Giant cell arteritis
Giant cell arteritis is a granulomatous large- and medium-vessel vasculitis of patients over 50 that threatens irreversible blindness through ischemic optic neuropathy. Diagnosis is clinical and must not delay treatment: start high-dose glucocorticoids immediately on suspicion, intravenous methylprednisolone pulse for visual loss, then confirm with temporal artery biopsy within 1 to 2 weeks and add tocilizumab as glucocorticoid-sparing therapy.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: giant cell arteritis (GCA), also called temporal arteritis, is a granulomatous vasculitis of large and medium-sized arteries, most often the extracranial branches of the carotid artery, in patients older than 50.
- Epidemiology
The most common primary systemic vasculitis in adults, with an annual incidence of about 19 per 100,000 people age 50 or older, and 10-20 per 100,000 in Europe.
- Risk factors
Age over 50: the dominant risk factor; GCA essentially does not occur before this age.
- Pathophysiology
Granulomatous panarteritis: mononuclear infiltrates involve the intima, media, and adventitia, with multinucleated giant cells in about half of biopsy-positive cases, clustered near a fragmented internal elastic lamina.
- Clinical features
New headache in a patient older than 50: present in more than 60% of patients, typically temporal but occasionally more diffuse, unilateral or bilateral; the essential feature is that it is new or of a new character for that patient.
- Differential diagnosis
Polymyalgia rheumatica alone: shoulder and hip girdle aching and stiffness without new headache, jaw claudication, or visual symptoms; normal markers are more common than in GCA (polymyalgia rheumatica).
- Diagnosis
The diagnosis is clinical, supported by the American College of Rheumatology (ACR) 1990 classification criteria: at least 3 of 5 of age at onset 50 or older, new headache, temporal artery tenderness…
- Management
First, start high-dose glucocorticoids immediately on clinical suspicion, before biopsy or imaging, because the risk of irreversible blindness outweighs the value of waiting for tissue confirmation.
- Complications
Irreversible blindness from arteritic anterior ischemic optic neuropathy: occlusion of the posterior ciliary or ophthalmic artery causes sudden monocular vision loss that is usually permanent once…
- Prognosis
Life expectancy is similar to the general population, though with an increased long-term risk of thoracic aortic aneurysm.
- Prevention
There is no primary prevention, since the trigger for GCA is unknown; prevention here means preventing blindness and treatment-related harm once disease is suspected.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Polymyalgia rheumatica
Polymyalgia rheumatica (PMR) is an inflammatory disorder of older adults causing aching and prolonged morning stiffness of the shoulder and hip girdles with elevated inflammatory markers, but without true weakness and with a normal creatine kinase. It is a clinical diagnosis, and treatment begins with prednisone 12.5 to 25 mg/day, which produces a dramatic response within days.
- Takayasu arteritis
Takayasu arteritis is a large-vessel vasculitis of the aorta and its primary branches, occurring almost exclusively in women under 40, that produces the pulseless disease phenotype of absent pulses, an interarm blood pressure differential, and bruits. Magnetic resonance or computed tomographic angiography makes the diagnosis, and treatment is high-dose glucocorticoid induction paired with a steroid-sparing agent such as methotrexate.
- Arteritic anterior ischemic optic neuropathy
Sudden painless monocular vision loss from occlusion of the posterior ciliary artery by giant cell arteritis infarcts the optic nerve head and threatens the fellow eye within days. Treatment with high-dose glucocorticoids must begin on clinical suspicion, before biopsy confirmation, because established blindness is usually permanent.
- Vasculitis: an overview
Vasculitis is inflammation and necrosis of blood vessel walls, classified by the Chapel Hill scheme into large, medium, small (ANCA-associated versus immune-complex), and variable-vessel disease, each with a vessel-size-predicted clinical syndrome. Diagnosis requires excluding mimics such as infective endocarditis and cholesterol embolization before confirming with serology and biopsy, and treatment is glucocorticoid induction plus cyclophosphamide or rituximab for organ-threatening disease.
- Amaurosis fugax
Amaurosis fugax is transient, painless monocular vision loss from retinal ischemia, most often microembolic from an ipsilateral carotid or a cardiac source, and it is treated as a TIA-equivalent with urgent carotid/cardiac workup and immediate aspirin 81 mg daily plus a high-intensity statin.