0.666). The AUC of the ROC curve for CRP was 0.978. There was no improvement in prediction of GCA using platelet count in combination with CRP (AUC=0.976).

CONCLUSIONS

Patients with GCA had significantly (p <0.0001) higher values of platelet count, ESR, CRP and WBC but lower values for hemoglobin and hematocrit compared to the NA-AION group. Predictive ability of an elevated platelet count did not surpass elevated ESR or CRP as a diagnostic marker for GCA. Thrombocytosis may complement ESR. Hemoglobin, hematocrit and WBC were much less predictive of GCA. Elevated CRP had a greater predictive ability for GCA compared to ESR or the other hematologic parameters; thrombocytosis in combination with CRP did not yield an improvement in prediction of GCA.

Occurrence of giant cell arteritis...suddenly

PURPOSE

To define the kinetics and mechanisms of frank arteritis onset in patients with giant cell arteritis.

METHODS

Cytokines were analyzed from tissue of a patient before and after the development of arteritis.

RESULTS

A temporal artery biopsy specimen from a patient with giant cell arteritis showed no pathologic changes on microscopic examination, but there was evidence of early tissue activation of inflammatory markers. A specimen from the contralateral artery 12 days later had high levels of IL-18 transcripts and abundant transcripts for CCL19. Also, CD83 and IL-1 were present, confirming that the vascular dendritic cells had fully matured. This second biopsy specimen showed floridly positive giant cell arteritis on histopathologic examination.

CONCLUSIONS

Partial activation of vascular dendritic cells is typically seen in patients with polymyalgia rheumatica in whom no inflammatory infiltrates are seen on histomorphologic examination. Dendritic cells become activated at an early stage of arteritis, beginning the pathologically evident arteritis, and are fully matured in microscopically florid arteritis.

Giant cell arteritis

Giant cell arteritis (GCA) is an immune-mediated vasculitis, affecting medium- to large-sized arteries, in individuals over the age of 50 years. Visual loss is a frequent complication of GCA, and once it occurs it tends to be both permanent and profound. Although major advances have been made in recent years in genetics, molecular biology and the description of the vessel wall morphology, the aetiology and pathogenesis of GCA are still incompletely understood. Over the years there has been much debate over whether polymyalgia rheumatica and GCA are separate or linked entities. Recent investigations support that polymyalgia rheumatica and GCA are two different expressions of the same underlying vasculitic disorder. A single cause or aetiological agent has not as yet been identified. Except for the histopathology of the arterial wall, there are no laboratory findings specific for GCA, and no particular signs or symptoms specific for the diagnosis. GCA typically causes vasculitis of the extracranial branches of the aorta and spares intracranial vessels. Transmural inflammation of the arteries induces luminal occlusion through intimal hyperplasia. Clinical symptoms reflect end-organ ischaemia. Branches of the external and internal carotid arteries are particularly susceptible. Corticosteroids remain the only proven treatment for GCA, the regimen initially involving high doses followed by a slow taper. However, early detection and treatment with high-dose corticosteroids is effective in preventing visual deterioration in most patients.

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.

Thrombocytosis in patients with biopsy-proven giant cell arteritis

OBJECTIVE

To compare the platelet counts, complete blood counts, and Westergren sedimentation rates (WESR) of patients with a biopsy positive for giant cell arteritis (GCA) with those of patients with negative biopsies.

DESIGN

Retrospective, case-control series.

METHOD

The medical records of 91 consecutive patients who underwent temporal artery biopsy for possible GCA, over an 8-year period, were reviewed.

MAIN OUTCOME MEASURES

Values obtained for the complete blood counts, including platelet counts, WESR, and biopsy results of 91 consecutive patients undergoing temporal artery biopsy were analyzed.

RESULTS

The mean platelet count of 47 patients with positive temporal artery biopsies (433 x 10(3)/microl) was significantly higher than that of 44 patients with negative temporal artery biopsies (277 x 10(3)/microl), P < 0.0001. There was no statistically significant difference in the mean WESR between the biopsy-positive (82 mm/hour) and biopsy-negative (70 mm/hour) groups, P = 0.12. The sensitivity of an elevated WESR for biopsy-positive patients was greater (79%; 95% confidence interval [CI], 64%-89%) than that of an elevated platelet count (57%; 95% CI, 42%-72%). However, the specificity (91% [95% CI, 78%-97%] versus 27% [95% CI, 15%-43%]), positive predictive value (87% [95% CI, 70%-96%] versus 54% [95% CI, 41%-66%]), and negative predictive value (67% [95% CI, 53%-78%] versus 55% [95% CI, 32%-76%]) favored an elevated platelet count compared with WESR, or to the combination of platelets and WESR, as a better test for diagnosing GCA in the 91 patients studied. The area under the receiver operating characteristic function for platelets (0.72) was greater than that for WESR (0.59) or the combination of platelets and WESR (0.65).

CONCLUSIONS

In patients suspected of having GCA, an elevated platelet count greater than 400 x 10(3)/microl is a useful marker of a positive temporal artery biopsy.

Risk factors for visual loss in giant cell (temporal) arteritis: a prospective study of 174 patients

OBJECTIVE

To determine the risk factors--especially the effects of thrombocytosis--for permanent visual loss in patients with temporal arteritis.

METHODS

One hundred seventy-four patients with temporal arteritis (147 biopsy proven) were prospectively observed for the development of permanent visual loss. We used multivariate logistic regression analysis to determine which of 17 pretreatment characteristics were associated with visual loss.

RESULTS

Visual ischemic manifestations occurred in 48 (28%) patients, including permanent visual loss in 23 (13%) patients. The independent predictors associated with an increased risk of permanent visual loss were a history of transient visual ischemic symptoms (odds ratio [OR] = 6.3; 95% confidence interval [CI]: 1.4 to 29; P = 0.02) and a higher platelet count (OR = 3.7 per SD; 95% CI: 1.8 to 7.9; P = 0.001). The presence of constitutional symptoms (OR = 0.14; 95% CI: 0.02 to 0.77, P = 0.01), polymyalgia rheumatica (OR = 0.04; 95% CI: 0.01 to 0.48, P = 0.02), and C-reactive protein level (OR = 0.35 per SD; 95% CI: 0.13 to 0.92, P = 0.03) were associated with a reduced risk. Upper limb artery involvement was excluded from the multivariate model, as no patients with that problem developed permanent visual loss. Of the 87 patients who presented with thrombocytosis (platelet count >400 x 10(9)/L), 32 (37%) developed ischemic visual symptoms, compared with 16 (18%) of those without thrombocytosis.

CONCLUSIONS

An elevated platelet count is a risk factor for permanent visual loss in temporal arteritis. The finding of thrombocytosis in a patient with suspected temporal arteritis should emphasize the need for urgent treatment, with consideration of using inhibitors of platelet aggregation or anticoagulation therapy.

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.

Implications of thrombocytosis in giant cell arteritis

PURPOSE

To bring attention to the implications of thrombocytosis in giant cell arteritis.

METHOD

Case report. Platelet counts were measured before and after corticosteroid therapy in a patient with biopsy-proven giant cell arteritis.

RESULT

Platelet counts were increased before corticosteroid therapy was begun and returned to normal levels after corticosteroid therapy was instituted.

CONCLUSION

Platelet counts in a patient with giant cell arteritis may have diagnostic, therapeutic, and prognostic value.

Thrombokinetics in patients with rheumatoid arthritis treated with D-penicillamine

The mechanism of D-penicillamine induced thrombocytopenia in rheumatoid arthritis was investigated by measuring platelet life-span and platelet production rate in 2 groups of rheumatoid arthritis patients treated with 250-750 mg/day D-penicillamine, 14 with a normal platelet count and 9 with thrombocytopenia (platelet count 50-130 X 10(9)/1). Age matched control patients not treated with D-penicillamine included 14 with rheumatoid arthritis and 9 with osteoarthritis. The platelet life-span was normal, but platelet production rate was significantly reduced in the thrombocytopenic patients, suggesting that D-penicillamine causes thrombocytopenia through bone marrow suppression.