Rheumatology · Vasculitis
The facts most likely to be tested
Giant cell arteritis is a large-vessel granulomatous vasculitis that almost exclusively affects patients older than 50 years.
The classic clinical presentation includes new-onset localized headache, jaw claudication, and scalp tenderness.
Patients frequently present with polymyalgia rheumatica, characterized by stiffness and aching in the shoulders and pelvic girdle.
The most feared complication is permanent vision loss due to anterior ischemic optic neuropathy caused by occlusion of the ophthalmic artery.
The initial diagnostic step for a patient with high clinical suspicion is an elevated erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).
The gold standard for definitive diagnosis is a temporal artery biopsy showing granulomatous inflammation with multinucleated giant cells.
Immediate treatment with high-dose systemic corticosteroids (e.g., prednisone) must be initiated prior to biopsy to prevent irreversible blindness.
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A 74-year-old woman presents to the clinic complaining of a persistent, throbbing temporal headache and scalp tenderness when brushing her hair. She reports significant jaw pain while chewing dinner and generalized morning stiffness in her shoulders. Physical examination reveals a tender, non-pulsatile temporal artery. Her ESR is markedly elevated at 95 mm/hr.
What is the most appropriate next step in management?
Initiation of high-dose systemic corticosteroids
The patient presents with classic symptoms of giant cell arteritis; because of the high risk of permanent vision loss, systemic corticosteroids must be started immediately without waiting for the temporal artery biopsy results.
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Etiology / Epidemiology
Affects patients >50 years old; strongly associated with polymyalgia rheumatica. Incidence increases with age.
Clinical Manifestations
New-onset unilateral headache, jaw claudication, and scalp tenderness. Sudden vision loss is the primary emergency.
Diagnosis
Temporal artery biopsy is the gold standard. ESR >50 mm/hr is a classic supportive finding.
Treatment
Start high-dose prednisone immediately to prevent blindness. Do not delay treatment for biopsy.
Prognosis
Risk of permanent blindness if untreated. Requires long-term corticosteroid tapering.
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Epidemiology & Etiology
Primarily affects individuals >50 years old, with a peak incidence in the 70s. It is a systemic granulomatous vasculitis of medium and large vessels. There is a significant genetic predisposition and a strong clinical overlap with polymyalgia rheumatica.
Pertinent Anatomy
Predominantly involves the extracranial branches of the carotid artery, specifically the temporal artery. Involvement of the ophthalmic artery is the anatomical basis for the most feared complication: ischemic optic neuropathy.
Pathophysiology
T-cell mediated immune response leads to the formation of giant cells within the vessel wall. This results in intimal hyperplasia and subsequent luminal narrowing. The resulting ischemia causes the characteristic clinical symptoms of claudication and tissue infarction.
Clinical Manifestations
Patients present with a new-onset, localized headache and jaw claudication (pain with chewing). Scalp tenderness is often noted when brushing hair. Sudden, painless monocular vision loss (amaurosis fugax) is a medical emergency. Systemic symptoms include fever, weight loss, and polymyalgia rheumatica symptoms.
Diagnosis
The temporal artery biopsy is the gold standard for definitive diagnosis. Laboratory markers show an ESR >50 mm/hr and elevated CRP in the vast majority of cases. Ultrasound may show the halo sign, but biopsy remains the definitive diagnostic step.
Treatment
Initiate high-dose prednisone (40-60 mg/day) immediately upon clinical suspicion. Do not wait for biopsy results to start steroids, as this risks permanent blindness. Add tocilizumab as a steroid-sparing agent in refractory or relapsing cases.
Prognosis
The primary risk is permanent blindness due to anterior ischemic optic neuropathy. Patients require long-term monitoring for steroid-related side effects like osteoporosis and hyperglycemia. Most patients require treatment for 1-2 years.
Differential Diagnosis
Polymyalgia rheumatica: proximal muscle stiffness without headache or vision loss
Migraine: episodic, usually younger patients, no elevated ESR
Trigeminal neuralgia: sharp, lancinating facial pain, not associated with systemic symptoms
Takayasu arteritis: affects younger patients (<40) and involves the aortic arch
Non-arteritic anterior ischemic optic neuropathy: usually painless, lacks systemic inflammatory markers