Tackling underdiagnosis of Large Artery Giant Cell Arteritis: a prevalence and phenotype study.

Inflammation of an artery in the region of the temple is the cause of temporal
arteritis with complaints being new onset headache, jaw claudication and an
elevated erythrocyte sedimentation rate. Temporal arteritis is a subset of
giant cell arteritis and is more and more thought to be associated with
extracranial large-vessel-vasculitis. The aorta and its major branches are
mainly affected. Varying imaging techniques such as PET, MRI and CT, have been
used to assess large vessel inflammation in patients suffering from temporal
arteritis. However, the exact prevalence of large-vessel-vasculitis in these
patients has not been studied well and therefore is not known.
Using the above-mentioned imaging techniques large-vessel-vasculitis has been
diagnosed in patients with symptoms not suggestive of temporal arteritis but a
more systemic inflammatory response with an unexplained elevated erythrocyte
sedimentation rate. This could be a reason to screen patients with a systemic
inflammtory response of unknown origin using PET/CT. In this selected group,
however, the prevalence of large artery inflammation is also unknown.
Previous studies have tried to correlate large-vessel-vasculitis with clinical
and biochemical parameters. None of the studied parameters could have been
assessed as a predictor of large artery inflammation.

The primary objectives of the study are to assess the prevalence of large
artery inflammation in patients with temporal arteritis or an unexplained
inflamatory response and the diagnostic utility of 18FDG-PET/CT in patients
with an unexplained inflammatory response.
Secondary objectives are to determine clinical and/or biochemical factors that
could predict large artery inflammation and to determine sensitivity and
specificity of a temporal artery biopsy in patients with
large-vessel-vasculitis.

Temporal arteritis patients or patients with an unexplained prolonged
inflammatory syndrome will be included from the VU medical centre or one of its
affiliated hospitals. Informed consent will have to be signed. A history will
be taken and physical examination wil be performed. Blood will be drawn (and
stored first for practical reasons, only after patient's approval) to be able
to determine the association between biochemical parameters and
large-vessel-vasculitis. Some blood will be saved for possible future
DNA-research. Imaging studies for temporal arteritis patients comprise of a
PET/high-dose-CTa and for patients with an unexplained prolonged inflammatory
syndrome a PET/low-dose-CT. Finally a temporal artery biopsy will be taken from
the temporal arteritis patients and from the patients with unexplained
inflammatory syndrome with a PET/CT compatible with large-vessel-vasculitis and
the first 10 patients whose PET/CT is not compatible with
large-vessel-vasculitis.

Risk:
- Possibiltiy of an anaphylactic reaction for patients undergoing
PET/CT-Angiography as a result of iodinated contrast administration.
Burden:
- One extra visit to the hospital.
- Temporal artery biopsy in patients with an unexplained elevated ESR who have
no signs of large-vessel-vasculitis: it's a minor invasive procedure with a
small chance of complications.
- Higher radiation dosage for patients undergoing PET/CT-Angiography.
- The drawing of blood samples (total of 5 samples at 1 occasion) might lead to
a hematoma, slight pain at the insertion site during, and after the insertion,
as well as the risk of failure and thus repetitive attempts.