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
where:
• 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
|
6.3
|
1.4 to 29
|
|
thrombocytosis
|
3.7 per SD
|
1.8 to 7.9
|
|
constitutional symptoms
|
0.14
|
0.02 to 0.77
|
|
polymyalgia rheumatica
|
0.04
|
0.01 to 0.48
|
|
elevated C-reactive protein
|
0.35
|
0.13 to 0.92
|
