Page 42 - The Vasculitides, Volume 1: General Considerations and Systemic Vasculitis

18 David S. Younger

Differentiation of Primary Vasculitides

Large Vessel Vasculitides

The concepts of GCA and TAK have evolved over a century, with considerable advances
in the past decade that have translated into more improved diagnosis and management.

Giant Cell Arteritis
First named temporal arteritis for the site of granulomatous giant cell inflammation and

vessel involvement [5], those with associated blindness due to vasculitic involvement of
ophthalmic and posterior ciliary vessels were subsequently classified as cranial arteritis [6],
and later generalized GCA [7] when giant cell lesions were discerned along the aorta, its
branches, and in other medium- and large-sized arteries at postmortem examination. There are
five discriminatory features of GCA including, age >50 years at onset, new localized
headache, temporal artery tenderness or decreased temporal artery pulse, ESR >50 mm/hour,
and biopsy of an artery showing necrotizing arteritis and a predominance of mononuclear
cells or granulomatous process with multinucleated giant cells (Figure 1), that collectively
serve as useful guideposts in recognizing GCA.

Unrecognized and therefore untreated or inadequately treated, there is a high likelihood
of large artery complication. Nuenninghoff and coworkers [8] reported patients with large-
artery complications representing 27% of 168 patients in a GCA cohort at the Mayo Clinic
between 1950 and 1999 that included aortic aneurysm or dissection in 18%, large artery
stenosis in 13%, cervical artery stenosis in 9%; and subclavian, axillary or brachial artery
stenosis in 4%.

Temporal artery biopsy is the only sure way of establishing the diagnosis however false
negative findings on the contemplated affected side may be due to inadvertent sampling of a
vasculitic-free length of vessel. The pathological heterogeneity of GCA was further
exemplified by the occasional finding of intracranial lesions in several patients who also
qualified for the diagnosis of granulomatous angiitis of the nervous system (GANS) [9];
however PNS involvement in GCA remains exceedingly uncommon [10].

Takayasu Arteritis
Contemporaneously, another LVV was described in the Japanese literature as unusual

changes of the central vessels of the retina in the absence of peripheral arterial pulses in
women [11]. Patients with so called pulseless disease [12], occlusive thromboaortopathy [13]
or TAK [14], manifested constitutional complaints of malaise, fever, stiffness of the
shoulders, nausea, vomiting, night sweats, anorexia, weight loss, and irregularity of menstrual
periods weeks to months before the local signs of vasculitis were recognized in up to two-
thirds of patients. TAK is the commonest large vessel vasculitis among Asian women.

The non-invasive assessment of LVV includes performance of color-Doppler sonography
(CDS), contrast enhanced high-resolution magnetic resonance imaging (MRI) combined with
MR angiography (MRA), and contrast-enhanced computed tomography (CT) combined with
CTA to visualize the vessel wall and the lumen of large vessels. The signs of early
inflammation that include vessel wall thickening and mural inflammation, as well as the late
complications of stenosis and aneurysms, can be ascertained.

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