Patients with giant cell (temporal arteritis) may develop visual loss. The presence of certain factors may help identify patients who are at a greater risk for blindness and who may benefit from more aggressive therapy. The authors are from Limoges, France and Geneva, Switzerland.


Factors associated with an increased risk of visual loss:

(1) transient visual ischemic symptoms (amaurosis fugax lasting for seconds or minutes; intermittent blurred vision; transient diplopia)

(2) elevated platelet count (> 400,000 per µL; with risk of permanent visual loss very high when the platelet count > 600,000 per µL)


Factors associated with a decreased risk of visual loss:

(1) constitutional symptoms (body temperature >= 38°C for at least 1 week; severe asthenia; weight loss > 5%)

(2) polymyalgia rheumatica

(3) elevated C-reactive protein



• The normal range for the platelet count was 150,000 to 400,000 per µL. Thus a count of 600,000 per µL is 1.5 times the upper limit of normal (ULN).

• Amaurosis fugax = transient monocular partial or complete blindness

• Asthenia = loss of strength and energy

• Polymyalgia rheumatica = syndrome in the elderly with pain in muscles and proximal joints and with an elevated ESR.

Risk Factor

Odds Ratio

95% Confidence Interval

transient visual ischemic symptoms


1.4 to 29


3.7 per SD

1.8 to 7.9

constitutional symptoms


0.02 to 0.77

polymyalgia rheumatica


0.01 to 0.48

elevated C-reactive protein


0.13 to 0.92


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