Diagnosing giant cell arteritis: a comprehensive practical guide for the practicing rheumatologist.

GCA is the most common large vessel vasculitis in the elderly population. In recent years, advanced imaging has changed the way GCA can be diagnosed in many locations. The GCA fast-track clinic approach combined with US examination allows prompt treatment and diagnosis with high certainty. Fast-track clinics have been shown to improve prognosis while being cost effective. However, all diagnostic modalities are highly operator dependent, and in many locations expertise in advanced imaging may not be available. In this paper, we review the current evidence on GCA diagnostics and propose a simple algorithm for diagnosing GCA for use by rheumatologists not working in specialist centres.

Fast track clinic for early diagnosis of polymyalgia rheumatica: Impact on symptom duration and prednisolone initiation.

OBJECTIVES: To evaluate the efficacy of a fast track clinic (FTC) for patients suspected of polymyalgia rheumatica (PMR) regarding symptom duration, prednisolone initiation before rheumatological assessment, number of hospital contacts before diagnosis, and cancer diagnosis. METHODS: It is a retrospective cohort study with a one year follow-up period. Patients referred to the FTC (1st August 2016 to 25th June 2019) were compared to a historical cohort of PMR patients (1st August 2014 to 1st August 2016). Referral criteria are: age over 50, symptoms of PMR but not cranial GCA, and increased C-reactive protein. Data were obtained from patient journals. RESULTS: Ninety-seven PMR patients in the historical cohort and 113 FTC patients, of whom 83 patients had PMR, were included. The median (interquartile range) number of days from symptom onset until PMR diagnosis were 53 (31-83) days in the FTC versus 80 (58-132) days in the historical cohort (P<0.001). Prednisolone was prescribed before rheumatological assessment to 11% in the FTC versus 42% in the historical cohort (P<0.001). Patients in the FTC had significantly fewer contacts with the hospital before the diagnosis compared with the historical cohort. Four patients in the FTC were diagnosed with a cancer, all of which were found by imaging. CONCLUSION: The FTC reduced the time from symptom onset until diagnosis, lowered prednisolone initiation before rheumatological assessment, and resulted in fewer hospital visits. The frequency of cancers was low in patients suspected of PMR and cancers were discovered by imaging.

Imaging in large-vessel vasculitis.

Imaging has recently been acknowledged as at least equivalent to histology for confirming large-vessel vasculitis in the recommendations of scientific societies. Many studies have been recently published on the use of ultrasound, magnetic resonance imaging (MRI), computed tomography (CT) and fluorodeoxyglucose (FDG) positron emission tomography (PET) in giant cell arteritis and Takayasu arteritis. Ultrasound, MRI and CT show concentric, arterial wall thickening in vasculitis. PET demonstrates enhanced FDG uptake of inflamed artery walls due to increased glucose metabolism. Ultrasound is particularly useful for smaller arteries like the temporal arteries due to its high resolution. MRI and PET/CT provide an excellent overview particularly on extracranial arteries. However, ultrasound can also detect extracranial vasculitis while PET/CT may delineate vasculitis in temporal arteries. The diagnosis needs to be confirmed without delay as the sensitivity of imaging decreases with treatment. Ongoing studies are evaluating the role of imaging for follow-up.

Mechanisms involved in increased sensitivity to adenosine A(2A) receptor activation and hypoxia-induced vasodilatation in porcine coronary arteries.

Hypoxia-induced coronary vasorelaxation is a compensatory mechanism increasing blood flow. We hypothesized that hypoxia shares pathways with adenosine and causes vasorelaxation through the adenosine A(2A) receptor and force suppression by increasing cAMP and phosphorylated heat shock protein (HSP)20. Adenosine receptors in porcine left anterior descending coronary arteries (LAD) were examined by RT-PCR and isometric tension recording in myographs. Vasorelaxation was induced by adenosine, 1% oxygen, or both in the absence or presence of ZM241385, an adenosine A(2A) receptor antagonist. cAMP was determined by ELISA and p-HSP20/HSP20 and p-MLC/MLC were determined by immunoblotting and densitometric analyses. In coronary arteries exposed to 1% oxygen, there was increased sensitivity to adenosine, the adenosine A2 selective agonist NECA, and the adenosine A(2A) selective receptor agonist CGS21680. ZM241385 shifted concentration-response curves for CGS21680 to the right, whereas the adenosine A1 antagonist DPCPX, the adenosine A2B receptor antagonist MRS1754 and the adenosine A3 receptor antagonist MRS1523 failed to reduce vasodilatation induced by CGS21680. 1% oxygen or adenosine increased cAMP accumulation and HSP20 phosphorylation without changing T850-MYPT1 and MLC phosphorylation. ZM241385 failed to change 1% oxygen-induced vasodilation, cAMP accumulation, HSP20 phosphorylation and MLC phosphorylation. The PKA inhibitor Rp-8-CPT-cAMPS significantly reduced vasorelaxation induced by 1% oxygen or CGS21680. Our findings suggest that the increased sensitivity to adenosine, NECA, and CGS21680 at 1% oxygen involves adenosine A(2A) receptors. Adenosine and 1% oxygen induce vasorelaxation in PGF2α-contracted porcine coronary arteries partly by force suppression caused by increased cAMP and phosphorylation of HSP20.