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Temporal Arteritis / Giant Cell Arteritis

posted May 22, 2014, 2:44 PM by Eliany Mejia   [ updated May 30, 2014, 1:01 PM ]

Monte Minute by David Dayan-Rosenman - PGY3

Introduction

Temporal arteritis / Giant Cell Arteritis (GCA) is a vasculitis of medium and large vessels (any vessel that has an internal elastic membrane). It affects older adults (mean age of onset is 72 year-old) and can have many clinical manifestations: both local (headache) and systemic (fatigue, weight loss). In this Monte Minute, I will review the presentation, diagnosis, treatment and prognosis of GCA.

Epidemiology

As stated above, mean age of diagnosis is 72 and GCA is virtually unknown in persons younger than age 50.  GCA is more common in persons of  Nordic descent. The prevalence is about 1:500. Women are 2-3 times more likely to be affected.

Presentation

Gradual onset is most common; about 50% of patients presenting with fatigue, low-grade fever, weight loss.

- New headache is seen in 2/3 of patients – we think of it as temporal HA related to arteritis of the temporal arteries but GCA can affect any of the extra-cranial arteries. - Jaw claudication can be seen in up to ½ of patients and is thought to be the most specific symptom of GCA (it is due to ischemia of the mastication muscles).

- Visual complications leading up to permanent blindness are the most feared complication of GCA. We classically think of Amaurosis Fugax (transient loss of vision) but other visual symptoms are also common such as diplopia. The probability of developing loss of vision in the natural history of GCA is unclear as patients presenting to medical attention with loss of vision are likely overrepresented.

- Stiffness and pain of the shoulders and hips is also commonly seen and there is  substantial overlap between GCA and Polymyalgia Rheumatica ( PMR is seen in about 50% of patients with GCA; conversely GCA is seen in 15% of patients with PMR)

- Ascending aorta aneurysm and non-aneurysmal dissection of the aorta can also be seen (sometimes accompanied by a new aortic regurgitant murmur).

- Finally, involvement of the ICA and vertebral arteries can lead to neurologic events but the intracranial vessels are seldom involved themselves.

Pathophysiology

GCA results from the inflammation and resultant hyperplasia of the medial layer of medium and large sized arteries; It takes its name from the appearance of that layer when watched under a microscope – it has, you guessed it, giant cells.

Diagnosis:

courtesy Izio Rosenman
The American College of Rheumatology has put forth in 1990 a set of criteria to diagnose GCA and distinguish it from other forms of vasculitides:

1. Age at disease onset >=50 years

2. New headache

3. Temporal artery abnormality: tenderness to palpation or decreased pulsation, unrelated to arteriosclerosis of cervical arteries

4. Elevated erythrocyte sedimentation rate  >=50 mm/hour

5. Abnormal artery biopsy

Need at least 3 of these 5 criteria for Diagnosis. The presence of any 3 or more criteria yields a sensitivity of 93.5% and a specificity of 91.2%

--> Picture:(courtesy Izio Rosenman)

Treatment

- Given the risk of vision loss, immediate initiation of treatment is essential (once a reasonable expectation that one is dealing with GCA exists -  either on physical exam or aided by results of the ESR/CRP in the clinical context (low threshold for treating given the low morbidity of a short course of steroids while pending verification of diagnosis with biopsy).

- Yield of temporal artery biopsy to confirm diagnosis does not substantially change for at least 2 weeks after initiation of steroids. If the occipital artery is more symptomatic, it is a reasonable target for biopsy instead.

- Treatment is with high dose steroids (0.5-1mg/kg/day of PO prednisone ) tapered over the course of 6months to 2 years. It is worth noting that the initial dose is much higher than that seen in PMR.

- Given the expected length of treatment, Bone Density Scanning and initiation of bisphosphonate are reasonable. Evaluation of the aorta and pulmonary arteries with imaging to screen for aneurisms resulting from GCA has also been suggested.