Giant cell arteritis is a vasculitis, i.e. inflammation of the artery walls, which generally affects people over the age of 50. Diagnosis can be long and difficult, as the clinical signs are not specific (headache, pain in the jaw, scalp, shoulders and/or pelvis, abdominal pain, weight loss, etc.), but it must be made quickly, given the risk of complications.

The reference method for diagnosis was initially based on clinical suspicion and analysis of a "piece of temporal artery" (biopsy) performed in the operating theatre under local anaesthetic. Since the mid-1990s, improvements in ultrasound techniques have made it possible to identify a sign, known as a halo, on the temporal arteries that is typical of patients with Giant Cell Arteritis. A prospective multicenter study published in 2024 demonstrated that, in patients with a clinical suspicion of Giant Cell Arteritis, if a halo was found on both temporal arteries by ultrasound, there was no need for a biopsy. This study is at the origin of a change in practices in the diagnosis and care of patients suffering from this disabling disease.

To facilitate early diagnosis, a fast-track pathway has been set up. The aim is to make a rapid diagnosis, thereby reducing the risk of after-effects, shortening the length of hospital stays, considering outpatient treatment and limiting the number of biopsies.

The investigators propose to evaluate the performance of this fast-track pathway.

Giant Cell Arteritis (GCA) or temporal arteritis is a systemic vasculitis (inflammation of the artery walls) that generally affects people over 50 years old, with a peak frequency between 70 and 80 years. The diagnosis is sometimes long and difficult to make due to non-specific clinical signs but must be rapid because of the risk of arterial occlusion that can lead to vision loss or stroke.

Two GCA presentations can be detected :

• an aortic form, i.e. inflammation of the aorta with specific clinical signs (abdominal pain, weight loss, ...)
• a cephalic form with unusual headaches, jaw pain, scalp pain, shoulder and/or pelvic girdle pain, and inflammatory biological signs.

The reference method for diagnosis has been based on clinical presumption. The presence of an inflammatory syndrome in biology and the analysis of a temporal artery biopsy.

Since the mid-1990s, the improvement of ultrasound techniques, particularly with the appearance of high frequency probes, made it possible to detect inflammation of the temporal arteries in some cases. Each center published retrospective studies with the aim of avoiding biopsy but without really allowing the modification of clinical practices.

A prospective multicenter study (doi: 10.7326/M23-3417) published in 2024 proved that in patients with high clinical probability of GCA, in case of bilateral positivity on temporal artery ultrasound (hypoechoic halo) it was not necessary to resort to a biopsy.

When the ultrasound of bilateral arteries (particularly temporal and axillary) showed an abnormality such as a halo (inflammation), the diagnosis was made and did not require a biopsy.

When the ultrasound was negative (or only present on one artery or another arterial axis), biopsy was necessary. In 50% of cases, the biopsy result was negative. Among these negative cases, a certain number were nevertheless retained as Giant Cell Arteritis, according to the clinician's assessment, and others were subjected to differential diagnoses.

While with a biopsy the time to perform the procedure and obtain its interpretation was 10 days, ultrasound only requires one day to make a diagnosis.

This study is at the origin of a change in diagnosing and treating patients with this Giant Cell Arteritis.

In order to facilitate early diagnosis, a fast-track pathway has been set up based on the model published in 2024 (doi: 10.26635/6965.6376).

The investigators propose to evaluate the performance of this fast-track clinic.

Inclusion Criteria:

• Patient suspected of GCA

Exclusion Criteria:

• Opposition to the use of their data

Patients from North Charente-Martime with suspicion of GCA that are sent to la Rochelle hospital for fast track diagnosis

All of the individual participant data collected during the study will be shared after deidentification.

Study protocol and statistical analysis plan will be available. Data will be available immediately following publication. Researchers who provide a methodologically sound proposal will have access to the data.

Data will be available at www.recherche.data.gouv.fr