Page 367 - The Vasculitides, Volume 1: General Considerations and Systemic Vasculitis

Ophthalmologic and Neuro-Ophthalmologic Aspects of Vasculitides 341

followed by the oral prednisone. Salvarani and colleagues [24] employed 40 mg to 60 mg oral
prednisone for GCA, and intravenous methylprednisolone 1g per day for 3 day for those with
recent or impending visual loss. The addition of low dose aspirin to corticosteroid therapy
was beneficial in preventing cranial ischemic complications including acute visual loss and
cerebrovascular complications of GCA than steroids alone. Patients treated with aspirin and
corticosteroids are five-fold less likely to experience cranial ischemic complications than
those who received corticosteroids alone [25]. Aiello and colleagues [26] noted visual
improvement in 15% of eyes after commencing therapy for GCA and estimated a probability
of further visual loss developing of 1% in the absence of a defined visual deficit, compared to
13% when an established deficit was ascertained. Danesh-Meyer and colleagues [27]
evaluated the incidence and extent of visual recovery of 34 patients with biopsy-proven GCA
treated with high dose systemic corticosteroids noting that 27% of eyes suffered loss of visual
acuity by two or more lines within one week of starting corticosteroid treatment, while 15%
of eyes so treated showed an improved visual acuity of 2 or more lines. Of the 15% of eyes
that showed an improvement in visual acuity, none showed further improvement in visual
fields or color vision, leading the authors [27] to conclude that the improvement in visual
acuity may reflect learning to view eccentrically. Liu and colleagues [28] investigated 45
patients with biopsy-proven GCA, 25 of whom were treated with intravenous
methylprednisolone, and 20 treated with oral prednisolone. Visual loss remained unchanged
in 49% so treated, worsened in 17%, and improved in 34%, defined as visual acuity
improvement of two or more lines and final acuity greater than 20/80. Fellow eye
involvement more often occurred in patients receiving oral corticosteroid therapy compared
to those receiving intravenous therapy. Similarly, visual acuity was more likely to improve
after a course of intravenous treatment than oral therapy (39% versus 28%).

Takayasu Arteritis

This systemic necrotizing LVV is characterized by thrombosis of the vessels arising from
the aortic arch. TAK predominantly occurs in young Japanese females, typically arising
before the age of 40, in a 9:1 female to male ratio [29-31]. The incidence of TAK is estimated
to be between 0.4 to 2.2 per million people, [32, 33] with higher rates in South East Asia,
Africa and South America [34, 35].

The ACR [36] selected six criteria for the classification of TAK, from which three or
more in a given patient were associated with a sensitivity of 90.5% and a specificity of
97.8%, from among the following: age less than or equal to 40 years, claudication of an
extremity, decreased brachial artery pulse, greater than 10 mmHg difference in systolic blood
pressure between arms, a bruit over the subclavian arteries or the aorta, and arteriographic
evidence of narrowing or occlusion of the entire aorta, its primary branches, or large arteries
in the proximal upper or lower extremities. Although the histopathology of TAK is not
included as part of the ACR criteria [36], it may aid in the diagnosis, and it is characterized by
an acute periarteritis with extensive cellular infiltration, necrosis of the media, and intra-
arterial thrombosis [37]. Ocular features not formally part of the criteria of TAK occur in 35%
to 68% of patients [38-40], typically due to ischemia and hypoperfusion resulting from
occlusive arteritis of the aortic arch branches, while those arising in the setting of
hypertension result from vasculitic renal artery involvement.

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