Temporal Arteritis: Likelihood Ratios

Introduction: also known as Giant Cell Arteritis.

The estimated 5-year probability of developing visual loss after initiating corticosteroid therapy was 1%; that of additional visual loss in patients who already had visual loss was 13%.

Symptoms not specific to TA: anorexia, arthralgia, fatigue, fever, temporal headache, myalgia or polymyalgia rheumatica, unilateral vision loss or any visual sx, vertigo

Signs not specific to TA: optic atrophy/neuropathy, fundoscopic abnormality, absent temporal artery pulse, anemia.

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Tags: Autoimmune Vasculitis Tag this Diagnosis.

Prevalence

Population / Calculator	Prevalence	Comments / Study / Link
Age < 50	0%	only 2/1435 patients with temporal arteritis were <50. JAMA 2002 Jan 2;287(1):92-101. PMID 11754714
Women	0%	more common than in men
Patients referred for TA biopsy	39%	JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
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The likelihood ratios of findings for Temporal Arteritis are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] Temporal Artery Biopsy	+ 0 -	inf	0.1
for one biopsy. Sensitivity increases with longer artery segment biopsied, or multiple sites. specificity assumed to be 100%, as this is the gold standard. Study: Invest Ophthalmol Vis Sci. 2007 Feb;48(2):675-80. PMID: 17251465
[ + ] ACR Criteria	+ 0 -	10.4	0.1
in patients with "a" vasculitis. >=3/5 criteria: * Age greater than or equal to 50 years at time of disease onset * Localized headache of new onset * Tenderness or decreased pulse of the temporal artery * Erythrocyte sedimentation rate (ESR) greater than 50 mm/h * Biopsy revealing a necrotizing arteritis with a predominance of mononuclear cells or a granulomatous process with multinucleated giant cells. Study: Arthritis Rheum 1990 Aug;33(8):1122-8. PMID 2202311

Good Negative Likelihood Ratio
Finding	Result	+LR	-LR
[ + ] Elevated ESR	+ 0 -	1.1	0.2
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Elevated ESR	+ 0 -	1.2	0.4
>50mm/hr. in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92

Negative Findings
Finding	Result	+LR	-LR
[ + ] Synovitis	+ 0 -	0.4	1.1
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92

Poorly Diagnostic Findings
Finding	Result	+LR	-LR
[ + ] Scalp tenderness	+ 0 -	1.6	0.9
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Elevated ESR	+ 0 -	1.9	0.8
>100mm/hr. in patients with suspected TA. Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Temporal Headache	+ 0 -	1.5	0.8
Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Weight loss	+ 0 -	1.3	0.9
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Headache	+ 0 -	1.2	0.7
(not necessarily temporal.) in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92

Good Positive Likelihood Ratio
Finding	Result	+LR	-LR
[ + ] Beaded temporal artery	+ 0 -	4.6	0.9
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Jaw claudication	+ 0 -	4.2	0.7
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Diplopia	+ 0 -	3.4	1
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92
[ + ] Tender temporal artery	+ 0 -	2.6	0.8
in patients with suspected TA Study: JAMA. 2002;287:92-101. http://jama.ama-assn.org/cgi/content/full/287/1/92