Temporal (or Giant Cell) Arteritis

What is it? A large vessel vasculitis of unknown etiology that affects the temporal artery and it's branches.

Why is it dangerous? It can lead to permanent blindness if not diagnosed and treated expeditiously.

Who gets it? People over the age of 50 (median age = 72), commonly of Northern European descent, and commonly with the HLA-DR4 haplotype. It is much more common in those with Polymyalgia Rheumatica.

What are the symptoms? Classically, this presents subacutely with a localised headache in the temporal region, jaw claudication ("I get a cramping pain when I chew my food"), decreasing visual acuity, or blindness in one or both eyes. Patients may also describe exquisite scalp tenderness ("It really hurts to comb my hair"). It is very closely associated with Polymyalgia Rheumatica - roughly 15% go on to develop temporal arteritis. These patients will typically describe an aching pain in the shoulders, hips, and neck.

What Do you see on Physical Exam? Patients will appear unwell. Feel the temporal artery for tenderness, enlargement, and to see if a pulse is indeed present. An ophthalmologic exam is warranted - looking for ischemic neuropathy (swollen disc +/- blurred margins).

Any pertinent diagnostic tests? By definition, the erythrocyte sedimentation rate (ESR) should be greater than 50 mm/hr, however it is usually over 100. A definitive diagnosis can be made via temporal artery biopsy. This is often a contentious issue for a few reasons (see review article below), and may be difficult to arrange expeditiously. Regardless, you should not delay treatment waiting for biopsy. Interestingly, ultrasonography of the temporal arteries may be helpful . See this NEJM article from 1997 for details.

What about treatment? Prednisone in high doses (like 1mg/kg) initially. Patients will need months and months of therapy with a slow taper guided by their symptoms. Remember bone protection while on steroids - Calcium, Vitamin D, and a Bisphosphonate.

A great review article here on Polymyalgia Rheumatica and Temporal Arteritis from the Annals of Internal Medicine.