Optic Nerve Sheath Ultrasound in Giant Cell Arteritis

Study Overview
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Brief Summary
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The objectives of this observational cohort study are : To assess the ability of optic nerve (ON), optic nerve sheath diameter (ONSD) and optic nerve sheath thickness (ONST) measured by ultrasound to predict Giant Cell Arteritis. To evaluate changes in ON, ONSD, ONST measurements in patients with confirmed GCA after three months of therapy To assess dynamic changes in ON, ONSD, ONST measurements in patients with relapsing GCA

Detailed Description
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Giant Cell Arteritis is the most common primary vasculitis in adult patients. GCA is difficult to diagnose, and no single test allows perfect classification of GCA. Imaging in GCA such as high resolution ultrasound is gaining populatity and allows identification of patients that would have been otherwise missed. Recently, optic nerve sheath enhancement on MRI has been described and associated with the presence of GCA. Evaluation of the optic nerve and optic nerve sheath using ultrasound is easy to perform but has never been assessed in GCA. Objectives: To assess the ability of optic nerve (ON), optic nerve sheath diameter (ONSD) and optic nerve sheath thickness (ONST) measured by ultrasound to predict Giant Cell Arteritis. To evaluate changes in ON, ONSD, ONST measurements in patients with confirmed GCA after three months of therapy To assess dynamic changes in ON, ONSD, ONST measurements in patients with relapsing GCA

Official Title
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Optic Nerve Sheath Ultrasound as a Predictor and Biomarker in Giant Cell Arteritis

Conditions
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Giant Cell Arteritis, Anterior Ischemic Optic Neuropathy, Optic Neuropathy, Ischemic

Intervention / Treatment
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* Diagnostic Test: Optic nerve ultrasound


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients referred to our fast-track vasculitis clinic with a clinical suspicion of new-onset GCA. Must have a duration of glucocorticoid treatment of less than 14 days. Must sign informed consent Participation must be able to attend a 3 month follow-up visit, and in those with GCA, longitudinal clinic visits Exclusion Criteria: Chronic use of immunosupressive therapy or glucocorticoids for more than 14 days Pre-existing known retinal or optic nerve disease

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 95 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: Optic nerve ultrasound|The patients are examined in a supine relaxed position. The probe is gently placed on the closed eyelid with a standard ultrasound gel and adjusted to a suitable angle to display the optic nerve entry into the eyeball. Measurements are done 3mm distal to the posterior aspect of the ocular globe. Ultrasosonographic 14L5 probe is used with a safe thermal index, mechanical index and intensity limit. All patients will also undergo a bedside fundoscopic examination. Official ophthalmology consultation will be requested in patients with visual symptoms or abnormal fundoscopy.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Comparison of ON, ONSD, ONDT measurements in participants with and without GCA |  | Baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| In participants with GCA, evaluate ON, ONSD, ONDT measurement changes while on therapy. |  | 3 months after baseline visit | 
| In participants with suspected GCA relapse, evaluate ON, ONSD, ONDT measurement changes |  | From month 3 to month 24 (following baseline visit) |