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
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 |
Specialty: Ophthalmology, Immunology/Rheumatology