7 responses to “Giant Cell Arteritis Part 1: Diagnosis”

  1. How does detection of large vessel vasculitis change the therapy? Is this imaging appropriate in a similar time frame as the TAB? Thank you

  2. who do we refer to get a biopsy?
    Dosage of steroids?
    Thank you

  3. A good review but I don’t really see how this is practice-changing? The article mainly follows what I have been classically taught, except for the following 2 points:
    – Ultrasound as alternative to TAB. I’m curious about this since I know there is actually quite a bit of literature accumulating. It is a 1st-line confirmatory test according to latest British Rheumatology guidelines (preferred over TAB in most cases), but was not discussed much in the article.
    – Large-vessel screening. This is news to me but I don’t understand how it changes management?

    Annie Gareau – in our neck of the woods this is done by general surgery. I think it may vary by centre?

  4. I always have difficulty arranging the biopsy in timely manner
    Other specialties are generally not aware this is an emergency

  5. Screening for other large vessel vasculitis is also news to me but if it is quite prevalent, I wonder if it would require monitoring in order to guide the speed of tapering of the steroid dosage.

  6. Thank you everyone for your questions and comments.
    We have addressed the questions individually below:

    How does detection of large vessel vasculitis change the therapy? Is this imaging appropriate in a similar time frame as the TAB?

    – Detection of large vessel involvement can be helpful in the following ways:
    1. Sensitivity of TAB ranges 30-70%. Given the possibility of false negative results, large vessel imaging can aid in diagnosis in cases where TAB is negative but the clinical suspicion for GCA remains high.
    2. Patients with LVV have poorer prognosis, require longer duration and higher cumulative dose of GC compared to those without LVV. Therefore, in the presence of LVV, clinicians should consider starting steroid sparing agents early on (concurrently with high dose prednisone).
    3. Involvement of the aorta is a risk factor for developing aortic dilatation/ aneurysm in the future. Therefore, knowledge of this will help with appropriate monitoring for long-term complications of GCA.
    4. Detection of large vessel disease can also help with disease monitoring. For example, some patients will relapse with tapering prednisone as evidenced by persistently rising CRP. However, they may not have cranial symptoms such as headaches. In these patients, imaging to assess for worsening of large vessel involvement will be helpful. Having baseline imaging will help with assessing for interval change in the future.

    – Imaging can be done in a much longer time frame compared to TAB. Imaging within the first few weeks is adequate. This is because large vessel imaging findings typically take longer to resolve.

    who do we refer to get a biopsy? Dosage of steroids?
    – Referral for biopsy is center-dependent. Generally vascular surgery, ophthalmology, plastic surgery, otolaryngology and sometimes general surgery perform this procedure. In Vancouver, ophthalmology and vascular surgery routinely perform this procedure.

    – Steroid dose is typically started at 1mg/kg (maximum dose 60 mg). Another article on GCA treatment will follow in the next few weeks.

    Ultrasound as alternative to TAB. I’m curious about this since I know there is actually quite a bit of literature accumulating. It is a 1st-line confirmatory test according to latest British Rheumatology guidelines (preferred over TAB in most cases), but was not discussed much in the article. – Large-vessel screening. This is news to me but I don’t understand how it changes management?

    – There is a growing body of evidence regarding utility of ultrasound in GCA diagnosis. Currently, the 2018 EULAR (European League Against Rheumatism) recommendations suggest using ultrasound as the first imaging modality in patients with cranial GCA. However, since the use of US for diagnosis of GCA is not widely available and highly operator/centre dependent, it is not yet the standard of care in North America. Therefore, TAB is still the gold standard in most centres. Currently, in Vancouver, we are conducting a study comparing the accuracy of US compared to TAB to determine the specificity and sensitivity of US at our centre.

    – Please see our response above regarding the second question.

    I always have difficulty arranging the biopsy in timely manner Other specialties are generally not aware this is an emergency

    – Referring to the specialists who typically do this procedure and marking it as urgent (within 10 days) is usually how we try to book this in a timely fashion. In Vancouver, vascular surgery and ophthalmology do this procedure and usually arrange it within 14 days. Referral to Rheumatology if possible is highly recommended. The Rheumatologist can assist with organizing appropriate investigations, diagnosis, and treatment.

    Screening for other large vessel vasculitis is also news to me but if it is quite prevalent, I wonder if it would require monitoring in order to guide the speed of tapering of the steroid dosage.

    – Please refer to the answer above.

  7. Thanks for the excellent responses!

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