Giant Cell Arteritis (GCA)

A 55-year-old female presents with a 7-day history of right-sided temporal headache and an episode of sudden, painless, transient monocular visual loss lasting 15 to 20 minutes. She also reports scalp tenderness, jaw claudication, bilateral shoulder stiffness, fatigue, weight loss, and low-grade fever. Examination reveals a tender, thickened temporal artery with reduced pulsation. ESR is 100 mm/hr, CRP is elevated, and anemia of chronic disease is present. Temporal artery biopsy shows granulomatous inflammation with multinucleated giant cells. CT angiography demonstrates arterial wall thickening with carotid luminal narrowing. Diagnosis?

Diagnosis is Giant Cell Arteritis (Temporal Arteritis).

1. Definition

Giant cell arteritis (GCA) is a granulomatous vasculitis of large and medium-sized arteries occurring almost exclusively in adults 50 years or older. It commonly affects branches of the carotid artery, particularly the temporal artery, and may also involve the aorta and its major branches.

GCA is strongly associated with polymyalgia rheumatica (PMR).

2. Pathogenesis

Immune-mediated arterial inflammation causes:

1.      Granulomatous inflammation

2.      Damage and fragmentation of the internal elastic lamina

3.      Intimal hyperplasia

4.      Luminal narrowing and tissue ischemia

3. Clinical Features

3.1 Cranial Features

1.      New-onset headache

2.      Scalp tenderness

3.      Jaw claudication

4.      Visual symptoms, including amaurosis fugax, diplopia, and permanent visual loss

5.      Tender, thickened, or poorly pulsatile temporal artery

3.2 Systemic Features

1.      Fever

2.      Fatigue

3.      Weight loss

3.3 Associated Polymyalgia Rheumatica

1.      Bilateral shoulder and hip girdle pain and morning stiffness

In this patient, transient monocular visual loss represents amaurosis fugax, a manifestation of cranial ischemia and an important warning sign for permanent visual loss.

4. Diagnostic Evaluation

4.1 Laboratory Findings

1.      Markedly elevated ESR and CRP

2.      Normocytic anemia

3.      Thrombocytosis may occur

4.2 Imaging

1.      Temporal and axillary artery ultrasound is the preferred first-line imaging modality in the EULAR approach when appropriate expertise and rapid access are available

2.      Ultrasound may demonstrate a halo sign due to inflammatory arterial wall thickening

3.      Temporal artery biopsy remains an important diagnostic standard and is favored by ACR guidance where vascular ultrasound expertise is limited

4.      CTA, MRA, or FDG-PET may be used to evaluate extracranial large-vessel involvement

5.      Diagnostic testing should not delay treatment when clinical suspicion is high

4.3 Temporal Artery Biopsy

Typical findings include:

1.      Transmural granulomatous inflammation

2.      Multinucleated giant cells may be present but are not required

3.      Fragmentation of the internal elastic lamina

4.      Intimal thickening with luminal narrowing

GCA may have segmental skip lesions, so a negative biopsy does not completely exclude the diagnosis when clinical suspicion remains high.

5. Management

GCA with visual symptoms is a medical and ophthalmic emergency because irreversible visual loss can occur.

Glucocorticoid therapy should be started immediately and should not be delayed for biopsy or imaging.

5.1 With Threatened Visual Loss

1.      Guidelines conditionally favor IV methylprednisolone 500 to 1000 mg daily for 3 to 5 days

2.      This is followed by high-dose oral glucocorticoid therapy

3.      Because this patient has amaurosis fugax, immediate treatment is required

4.      If IV therapy cannot be started promptly, high-dose oral glucocorticoid therapy should not be delayed

5.2 Without Cranial Ischemia

1.      High-dose oral prednisone or prednisolone, commonly 40 to 60 mg daily, is generally used initially

5.3 Glucocorticoid Taper

1.      Glucocorticoids should be tapered gradually after disease control

2.      There is no single established duration of therapy

3.      The taper should be individualized according to:

o    Clinical response

o    Relapse

o    Inflammatory markers

o    Treatment toxicity

o    Use of glucocorticoid-sparing therapy

5.4 Steroid-Sparing Therapy

1.      Tocilizumab is an effective glucocorticoid-sparing agent and may be used in newly diagnosed or relapsing GCA

2.      Methotrexate may be considered when tocilizumab is unsuitable or unavailable

5.5 Aspirin

1.      Routine aspirin is not recommended solely because a patient has GCA

2.      Low-dose aspirin may be considered when there is critical or flow-limiting vertebral or carotid artery involvement

3.      Aspirin should also be used when there is another established cardiovascular indication

6. Major Complications

1.      Permanent visual loss, most commonly due to arteritic anterior ischemic optic neuropathy

2.      Stroke

3.      Large-artery stenosis

4.      Aortic aneurysm

5.      Aortic dissection

7. Key Clinical Insight

Age ≥50 years + new headache + scalp tenderness + jaw claudication + elevated ESR/CRP should strongly raise suspicion for GCA.

Amaurosis fugax in suspected GCA represents cranial ischemia and is a warning sign for potentially irreversible visual loss.

Start glucocorticoid therapy immediately. Do not wait for biopsy or imaging.

References

1.      Maz M, Chung SA, Abril A, et al. 2021 American College of Rheumatology/Vasculitis Foundation Guideline for the Management of Giant Cell Arteritis and Takayasu Arteritis. Arthritis Rheumatol. 2021;73(8):1349-1365. doi:10.1002/art.41774.

2.      Dejaco C, Ramiro S, Bond M, et al. EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice: 2023 update. Ann Rheum Dis. 2024;83(6):741-751. doi:10.1136/ard-2023-224543.

3.      Mackie SL, Dejaco C, Appenzeller S, et al. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis. Rheumatology (Oxford). 2020;59(3):e1-e23. doi:10.1093/rheumatology/kez672.