Case Published: June, 2021
Author: Megan Milne, MD (Duke Rheum Fellowship instagram)
Case editors: Stacy Bagrova, MD; Lisa Criscione-Schreiber, MD
Final diagnosis: Giant Cell Arteritis
Case outcome: Soon after her presentation to teh hospital, the patient was started on 1g of methylprednisolone for 3 days (known in rheumatology as “pulsing”), followed by 1 mg/kg dose (high-dose steroids), and plan for initiation of tocilizumab (see below for more information on this medication). Unfortunately, her vision did not improve despite appropriate treatment.
Great job! Let’s dissect this case. The patient is a female over the age of 50 who presented with monocular vision loss, jaw claudication, and AION on exam. This should immediately bring giant cell arteritis, one of the few rheumatologic emergencies, to the top of your differential diagnosis. The presence of anemia, thrombocytosis, and low albumin point to chronic inflammation, further supporting the diagnosis of GCA. The temporal artery biopsy showing giant cells and disruption of the internal elastic lamina confirmed the diagnosis of GCA>
GCA is an autoimmune-mediated vasculitis that occurs as a result of granulomatous inflammation of large and medium-sized arteries (1). Inflammation is driven by IL-1, IL-6, and INF-γ. This leads to both systemic inflammation and macrophage activation within the arterial walls (1). Hyperplasia of the arterial intima leads to arterial stenosis with resultant tissue ischemia (1). The American College of Rheumatology classification criteria for GCA is composed of clinical features and laboratory tests, and requires a score of at least three points (2). These criteria include: age at onset at least 50 years old (1 point), new headache (2 points), temporal artery abnormality such as tenderness to palpation or decreased pulsation (3 points), ESR greater than or equal to 50 mm/hour (4 points), and an abnormal artery biopsy showing vasculitis with mononuclear cell or granulomatous inflammation (5 points) (2). It should be noted that these classification criteria are for research purposes, not clinical diagnosis. Temporal artery biopsy is the gold standard for diagnosis of GCA (2).
Blindness as a consequence of temporal arteritis is one of the most feared consequences of cranial GCA. If vision changes are left untreated, vision loss will occur within days in approximately 50% of patients (3). The chances of vision recovery in patients with anterior ischemic optic neuropathy or complete vision loss has previously been described as “grim”(3). Our patient did not recover vision in her left eye despite pulse dose steroids, a high-dose prolonged oral steroid taper, and initiation of tocilizumab (an IL-6 inhibitor, which is now standard steroid-sparing therapy for GCA).
Headaches, jaw claudication, and scalp pain can precede ocular involvement in GCA (3). It is also important to note that lower levels of inflammatory markers have associated with a higher risk of irreversible visual complications (3). Do not wait to start steroid treatment until biopsy results as the consequences can be devastating. Monocular vision loss and amaurosis fugax in the setting of GCA are ocular emergencies and are considered to be a CVA and TIA respectively. If a patient reports any visual deficits, he or she requires emergent evaluation and consideration of pulse-dose steroids (4).
Patients with suspected GCA should also be referred urgently for temporal artery biopsy (4). Biopsy should be performed as soon as possible after starting steroids as treatment can decrease the sensitivity of the biopsy (4).
Of note, approximately 50% of GCA patients present with polymyalgia rheumatica (PMR) symptoms either at the time of diagnosis, after diagnosis, or even before diagnosis (5). Both PMR and GCA have a peak incidence between the ages of 70-80 years old and occur more frequently in women (5). Patients with PMR may have subclinical vasculitis, and symptoms of GCA may appear when steroids prescribed for PMR are tapered (5). Close monitoring for GCA symptoms should be performed in patients with PMR.