-Definition: Giant cell arteritis is the most common type of vasculitis in adults, affects medium and large arteries, and can result in blindness.
-ESR and CRP. Will get both acute phase reactants because the CRP is more sensitive than ESR and both are combined, the sensitivity reaches 99% and specificity increases to 97%. (AFP 2013)
-CBC and CMP: To check for mild to moderate normochromic anemia and thrombocytosis are common with GCA. Also, an elevated level of alkaline phosphatase occurs in up to one-half of patients, many of whom have a decreased albumin level.
-Will consider adding TSH and 25-hydroxy Vit D.
-Will get urinalysis and chest radiography per BSR/BHPR guidelines since the differential diagnosis for GCA includes neoplasms, systemic infections, intracranial pathology, herpes zoster, cervical spondylosis, temporomandibular disorder, and other vasculitides.
-Will monitor for the signs of PMR because of the association between GCA and PMR. Patient educated to watch for signs of PMR as well.
-Diagnosis of GCA to be made by biopsy of the superficial temporal artery (length of at least 2 to 3 cm since the vasculitis can have skip lesions).
-Low dose aspirin: Aspirin 81mg daily initiated as adjunctive treatment to reduce the stroke risk.
-Treatment with High dose steroids: Prednisolone 40 to 60 mg QD for this uncomplicated GCA (no jaw or tongue claudication or visual changes). If it evolves into a complicated GCA (with evolving visual loss or history of amaurosis fugax) we will initiate IV methylprednisolone 500 mg to 1 g per day for three days, then oral prednisolone, 60 mg per day.
–Urgent referral to a rheumatologist.
-Referral to ophthalmology, considered.
-Osteoporosis management (with Bisphosphonate, calcium, and vitamin D) and GI ulcer prophylaxis (with PPI) will be initiated when diagnosis is confirmed by biopsy because long-term steroids will be needed.
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HPI, hx:
Patient endorses New-onset headaches especially in the temporal area, vision change, temporal tenderness, and fatigue/tiredness, and insomnia.
Also, thinks she has experienced some jaw claudication.
“The classic presentation includes of GCA is new-onset headache with constitutional symptoms such as fatigue, anorexia, and weight loss in a patient older than 50 years, with or without jaw claudication”
“Inflammatory Markers. An ESR greater than 50 mm per hour is seen in up to 89%35 of patients with giant cell arteritis (mean ESR = 88 mm per hour).34 A normal ESR does not exclude giant cell arteritis, however.34 The highest rate of visual loss occurs in patients who have an ESR of 70 to 100 mm per hour; values greater than 100 mm per hour may reflect a protective influence.38 The C-reactive protein measurement is more sensitive; when this test is combined with the ESR, the sensitivity reaches 99% and specificity increases to 97%.”AFP
- PMR is tx with low dose steroids (Prednisone 15 mg daily) while Giant Cell Arteritis is treated with high dose steroids (Prednisone 40-60mg daily).
- PMR and GCA are associated but they are not the same entity. “Despite their similarities, polymyalgia rheumatica and giant cell arteritis have distinct symptoms, corticosteroid requirements, and prognoses.” AFP Journal.
“Corticosteroid therapy in patients with suspected giant cell arteritis should not degrade the accuracy of temporal artery biopsy if the biopsy is performed within four weeks of corticosteroid initiation. Temporal artery biopsy can be performed up to four weeks after starting high-dose corticosteroid therapy.” (AFP 2017)
Reference
- Am Fam Physician. 2013 Nov 15;88(10):676-684. (Recognition and Management of Polymyalgia Rheumatica and Giant Cell Arteritis) http://www.aafp.org/afp/2013/1115/p676.html
- Am Fam Physician. 2017 Jan 15;95(2):116-117. http://www.aafp.org/afp/2017/0115/p116.html
- Cecil Essentials of Medicine, 9th Edition, page 796
- https://academic.oup.com/rheumatology/article/49/8/1594/1789465/BSR-and-BHPR-guidelines-for-the-management-of