70yoM with headache and R temporal artery tenderness.
What are the usual findings of temporal arteritis? What does your workup really mean?
Pathophysiology:
Giant cell arteritis (GCA)= chronic vasculitis of medium and large vessels, age > 50, peaks 70-80yo.
Vasculitis of extracranial branches of aorta, spares intracranial branches.
Transmural inflammation -> intimal hyperplasia -> luminal occlusion.
“Why don’t my patient’s with GCA have bulging temporal artery like Netter’s Atlas shows?”
Incidence of clinical signs of GCA:
Weight loss or anorexia 50%
Decreased temporal artery pulsations 46%
Fever 42%
Artery tenderness 27%
Erythematous or swollen scalp arteries 23%
Large artery bruits 21 %
Fundoscopic abnormalities 18%
Does a negative ESR rule out GCA?
ESR had a sensitivity of 76% to 86% for temporal arteritis,
while an elevated CRP (>2.45 mg/dl) had a sensitivity of 97.5%.
When using the criteria of an elevated ESR or CRP, or both, the sensitivity was 99.2%.
My pt has RA and her ESR is high, is there another test that makes GCA more likely?
Thrombocytosis (platelets >375,000) is more helpful for ruling in temporal arteritis than an elevated ESR. Specificity of 91% compared to 27% of ESR.
Should I give methylprednisone IV or prednisone po?
In a retrospective study of 100 high-risk patients with visual symptoms, IV steroids found to improve visual symptoms quicker.
The NIH recommends treating GCA with a 3-day induction dose of IV methylprednisolone, 15 mg/kg/d, followed by oral prednisone maintenance therapy at an initial dose of 1 mg/kg/d or between 40 and 60 mg/d. Higher doses of 80 to 100 mg/d are suggested for patients with visual or neurological symptoms of GCA.
In conclusion: CRP is more sensitive. Combine ESR, CRP and platelets for improved specificity. If visual symptoms start with IV steroids otherwise po prednisone is fine for those “just-in-case” cases.
References:
Parikh M, Miller N, Lee A, et al. Prevalence of a normal
C-reactive protein with an elevated erythrocyte
sedimentation rate in biopsy-proven giant cell arteritis.
Ophthalmology 2006;113(10):1842-5.
Foroozan R, et al. Thrombocytosis in patients with biopsy-proven giant cell arteritis. Ophthalmology. Jul 2002;109(7):1267-71.
The Treatment of Giant Cell Arteritis
J. Alexander Fraser.
Rev Neurol Dis. Author manuscript; available in PMC 2011 January 4.
Steroid management in giant cell arteritis.
Chan CC. Br J Ophthalmol. 2001 Sep;85(9):1061-4.
